Cab Battery drain.

[haganap]

Ok I will start at the begining, looking for confirmation really but any advice/different ideas welcome.

My van is set up as follows.
I have the usual charging system connected to a 400 amp battery bank. This includes a soar panel with battery bias to Hab then cab.
Separately to all of this. I have 200 amps of Battery charged via a B2B charger which runs an 1800w pure sine inverter and I use this for Microwave, hairdyrer etc so not to disturb the normal running of the "normal" batteries. These are only charged when the engine is running via the b2b.

Recently I fitted a new Stereo (just to add a complication to the matter) please ignore for the time being.

I recently went for a weekend away (wilding) and after a while I had an issue with the CAB battery being low. The van started OK (little cranky) and I got home and put it on electric hook up. After a few days despite being on hook up the Cab battery again registered as low and this time no juice to start the van.

Being super impatient I thought that maybe the cab battery was knackered and being it was 6 months old with a 4 year warranty it must be so I purchased a new one. (one nearly new battery for sale shortly). All fitted, every fuse checked and left to see. Previous battery brought in doors and fully charged to 14.4V. After 2 days still showing 14.2V so now thinking that the battery is ok, explore more.

New CAB battery now reading 12.6 and sinking bit by bit.

So tonight I have checked the Inverter Hab batteries and they are showing 12.v Could these batteries be bringing down the CAB battery as in one of them is knackered?

I had no idea that the circuit created from the CAB- B2B- HAB would be able to do this? Is it possible that these in parallel in much the same way that obviously if you have 2 batteries in parallel and one gets knackered and drops the Voltage the other suffers hence always buying 2 new...

 

[Jaws]

Ok I will start at the begining, looking for confirmation really but any advice/different ideas welcome.

My van is set up as follows.
I have the usual charging system connected to a 400 amp battery bank. This includes a soar panel with battery bias to Hab then cab.
Separately to all of this. I have 200 amps of Battery charged via a B2B charger which runs an 1800w pure sine inverter and I use this for Microwave, hairdyrer etc so not to disturb the normal running of the "normal" batteries. These are only charged when the engine is running via the b2b.

Recently I fitted a new Stereo (just to add a complication to the matter) please ignore for the time being.

I recently went for a weekend away (wilding) and after a while I had an issue with the CAB battery being low. The van started OK (little cranky) and I got home and put it on electric hook up. After a few days despite being on hook up the Cab battery again registered as low and this time no juice to start the van.

Being super impatient I thought that maybe the cab battery was knackered and being it was 6 months old with a 4 year warranty it must be so I purchased a new one. (one nearly new battery for sale shortly). All fitted, every fuse checked and left to see. Previous battery brought in doors and fully charged to 14.4V. After 2 days still showing 14.2V so now thinking that the battery is ok, explore more.

New CAB battery now reading 12.6 and sinking bit by bit.

So tonight I have checked the Inverter Hab batteries and they are showing 12.v Could these batteries be bringing down the CAB battery as in one of them is knackered?

I had no idea that the circuit created from the CAB- B2B- HAB would be able to do this? Is it possible that these in parallel in much the same way that obviously if you have 2 batteries in parallel and one gets knackered and drops the Voltage the other suffers hence always buying 2 new...

Darrell bought a very high spec all singing and dancing stereo for his van.. two weeks later flat battery
He asked me to take a look.
Turned out to be the posh new radio,,, ( sorry cannot remember the make but it was a main stream well known one )
Might be a pain but it would be my first port of call. Disconnect the radio and see what happens

 

[andy63]

Hi Paul.. Just reading your post..not sure I can help but a few things may be worth chrcking..
It will bump it anyway

After a few days despite being on hook up the Cab battery again registered as low and this time no juice to start the van.

I'd be having a look into that assuming it was normal for the vehicle battery to receive a charge when on hook up..

If this is a recent problem establish the drain on the vehicle battery now when the vehicle is stood a while.. If it doesn't appear excessive check the alternator is charging it.. As the solar possibly isn't doing much for it this time year..
I suppose what I'm saying is get a meter out and check voltages and currents under different circumstances ie resting .engine running ..hook up and solar and find out if there is a problem..
Unless the btb charger is faulty I can't see it bringing down the engine battery ..and again the problem could lie with the alternator.. If your inverter batteries are going low..

I can't see how a voltage on a rested battery can remain as high as 14.2 with no charging source..
And 12.6v isn't a bad reading on your start battery anyway..
Andy.

