Dual Battery System

[Damo89]

So recently I've had issues with my auxiliary battery stopping the supply of power to the outlets after the Defender has been switched off for about 5 hours. Its not the battery, its voltages are fine. I have the Traxide USI-160 isolator, and after a chat with Tim on the phone, he suggested it could be a faulty earth wire somewhere. I tested the voltages of the earth, no dice. I have three outlets. A dual USB, an Engel plug and a cigi plug.

After a quick chat with a guy on a beach I was driving on today, he suggested that I should have a DC to DC charger to fully charge the deep cycle battery I have - and that may be why its cutting out. However, when its cut out, the battery is still sitting at about 12.3V.

So - any suggestions? I am at a loss. I didn't have this problem when the setup was first installed, its only recently that it has been playing up. Any help would be greatly appreciated.

[Blknight.aus]

they guy on the beach is an idiot.

you are getting voltage drop under load which is causing the cutout.

it doesnt have to be an earth it could be one of the positives as well. you need to measure each leg of the positve from the battery to the isolator and the load as well as back from the load to the negative and this is where it gets fun.. if you're not earthed directly back to the battery and the isolator is measuring its voltage from the body mount or any where else you've now got multiple earth paths and you're in for a world of fun. Going point to point, from one end of each wire to the other you need to see less than .1v drop under load. if you see any drop with the system turned on and not under load then you've got some proper problems.

When you do your probing, dont forget to probe at both the terminal and the cable coming out of the lug. I've seen 2v drops from the lug and the wire caused by poor crimping, and corrosion inside the crimp caused by bad insulation.

It could also be that your cut out unit is set to cut out at say 12V and then when the load comes off the voltage creeps up .3v.

when you say you checked the voltages on the battery, how did you check them? the battery may be on the way out and is dropping down under load and then recovering to just below the cut in voltage for the traxde (From memory the minimum low cut out is 10.5 and the auto hookup voltage is 12.8, Tim'll correct me on that)

edit..

I just checked the functional layout on the usi160, it doesnt do load isolation (unless tims changed it and not updated his website). How is the load hooked up to the aux battery and what are you using to do the low voltage cut out for the load

[drivesafe]

Hi Damo, do you have an ABG-25 fitted as well as the USI-160?

Or are you running your accessories power sockets straight from the auxiliary battery?

[drivesafe]

they guy on the beach is an idiot.x2


when you say you checked the voltages on the battery, how did you check them? the battery may be on the way out and is dropping down under load and then recovering to just below the cut in voltage for the traxde (From memory the minimum low cut out is 10.5 and the auto hookup voltage is 12.8, Tim'll correct me on that)
Hi Dave, the USI-160 isolates at 12.0v in SHARED mode, 12.7v in IGNITION mode and 10.0v in WINCH Mode.

All modes cut-in at 13.2v

The ABG-25 isolates at the USER SELECTABLE settings of 11.6v, 11.8v, 12.0v or 12.3v, and cuts in at 12.7v

Damo's problem is a bit of a brain teaser, but I bet it turns out to be something simple but not so obvious.

[Damo89]

Hi Damo, do you have an ABG-25 fitted as well as the USI-160?

Or are you running your accessories power sockets straight from the auxiliary battery?

Hey Tim,

Thanks for your time on the phone yesterday as well. I didn't install the system as I am an absolute numpty when it comes to wiring, but from what I understand it is wired from the battery, to a fuse box then to the sockets.

I don't have the ABG-25

[Damo89]

This one might be above my scope as well to finally diagnose and fix - can anyone recommend a good auto electrician in Sydney, maybe a Land Rover specialist?

[Blknight.aus]

This one might be above my scope as well to finally diagnose and fix -

rubbish, can that rot, this will be as simple as a dicky connection or a screwed up wiring connection. if you can draw line pictures, if you have a multimeter and you have a digital camera this will be simple.

the basic steps will be.

draw a picture of all the parts of the system laid out in a pattern you can understand. (put the batteries at the top of the page, the loads at the bottom and draw lines for wires and boxes for control units as they appear in the system.

grab your multimeter and measure the voltage at all parts of the system start at the earth of the main battery and goto all the points in the system that should have 12V, write those numbers down and call them B1+(x)V do the same from the aux battery and label them as B2+(x)v swapping X for the value on the meter.

now go start to finish on each wire and write that down as (x)Vdrop.

and thats step one to being an auto sparky.

easy.

[Damo89]

Alright I've gone through it and come up with this diagram. Everything was tight and in good condition. Hope the diagram is not too confusing, I was a little confused with the Vdrop numbers...

On a side note, I didn't have the fridge in last night and it didn't die and has been sitting idle for almost 24 hours now. Is it a load issue after all?

I've also taken a bunch of photos of all the connections etc so let me know if you want to see them.

