Traxide SC80 Battery Controller

[Franz]

I have just installed an SC80 battery controller and relocated by auxiliary battery to the driver’s side rear storage bin.


I have a few queries for those in the know:


I was going to use 6B&S 13mm cable to connect the auxiliary to the main but was told that I don’t need anything bigger than 7.9mm and have used that. I read somewhere that AGM’s require high levels of charge rate and wonder if the 7.9mm cable is adequate for this task.


I have run the auxiliary earth to and earth point on the D pillar – is that good enough or should I run it back to the main battery?


Once the auxiliary battery was installed I decide to charge it. I did not disconnect the auxiliary battery from the main and began charging it with a 6 amp, 3 stage charger. This took ages and I decided to disconnect the auxiliary from the main. The auxiliary battery then showed full charge within minutes. This leads me to believe that the charger was trying to charge both batteries – is this the case?


Today, my auxiliary battery was showing 12.3 Volts. When I disconnected it from the main it immediately jumped to 12.5 Volts – could the main be drawing power from the auxiliary?


I note from the installation instructions that a circuit breaker should be installed – what is the purpose of this circuit breaker?


Thanks for any input.


Cheers,


Franz

[drivesafe]

Hi Franz.


I have just installed an SC80 battery controller and relocated by auxiliary battery to the driver’s side rear storage bin.

I was going to use 6B&S 13mm cable to connect the auxiliary to the main but was told that I don’t need anything bigger than 7.9mm and have used that. I read somewhere that AGM’s require high levels of charge rate and wonder if the 7.9mm cable is adequate for this task.

Fist off, because your battery is in the rear of the vehicle, while 8B&S ( 7.9mm2 ) will allow your auxiliary battery to charge, if the auxiliary battery is low, the current draw it will try to place on the 8B&S cable will cause a fair bit of voltage drop, slowing the charging and increasing the amount of driving time needed to recharge a low battery.

For batteries located in the engine bay, a single positive 8B&S
cable is fine, but with the battery in the rear, the distance means you need thicker cable to reduce the voltage drop. Here TWIN 6B&S ( 13.5mm2 x 2 ) is a much better choice.





I have run the auxiliary earth to and earth point on the D pillar – is that good enough or should I run it back to the main battery?

As above, it is better and gives a guarantied good earth every time if you run the from battery to battery.





Once the auxiliary battery was installed I decide to charge it. I did not disconnect the auxiliary battery from the main and began charging it with a 6 amp, 3 stage charger. This took ages and I decided to disconnect the auxiliary from the main. The auxiliary battery then showed full charge within minutes. This leads me to believe that the charger was trying to charge both batteries – is this the case?

YES, the SC80 allows all batteries to be charged at the same time, UNLESS the common voltage has dropped below 12v and the SC80 has turned off ( cut-out ).

In this case, if the battery charger is connected to the auxiliary battery(s), only the auxiliary battery(s) will charge.

If the charger is connected to the cranking battery, once the charge voltage rises above 13.1v, all batteries will then be connected to the charger.





Today, my auxiliary battery was showing 12.3 Volts. When I disconnected it from the main it immediately jumped to 12.5 Volts – could the main be drawing power from the auxiliary?

Yes and this is one of the main advantages of the SC80. If your have only done a short drive and your auxiliary battery is in a higher state of charge when you turn the motor off, the auxiliary battery will help to put some additional charge back into the cranking battery.

While this feature was not a designed intention, owners of D3s, D4, and RRSs who were getting “LOW VOLTAGE” warnings before they had one of my systems installed, because of the back feed, the messages stop occurring because the system improves the state of charge of the cranking battery and this also helps to extend the operating life of the cranking battery





I note from the installation instructions that a circuit breaker should be installed – what is the purpose of this circuit breaker?

You need circuit breakers on the positive cables that come from any battery in a dual battery system because if you have an accident where the cable is shorted out you could end up with a fire if each battery is not protected by a circuit breaker ( or fuse ).

[austastar]

You need circuit breakers on the positive cables that come from any battery in a dual battery system because if you have an accident where the cable is shorted out you could end up with a fire if each battery is not protected by a circuit breaker ( or fuse ).

As I discovered when I forgot that there was another battery on the other end of the wires I had just disconnected from my Aux battery.

Just a quick flash of spark and then the reality hit me of what I had done!

Very glad of that 60A fuse.

cheers

[bbarkz]

Hi Franz,I have wired up a triple battery system in my 96 D1 v8 and I used 6B&S all the way from under bonnet to the rear cargo area of the vehicle.I run 3 Exide Orbital batteries (1 crank and 2 aux),these are spiral wound gel batteries and do require 14.2 to 14.4 volts to charge properly which is similar to the AGM batteries.Also I set up an extra charge cable in 6B&S from my alternator to my crank battery which gives my 14.2 v at idle and approx 14.4 ish at 1500 odd RPM and I get this all the way to the rear of the car.So I would suggest 6B&S all the way if possible.:)By the way I also installed a Maxi fuse between the extra alternator charge cable and between the 2 aux batteries with a 100 amp fuse.Hope this helps...

[Graeme]

IMO connecting the aux battery's earth to the body is better than using a cable connecting to the primary battery because there will be no voltage drop by connecting to the body but will be if using a cable. There's going to be voltage drop from the positive cable without adding to it with an earth cable. Don't connect to the D2's chassis though because it isn't positively earthed ex-factory, only via steering linkages etc although fitment of a winch with its earth connected directly to the battery usually overcomes this.

