# Mysterious drain on leisure batteries



## Bryan (Aug 9, 2006)

Hi all,

I have an American RV with 2 leisure batteries, both of them being 125 amp Elecsol batteries, both only three weeks old. I replaced them as I had a mysterious battery drain on my previous batteries which I still have after replacing them, so I know it's not the batteries at fault.

The trouble is, I don't know the best way of tracing and identifying what is taking the power from the batteries...

They had a good charge from the alternator whilst coming back from Stratford this weekend and as soon as I killed the engine they were reading 13.8 volts.

By the time I had emptied the tanks and the RV and put it to bed the batteries were reading 12.83v and that was yesterday at 3pm. I will check them again tonight and post the reading but to give you an idea, I expect them to read less than 12v within 3 days. Tho only active circuit I can think of is the 12v feed to the fridge's circuit board (fridge runs on gas but it's circuit board needs 12v otherwise it shuts off)

What is the best/fastest way to identify what is drawing the power?

Should I:

Disconnect the red wires one by one, putting an ammeter in-line and checking for current?
Disconnect ALL red wires and reconnect one by one watching for voltage drop?
Disconnect the red wires one by one watching for voltage improvement as the troublesome draw gets isolated?

or...?


I can't trace the wires as they are all red and disappear into black tubing and then through the bulkhead.

I have started compiling a list of circuits/items that run from 12v so that as I work through a solution I can check what is still working and what is not.

My list so far:

Lights - Internal
Lights - External
CD Radio in dash (already disconnected
Inverter for TV (already disconnected)
12v power outlets
TV in bedroom (already disconnected)
Step
Fridge circuit board
Water pump
Oyster satellite receiver/controller

Can you add anything that I've missed?


I do have a solar panel and when the sun is shining it can read as high as 7 amps and when it does, the battery bank voltage goes up which implies it is charging. I have checked the solar panel output and it has read as high as 18v so it also looks like the solar panel regulator is working too.

I did have one connection that was a problem (found with the help of Glen (Tinaglen), thanks very much) and that was a sky digibox on standby 24/7 from a 75 watt inverter. This inverter is now disconnected and although it must have made a difference, the batteries are still suffering.

Sorry for the long post but I wanted to give as much information as I could so that it might help you - to help me 

I would appreciate any help in either adding to my list of items that are powered from the leisure batteries, or in helping me trace the 'thing' that is sucking the life from my batteries in the easiest and fastest way I can.

TIA

Bryan


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## Snelly (Aug 20, 2005)

Do you have an alarm system connected?? In the past I have found they can drain batteries... although not as quick as your drain appears to be.


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## DABurleigh (May 9, 2005)

Bryan,

"I wanted to give as much information as I could so that it might help you - to help me"

Thank you. Do you have various 12V circuit breakers rather than pulling and replacing red wires? 

I'd remove the earth terminal from your battery bank, and connect a multimeter in series, in ammeter mode (on say 10A setting in case lower one blows a small multimeter fuse). Check your problematic discharge. It should be consistent with the observed voltage drop of your battery bank, given its capacity.

If you have 12V breaker switches, flip each off in turn checking for significant change in the drain. 

If no switches, then pull the easiest/ most likely source red wire for the same.

Et seq.

Dave


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## Bryan (Aug 9, 2006)

I do have an alarm system which incorporates PIR's in the habitation areas and locker contact blocks. It is not armed as the RV is under lock and key (and cctv for that matter).

There is also an immobiliser and that works fine.

OI too would not expect these systems to draw much as most cars have them as well, and they can have very small batteries but will still work after several weeks idle.

The RV is nomally on hook-up whilst stored anyway and whilst the american inbuilt charger is v. poor it should be able to keep up with small drains.

I have left it off hookup at the moment as I need to be able to test without any external factors.

And after the alternator powered charge on the way back from Stratford I would expect many days before the batteries dropepd to 12v.


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## sallytrafic (Jan 17, 2006)

The initial drop just coming off charge is normal (referred to as the surface charge), otherwise I would do as Dave suggested. Inferring what is happening using a voltmeter is no substitute for measuring what is happening using an ammeter.


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## Bryan (Aug 9, 2006)

> Do you have various 12V circuit breakers rather than pulling and replacing red wires?


No, but near the brown Magnatec (?) electrics in the bathroom I have some 12v fuses. I also have 12v fuses near my left foot under the dash. I also have some in a box with some relays under the hood.



> I'd remove the earth terminal from your battery bank, and connect a multimeter in series, in ammeter mode (on say 10A setting in case lower one blows a small multimeter fuse). Check your problematic discharge. It should be consistent with the observed voltage drop of your battery bank, given its capacity.