 

[haganap]

Hi Paul.. Just reading your post..not sure I can help but a few things may be worth chrcking..
It will bump it anyway

I'd be having a look into that assuming it was normal for the vehicle battery to receive a charge when on hook up..

If this is a recent problem establish the drain on the vehicle battery now when the vehicle is stood a while.. If it doesn't appear excessive check the alternator is charging it.. As the solar possibly isn't doing much for it this time year..
I suppose what I'm saying is get a meter out and check voltages and currents under different circumstances ie resting .engine running ..hook up and solar and find out if there is a problem..
Unless the btb charger is faulty I can't see it bringing down the engine battery ..and again the problem could lie with the alternator.. If your inverter batteries are going low..

I can't see how a voltage on a rested battery can remain as high as 14.2 with no charging source..
And 12.6v isn't a bad reading on your start battery anyway..
Andy.

alternator is charging Hab battery no issue.
B2B kicking in 50 amps when engine running to the bank batterys

 

[HandyAndy]

two ways to attack this I think..
First separate hab and cab battery circuits.
Charge both seperately
Observe levels for a week.

1. the Hab circuit should not be connected to / drain the cab battery at all when the vehicle is off.
What is the link between HAb and Cab circuit? B2B or VSR?

Ahh seems like two things connect hab to cab, both B2B and dual output solar controller..
Disconnect both circuits to / from and charge everything seperatly with a normal battery charger.
12.6v is a rested but fully charged battery
14.2 volts reading on a battery means something was still hooked up to it.

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[haganap]

two ways to attack this I think..
First separate hab and cab battery circuits.
Charge both seperately
Observe levels for a week.

1. the Hab circuit should not be connected to / drain the cab battery at all when the vehicle is off.
What is the link between HAb and Cab circuit? B2B or VSR?

Ahh seems like two things connect hab to cab, both B2B and dual output solar controller..
Disconnect both circuits to / from and charge everything seperatly with a normal battery charger.
12.6v is a rested but fully charged battery
14.2 volts reading on a battery means something was still hooked up to it.

Ok, but first things first, I set this system up months and months ago and it's not been an issue until now.

I think for clarity - I have two circuits. One normal standard as it came from the factory. I have then added a B2B direct to 2 additional batteries separate of this. so the B2B goes direct to the Batteries. What I am trying to assertain is whether this counts as batteries in Parallel as I am aware this would be an issue although I always thought that the B2B would separate this somehow.

Also, just for clarity as I know you know a great deal about these things (I've stalked you on other forums where you've commented on similar issues)

If you did hace say 3 batteries in Parallel at 12.6 v and you added a new fully charged battery at 14 v what would the reading be on the new battery once connected? would it be an immediate drop to 12.6? or a slow decrease.

 

[Pausim]

Your B2B should separate the engine and leisure batteries but many electronic devices take a small amount of power even when off. I have a relay that completely disconnects my B2B from the engine battery when it is not needed to prevent this. A B2B may have a trickle charge feature for engine battery charging when on hook up because some B2B set ups prevent the mains charger from doing this. My relay prevents this from happening but my mains trickle charge function has not been interrupted.

 

[haganap]

Your B2B should separate the engine and leisure batteries but many electronic devices take a small amount of power even when off. I have a relay that completely disconnects my B2B from the engine battery when it is not needed to prevent this. A B2B may have a trickle charge feature for engine battery charging when on hook up because some B2B set ups prevent the mains charger from doing this. My relay prevents this from happening but my mains trickle charge function has not been interrupted.

Ok so that's what I thought.... but.
When I run the hairdryer through the inverter not only the bank 2 of leisure batteries drain, the main cab battery drains too. hence why I suspect an issue

 

[Pausim]

Ok so that's what I thought.... but.
When I run the hairdryer through the inverter not only the bank 2 of leisure batteries drain, the main cab battery drains too. hence why I suspect an issue

That sounds like a wiring problem, perhaps something is bypassing the B2B. Have you overridden or disconnected the original battery linking mechanism?