A CB or fuse is required at each end of the inter-connecting power cable because if there's a short circuit part way along, neither battery must be able to provide unrestricted current so as to prevent a fire.

[austastar]

IMO connecting the aux battery's earth to the body is better than using a cable connecting to the primary battery because there will be no voltage drop by connecting to the body but will be if using a cable.

Hi,
I started off this way, with my Aux battery Negative connected to my Defender passenger seat rail bolt very securely. (6 B&S twin cable)

My Aux battery was not charging properly, and the voltage across the Aux battery was about 1 Volt less than the Crank battery.

Drivesafe talked me through some testing with a multimeter, and we could measure a difference in Voltage across the two battery Negative terminals. My you beaut tightly connected Earth return via the seat rail bolt wasn't so you beaut.

I couldn't connect to the Crank battery Negative because of the ridiculous type of cable used on the Defender, but the other end of the Original Earth return at a transfer case bolt was accessible.
A length of 6 B&S (terminated with proper connections) from the seat rail bolt to the transfer case bolt brought the Voltage drop to zero and solved the charging problems.

I would now recommend connecting the Negative back to the battery or the other end of the battery earthing cable on the engine block.

cheers

[101RRS]

Where can you buy this heavy duty cable - I need to run cable from my battery - 15 feet to the rear then another 15 feet to the rear of the van - so a long way to send 12v power and expect some oomph at the end.

Thinking about welding cable but is a bit expensive.

Garry

[Franz]

Hi Franz.



Fist off, because your battery is in the rear of the vehicle, while 8B&S ( 7.9mm2 ) will allow your auxiliary battery to charge, if the auxiliary battery is low, the current draw it will try to place on the 8B&S cable will cause a fair bit of voltage drop, slowing the charging and increasing the amount of driving time needed to recharge a low battery.

For batteries located in the engine bay, a single positive 8B&S
cable is fine, but with the battery in the rear, the distance means you need thicker cable to reduce the voltage drop. Here TWIN 6B&S ( 13.5mm2 x 2 ) is a much better choice.






As above, it is better and gives a guarantied good earth every time if you run the from battery to battery.






YES, the SC80 allows all batteries to be charged at the same time, UNLESS the common voltage has dropped below 12v and the SC80 has turned off ( cut-out ).

In this case, if the battery charger is connected to the auxiliary battery(s), only the auxiliary battery(s) will charge.

If the charger is connected to the cranking battery, once the charge voltage rises above 13.1v, all batteries will then be connected to the charger.






Yes and this is one of the main advantages of the SC80. If your have only done a short drive and your auxiliary battery is in a higher state of charge when you turn the motor off, the auxiliary battery will help to put some additional charge back into the cranking battery.

While this feature was not a designed intention, owners of D3s, D4, and RRSs who were getting “LOW VOLTAGE” warnings before they had one of my systems installed, because of the back feed, the messages stop occurring because the system improves the state of charge of the cranking battery and this also helps to extend the operating life of the cranking battery






You need circuit breakers on the positive cables that come from any battery in a dual battery system because if you have an accident where the cable is shorted out you could end up with a fire if each battery is not protected by a circuit breaker ( or fuse ).
Thanks all for your useful responses.

Tim - what you are saying is that I need to run 13.5mm cable all the way from my main battery to the SC80 and onwards to the auxiliary battery - 6.5 metres of cable all up. I only just managed to get the 7.9mm cable onto the 2 connector plugs - how on earth do I get 13.5 mm cable to work?

Where do I mount the circuit breaker - between the main battery and the auxiliary or between the SC80 and the auxilary battery?

Oh, what does 6B&S mean and what's the difference between it and 8B&S?

Cheers,

Franz

[Franz]

Where can you buy this heavy duty cable - I need to run cable from my battery - 15 feet to the rear then another 15 feet to the rear of the van - so a long way to send 12v power and expect some oomph at the end.

Thinking about welding cable but is a bit expensive.

Garry
Autobarn, SCA, Repco or caravan accessory suppliers.

[Pedro_The_Swift]

just use the voltage drop calc to find your cable size over known distance


http://www.kilowatts.com.au/calculator-voltage-drop.php

[Franz]

IMO connecting the aux battery's earth to the body is better than using a cable connecting to the primary battery because there will be no voltage drop by connecting to the body but will be if using a cable. There's going to be voltage drop from the positive cable without adding to it with an earth cable. Don't connect to the D2's chassis though because it isn't positively earthed ex-factory, only via steering linkages etc although fitment of a winch with its earth connected directly to the battery usually overcomes this.

A CB or fuse is required at each end of the inter-connecting power cable because if there's a short circuit part way along, neither battery must be able to provide unrestricted current so as to prevent a fire.
Graeme,

I used the earth point on the DS D pillar (under the brake light).

So, is 7.9mm cable sufficient for the earth (it's only 350mm long) or do I need to go to 13.5mm cable here as well?

Cheers,

Franz

[Franz]

just use the voltage drop calc to find your cable size over known distance


Voltage Drop and Cable Size Calculator (http://www.kilowatts.com.au/calculator-voltage-drop.php)

Thanks for that Pedro.

How do I determine the maximum current demand? When my fridge fires up it will draw 5 amps plus for short periods. If I fire up the ARB compressor, it draws about 8 amps or more.