Both batteries have their Negative terminals connected to the chassis at the same point, are you saying that I should remove this connection at the chassis and put my meter in-line (is that the same as in series?) and read the amps there? If you are is that because then this will show me the TOTAL current drain as opposed to the individual drains as per my suggestion?



> If you have 12V breaker switches, flip each off in turn checking for significant change in the drain.
> If no switches, then pull the easiest/ most likely source red wire for the same.


No trips, but could I pull fuses instead of red wires first? Much easier to do...


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## artona (Jan 19, 2006)

Hi

I once had a problem with a slow drain on the battery and it turned out to be an earthing problem Bryan


stew


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## Bryan (Aug 9, 2006)

artona said:


> Hi
> 
> I once had a problem with a slow drain on the battery and it turned out to be an earthing problem Bryan
> 
> stew


Slow drain? I think I was followed home by Powergen the amounts of amps I dropped all over my pitch at Stratford  :lol:

Where was your earth problem, Stew?


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## DABurleigh (May 9, 2005)

Yes, I'd measure the TOTAL drain AT the leisure batteries. If the negatives have a common chassis point, unbolt that and put the ammeter in-line.

After that, it is a matter of pragmatically (only you can judge the ease) disconnecting 12V loads from the system and looking for significant change in terms of % of your drain.

If everything gets switched off and the drain hasn't changed much, then either you are missing a valid load or you have an invalid load, ie an earthing problem 

Dave


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## 107558 (Oct 10, 2007)

> No, but near the brown Magnatec (?) eletrics in the bathroom I have some 12v fuses.


These are most probably your habitation fuses. See if they are labeled (they should be).



> I also have 12v fuses near my left foot under the dash. I also have some in a box with some relays under the hood


These are most likely engine/dash electrics fed from the engine battery. Again see if they are labeled.

The fuses may be numbered if so refer to your handbook for the key.


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## 107558 (Oct 10, 2007)

I forgot to mention that I had a problem with my electrics which was cured by checking the quality of the connections on the + of the leisure batteries.

I removed all the + connections, cleaned them with a wire brush then with brasso, polished off any residue, reconnected them and covered them with electrolytic grease. Job sorted!

I also did the same with the negative connections and I also checked all connections in all the fuse boxes for tightness (some were a bit loose).

Though this won't necessarily fix your problem I would recommend you do it while checking each connection as it will help mitigate problems later.

I would check, where possible, all your cables for chaffing.


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## G2EWS (May 1, 2006)

Hi Bryan,

That seems to be a significant drain, particularly if you have new batteries as suggested.

Get that ammeter in series, which is not the same as parallel. Basically disconnect the earth as suggested and connect your ammeter on it's highest setting between the earth cable and the chassis.

I am sure we will all be very interested to see what the reading is.

Regards

Chris


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## 103279 (Mar 5, 2007)

A thought: 

In most alarm systems the PIRs are still active and draw current even when the system is unarmed.

The solar panel blocking diode may be short circuit or its regulator may be faulty.

Those fancy touch button control panels draw current all the time, mine draws about 50mA.

Good luck!


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## artona (Jan 19, 2006)

Hi Bryan

The earthing problem was the way it was described but it was in solved by cleaning all terminals and greasing them has already mentioned in an earlier post. 

There is a recommended grease and I can't remember totally (mainly cus I am chicken in case I am wrong) but it might have been called copper grease or something, probably just normal grease but more expensive.

That actually solved the problem quite quickly and before we went and checked all equipment.


stew


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## Waleem (Nov 1, 2006)

You can use copper grease, but I find vaseline just as good and much cheaper. Dont use any other type of grease though as it will interfere with the connection. If cleaning up battery cables (which is an excellent place to start with any 12 v problem) dont forget to dismantle and clean BOTH ends of each lead, replacing any corroded connecting bolts or washers with new, and ensuring that there is clean bright metal underneath any earthing bolts.


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## Bryan (Aug 9, 2006)

Thanks for all the replies - I CAN tell you that when the batteries were replaced three weeks ago, all the connections to the batteries were either cleaned or re-terminated with new connectors. 


Luckily one of my multimeters (the one that I CAN find  ) does do 10 amps so I will be testing it tonight.

Hopefully the irksome circuit will show itself quickly. The batteries have approx a dozen red wires so it will probably be number 11 :wink: 

Regarding the solar panel...
I'm aware that they have a blocking diode that stops the power going from the batteries to the panel, and I wondered if it could be a failed diode that was causing the problem. But I have been informed that if the diode fails then the panel won't charge the batteries either and the fact that my panel is sending up-to 18v to the regulator proves that the diode is okay.


