Interesting battery information

[Mundy]

Hi All,
At my 4wd club meeting a few days ago, we had a presentation from a battery expert who provided a lot of very interesting information, which I thought I might share with you. Some of it you will know, but its been my experience that there's a lot of myth and misinformation around regarding batteries.

1. AGM/Gel batteries charge much faster than wet cell batteries.
2. Charging a discharged deep cycle battery takes time. For example, even if you have a 100A alternator with 60A available and wish to charge a 60Ah battery, it will take hours to charge, not under an hour as the simple maths would imply. Wet cells are worse.
3. Heat is the enemy of batteries. If possible your second battery should not be the engine bay but if it is, is should be as close to the front as possible and away from the turbo or exhaust.
4 AGM/Gel batteries maintain a significantly higher voltage during discharge than a wet cell battery. To maintain power when running a fridge, a wet cell will therefore draw more current as the voltage drops making matters worse. This means that, for two nominally 100Ah batteries, one AGM and one wet cell, if you are running a fridge, you may not be able to get to the full capacity of the wet cell battery as the voltage drops below a usable level.
5 Car alternators almost universally won't fully charge a deep cycle battery, certainly not over a short period of time. This relates to voltage input. Apparently the alternators in new Prados, for example, only provide 13.3 to 13.8 volts which means some batteries won't charge beyond 50%. If you wish to charge a battery fully, you need to use a battery charger.
5. Calcium batteries require 15V to charge properly and don't make good second batteries as they are almost never fully charged and often go flat after a few days.
6. Second batteries need to be exercised. That is, if you don't use it (ie put a load on it) occasionally, when you come to go on holidays, it won't perform well. Again, a good battery charger will not only fully charge the battery but also cycle a load onto it so it maintains peak condition.
8. Legally, any cable attached to the battery which is over 30cm in length must be fused. Often winches aren't fused but they need to be, too. He gave examples of insurance being refused where a short caused fire because of lack of fuses. The fuse needs to be as close to the battery as possible and for cables running between the main and second battery and/or alternator, you need a fuse at each end of the cable.
9. Different batteries have different internal resistances and these resistances change over the life of the battery. If you connect batteries in parallel (for discharge not charging), you must have the same brand, capacity and age or inevitably, and eventually, both batteries will be stuffed.
10. Wet cell batteries need to be in a ventilated area due to gas discharge. This is so, even if it says its maintenance free but it is a wet cell. Maintenance free wet cell batteries can spill if tipped over.

Hope you find this informative.

Cheers
Mundy

[drivesafe]

Hi Mundy, sorry mate but most of that info your “EXPERT” gave you is based on many of the myths surrounding batteries and there uses.

For a start, AGM and GEL batteries are two different types of batteries and a Gel battery is more similar to a flooded wet cell battery and has many of it’s characteristics and while Gels make for good cranking batteries, a flooded wet cell battery is far better all round because they tolerate automotive environments better than most other types of batteries, including most AGMs.

While different types of batteries do have different voltage levels while discharging, the difference is so marginal that it is irrelevant for what they are being used for, like running a fridge and certainly will not make one battery type better than an other based on this.

The reference to Calcium batteries is a bit vague as most batteries have some % of calcium in them and you will find that it is batteries specifically labelled as Calcium/Lead/Calcium batteries that require the 15 volt charge to get them to a full charge but even this is deceptive because the additional voltage will at best only add about 5% to this type of batteries total capacity and will have little, if any effect on this type of batteries overall life span.

The one I love is this crap that you can’t use batteries of different types, size, age and so on. It surprises me they don’t demand that the batteries bo of the same colour, have the same size hand grips, what a load of BS.

If you have two identical batteries and one dies, for what ever reason, there is every chance that the other battery will be stuffed as well, unless you find the problem quick enough and there is a lot more to it but the fact that your so called “EXPERT” made such a statement shows just how little he really knows.

Now to fusing cables. To my knowledge, unlike AC wiring, there are NO mandatory requirements to fusing anything in a motor vehicle. There are STANDARDS and if you don’t meet these STANDARDS, if an insurance company actually knows about these STANDARDS then there is every chance that they will use these STANDARDS as a means of trying to avoiding a pay out.