Cheers,

Franz

[Graeme]

My you beaut tightly connected Earth return via the seat rail bolt wasn't so you beaut.
That's because it wasn't a dedicated earth bolt - it was holding at least 2 pieces of metal together with an unknown/unreliable surface between them.

[Graeme]

I used the earth point on the DS D pillar (under the brake light).

So, is 7.9mm cable sufficient for the earth (it's only 350mm long) or do I need to go to 13.5mm cable here as well?
Hi Franz,

IMO that's a good earth point.

I cannot advise on cable current carrying capacities.

[101RRS]

Autobarn, SCA, Repco or caravan accessory suppliers.

Ok - I will have to go visit them again - never seen real heavy stuff at any of the auto shops - was just at SCA and they do not have anything heavy like I have on my van.

Cheers

Garry

[Franz]

Ok - I will have to go visit them again - never seen real heavy stuff at any of the auto shops - was just at SCA and they do not have anything heavy like I have on my van.

Cheers

Garry
Also try Battery World.

[TonyC]

Or Jaycar

Jaycar Electronics - Search results (http://jaycar.com.au/productResults.asp?MID=1&SSUBID=792&SUBCATID=995&keyform=CAT2#1)

Tony

[scott oz]

Don't know how true it is but I was always told that earthing to the body etc promoted corrosion. It was always better to earth back to the battery.

Is this an urban myth:eek:

[Blknight.aus]

a tip for your main cable circuit breakers and fuses

connect a small light (or bi directional led with a suitable resistor) across each one, when one lets go it will provide an indication that the thing is doing its job and has gone open circuit.

[cookiesa]

Thanks for that Pedro.

How do I determine the maximum current demand? When my fridge fires up it will draw 5 amps plus for short periods. If I fire up the ARB compressor, it draws about 8 amps or more.

Cheers,

Franz

Depending on the model of compressor it will draw more than that, once up around 30 psi 20+ amps is normal

Rule number one with cabling is if in doubt go larger, larger wont hurt, smaller will.

If you are running a charging style cable to a camper or similar there are better ways of doing it such as the REDARC BCDC charger. Check out REDARCS website for lots of useful info on wiring to.

[Pedro_The_Swift]

cookiesa,, maybe use the word "other"
as in, there are other ways,,


or you could explain why it is better:cool:

[cookiesa]

Sure...

But without going in to a twenty page expanation, basically...

Something along the lines of the BCDC 12v charger elimantes any issue of voltage drop. Voltage drop isn't the only issue with charging a battery ina camper the distance is too. Basically, (very basically it isn't of course quite this simple but..) when your alternator is charging the power "out" will take the path of least resistance, this is why your primary battery can end up charged but your auxillary in the trailer never gets properly charged (also why it is recommended to put the camper battery on a decent charger regularly).

A 12v charger also adresses this issue charging the camper battery as it's own entity, not by simplying linking them together.

For those that just run an anderson back and plug them together for charging, yes it will work, but not as effecitvely from both a battery energy storage point or view as well as battery life span.

Again this is simplified, but an overview of why it is a "better" rather than just another way of doing it.

[drivesafe]

Hi cookiesa, and while I did not reply to your fist post and most certainly replying to this one.

The bulk of your post is fresh of the advertising hype used to sell DC/DC devices and while is all sounds good and well, the single factor that is “ALWAYS” omitted when some one is promoting these devices is the fact that they are only good for topping off battery that are only been used a bit but if the battery, and I emphasis a single battery, if the battery is in a low state then unless you are driving long enough you are not going to get any additional advantage from these devices.

With a low battery, it is highly unlikely that you will drive long enough to fully charge it no matter what type of charging you use.

Furthermore, when your off on that long holiday, WHY DO YOU NEED TO FULLY CHARGE YOUR BATTERY.

This is one of the myths the sellers of these products try to promote and while their devices are in no better position to fully charge a battery if the battery is low and the drive time is too short, they try to give the “illusion” that their device will fully charge your battery.

In the few instances where one of these devices could fully charge a battery quicker than an alternator, it’s only because you have stopped driving before your alternator has had a chance to fully charge the battery.

So you have spent $400+ to gain, at most, maybe a 10% advantage, and again, this is only if you don’t drive long enough to give an alternator time to fully charge the battery.

So for $400+ you now have at the very most, 10Ah more battery capacity. That’s one hell of an expensive way to get such a little extra capacity, and again, this is only in a few cases, not the majority of cases.

In the case of a house battery in a camper trailer or caravan, a far cheaper set up improvement, with much greater advantages and is must kinder on your batteries, is to fit a second house battery.

The simple addition of another battery gives you additional capacity, and if you had a single 100Ah battery and used all 80% available, which takes your house battery down to 20% SoC, by adding another 100Ah battery and using the same amount of capacity only takes your two batteries down to 60% Soc and it will take your alternator hours less time to bring two 100Ah batteries to a fully charged state than these DC/DC devices can bring either a single 100Ah battery up from 20% SoC or two 100Ah batteries up from 60% SoC.

And there are heaps more advantages to be gained by simply adding a second battery, advantages that these DC/DC devices can not give, and the second battery system is usually cheaper the set.

Cookiesa, as I have posted many times, there is more than one way to skin a cat and these DC/DC devices are just one of a number of option, but they are the most expensive for the smallest improvement, if there is actually any improvement at all.