 

[SidJames]

Hi Paul. Firstly is the cab battery getting any charge from the mains charging curcuit? Check the voltage of the cab battery with charger off and the on, the voltage should go up to 14v ish.
Checking the drain from the cab battery. To do this you need a meter with a shunt, most have a 10amp shunt. Make sure everthing is off, main charger etc. You disconnect the positive lead from the cab battery and with meter in shunt mode connect the meter between the battery positive terminal and the positive battery lead. (I doubt there will be more than an 10amp drain. There will be a 10amp fuse in the meter for protection. This will tell you the current being drained from battery at rest. Things that will draw current are alarm, tracker, and radio (in most motorhomes the radio is connected via the hab curcuit)
This will give you a starting point to trace an excessive leakage.
This is a starting point.
Regards
Colin

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[HandyAndy]

Evening haganap
Can you confirm your layout, it's been a bit confusing or you are using the wrong terminology.

 

[haganap]

Hi Andy see attached- But basically and I hope the diagramme explains it is the following. When the van comes from the factory it has it's wiring system in place. I have simply added 2 new batteries that take there charge from the B2B. These batteries then fire up the inverter which I use off hook up. The way I see it, although you may be about too prove me wrong is that I have two different systems independent of each other... The solar is factory fitted allowing an 80/20 bias for hab over cab... the microwave is simply either plugged to the inverter or 12v depending on what power source there is.


just for clarity, there are fuses all over the place that I haven't entered but between alt and battery as is standard, between cab and b2b between each battery bank source and wherever else they came as standard




other.

 

[Pausim]

Which B2B are you using?

 

[jongood]

HI Paul
I'm no expert on this stuff but I vaguely remember the previous owner having an electrical issue when he first had it and I'm pretty sure it turned out to be the solar panel so TW replaced it. have yout ried disconnecting the panel - Diode failure?

Jon

 

[haganap]

Which B2B are you using?

this one https://www.12voltplanet.co.uk/ster...f-battery-to-battery-charger-12v12v-120a.html

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[haganap]

jongood yes that was a seperate issue, sorted by Dave Newall..

 

[funflair]

HI Paul

You said at the top "forget the radio for now" but if the problems coincided with this addition surely you can not forget it and is it not worth disconnecting it to prove a point.

Martin

 

[Pausim]

this one https://www.12voltplanet.co.uk/ster...f-battery-to-battery-charger-12v12v-120a.html

That is a big beast. Is your alternator up to supplying that much whilst also charging the engine battery and the other leisure bank?

 

[haganap]

HI Paul

You said at the top "forget the radio for now" but if the problems coincided with this addition surely you can not forget it and is it not worth disconnecting it to prove a point.

Martin

Well, that's where I thought I should have started. It's a radio I got from Polche with the sat nav for motorhomes. However, the drain from this comes purely from the hab batteries, Even with the cab battery disconnected it's still working. The wiring harness for this was pretty simple and more or less plug and play wiht some minor adjustments. The only thing I can't get it to do is to immediately show the reverse camera when selecting reverse, I have to go via the inputs on the stereo. There is one wire in there that is "homeless" from the previous pioneer, I suspect this was what it was for.

 

[haganap]

That is a big beast. Is your alternator up to supplying that much whilst also charging the engine battery and the other leisure bank?

sorry mate, should have made it clearer, point was to show the model, it's only a 60 amp version of that model..

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[haganap]

So i think today's task is to go simple.

I will remove said Battery 2 Battery charger...
I will remove said second battery bank and charge both batteries overnight.
Having done this I will see which one is knackered.
result - If 1 is knackered and has been somehow dragging the cab battery down- point proven, sell B2B revert back to a bigger battery bank in one bank.
Result - if both hab batteries are fine, time to remove the stereo and change it back to the old one.

I will still dump the B2B though, The N&B has a really good charging system anyway.


coming for sale soon.

1 B2B Charger
1 Nearly new Cab battery
1 Really good stereo with built in Sat Nav... just a case of which one.

And if all else fails? who knows.

 

[jongood]

So i think today's task is to go simple.

I will remove said Battery 2 Battery charger...
I will remove said second battery bank and charge both batteries overnight.
Having done this I will see which one is knackered.
result - If 1 is knackered and has been somehow dragging the cab battery down- point proven, sell B2B revert back to a bigger battery bank in one bank.
Result - if both hab batteries are fine, time to remove the stereo and change it back to the old one.

I will still dump the B2B though, The N&B has a really good charging system anyway.


coming for sale soon.

1 B2B Charger
1 Nearly new Cab battery
1 Really good stereo with built in Sat Nav... just a case of which one.

And if all else fails? who knows.

For when you have solved the original problem I've got one of the little cbe relays between the hab and cab batteries just keep a little going into it when stopped for a few days off grid. Seems to work ok.