To prove my point, have a look at your own vehicle and see how long your cable is between the alternator and the battery, and the battery and the starter motor. One or both will most likely be longer than 30cm and if it was a MANDATORY requirement that there be fuses in such situations, don’t you think the vehicle manufacturers would be in breach of such a requirement if it existed.

[THE BOOGER]

Many people confuse standards with laws. Laws require an act of parliament, standards can be anybodies standards:p. And the one about battery types have to match has been going around for along time. I know plenty of people who have wet cells for starting and agm for second and no problems(me). Many experts try to push their own products alot he said about short trips and chargeing with a charger are correct, he didnt have a line of batteries and chargers for sale did he.(if he did were any of them good value) Not picking on you Mundy:D

[Mundy]

I guess its going to be up to everyone to make up their own minds. That means checking out reputable sites not just forums (the irony of my own email is now not lost on me). One of the best sites can be found at: Technical Information (http://www.fridge-and-solar.net/info.htm). Read the articles. You can find others, too.

In particular response to Bodger and Drivesafe, I make the following comments
1. I made no judgement on whether wet cell, agm or gel batteries were better, just described the differences.
2. Of my 10 points, Drivesafe, you disparage the whole thread while making reference to 2 items only. I don't know about the discharge rate and/or discharge state versus voltage output; I will have to look into it more. But on the matter of dissimilar batteries, you are just wrong. Different batteries can have significantly different internal resistances which means if you connect two batteries with a large difference one battery will be flattened well before the other, to the long term detriment of both. On my other 8 points I will say to others, go do your research.
3. Clearly, Bodger you didn't read/understand the point regarding connection of different batteries. I too, have had a wet cell starter battery a AGM deep cycle but they are not connected (in parallel or otherwise) when the car engine is off ie when the second battery is providing the electrical current, because of the isolator. The context of the advice, which I should have included it seems, was in having a second and third battery as power supply, for some of those people who camp in one place for days at a time. It was suggested to stick to a single second battery and top up with a solar panel.
4.There are not just standards and laws, there are design rules and regulations and its my understanding that the fusing requirement is not just a myth. I haven't read the design rules and there may be an exception for the cable from alternator to battery for other good reasons.

I don't wish to start a debate; just wanted to help out.

Mundy

[drivesafe]

Hi Mundy, my first post was not aimed at you but at the incorrect info your “EXPERT” was spouting, this post is aimed at you.

I only cover two or three points in your thread as I didn’t have the time to go through every point one at a time.

There is no legitimate reason for not connecting dissimilar batteries in parallel.

As to one battery going flat before the other, yes that could happen if you applied a load of say a couple of hundred amps to an AGM and a flooded wet cell ( FWC ) battery connected in parallel.

The AGM would go flat before the FWC but it would be a difference of only a few seconds to maybe a minute and both batteries would be permanently stuffed

Back in the real world, there would be no difference in the discharge rates of two batteries connected in parallel when supplying power for a fridge, an inverter and a few lights all at the same time, the battery voltages would be the same from full charge to what ever level of discharge they were taken down to.

This is not a case of battery types but the laws of physics.

I design, manufacture and supply dual battery charge control equipment to the trade and I can assure you that connecting batteries in parallel is no problem and again, I can assure you your “EXPERT” was anything but.

As to your link, the guy has some good info there but while reading it, remember, he sells AGM batteries and some of his info is very heavily weighted in favour of these batteries and I’ve met him and found him to be very helpful but he is a SALESMAN, not a technician.

[THE BOOGER]

As with drivesafe i wasnt picking on you just some of the things said by the "expert" i agree short drives will not charge batteries properly and that charging with a charger is often the best way to go when not out in the bush.
I have had in a previous 4wd 2 secondary batteries 1 x agm deep cycle 1 x marine deep cycle(wet cell) they worked well for about 3 years till the wet cell shorted internally.


By the way if there are two different ways of looking at something it will cause a debate on most forums here is no different so dont get upset about anything its not personal.

[Mundy]

Fair enough guys. I'll try not to be so sensitive i future.

Mundy

[p38arover]

8. Legally, any cable attached to the battery which is over 30cm in length must be fused.

The leads to the starter motor aren't fused. They'd need a flaming big fuse to carry the hundreds of amps drawn by a starter motor.

[JDNSW]

The leads to the starter motor aren't fused. They'd need a flaming big fuse to carry the hundreds of amps drawn by a starter motor.