[B92 8NW]

OH CRAP NOT DC-DC CHARGERS AGAIN!!!!

Going outside to hug my USI160:D:D.

[cookiesa]

It is not adverting hype but in fact very solid scientific fact based on research done by botrh companies such as REDARC, Century and exide here in Australia, no doubt duplicated in other countries.

But then again you have a vested interest in pushing your ideal. I also haven't touched on load sensing ECU based alternator charging and the like which also introduces a whole different set of issues with just linking two batteries together.

There are several methods as you say, and indeed one of the reasons there is no "one set up" suits all.

Great idea having two batteries, extra capacity and a longer charge time! (The last stages of charging are much slower than the initial bulk charge, but hey you know that, just failed to mention it in this post)

[Fluids]

The other factor is what type of battery/ies you're using .... some recharge faster than others ... Optima Yellow Top AGM's for example, can be recharged lightning fast compared to a wet cell deep cycle style battery ... so the Yellows will recharge faster on a shorter drive.

Adding a second battery is of great benefit. Dual 100A/Hr batteries at a 10A discharge (5A/Hr each) for 5Hrs will leave more charge in each battery than a single 100A/Hr battery at 10A discharge for 5Hrs ... the slower the rate of discharge of each battery, the more A/Hrs the battery can deliver ... therefore dual batteries will need less A/Hrs to recharge for the same discharge as a single battery.

An extra battery (dual batteries) vs a single battery won't take longer to recharge if the discharge was the same. It will take less time.

[drivesafe]

Hi and thanks Fluids.

Hi again cookiesa, and if there has been “solid scientific research” done, why don’t they post up the results when the promote these devices. Lets face some REAL facts, if such research has been done and the results were so in favour of these devices, they would have already been posted up and used in their advertising.

What such research would show is that yes, these devices can fully charge a battery, but for the research to be relevant, it would have to show a comparison between what these devices can do as to what an alternator can do, in the REAL WORLD.

First off, because an alternator can automatically adjust the amount of current being produced, an alternator will increase it’s output if there is an additional battery added to the set up, and as an alternator can increase it’s current production, the two batteries will be charged in about the same time a single battery is charged.

With the above in mind, if the two batteries are only discharged down to 60% SoC, an alternator is going to fully charge them, to 95% or better, hours quicker then a DC/DC devices can bring a single battery, discharged to 80% SoC to a fully charged state.

Now alternators, because they use constant voltage charging, as the battery nears a full state, the charging current tapers off, and means it will take a lot longer to fully charge the two batteries much passed 95%.

But cookiesa, you neglected to mention the fact that DC/DC devices and multi stage battery chargers also step back the charging current once the battery reaches about 80% SoC, and so it would seem that these devices have to copy what an alternator does naturally.

Next, as I have already posted, it is highly unlikely that a house battery in a low SoC at the start of a days drive, will ever be fully charged while driving, no matter what system you use.

So cookiesa, while you are making claims that these devices better charge a battery than an alternator, which while in a laboratory might be the case, it is not so in the REAL WORLD, and as such, can you post up a link to any battery manufacturer, including Exide, where they state that their batteries must be fully charged every time they are use or the battery’s life span will be affected.

Now for some REAL facts, first off, it is not necessary to fully charge a battery every time you use it to get maximum life out of the battery, a fact that is stated on the SuperCharger battery site in the info on Allrounder batteries.

One little bit of info that seems to have CONVENIENTLY overlooked when comparing a single battery + DC/DC devices with a two battery set up using the same amount of power, is the fact that the lower you discharge a battery the short the life span for the battery.

This info is available on just about every battery manufacturer’s web site.

So once again, needing to discharge a single battery down to 20% SoC is actually quite harmful on a battery, while the two battery set, because you only take them down to 60% SoC for the same amount of power used, is, according to all battery manufacturers, far more beneficial for the batteries.

Furthermore, in a single battery set up, all the load is coming from one battery, in a two battery set up, the load is spread over the two batteries and is reduced by at least half.

Another fact is that reducing the load on any battery will help extend it’s life span, so again, the two battery set up is far more beneficial for the batteries than a single battery + DC/DC device set up is.

There are situations where these devices have a use, but to claim they will do a better job than what an alternator can do is simply not the case in the vast majority of set ups.

[cookiesa]

I'm wasting very little time in this my last response, you have an agenda to push and will continue to do so..

EXIDE..

To help maximise the life of your battery, follow these helpful tips:
Keep batteries topped upMaintaining a sufficient electrolyte level ensures the electrolyte is neither too high or too low. Use distilled or deionised water and never over fill. Maintenance free batteries will usually not require topping up. Low maintenance batteries require the addition of water only once or twice per year depending on conditions.


Batteries have a limited shelf life and when stored gradually lose their power to perform. On average, a fully-charged battery takes about 13 weeks to gradually discharge to less than its optimum operating level.

Whilst in storage batteries that have not been recharged and allowed to go flat, may be permanently damaged. Recharging every four to eight weeks, depending on storage conditions, will restore batteries to "as new" condition.

Also quite common knowledge.

The use of a DC/DC charger was mentioned in relation to fitting them ina camper or similar where voltage drop is a big consideration. As mentioned by Fluids, battery type makes a big difference, which is why it is preferable to not mix battery types with basic isolation systems. Something a DC/DC charger can also overcome.

