# Batteries running down quicker than expected!



## richardsnow (Dec 9, 2007)

I have a Compass Avantguard and it is now fitted with 2 x 125 amp NEW batteries. I have a 60watt solar panel which as tested seems to be working as it should be.

I am concerned that my batteries seem to lose power quite quickly (it is more noticeable when the solar panel is actually switched off)

I have a feeling that something is using power but I really do not know how to find out what may be at fault. The only thing permanently on is the radio presumably on stand by mode to retain settings.

Any ideas of where to start would be very helpful please.


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## Mrplodd (Mar 4, 2008)

"Seem to be losing power quiete quickly" ??

Please define what makes you say that. Are they going flat with nothing (you know of) switched on? If so over what sort of time period and what is the acdtual voltage drop, etc etc

A bit more info will enable people to give you a more detailed response.

Do you have any lights in any little used lockers??


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## 747 (Oct 2, 2009)

You should have a switch (usually in the footwell of the hab door). It cuts off the 12 volt supply in the van. Does this stop the battery drain?

Also, if it was the radio at fault, the van battery would be going flat not the leisure ones.

If your van has the standard blade type fuses, go to Maplin and buy a car current tester for £9.99. It gives a digital readout of circuits. You remove one fuse at a time, fit it into the tester then plug the tester into the fuse holder. If there is a drain, you will spot it. Work your way through the fuse box.


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## richardsnow (Dec 9, 2007)

Mrplodd said:


> "Seem to be losing power quiete quickly" ??
> 
> Please define what makes you say that. Are they going flat with nothing (you know of) switched on? If so over what sort of time period and what is the acdtual voltage drop, etc etc
> 
> ...


After driving 100 miles or so battery seems fully charged and after settling down it reads at 12.7v but within 24 hours has dropped to about 12.4v with nothing actually switched on except the stand-by on the radio (which is wired to the leisure battery and NOT the motorhome vehicle battery) - that seems a big drop with 250AmpH battery.

No lights in any lockers or elsewhere that could possibly be left on either!!


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## cabby (May 14, 2005)

does it go any lower than that if you leave it.
if so down to what and over what period of time please.

cabby


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## richardsnow (Dec 9, 2007)

747 said:


> You should have a switch (usually in the footwell of the hab door). It cuts off the 12 volt supply in the van. Does this stop the battery drain?
> 
> Also, if it was the radio at fault, the van battery would be going flat not the leisure ones.
> 
> If your van has the standard blade type fuses, go to Maplin and buy a car current tester for £9.99. It gives a digital readout of circuits. You remove one fuse at a time, fit it into the tester then plug the tester into the fuse holder. If there is a drain, you will spot it. Work your way through the fuse box.


Have not actually switched off the main switch by the door so am unable to comment yet. Will try that.

Radio is in habitation area and wired to leisure battery.

Current tester from Maplin sounds like a good plan thank you. I wonder what can cause a leakage of current without me being able to spot the cause?


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## richardsnow (Dec 9, 2007)

cabby said:


> does it go any lower than that if you leave it.
> if so down to what and over what period of time please.
> 
> cabby


Not sure but it seems to be continual. Unfortunately up until now I have allowed the 60w solar panel to mitigate the effects by constantly charging it up.


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## richardsnow (Dec 9, 2007)

747 said:


> You should have a switch (usually in the footwell of the hab door). It cuts off the 12 volt supply in the van. Does this stop the battery drain?
> 
> Also, if it was the radio at fault, the van battery would be going flat not the leisure ones.
> 
> If your van has the standard blade type fuses, go to Maplin and buy a car current tester for £9.99. It gives a digital readout of circuits. You remove one fuse at a time, fit it into the tester then plug the tester into the fuse holder. If there is a drain, you will spot it. Work your way through the fuse box.


Just looked at Maplin's site and they offer two testers - one for maxi fuses and one for mini!! Which do I need?


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## geraldandannie (Jun 4, 2006)

richardsnow said:


> Just looked at Maplin's site and they offer two testers - one for maxi fuses and one for mini!! Which do I need?


You need to check your fuses. Hopefully, there should be two pictures here which show the maxi and mini fuses:

MAXI









MINI









Gerald


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## JeanLuc (Jan 13, 2007)

This thought may be completely off the mark, but you refer in the first post to the current drain seeming to be greatest when the solar panel is switched off. Not sure what you mean by this, but is the panel connected via a charge controller that has a blocking diode included in its circuit? If there is not one, and the panel is connected to the batteries overnight, then that could be the source of your drain. The blocking diode is an electrical one-way valve and prevents the panel from taking current out of the battery and 'giving it back' to the environment whilst it is dark.

p.s. I don't think 12.7 volts is very high for a fully charged battery after a settling period. Mine normally registers 13 or a little more.