While fusing has become a lot more popular in recent years, I would point out that Series 1 had exactly one fuse, and the only protected circuits were those that came on with the ignition (but not the ignition). Series 2a added a second fuse - but this only protected the optional interior light.

John

[drivesafe]

Hi Mundy, unfortunately most people involved with vehicles, have little to no experience with automotive electrics.

This in itself is a problem because there are plenty of self proclaimed experts that are only too happy to jump up and tell you how it is, but these self proclaimed experts are usually nothing more than parrots, they read something on the side of a Corn Flakes packet and suddenly they know all about the subject at hand.

I’ve been designing, manufacturing and supplying the trade with automotive electronics for over 35 years, I’ve been producing dual battery controllers for just over 20 yeas and I do not, for one minute, consider myself an expert in this field. But I do have enough hands on experience to know when someone else is NOT an expert.

There are heaps of rogues out there, making a buck out of the ignorance of others and they can continue to do this because very few people have any real knowledge of this subject, to be able to question those who prey on others.

As THE BOOGER posted, did your expert have something he was pushing, this is usually a sure sign that he is about to try to empty your pocket by making out he is the only one that can solve your problem, usually a problem that you never actually had till he came along and made out you did.

We had one of these “EXPERTS” trying his act here about 12 months ago, but he quickly found that there are plenty of people here that were already aware of his carryings on and he left.

The same scum bag was literally run off the Overland forum for the same reason.

Having said all that, Mundy, please don’t take this one thread as a reason not to post something you feel is of benefit to others in the future. You unfortunately struck a rogue but hopefully you ( and others ) have actually been saved from making some costly purchases based on his B/S.

[waynep]

What's with all these bad people wearing red lipstick ?

[p38arover]

What's with all these bad people wearing red lipstick ?

¿Qué? :confused:

[PAT303]

Drivesafe I read somewere,can't remember that one expert thought the best way to send power to a van was throught a 7 pin trailer plug.We might be talking about the same expert. Pat

[zwitter]

Some of the 10 points have some merit but others are just not true.

I doubt any one would have a battery charger for automotive batteries that cycles them with a load and charge for home use.! Common for little rechargables and phone batteries for home use but not a car battery.

However I agree batteries tend to last longer if used on a regular basis than if left for long periods.

Heat does kill batteries usually due to fluid loss or undesirable chemical reactions.

Different batteries have different requirements in charging and use but for the most part 4WD use will never be optimal in any respect and when the battery fails after 2 or 3 years, just buy another one. The batteries of today are much better technically than those of only a few years ago!

I have discussed batteries and charging on AULRO before with Drivesafe and Bellaposs and others and we tend to have some differences of opinion. I do not want to re hash it all again.

On the insurance angle. Any modification to your vehicle should be notified to the insurance company and inspected if they want/need to. If they have suspicion or cause to deny payment then the fine print and liability can often consume more than the value of the claim. I always laugh at the question on the policy form. " will the vehicle carry flamable liquids" I have asked the underwriter about the fuel tank full of deisel or petrol but they still said answer truthfully as you see fit!

Within reason I would fit a fuse. But as a firefighter have seen electrical fires in cars from wiring faults or collision damage with the only solution to remove the batteries by what ever means!

Zwitter
James

[DRanged]

Hey mundy

Well done with posting those points. The intentions were good.

You could post that black is black on here and someone will tell you its white;)

Go and talk with an old school auto electrician. Find the right one and they will sort you out.

Justin

[drivesafe]

You could post that black is black on here and someone will tell you its white;)

Go and talk with an old school auto electrician. Find the right one and they will sort you out.

Curious, how do you know if you have found the right one, if you don’t have the correct info in the first place, particularly when most auto electricians do not do dual battery installations and many of those that do, usually don’t know what they are doing.

I’d say this would be a case of the blind leading the blind.

One of the most common faults that auto electricians fall into is one that Pat raised above and thats the use of a 7 pin trailer plug to supply charging power for a caravan or trailer mounted auxiliary battery.

That’s a good one to look for when trying to work out if the auto elec actually know what he is doing. If he recommends using a trailer plug to get the power to the trailer’s battery, go look for another auto elec and start again.

[Hoodoo Brown]

I have to comment...As a battery engineer with over twenty years in the business most of the comments seen here are pure fantasy and conjecture.