As I said, horses for courses but obviously you are incapable of believing any product other than yours may be better in the correct context.

There is nothing wrong with your system, if used appropriately, but there are other systems out there, some of which will be better in some circumstances than yours. But hey, keep flogging away.

You also mention alternator output, love that one as most new vehicles now have ECU controlled alternators that are no where near as good at charging extra loads, and in some cases if wired traditionally won't charge them at all.

The biggest limiting factor in charging is the battery itself, just because you have a 100amp alternator (good luck actually getting 100amps out of it in "real life"). The battery will not take a 100amp charge. (With the exception of some specialty batteries)

As for charge times on a twin set up the charge will take longer, regardless of the system used than a single battery due to the batteries own internal resistance which will increase as the battery gets closer to being charged.

But yes twin batteries will last longer as you are not cycling them as deeply (assuming comparing apples with apples)

Over and out

[drivesafe]

Cookiesa, mate, I don’t know if you’re try to have a lend of us or that you are really that naive. The info you have in bold print relates to keeping the electrolyte in the battery topped up and has nothing to do with charging the battery.

Again, what does having batteries fully charged before storing them, have to do with charging them while driving.

Also, while it may be a problem trying to charge paralleled dissimilar batteries with a DC/DC device, because they use constant current charging, this is one of the big advantages of using an alternator.

An alternator, as posted earlier in this thread, is a constant voltage charger and as such can charger any mix of dissimilar batteries and any mix of batteries with different States of Charge, and every battery in the set up will be charged at each individual battery’s own optimum charge rate.

You sure as hell can’t do that with either a DC/DC device or a multi stage battery charger.

So once again, there is a very large advantage to be gained by simply using two auxiliary/house batteries rather than the limited use a single battery + DC/DC Device offers.

And once more and in more detail, because you obviously don’t understand how an alternator works, an alternator can charge two batteries in the same time it takes to charge one, PROVIDING the alternator is big enough.

So if you have two low 100Ah batteries and you want to charge them from an alternator, then as long the alternator is 80 amps or bigger, you will easily charge both batteries in the same time it would take the same alternator to charge a single battery, and you would still have enough power for the rest of the vehicle’s normal requirements.

Where as, if you have a 20 amp DC/DC device, thats all you have and if you need to add a second battery to your set up, you now have a situation where it will take you nearly twice as much driving time to charge the two batteries while the same set up with an alternator will take no longer.

And one more point, so far you are the only one that tried to compere my isolators with DC/DC devices, I have been talking about standard isolators in general.

BUT, if you really want to compere my isolators and what they can do, your DC/DC devices are going to look like nothing more than an expensive joke.

[drivesafe]

Hi folks and sorry if this is taking this thread off subject but I have had a gut fill of people reading some advertising hype and then posting up the info as if it was the gospel.

We all know ( well most of us ) that Australian advertisers NEVER LIE, or exaggerate or forget to give the whole story.

Well these DC/DC devices are by far the greatest con job going. Will they full charge a battery, given enough time yes they will, and I have tested enough of them to confirm that.

The problem is that none of the advertising, that I have seen, comperes the way these devices charge as compered to what an alternator can do.

But in my case, with the way my isolators work, and this thread is about the use of one of my isolators, people need to have a lot more info provided before they can make a fair observation as to whether these DC/DC devices are going to be any more effective at recharging a battery while driving.

The charts below show the average charging characteristics of three different set ups. That of a standard isolator ( also how my USI-160 works when set to IGNITION mode ), a 20 amp DC-DC converter, and my SC80 ( this is also how my USI-160 operates when set to SHARED mode ).

During the tests, I used calcium/Calcium ( Ca/Ca ) batteries for both the cranking battery and the auxiliary battery, this means the info would be slightly longer times for standard flooded wet cell batteries and much short times if automotive type AGMs were used, like Optimas or Odyssey or Exide Orbital batteries.

But the difference in time would only relate to ordinary isolators and the SC80 ( USI-160 in SHARED mode ). There would be no change in times for the DC/DC device.

Chart 1 shows in REAL WORLD use, how nothing else achieves faster replacement of used battery capacity as what the SC80 ( and USI-160 ) can and all other set ups will be considerably dearer to fit to give the same capacity that the SC80 ( and USI-160 ) give.


https://www.aulro.com/afvb/images/imported/2013/06/1248.jpg

NOTE, each set up in Chart 2 below assumes that the vehicle already has a 100Ah auxiliary battery installed, and the costs are based on the amount of additional gear and cost that other systems need, to gain the equivalent 130 Ah that this sort of set up can give when adding nothing more than an SC80 Isolator.


https://www.aulro.com/afvb/images/imported/2013/06/1249.jpg

[101RRS]

Where can you buy this heavy duty cable - I need to run cable from my battery - 15 feet to the rear then another 15 feet to the rear of the van - so a long way to send 12v power and expect some oomph at the end.

Thinking about welding cable but is a bit expensive.

Garry



Autobarn, SCA, Repco or caravan accessory suppliers.



Also try Battery World.


Ok - I will have to go visit them again - never seen real heavy stuff at any of the auto shops - was just at SCA and they do not have anything heavy like I have on my van.

Cheers

Garry


I went out to buy 6.5m of cable to wire up the RRS so that I have power at the rear so I can charge the van batteries when on the move. This is the twin core cable I am after.

http://i42.photobucket.com/albums/e334/gazzz21/Forum%20Posts%20Album/07012012.jpg

I tried two auto electricians, Battery World, the Battery Factory, Jaycar, Repco, Autobarn, SuperCheap, Pride 4wd and Lloyds caravans - all without success.