I'm still scratching my head.

On another note - the Anderson plug was installed to be a charging point to plug a solar panel into, still - not sure why its coming up as 0.0V. And not sure why the relay to the fuse box is coming up so low...

http://rogueshots.com.au/Wiring.jpg

[Aguy]

What is at the centre of the top red horizontal line?

Strange that you get volts there but not on the right hand plug. Is it the wiring between that and the plug? The plug itself or bad earth on plug?

[Blknight.aus]

OK, so heres how Im reading that.

1. youve measured all the voltages with the meter probe on an earth point

2. if the blocks connected from the batteries to the fuse block and the anderson plug are relays (which you seem to indicate) then for the relay in the fuse block line you've read either the signal voltage (which comes from the ignition or you've picked the earth for the relay. (point 4 ties into this to cover another relay type I remembered after I covered the diode protected self latching relay)

3. the relay to the anderson plug will most likely have a diode protected relay thats self latching off of the anderson plug which prevents the anderson plug being live if its not receiving power

2. there are relays known as VSR;s (voltage sensitive relays) they are usually used to drive heavy loads in luxobarges like heated seats, windshield and rear glass demisters so that if the engine is only idling or the battery is trying to drag a charge and the voltage is low what there is availabe is saved for keeping the engine running. massively simplifying the concept (sorry tim) this is what the traxide units are. Now if your relay is a VSR once they trip out on low voltage they wont reconnect until they get a much higher voltage.

so now...

Pictures.

[Damo89]

What is at the centre of the top red horizontal line?


It is a relay I believe, see figure 5.

1. Battery Bay

http://rogueshots.com.au/1.jpg

2. Cranking Battery Positive Terminal

http://rogueshots.com.au/2.jpg

3. Auxiliary Battery Positive Terminal

http://rogueshots.com.au/3.jpg

4. Auxiliary Battery Earth Terminal

http://rogueshots.com.au/4.jpg

5. Relays

http://rogueshots.com.au/5.jpg

6. Traxide USI-160

http://rogueshots.com.au/6.jpg

7. Mulgo Exbox with Fuse Block from Auxiliary Battery

http://rogueshots.com.au/7.jpg

8. Fuse Block

http://rogueshots.com.au/8.jpg

[Aguy]

They don't look like relays to me, maybe fuses? although they do look chunky for 30amps. did you test voltages on both lugs?


Maybe I'll stay out of this one and let the other guys help out, they seem very knowledgeable :)

[Aguy]

I googled the picture on fig 5 and it's apparently a circuit breaker. some are manual reset some are auto reset.
Didn't know you could get them that small.
Maybe one of yours are faulty?

[Blknight.aus]

ok first up..

those are not relays they are circuit breakers... these if over used will fail either fully closed or fully open or as a very high resistance if they burn their contacts.


what you need to do now is measure the voltage from both terminals of both circuit breakers to earth.

lets fault find only the circut breaker for the anderson plug first because doing so will let you wrap your head around the testing process

if the circuit breaker is closed (conducting current) then its terminals should both read the same voltage

if the circuit breaker is open the terminal closest to the battery (electrically speaking) will show battery voltage and the one closest to the load will show 0v.

so... if your battery voltage is 12.53 and the voltage on the terminal closest to the battery is 12.53 BUT the voltage is 0v on the other side of the breaker then its failed open. (thats what its ment to do dont panic yet) to confirm this put the meter directly across the 2 terminals of the circuit breaker. Assuming that you have nothing connected to the anderson plug what you really want to see is 0v but I'm going to guess you're going to see some kind of voltage. If you see anything more than about half a volt (and really you want a 0V reading) then you have a short in the wire from the output of the circuit breaker this is bad and needs to be fixed before you can safely replace the circuit breaker.

NOW...

my favorite trick.
go get yourself a minimum 50W headlight bulb. make up some connections on it to suit blade fuses (spade connectors) and then get some small aligator clips and put female spades on them so you can connect the light onto the terminals of your circuit breakers or onto other bits and pieces as you need to. This is your current limiter. its a Vital diagnostics tool. the advanced version includes a 10A circuit breaker like the one you have there.

AUTO SPARKIES MOST IMPORTANT RULE.

Before you screw around with a terminal thats hot or has a fuse you do not want to blow if you own spanners, fingers and eyesight that you value DISCONNECT ALL EARTHS from the battery. Then disconnect the terminal you want to play with and then put the earth leads back on AFTER you have insulated the hot cable you just removed.

because of the magic of electricery you can put your current limiter in the earth path and its still going to work BUT you can get some wierdo readings if you have other loads still connected.