Try designing a battery system, that has to last over twenty years, giving 80% of its original capacity at end of life. Consider the battery environment. Heat, cold, ventilation, vibration protection, charging requirements, earthquake considerations and most of all the initial cost and ongoing maintenance costs.I have to get it all right as my livelihood depends on it.Try justifying spending $200,000 on one battery to the wife, and then telling her you need four of them in switch able parallel to do the job.

I purchased a battery for my 4WD in 1998 to run the Engel in the Nullabor whilst working there for several weeks.It then went in my Patrol for several years and on to the Freelander where it eventually failed after 10 years three months.It had been discharged to near zero on several occasions and upon recharge it came good again.

In my case , buy the best you can afford, gain the knowledge and look after the battery.It will serve you well.

Ignore the so called experts who mean well, as they are not spending the money. YOU ARE !!

Seek advise from experts.

[p38arover]

Seek advice from experts.

The problem is finding one. Who does one believe?

I'm am an electronics tech but batteries are not my field. I've done a lot of reading on the 'Net and found lots of articles about batteries and charging.

An amazing number are copied from a website somewhere else. I wonder how much of the stuff I have read is useful or can be relied upon. Not a lot, I suspect.

I don't think my old elec. engineering (c.1965 or older) books (if I can find them) cover this stuff. Battery manufacturers don't seem to provide much useful info via the 'Net.

My local library hasn't any useful books on the subject.

[Blknight.aus]

Definately wouldnt be inviting him around to play with the charging gear or batteries at work......

on the fusing front.....

go look at some of the newer BMW's the battery is in the boot and all of the fuses are up the front.

[p38arover]

My battery experience is pretty much limited to checking batteries at work, i.e., SG, temperature, ripple, etc. on 50 volt banks made up of 24 x 2 volt wet cells, each of about 2000AH each - a bit like these:



http://www.enersysreservepower.com/images/web_g.jpg

[Hoodoo Brown]

Looks like a Telstra wet cell to me.Theres still a few installations left like this in Telstra none in Optus, most have gone to sealed units of 110 amp capacity. Try putting 118 of those cells in series to 265 volts and discharging at 1260 apms for 1 hour to pass acceptance testing.

Battery experts, both electrical and chemical are out there. The hard part is finding an independant one who does not push a particular brand, and assesses each situation on its merits.

"Handbook of batteries" is an expensive text available thru... to borrow from the library.

The best information is often in the older text books and leaflets before they became a "product bible" pushing the company product.As the battery principal has not changed much for the auto industry in the last 50 years.

Salesman pushing a product are usually back by company technical experts however they are hard to get thru to, unless you have LOTS of money to spend. That leaves most 4WD buyers and the general public without help, unless they have outsider information.

I have just put a pair of batteries in my Disco to run the fridge and inverter without much change from $1000.

Can you imagine the rubbishing I get when I have a flat battery.

[Hoodoo Brown]

Try batteryuniversity.com

Lots of good information for the beginner

Battery Bible is another one. Use your Google.

[p38arover]

I worked for OTC, then Telstra after we were merged. We ripped out the wet cells when I was managing the Broadway and Paddington buildings and replaced them with sealed units. The plant guys worked for me.

We had large UPS systems to backup the 240VAC gear. Imagine the embarrassment when, after a power failure, the UPS didn't hold up long enough for the standby generator to come on line (less than a minute). The batteries in the UPS were shot. When we checked the batteries in Perth, we found they were the same. That's when we started measuring ripple on the batteries.

The batteries were Fulman.

[Hoodoo Brown]

I installed the start batteries on the generators at Paddington quite a while ago.
At least they worked to start the gen sets.Sorry about the UPS. IEEE recommends testing the UPS batts on an annual basis, however it is never done.
Try doing that at a nuclear power station or a reactor. Hello Chernoble.

Fulman wet cells are not too bad. Fulman sealed I would not recommend.
Usually Fulmen cells arrive with the complete UPS equipment that is purchased from France/overseas and subsequently has no local support. I make lots of service calls that way.