Single core yes - but not twin core.

So any other suggestions on where to buy this stuff.

Thanks

Garry

[bee utey]

Ebay:

10 metres of 6B&S twin core cable12v dual battery system | eBay (http://www.ebay.com.au/itm/10-metres-6B-S-twin-core-cable12v-dual-battery-system-/110769154825?pt=AU_Car_Parts_Accessories&hash=item19ca5b2b09)

6B&S TWIN CORE CABLE DUAL BATTERY SYSTEM 12V x 10 METRES | eBay (http://www.ebay.com.au/itm/6B-S-TWIN-CORE-CABLE-DUAL-BATTERY-SYSTEM-12V-x-10-METRES-/110801067844?pt=AU_Car_Parts_Accessories&hash=item19cc421f44)

Big enough?

Or this:

DUAL BATTERY & ANDERSON PLUG WIRE - 140AMP 3 CORE CABLE | eBay (http://www.ebay.com.au/itm/DUAL-BATTERY-ANDERSON-PLUG-WIRE-140AMP-3-CORE-CABLE-/310369970439?pt=AU_Car_Parts_Accessories&hash=item48437de907)

[Fluids]

Traxide ....

25mm sq twin red & blue in a clear sheath ... cable (http://www.traxide.com.au/Wire_7.html)

[cookiesa]

Is there a reason your against single core?

[101RRS]

Is there a reason your against single core?


Because all the advice on here seems to be that power from the battery needs to come direct from both terminals. I am not sure why as it would be a hell of a lot cheaper to just run the positive direct from the battery and bolt the earth to the car chassis near the rear anderson plug.

Garry

[Tombie]

Because all the advice on here seems to be that power from the battery needs to come direct from both terminals. I am not sure why as it would be a hell of a lot cheaper to just run the positive direct from the battery and bolt the earth to the car chassis near the rear anderson plug.

Garry

Because LR earth is not chassis based and is a very poor connection :cool:

[101RRS]

Because LR earth is not chassis based and is a very poor connection :cool:

Well body based earth then.

Garry

[bee utey]

Well body based earth then.

Garry

An accessory running at 10 amps would be OK to earth to the body. At 100 amps it isn't enough. I've run rear batteries on rally cars, and it is always better to run a separate earth from at least the transmission casing to the rear. So yes you could save a couple of metres of earth cable by relying on the alloy trans casing, but the body, not so much.

[Tombie]

Yes, always better to return to the source..

Prevents voltage differentials too, seen them do wild and crazy things to vehicles...

Same for people wiring CBs UHFs HFs and Amplifiers... Go back to the battery for a good clean feed.

[101RRS]

Thanks guys.

Thats what I have previously been told but certainly do not understand the logic, particularly as all the cars systems use the body as earth and generally do not run cables back to the negative terminal of the battery. Surely the cars body can carry far more current than any cable can - I suspect the limitation is in fact the size of the standard cable that connects the negative terminal of the battery to the car body and provides all the negative side of car electrical services.

However, I certainly accept the advice of smarter minds than mine and that is why I am after twin cable like I have shown.

Cheers

Garry

[bee utey]

A 25mm2 cable of a particular length will have considerably less resistance than the steel body between two points the same distance apart. Steel isn't that great a conductor compared with copper. Localised corrosion under an earth tag will cause poor conduction and heating, D2's are supposedly renowned for failing earth points on the body all the time. A copper tag on a steel bolt isn't a good idea unless it is occasionally dismantled and cleaned. A continuous cable is more reliable, with only an occasional inspection needed directly at the battery.

[drivesafe]

Thanks guys.

Thats what I have previously been told but certainly do not understand the logic, particularly as all the cars systems use the body as earth and generally do not run cables back to the negative terminal of the battery.

Hi Garry, as Tombie and bee utey posted, if you are running something with a small power requirement, then a body/chassis is going to work but if you have a look at the type of devices the vehicle manufacturers connect to the body.

They usually fix the earth returns for things like turn and stop light globes to the body but high current returns are usually fixed to a chassis point that, by design, THEY KNOW is a good earth return.

Whereas we as installers, professional and DIYers alike, do not have access to the manufacturers info so the safest way to guaranty a good earth return is to run your own. Can’t go wrong then.

[Franz]

Tim,

I have a question about the SC80 battery controller.

How does the controller react in the event of differing voltages between the main and auxilliary battery. Fo example, the main battery on full charge shows 12.8 Volts and the auxilliary 13.1 Volts. Is there any form of equalisation and if so, in which direction?

Oh, and on an aside, the CD that accompanied your product has gone beely up and is no longer readable - where can I get copies of the two files on the cd?

Thanks for your input.

Cheers,

Franz

[drivesafe]

Hi Franz, and if the batteries are all in your vehicle, meaning none are in a trailer or caravan that can be disconnected and the batteries can be discharged to lower levels than those in the tow vehicle.

While all the batteries are in the vehicle, because the SC80 ( and the USI-160 ) keep all the batteries connected till the common voltage of all the batteries drops below 12.0v, all batteries should be at the same State of Charge ( SoC ) at just about all times.