Can anyone confirm this?


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## artona (Jan 19, 2006)

Hi Bryan

did they check the battery leads the other end as well?

stew


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## DABurleigh (May 9, 2005)

In can fail short, or if overcurrent is high enough, fail open. 

Take that wire off first 

Dave


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## Bryan (Aug 9, 2006)

> Hi Bryan
> 
> did they check the battery leads the other end as well?
> 
> stew


The red wires dissappear so no, they are connected wherever they are connected. They did replace the wire that connects the two batteries positive terminals together though.

The negative from batteries to chassis, no they didn't clean that. It's never been touched in it's life so that WILL be coming off tonight.



DABurleigh said:


> In can fail short, or if overcurrent is high enough, fail open.
> 
> Take that wire off first
> 
> Dave


The solar panel regulator has three sets of wires to it. One from the panel, one from the leisure batteries and one from the chassis batteries.

Whilst at Stratford we did remove the wire from the panel to the regulator to check 'raw' voltage - that's where we saw it say 18v.
I'm assuming that it's at the solar panels regulator where the panel connect to the batteries? The RV is indoors and the solar panel regulator is showing zero amps so if the diode had failed open I would have hoped to see the draw to the panel on the regulator, no?

I will disconnect the solar panel from ther regulator first (after connecting ammeter to chassis earth point and batteries) anyway.

Thanks for all the help


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## DABurleigh (May 9, 2005)

Bryan,

The diode is probably within the regulator. So the panel could be generating 18V fine. If the diode failed open, it would still be 18V going into the regulator, but nothing to the batteries. If it shorted, your battery could be discharging through the solar panel.

But diagnostic speculation is wearing. There is no shortcut (pardon pun) to actually getting on with it and letting the evidence lead you to the fault, not your speculation 

Dave


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## 90487 (May 1, 2005)

Do you have a "Fantastic Fan"? These draw current when switched off, closed unless the speed switch is in "0" position. As these units have their own fuse they are sometimes not through a trip switch.

Our propane Gas alarm was also wired direct to the battery feed. It took a while to find these two drains on our coach battery, not obvious items. Checked with a ammeter, though connected it in line with the "+" battery terminal as it was easier to access (be careful not to touch any other metal 8O )

Carol


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## G2EWS (May 1, 2006)

Hi Bryan,

Don't mess around with all those red wires! Just check what drain (amps) you are getting through the earth terminal as mentioned previously, making sure nothing else is connected to the negative side of the batteries of course.

Once this is done and we are all expecting you to find a large drain, you will then as mentioned by others disconnect fuses or trips one at a time and see if that changes the drain.

Solar panel regulator is a simple affair and if the above does not find the fault then the next stage would be to disconnect the regulator to the batteries.

Regards

Chris


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## Bryan (Aug 9, 2006)

Well I popped up to the RV after work and things didn't really work as planned or hoped  

The RV had been left off hookup and with everything turned off (lights etc.) with only the fridge working as normal.

The voltage had dropped from 12.8 to 12.10 in 27 hours!

So as suggested i removed the earth connection for both batteries from the chassis and put my meter in series...set to 10A dc (three dots with a straight line above). NOTHING! 0.00 amps which can't be right.

So, reconnected earth to chassis and started pulling fuses whilst meter displaying volts on batteries.

As another ampere test I switched on the dash fans, pulled the fuse for them and connected the meter across the fuse holder. I expected this would let the current flow throught the meter, display the amps and make the fans come back on. Nope...No reading and no fans.

Carried on pulling fuses and when I pulled the one for the CO detector the voltage rose a tiny amount, and the fuse sparked a little on the holders when I removed it indicating a draw(?)

I moved to the fuses on the Magnatek in the bathroom and that's where I saw the biggest change. When I removed the 4th one the voltage went up from 12.10v to 12.13v. Check it was this fuse by replacing and removing and the voltage flicked between 12.10 and 12.13

On the label it just says 'Passenger' - helpful that :roll: 

Whilst the fuse is out the only the fridge goes off. So I guess that that is what it does.

So, I have left it with the two fuses out and I have now put it on hookup to put some charge in.

My plan is to get the voltage back up and remove the mains to see if it still drops...BUT I want to know what I did wrong re: checking the amps...

I reckon that that is the only way to know what is going on and I'm gutted that it never worked as expected/hoped.


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## artona (Jan 19, 2006)

In th emeantime Bryan get into the chat room


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## DABurleigh (May 9, 2005)

Sounds like your ammeter has blown a fuse :-(


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## Bryan (Aug 9, 2006)

DABurleigh said:


> Sounds like your ammeter has blown a fuse :-(


Could it still work as a voltmeter whilst not working as an ammeter?