[LOVEMYRANGIE]

I agree with most of what has been refuted, however on the point of different size batteries being connected together, the ability of the smaller unit to kill the bigger unit does happen.
I had an N50Z that was only 18months old and I added an N70ZZ as a second unit connected direct to the N50Z to increase starting capacity etc etc. The batteries equalised over a period of time and after less than 8 or so months, both started to drop off considerably. After 2 years, it would struggle to start.
I took the older smaller unit out, replaced it with a matching unit to the larger and put the previous N70ZZ on charge with new acid and INOX etc etc.
The N70ZZ had already started to sulfate due to the older unit killing it and yet again in the same timeframe, the N70ZZ failed and started killing the newest unit.
I replaced both recently with 2 Supercharge Allrounders and have not had one little bit of drop in either voltage or amps as it still cranks over as fast as it did when they went in.

But yes, these "experts" are there to gain sales and get word of mouth business "coz this guy knows everything about batteries.." FFS, they're Sales Reps.........

Cheers

Andrew

[drivesafe]

Hi lovemyrangie, while I can’t give you a reason for why your specific set up failed, I can only go on the feed back of my many thousands of customers who don’t have such problems.

I’ll explain, in basic, how my Smart Chargers work so you can then see where I base my experience.

Unlike all other controllers, my dual battery controllers do NOT separate the cranking battery from the Auxiliary battery(s) after the motor is turned off.

The batteries remain connected until the common voltage drops bellow 12 volts.

Now, in most cases, the vehicles are the owners every day drive and as it can easily take a month or more for the batteries to self discharge below 12 volts and as the majority of my customers rarely leave their vehicles unused for more than 3 days at the longest, the two ( or more ) batteries are connected in parallel for MANY YEARS at a time and the feed back is now showing that their batteries are actually lasting longer than is usually expected and I might also point out that very, VERY few of my customers set ups comprise two identical batteries.

I don’t give a damn what the so called experts say, from 2 decades of hands on experience and thousands and thousands of satisfied customers, who’s batteries are connected in parallel for years at a time, the EX-SPERTS are full of B/S.

[p38arover]

I installed the start batteries on the generators at Paddington quite a while ago.
At least they worked to start the gen sets.



I wonder if we ever met? I tried to meet all the big contractors. I went down to one job and found a long time friend I hadn't seen for years. We used to fly model helicopters together. His name was Barry Neaton and worked for a battery supplier (Exide, I think). They were installing new sealed batteries after we pulled out the wet cells.


Sorry about the UPS. IEEE recommends testing the UPS batts on an annual basis, however it is never done.
Try doing that at a nuclear power station or a reactor. Hello Chernoble.

I took over the building managrement not long before the failure. We did regular load testing.


Fulman wet cells are not too bad. Fulman sealed I would not recommend.
Usually Fulmen cells arrive with the complete UPS equipment that is purchased from France/overseas and subsequently has no local support. I make lots of service calls that way.

They were Fulman sealed. :( I can't think of the brand of UPS - thought it was an Australian brand - or at least sold with an Australian name.

After Telecom took over and pushed OTC people out (after the merger and renaming as Telstra) and stuffed everything, they gave the building management to Transfield so it went backwards from then on. I lost all my plant staff, cleaners, etc., and went back to my old job of submarine cable maintenance, fisheries liaison, litigation involving commercial fishermen, maintenance ship contracts, etc. so I lost a lot of building maintenance contact (although I was still involved).

I loved the site/building management job - dealing with lawyers wasn't the same. Being physically threatened by commercial fishermen in meetings was, umm, interesting! At least dealing with AFMA was good, all the people I dealt with there were really good.

[Gold_TD5]

Hi lovemyrangie, while I can’t give you a reason for why your specific set up failed, I can only go on the feed back of my many thousands of customers who don’t have such problems.

I’ll explain, in basic, how my Smart Chargers work so you can then see where I base my experience.

Unlike all other controllers, my dual battery controllers do NOT separate the cranking battery from the Auxiliary battery(s) after the motor is turned off.

The batteries remain connected until the common voltage drops bellow 12 volts.

Now, in most cases, the vehicles are the owners every day drive and as it can easily take a month or more for the batteries to self discharge below 12 volts and as the majority of my customers rarely leave their vehicles unused for more than 3 days at the longest, the two ( or more ) batteries are connected in parallel for MANY YEARS at a time and the feed back is now showing that their batteries are actually lasting longer than is usually expected and I might also point out that very, VERY few of my customers set ups comprise two identical batteries.