Ok so now disconnect the lead from the circuit breaker and hook up your current limiter in place. with nothing in the anderson plug it should stay off. IF it comes on then you have a short, go track that down, remove it and thats the first half of the problem solved. you'll know you've removed the short when the light goes out.

to prove the concept (assuming that there is no short).. make sure you have the circuit breaker out of the system and only the current limiting light in place of the circuit breaker. Go and short out the anderson plug the light will come on, remove the short and tading. theres one of your most valuable fault finding tools for heavy current failures and blowing fuses.

[Blknight.aus]

Maybe I'll stay out of this one

yeah you could... or you could get involved

lets check the facts in play to support this.

you identifed the components
you identified a potential fault
you identified a valid test procedure.
You got there before I did.

It might just be me but thats 3/3 of the primary requirements for fault finding and rectification and picked up the bonus points of doing it quickly.

[Blknight.aus]

guys watch for a couple of edits in the main post of mine 2 back, I didnt like the way it read back so I clarified some wording on terminals for the diagnostics part.

I knew what I ment but there was a chance it could be misread

[roverrescue]

Dave,
Just want to say it sometimes seems that internet fora are the home of negativity put downs and arguing... It's nice to see some encouragement.

Damo89 your 99% of the way to fixing this... Lots of questions lots of good info provided and voila your knowledge will increase and your Landy will be healed

Steve

[Aguy]

Dave,

I'm soon going to be installing the same kind of setup as Damo89 minus the second battery and minus the Anderson plug.
Do I need a fuse/breaker on the positive wire between the battery and NEW fuse block if it's only short? i.e, NEW fuse block will go in the same box as the battery.
If so, what would be a good reliable unit?

[Blknight.aus]

Yep, As a minimum you should have a fuse or manual reset circuit breaker, when I do the installs I stick in 2 layers of protection at each battery on each leg out of the battery a fuse as close to the battery as I can get it followed by a circuit breaker.

some basics.

total your maximum anticipated load thats the minimum rating that your circuit breaker needs to be the fuse should be 20% or the next largest rating over the selected circuit breaker or higher.

the reason for this is 2 fold

1. if the circuit breaker gets hot clicks closed and welds its contact its not protecting anything any more so the fuse will blow.
2. If you have a short you cant fix that repeatedly tripping the breaker you have a quick and easy way of isolating the circuit.

IF you're going to put in the same setup as Damo but arent going to put in a dual battery later on then you dont need the traxide but you DO need a low voltage cut out unit of some kind Or a switched relay to drop the load off of the main battery.

[Damo89]

Guys - you are absolute legends. As soon as I get home from work tomorrow I'll start off with checking those circuit breakers as Dave has mentioned.

As you say - if they are over used they may fail. If it has failed, should I be looking at a larger circuit breaker in there?

[Aguy]

Thanks for the info Dave.

[Blknight.aus]

Guys - you are absolute legends. As soon as I get home from work tomorrow I'll start off with checking those circuit breakers as Dave has mentioned.

As you say - if they are over used they may fail. If it has failed, should I be looking at a larger circuit breaker in there?

only if the load you are putting on it is more than its ment to handle.
IF its failed because of heat or a short overworking it then no.

ID go so far as to say that the 30 breaker for your current fuse panel load out (1 fridge, 1 cig socket and 2 usb) is oversize and Id have stuck a 15 amp breaker in behind a 20A fuse.


Im also tempted to suggest that I bet your early cut out problem is being caused by your fuse block, most likely one of the phillips head screws and spring washers holding down the delivery wires

[Damo89]

I've just poked around more and found the ABG-25 - is this a big game changer?

[The Beast]

hi Damo, sounds like the ABG25 is doing its job, but that doesnt mean there isnt a problem with the circuit breaker. i've just installed the same set up, so far so good. you're welcome to take a look and compare notes. just PM me.

[The Beast]

another thought, next step is crack open the ABG25 and see what voltage it is set to cut off at

[Damo89]

another thought, next step is crack open the ABG25 and see what voltage it is set to cut off at

I didn't know you could! I'll try at lunch :-)

[loanrangie]

hi Damo, sounds like the ABG25 is doing its job, but that doesnt mean there isnt a problem with the circuit breaker. i've just installed the same set up, so far so good. you're welcome to take a look and compare notes. just PM me.

I replaced my isolator only to find it was the circuit breaker at fault, figured it was 25yo so was probably due for replacement but it still works perfectly.

Sent from my GT-I9300 using AULRO mobile app

[Blknight.aus]

I've just poked around more and found the ABG-25 - is this a big game changer?

sure is, thats your low voltage cut out unit.

if its set high it'll cut out very early on. if its set at a reasonable voltage and you have a voltage drop between the battery and the input of the unit it will cut out early as well.

[Damo89]

Problem solved - dead battery. :wasntme:

Thanks for the help everyone - I learnt a hell of a lot!