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## DABurleigh (May 9, 2005)

Most definitely!


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## 90487 (May 1, 2005)

Bryan said:


> DABurleigh said:
> 
> 
> > Sounds like your ammeter has blown a fuse :-(
> ...


On my meter you have to pull the red lead off and plug it into the socket marked "10amp"


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## G2EWS (May 1, 2006)

Hi Bryan,

The measurement of volts is completely different from amps as Dave has suggested.

You have either not set the ammeter correctly, not put the leads in the right holes, an internal fuse has gone, or the meter is knackered!

You did the right thing by connecting across the fan fuse holder and the fans should have started up. Would be really great to know how much it is drawing.

I take it the Magnatek is the charger? Obviously not running as it was not on hook up.

The fact that the voltage dropped tells you straight away that there is something pulling it down. Any idea what happens when you remove this fuse?

Could 'passenger' be a light either inside or out?

Check the resistance of that fuse, I have seen them go high resistance and cause all sorts of problems.

Regards

Chris


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## Superk (Aug 22, 2005)

Just a thought - are the locker lights on?

 
Keith


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## 90487 (May 1, 2005)

> On the label it just says 'Passenger' - helpful that


Is your fridge on the passenger side? That fuse may control all the 12V accessories on the "passenger side" maybe you have another that says "driver"?

As I said previously the CO detector and the Fantastic Fan not switched to zero would drain a 110amp battery in a few days. You did not say if you had a FF or not.

Carol


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## Bryan (Aug 9, 2006)

> On my meter you have to pull the red lead off and plug it into the socket marked "10amp"


On mine too, and I did but no joy... :?



> You have either not set the ammeter correctly


I set it onto 10Adc with a picture of 3 dots under a straight line...



> not put the leads in the right holes,


Black probe in 'com' and red in '10A'



> an internal fuse has gone, or the meter is knackered!


oh, bugger... 



> You did the right thing by connecting across the fan fuse holder and the fans should have started up. Would be really great to know how much it is drawing.


I think that probably demonstrates best that the ammeter part of the meter is probably as dead as a parrot (ex)



> The fact that the voltage dropped tells you straight away that there is something pulling it down. Any idea what happens when you remove this fuse?


Yep, the fridge stops working...



> Could 'passenger' be a light either inside or out?


The label is handwritten so no idea why it says passenger, but the fridge at least does connect from it



> Check the resistance of that fuse, I have seen them go high resistance and cause all sorts of problems.


The fuse in question is 'different' to the others in the group, they are clear whilst this one is opaque, so it may have been changed in the past.

A concern I do have is that the voltage change was only 0.03 - not very big and I'm concerned that this may be a red herring 8O


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## Bryan (Aug 9, 2006)

witch said:


> Is your fridge on the passenger side? That fuse may control all the 12V accessories on the "passenger side" maybe you have another that says "driver"?
> 
> As I said previously the CO detector and the Fantastic Fan not switched to zero would drain a 110amp battery in a few days. You did not say if you had a FF or not.
> 
> Carol


Good point...It IS on the passenger side - I'll check if there is a 'driver' fuse 

No Fantastic Fan...


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## Bryan (Aug 9, 2006)

Superk said:


> Just a thought - are the locker lights on?
> 
> 
> Keith


I have checked and no, definately not :wink:


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## G2EWS (May 1, 2006)

Hi Bryan,

Why do you have the fridge on if you are not using the RV?

Your can check how bad the drain is by leaving the fuse out and monitoring the battery voltage over a few days.

However, your best bet would be to get a new multimeter, checking the current draw is a far more accurate method!

Maplins alway have a deal on.

Alternatively, where are you and is one of us nearby?

The fact that you removed the fuse and the voltage changed is significant because you should not really be drawing any voltage at all. But this really does depend on why you have the fridge running.

I leave everything off between trips and then fire up the fridge/freezer the day before as I have to get the beers chilled! Apart from the real ales, but then I am going off subject :lol: 

Regards

Chris


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## G2EWS (May 1, 2006)

Hi Bryan,

Just went to check something in my RV and remembered something crucial!

Electric steps!

If you have the door open, make sure you change the switch to leave the steps out, otherwise the circuit is made and ready, along with a light. I discovered this to my cost and drained my battery very quickly.

Oh, just about to order some new ones as mine are knackered!

Regards

Chris
ps Steps are on the passenger side!!!


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## Bryan (Aug 9, 2006)

Thanks for the replies Chris...