I don’t give a damn what the so called experts say, from 2 decades of hands on experience and thousands and thousands of satisfied customers, who’s batteries are connected in parallel for years at a time, the EX-SPERTS are full of B/S.


G'day drivesafe, so how long would you expect this set up to last running a fridge, inverter and some lights before you lost power and would be unable to start the car?
What safegaurds are there?
Then how long to recharge?
Thanks for your thoughts,
Cheers Lionel

[drivesafe]

Hi Lionel, as posted above, my dual battery controllers isolate at 12 volts. This means the cranking battery is left with a 50% SoC ( State of Charge ) and older vehicle can be started with batteries with 11.75 volts and most modern vehicles can be started from batteries with as little as 11 volts, so there is no problem with isolating the cranking battery at 12 volts.

Because my controllers share the load over both batteries, this means that neither battery is as low as would be the case with an ordinary dual battery set up with only the auxiliary battery providing all the power, so you will have fully charged batteries in a shorter time as both batteries are charged at the same time.

Again because my controllers share the load over both batteries, the operating time before you need to recharge the auxiliary battery is, on average, 50% longer than with ordinary dual battery set ups, so if you know how long your set up works, say it’s work for two days, then with my systems, your system will operate for at least 3 days, before needing to recharge.

My controllers have a number of other benefits, including the fact that because your auxiliary battery is not worked as hard as it would with any other dual battery controller, auxiliary batteries tend to last longer when used with my gear.

[longreach]

:mad:good on you drivesafe,you have just hi-jacked MUNDY thread,to sell you own dual battery kit,MUNDY has only posted 43 times on this forum,give the man a go.

[stuee]

:mad:good on you drivesafe,you have just hi-jacked MUNDY thread,to sell you own dual battery kit,MUNDY has only posted 43 times on this forum,give the man a go.

Hardly. Drivesafe and others started off simply correcting some of the mis-information fed to Mundy. The discussion then moved to industrial batteries, then back to pairing dissimilar batteries upon which drivesafe said he did not agree and in his experience that when using his controllers it was not an issue (or something along those lines).

So the discussion changed 2-3 times from Mundy's original topic. I'd say it was a combination of mebers (now also me) who hijacked the thread. Course if your being sarcastic ignore me :angel:.

[p38arover]

The topic is of interest to me.

I am an electronics tech (by training but no longer by profession) but I am NOT a battery specialist. My background helps me understand what is being said.

My 2-year old AGM auxiliary battery has a cracked case and needs replacement.

My starting battery is dying and will need replacement soon.

Noting my second battery is under the rear floor in the wheel well with my LPG tank, do I buy:



two identical starting batteries at the same time, or
another AGM and a starting battery, or
a sealed deep cycle and a starting battery, or
some other combination?

[drivesafe]

Hi Ron, it’s simple, buy the batteries that best fit in the two locations.

It doesn’t matter what type and if their the same or not, just as long as they fit.

[drivesafe]

:mad:good on you drivesafe,you have just hi-jacked MUNDY thread,to sell you own dual battery kit,MUNDY has only posted 43 times on this forum,give the man a go.

Longreach, as stuee pointed out, I used my experience, based on my gear, to show that the info that Mundy had posted, no matter how well intentioned and as also pointed out earlier, in no way aimed at mundy, but the information that the “EXPERT” had given to mundy was grossly incorrect, or are you of the opinion that I should just let this incorrect info be used by other, interested in setting up their own dual battery system and usually at unnecessary additional expense because of the incorrect info.

By the way, most people on here are already well aware of the equipment I sell so I don’t need to push my gear.

I might also point out that I deliberately did not mention my trading name or make specific reference by the name of my controllers, so try keeping your comments to the subject.

[Gold_TD5]

Hi Lionel, as posted above, my dual battery controllers isolate at 12 volts. This means the cranking battery is left with a 50% SoC ( State of Charge ) and older vehicle can be started with batteries with 11.75 volts and most modern vehicles can be started from batteries with as little as 11 volts, so there is no problem with isolating the cranking battery at 12 volts.

Because my controllers share the load over both batteries, this means that neither battery is as low as would be the case with an ordinary dual battery set up with only the auxiliary battery providing all the power, so you will have fully charged batteries in a shorter time as both batteries are charged at the same time.