The one exception is when you have been camping and used a fair bit of battery capacity, and even if you didn’t discharge the batteries down to 12.0v, the isolator will still have all the batteries connected, BUT if you were then to drive for a short time, not long enough to fully charge all the batteries, then there can be differences be the SoC of the batteries.

For instance, most D3s and D4s, fitted with my isolators, will, in the most part, also have an Optima Yellow Top Battery as an auxiliary battery.

In this case, because D3s and D4s have high capacity alternators and the fact that Optima batteries can safely take full inrush current when charging. If you were to go for a short drive, the Optima will take a much high current charge than the Calcium/Calcium ( Ca/Ca ) cranking battery will.

So when the motor is turned off, the Optima will back discharge into the lower cranking battery.

While not a design intended feature it has proven to be a winner with these vehicles because many, prior to having one of my dual battery systems fitted, would continually get “Low Battery Voltage” messages.

Within a week of my kit being fitted, no more “Low Battery Voltage” messages.

BTW, send me a PM with your E-mail address and the installation instructions you need and I will e-mail you back a compressed PDF file of the full instructions

[Franz]

Thanks Tim that explains a few things.

I recently installed a new 75 AH AGM with one of your controllers. I was disappointed with the run time on the AGM and suspected that one or the other battery might have a problem and therefore did a few simple tests.

Upshot of my testing is that the main battery gets to 13.77 V and shows fully charged and once disconnected from the charger it drops to 12.65 V within an hour and a half with nothing connected.



The second battery is fully charged at 13.77 Volts also and drops to about 12.78 Volts with nothing connected.





Now I connect the two batteries through the controller and the main goes up to 12.71 Volts and the auxiliary drops to 12.71 Volts



Leaving the car parked for a day and a half without driving it both batteries drop down to 12.4 Volts. I’m not sure if this is normal but am beginning to suspect that something is trying to drain the main battery (without me running anything off it). I pretty sure the auxiliary battery is OK as I have a Baintech meter on it which gives me SOC and current draw (which reads 0).





So the way I’m reading it is that the reverse charging facility is not good for the SOC of the auxiliary battery which is used for running fridges etc.



I saw a post somewhere on AULRO describing how to measure current draw from the fuse block and will have to do some measuring. Unfortunately, I have little information on the Caterpillar Calcium starting and deep cycle battery (two years old) that I run as a main and am not sure if the voltage drop is normal or abnormal. What I do know is that the voltage drop of the main with nothing connected is faster than the auxiliary.

Cheers,

Franz

[cookiesa]

If you have a multimeter most have a current function (optimistically they camandle 10amps generally, however unlikely the leads will!)

For what you are doing it will be fine. Basically just put it in line on either side of the positive supply to the fuse block. Better still take the leads off of the positive battery terminal and place your multimeter in line. This will tell you what is being drawn. If there seems to be power draw but everything is off then tale the fuses out one by one to work out which circuit/item is drawing the power. Inveters are a common source of power draw, it is often best to be able to isolate them when not being used.

There are current clamps and even standalone ones that plug straight in to the fuse holder, but a simple multimeter is sufficient for what you are looking to do.

Leaving any battery partially discharged is not good for it, because of the back drain in an ideal world you woulD keep the batteries of identical design and age with this set up, but that isn't practical or economical.

If your driving it most days it will be giving the auxillary a chage anyway and wont really matter, if your not then it would be better to disconnect the aux battery to avoid shortening the life of your aux battery.

What sort of items are you running on your battery, this might give us a better gauge or some suggestions to improve your run time, certainly it back draining to the main battery is not helping things.

[drivesafe]

Hi Franz, unfortunately there is a lot more info needed to be able to determine whether you have a problem or not.

Forget the readings you get after using a battery charger, they charge batteries in a different way to what happens while your driving.

Now you say your batteries “SETTLED” back to 12.4v.

This does not mean they “DISCHARGED” back to 12.4v and while I was not surprised at the readings you got just an hour and half after your stopped charging the batteries as this was still just surface volts not battery SoC.

Your actually need to leave the batteries in a No Charger/No Load state for at least 24 hours to get any form of true indication of what the real SoC of your batteries.

The other factor for the voltage reading is just how long you drove for before leaving your vehicle for the day and a half?

If you have done a few short drive and then left your vehicle for a day or two, the AGM will normally take a charge quicker that your cranking battery, NOTE this “ONLY” occurs when charging from an alternator, not when using a DC/DC device or battery charger, so if your have done a few short drives, your cranking battery might be down a bit and your AGM is keeping it topped up.

There is an easy way to check if there is a problem. Next time you know you are going to be leaving the vehicle unused for a day or two. Before you turn your motor off, switch the USI-160 In-Cab controller to the IGNITION mode, ( switch the switch towards the LED ) and leave it that way.

In SHARED mode the common battery voltage has to drop to 12.0v before the batteries are separated.

In IGNITION mode once the common voltage drops to 12.6v, the batteries will be separated, so with your USI-160 set to IGNITION mode. the batteries will separate at a much high voltage and you can then see if either ( or both ) battery settles to a lower voltage or just keeps discharging.

Now a note, if your cranking battery is a Calcium/Calcium battery then is it not uncommon for them to settle back as low as 12.2 but they will still be in an excellent condition.

As posted earlier, because of the way my isolators work, they tend to keep cranking batteries in a higher state of charge than normal, and this is why you need to bypass the SHARED mod to test your batteries.