The fridge is on between trips as the RV is is always on hookup between trips. No real benefit to switching it off, also means we don't have to empty and fill the fridge each trip. One thing I didn't check is if the voltage still drops with the fuse in but the fridge switched off... Must remember to do that.

Electrip step - Good point and well worth making, but I always switch it off on sites as I'm aware that it can be a big draw.


I will get a new meter today but unfortunatley no Maplins nearby so will have to be Focus Do-It-All  


I'm in the North West - near Lancaster and if anyone is near enough to help you are guranteed copious cups of tea/coffee (Delete as applicable) followed by beer if you solve the problem (I'm not daft - beer BEFORE work is never a good idea :wink: )


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## 90487 (May 1, 2005)

> The fridge is on between trips as the RV is is always on hookup between trips.


Does the fridge not run on 110V or 240V then on hook up :?: 

Carol


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## Bryan (Aug 9, 2006)

witch said:


> Does the fridge not run on 110V or 240V then on hook up :?:
> 
> Carol


The fridge runs on 110v when on hookup and gas when not - BUT it ALWAYS needs 12v to it's circuit board otherwise it switches the fridge off.


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## 90487 (May 1, 2005)

Bryan said:


> [The fridge runs on 110v when on hookup and gas when not - BUT it ALWAYS needs 12v to it's circuit board otherwise it switches the fridge off.


Ah :idea: I understand. Mine is not that sophisticated  
Carol


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## G2EWS (May 1, 2006)

Hi Bryan,

Looking forward to your new meter!

Chris


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## Bryan (Aug 9, 2006)

First of all - thanks to all for the help so far  

Update:

Well I bought a clamp meter than measures DC current and eagerly wrapped it around the wire that connects the negative terminal of my batteries to the chassis.

This should (if I understood the advice given) give me a reading that was the total number of amps being drawn from the leisure batteries.

It read 2 amps.

Now, I applied the following calculation... 250 amps of batteries divided by 2 amps gives 125 hours. Allowing for a drain to 50% charge means that I should be good for 62.5 hours before my batteries are at half charge (which Elecsol says is 12.4 volts) and ready for charging.

But unfortunately it was still lasting little more than a day.

I had spotted that the little window that shows charge state etc. (they are sealed brand new Elecsol) was not showing green as it 'should'. I emailed Elecsol who said that the little windows are not that accurate anyway.

So I took to charging the batteries via a separate battery charger (nothing fancy, just a £20 Halford jobby) and after a few days one of the two batteries is now showing 'green' which I think is the electrolyte level (not sure, it could represent charge state).

My thinking is that 2.0 amps draw is not significant - the only things running were the 12v circuit board for the fridge and the co monitor and the gas monitor. The fridge circuit board (remember: the fridge runs on gas, not 12v) was taking the bulk of those 2.0 amps.

So if the DRAW is not the problem, it must be the charging?

Anyway, that is where I am at and the 'current' (sorry!) state of play is that the RV is sat with the Halfords charger charging the leisure batteries AND is on hook-up so the on-board charger is doing its 'bit'. It will sit like that until next Wednesday so that it has a full week of 'better' charging and I'll see how it goes then. The only change I might make is to change the Halfords charger over. It is currently connected to the Positive of battery 1 and the negative of battery 2. As battery 1 is showing 'green' in the window but battery 2 isn't, I may connect the charger to battery 2 only.

Please feel free to comment on any of the above.

Bryan


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## G2EWS (May 1, 2006)

Hi Bryan,

2 Amps is very significant when you are not supposedly drawing anything! You should be in the mA's if anything at all. This has now proven that you have power draining the batteries from somewhere and you need to isolate it.

I think we went through disconnecting fuses, but I would be tempted to do it again and take readings. This will then allow you to work out what is drawing the 2 Amps.

Regards

Chris


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## Bryan (Aug 9, 2006)

when I pulled fuses I seem to remember that there were two fuses that when pulled reduced the draw to virtually zero.

One was for one of the monitors (CO or gas) but that was very small.

Nearly all of the 2.0 amps was through a circuit/fuse called 'passenger' which is located in the 12v fuse panel within the Magnatec unit.

When I pull this fuse the only thing that stops working as far as I can see is the fridge. Now the fridge is actually working off gas but needs 12 volts for the circuit board to work. 2.0amps for a circuit board could be high I suppose.

But one thing confusing me is the loss that 2.0amps seems to be causing. Even at 2.0 amps I would expect more stamina from the 250amp battery bank. I suppose I was hoping to find a circuit drawing loads of amps that was so obviously killing the batteries overnight.

That said, 2.0 amps for a circuit board on the fridge does sound high so I suppose I'd better investigate that :roll: 

Thanks again


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