Again because my controllers share the load over both batteries, the operating time before you need to recharge the auxiliary battery is, on average, 50% longer than with ordinary dual battery set ups, so if you know how long your set up works, say it’s work for two days, then with my systems, your system will operate for at least 3 days, before needing to recharge.

My controllers have a number of other benefits, including the fact that because your auxiliary battery is not worked as hard as it would with any other dual battery controller, auxiliary batteries tend to last longer when used with my gear.

Good reply Mate, Thanks, make perfect sense to me.

[Mundy]

I guess it is worthwhile having the debate but unfortunately I am not sure we have reached a collective agreement on the outcomes, meaning we may not have helped anyone. As I said before, it will be up to each to decide for themselves where reality lies.

I stand by my all my points except 6 and 9 for which I have been unable to find anything definitive or which are outside my experience. Still, I wouldn't use dissimilar batteries in circumstances where they were connected in parallel when discharging. And for me, allowing a starter battery to go to 50% discharge seems lunacy, unless its a hybrid battery. Even then, you'll impact the number of cycles you receive. Go and read manufacturers data on their batteries which describe impact of discharge depth on cycle life. So too, for point 4, go and look at discharge curves for various battery types and see for yourself.

Mundy

[THE BOOGER]

Hi Ron im not an expert, but I was looking at a high CCA agm as a starter and a deep cycle agm for the fridge, Optima,s seem to be popular but they are more expense. I like agm,s simply because there is less maint on them:)

[drivesafe]

I wouldn't use dissimilar batteries in circumstances where they were connected in parallel when discharging.

Hi Mundy, what do you base this on, because as posted, after 20+ years of parallel charging and discharging of dissimilar batteries, I have yet to find a problem but if you have an example of a reoccurring problem, then not only would I be interested, but I am sure those following this thread would be too.

[Pedro_The_Swift]

I have just put a pair of batteries in my Disco to run the fridge and inverter without much change from $1000.


I just gotta ask,,
any chance of a pic of these $500 batteries??

[p38arover]

I just gotta ask,,
any chance of a pic of these $500 batteries??

.....and being in the business, Hoodoo got them at trade! :eek:

[p38arover]

Hi Mundy, what do you base this on, because as posted, after 20+ years of parallel charging and discharging of dissimilar batteries, I have yet to find a problem but if you have an example of a reoccurring problem, then not only would I be interested, but I am sure those following this thread would be too.

Tim, I'm wondering about what would happen if the batteries have different terminal voltages. Wouldn't they try to equalise?

[drivesafe]

Hi Ron, batteries will “Equalise” ( for want of a better word ).

It doesn’t matter if you have two identical batteries or two totally different batteries, the results will be the same.

If you have a fully charged battery and you connect it, in parallel, to a very discharged battery, say with an SoC ( State of Charge ) of 10%, which is about 11.3 volts, the full battery will discharge into the low battery.

In this extreme case, the low battery will charge slightly but the bulk of the full battery’s charge will, putting simply, be used up by the low battery’s on going chemical reaction.

When ever you apply a voltage to a battery that is higher than the battery’s SoC, there will be a chemical reaction.

If the voltage is less than 1 volt higher than the battery’s SoC, the applied voltage’s energy will do little more than keep the chemical reaction going. ( this is still VERY important )

If the applied voltage is more than one volt above the battery’s SoC, the chemical reaction in the battery will cause the to absorb power. In other words, the battery starts to charge.

So while the full battery’s SoC is more than 1 volt above the low battery’s SoC, some of the current going from the higher to the lower battery will be absorbed as stored power but this will be very little of the capacity coming from the higher charged battery and once the voltage difference is at 1 volt or less, the power coming from the higher charged battery is simply wasted.

The “Equalise” of the two batteries voltage’s will not happen in an instant or even in a few hour but more likely take a few days.

Just some additional info. Where there is an applied voltage of less 1 volt higher than a battery’s SoC, two important things occur,.

1. The battery, while not being charged, it will not discharge either, this is how the float charge cycle of a multi stage battery charger keeps a batter fully charged without over charging it.

2. While any charge ( or discharge ) is occurring, a chemical reaction is occurring in the battery, so a battery will not sulfate, Sulfation is the most common cause of the early demise of stored batteries.

Hope this answers your question!