Use the chart below to determine the rough SoC of your batteries.

https://www.aulro.com/afvb/images/imported/2016/06/640.jpg

[Franz]

Hi Franz, unfortunately there is a lot more info needed to be able to determine whether you have a problem or not.

Forget the readings you get after using a battery charger, they charge batteries in a different way to what happens while your driving.

Now you say your batteries “SETTLED” back to 12.4v.

This does not mean they “DISCHARGED” back to 12.4v and while I was not surprised at the readings you got just an hour and half after your stopped charging the batteries as this was still just surface volts not battery SoC.

Your actually need to leave the batteries in a No Charger/No Load state for at least 24 hours to get any form of true indication of what the real SoC of your batteries.

The other factor for the voltage reading is just how long you drove for before leaving your vehicle for the day and a half?

If you have done a few short drive and then left your vehicle for a day or two, the AGM will normally take a charge quicker that your cranking battery, NOTE this “ONLY” occurs when charging from an alternator, not when using a DC/DC device or battery charger, so if your have done a few short drives, your cranking battery might be down a bit and your AGM is keeping it topped up.

There is an easy way to check if there is a problem. Next time you know you are going to be leaving the vehicle unused for a day or two. Before you turn your motor off, switch the USI-160 In-Cab controller to the IGNITION mode, ( switch the switch towards the LED ) and leave it that way.

In SHARED mode the common battery voltage has to drop to 12.0v before the batteries are separated.

In IGNITION mode once the common voltage drops to 12.6v, the batteries will be separated, so with your USI-160 set to IGNITION mode. the batteries will separate at a much high voltage and you can then see if either ( or both ) battery settles to a lower voltage or just keeps discharging.

Now a note, if your cranking battery is a Calcium/Calcium battery then is it not uncommon for them to settle back as low as 12.2 but they will still be in an excellent condition.

As posted earlier, because of the way my isolators work, they tend to keep cranking batteries in a higher state of charge than normal, and this is why you need to bypass the SHARED mod to test your batteries.

Use the chart below to determine the rough SoC of your batteries.

https://www.aulro.com/afvb/images/imported/2016/06/640.jpg
Thanks for your elaborate answer Tim - I'll do some more testing.

What is the USI-160 in cab controller that you refer to?

BTW, did you get my email regarding the user instructions?

Cheers,

Franz

[drivesafe]

Hi Franz and first off, I did get your E-mail and will fix that tomorrow.

Next, I forgot you have an SC80 not the USI-160.

You can do the same test by disconnect the earth lead on the SC80 when you turn the motor off and see what happens to each battery.

[Disco4pilot]

I went out to buy 6.5m of cable to wire up the RRS so that I have power at the rear so I can charge the van batteries when on the move. This is the twin core cable I am after.

I tried two auto electricians, Battery World, the Battery Factory, Jaycar, Repco, Autobarn, SuperCheap, Pride 4wd and Lloyds caravans - all without success.

Single core yes - but not twin core.

So any other suggestions on where to buy this stuff.

Thanks

Garry

Most marine stores have much better cabling and electronic accessories than automotive shops. Basically people tend to do a lot more of their own electrical work on boats so they have a much larger range of gear and of a much higher quality available. Also there are a lot of marine application that need very heavy duty wiring (anchor winches and bow thrusters etc) and all gear has to be run back to the batteries so should have twin core. Also in the marine environment a 20 foot cable run is nothing (front of the car to a caravan) Think of a 60ft plus cruiser with the engines at the back and an anchor winch at the front! There are some fantastic 12volt books available from Whittworths or Boat books that are equally as applicable to the 4wd and camper situation.

[newthings]

In the USA, you might consider these folks for dual wire cable.
Welcome to Polar Wire online store (http://store.polarwire.com)
Twin Cable Wire Arctic Superflex (http://store.polarwire.com/browse.cfm/bulk/2,618.html)

1/0 dual wire for usd $9.53/ft plus usd shipping from Alaska.
Not sure of the B&S conversion values. Google knows.
Cheers, Roy

[drivesafe]

Hi newthings and welcome, unfortunately the weight of the cable means the freight cost is way higher then the cable cost.

I regularly ship to the USA and Europe, and the cable’s weight in each kit, constitutes the bulk of the freight cost.

[Franz]

Hi Franz and first off, I did get your E-mail and will fix that tomorrow.

Next, I forgot you have an SC80 not the USI-160.

You can do the same test by disconnect the earth lead on the SC80 when you turn the motor off and see what happens to each battery.
Hi Tim,

One of the reasons for my batteries not holding charge is that the main, a lead calcium, has never been fully charged with the 6A, 3 stage charger that I have been using. I have now purchased a 21A charger that has a setting for lead calcium batteries.

My research indicates that lead calcium batteries take a higher charge than standard wet cell lead acid and AGM batteries. Does this therefor mean that I need to charge the two batteries seperately? If I pump a higher than normal voltage required for the lead calcium battery into the AGM (both batteries charge together because of the power sharing capabilities of the SC80), will I not do damage to the AGM?

Your input is appreciated.

Cheers,

Franz

[drivesafe]

Hi Franz and you MUST charge the batteries separately.

The Calcium setting will mean your charger is going to operate at 15V, or at least it should.

15v is way too high for AGMs.

If you have older flooded wet cell batteries, they are fine being charged with the Calcium setting and will actually benefit from the higher BOOST cycle.