[Pedro_The_Swift]

.....and being in the business, Hoodoo got them at trade! :eek:

Gotta love that name,,,:cool:
he was a big guy Hoodoo,, took me a while to figure out how to kill him,,




oops.
did I say that out loud?

oh yea,,,
sorry,


but he was a BAD man.

honest,
no really he was,,

had a crooked preacher man working for him,,

treated the gals badly,,




oops,,

:angel:

[leeds]

Sticking my head abovee theparapet. Have read this thread with interest and am not an expert on split charging or batteries so it is possible I have misunderstood the thread, if so apologies.

The system in my 110 is a South African Gensis system. This system charges the starter battery first and only when the starter battery is at full charge does it start to charge the auxilary battery. As far as I understand it these batteries are isolated from each other so that the primary starter battery can not be discharged by the auxilary circuits. It is possible to switch the batteries into a parallel mode so that you can have start assist from the second battery if the starter battery is low.

Is this a good type of split charging system to have?

Ducking below parapet :p

Regards

Brendan

[drivesafe]

Hi Leeds, with the exception of vehicles with very small alternators, there is no real advantage to charging batteries separately.

There is actually the problem of taking longer to charge the auxiliary batteries when done separately then when done in parallel and at the same time, but it also depends on use.

If your system has been working for you then it should be fine.

[bittersweet]

Thanks drive safe.

As a matter of interest what size of alternator is considered to be small?

Running a standard 65(?) amp alternator in my 110.

I have had issues with the 2 Optima yellow tops in the 110, they are about 3-4 years old and do not seem to be holding charge as well as they should. i.e. the auxilary yellow top voltage was 4.6volts after shipping back from Sydney i.e. 2 months at sea.

Optimas apparently have a reputation in UK for only lasting 3-4 years which coincides with a shift in manufacturing facilities.

Currently considering Odysseys as replacement


Regards


Brendan

PS Using Barbaras laptop

[drivesafe]

Hi Brendan, it’s a wonder you managed to get any charge back into the Yellow Top after having it get down to 4.6 volts.

Any other type of battery and you would have thrown it away.

If you not doing any long drives, you might try putting the batteries on a battery charger that has a float mode and leave them there for as long as you can and see if it bring the capacity up.

As far as your alternator goes, 65 is fine but you would need to drive for just a bit longer, depending on how low your batteries were when you started driving.

Optima batteries, like most batteries, will normally have a better life span in warmer climates, if looked after.

[drivesafe]

Hi again Brendan, one other thing you might try, but I must be honest, I really think the battery is beyond help BUT, if you know someone with a Ctek battery charge, try it on your battery.

The Ctek have a recovery mode that just might do some good for your battery.

Again, I am amazed that you managed to get any charge back in that battery so you can’t loose by trying the Ctek.

[Blknight.aus]

a small alternator is one that barely runs all your electrics....

fozzy when running on high beam with the fridge on, 3 fuel pumps running and with the fuel changeover valve in the powered position, radio on, 2 way on, dash lights on, and the gps on charge draws 31amps the alternator delivers 35.....

normal daytime running is 10-14 amps

night time running is 15-19 amps

[Hoodoo Brown]

Hoodoo back on line here....such disparaging remarks in my absence.

Pedro...The original Hoodoo Brown was a justice of the peace in Vegas in 1880s
Original name Hyman G Neill. nasty bastard. Not from the game "Gun".

Photos of the installation to come when the kids return the camera.

A pair of Odyssey 35 FC 1400 installed in the usual places for a 300TDI Disco with a Relec switch unit. I chose the Odyssey because I have just got TEN years three months working life out of one in my Freelander.

The Osyssey can be pulled down to 1.70 vpc x 6 =10.2 volts without a problem.A normal battery suffers at 1.80 vpc = 10.8 volts.Below that point it will eventually not recharge properly.

This is done by setting the cutoff point on the Liemack fridge at 10.2 volts. The fridge supplies 600 watts to an inverter to supply AC power when needed and also keeps my beer cold. Very important when working on the Nullabor on remote battery and solar sites for fibre optics.

No, I did not get a discount on the batteries, only the installation. They retail at over $450 each. So I better get another ten years.Unlimited warranty on these ones for five years. No I don't work for them.I just use and appreciate them.

The only other sealed type battery I have seen last ten years in actual service was a Gates battery manufactured in Swansea Wales. Unfortunately they were bought out and no longer exist.


Thanks all !!!