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## richardsnow (Dec 9, 2007)

JeanLuc said:


> This thought may be completely off the mark, but you refer in the first post to the current drain seeming to be greatest when the solar panel is switched off. Not sure what you mean by this, but is the panel connected via a charge controller that has a blocking diode included in its circuit? If there is not one, and the panel is connected to the batteries overnight, then that could be the source of your drain. The blocking diode is an electrical one-way valve and prevents the panel from taking current out of the battery and 'giving it back' to the environment whilst it is dark.
> 
> p.s. I don't think 12.7 volts is very high for a fully charged battery after a settling period. Mine normally registers 13 or a little more.


The reason that the drain is greatest with the solar panel off is because nothing is being put into the battery. I have an isolator switch that shuts off the panel completely if required. I do have a charge controller with blocking diode but that is not at issue as with panel off it can not discharge overnight anyway.

Regarding battery full charged state (with solar panel off) I always understood that 12.7v was fully charged??? Has anyone got any further thoughts on that one please?


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## geraldandannie (Jun 4, 2006)

There's a useful Members Motorhoming guide, written by Safariboy:

http://www.motorhomefacts.com/ftoptitle-65111-use-and-care-of-batteries.html

It might help :?

Gerald


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## geraldandannie (Jun 4, 2006)

There's also one written by Frank (sallytrafic) that has a table of battery voltages. 12.6 seems to be the minimum voltage for maximum charge.

See here:

http://www.motorhomefacts.com/ftoptitle-65110-12-volt-systems.html

Gerald


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## sallytrafic (Jan 17, 2006)

A couple of thoughts 

How are you measuring this voltage? In built meters not always reliable.

Solar panel regulators normally don't require the panel to have a blocking diode these days.

Using the Maplin test lead with a suitable meter is an excellent way forward

Can you measure the voltage whilst on charge from engine alternator then switch engine off and watch drop perhaps draw a little graph? You should find an on charge voltage of about 14v which drops fairly quickly (less than an hour) to the 12.6 12.9 sort of range.

Sorts of things people forget is always on: solar regulator, leisure control panel, waste and water tank gauges, some fridges even when on gas, some vans have their security system wired to leisure, tv on standby etc 

For example at the moment with no lights or any standby circuits, my NASA meter is recording 0.4A discharge, (if I isolate the solar panel which is just balancing that load at 6am.)

I have two 110Ahr batteries in parallel fed from a Amperor power integrator which combines a 25A battery to battery converter and a solar regulator I have a 130W kyocera panel this is all monitored by a NASA meter. We have been away all month and I haven't noticed less than 12.6v in the early morning. We famously have no tv and all my lights are LED. Most of my battery use is charging laptops iPad camera batteries etc. At the moment the panel is exactly matching the load and I have 12.8v

Hope this helps


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## sallytrafic (Jan 17, 2006)

Further thoughts 

125Ahr hmm not elecsols are they?

In any new installation of parallel batteries it is important to get them equalised. Simple chargers don't have enough clout to do this as you need to hold them at about the gassing voltage for long enough for this to happen. The article of mine that Gerald has linked too explains that.

My charging system gives them around 15v for a period once in every ten charges but even this wouldn't be long enough if the two batteries were mismatched. 

One way to make sure this isn't a problem is to isolate each battery in turn.

With 250Ahr of batteries a 60W panel is going to struggle and the sort of simple split charge system is going to as well. From 12.4v say 80% to get to 100% is 50Ahr are you sure you are getting there? For example a split charge held to a 13.8v probably less at the leisure battery end will never make it in any reasonable time, topping out at the right sort of voltage but only 90% or less. Negative plate chemistry requires gassing voltages or just a bit less to achieve the end of the charge. 

Note in all this voltages are only a rough guide.


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## Rosbotham (May 4, 2008)

Usual question...you haven't got a reversing camera fitted by chance? I've lost count of the number of times some numpty fitter has wired these unswitched to the battery (admittedly usually vehicle, but if the leisure was more convenient...)


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## CourtJester (Aug 26, 2009)

747 said:


> ... Also, if it was the radio at fault, the van battery would be going flat not the leisure one...


Not on my van. The radio is connected to the leisure battery.


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## richardsnow (Dec 9, 2007)

Rosbotham said:


> Usual question...you haven't got a reversing camera fitted by chance? I've lost count of the number of times some numpty fitter has wired these unswitched to the battery (admittedly usually vehicle, but if the leisure was more convenient...)


No reversing camera! Thanks for the thought. I have got lots of things to try from all the above contributions so will be busy with my test meter and so on.


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## richardsnow (Dec 9, 2007)

geraldandannie said:


> There's a useful Members Motorhoming guide, written by Safariboy:
> 
> http://www.motorhomefacts.com/ftoptitle-65111-use-and-care-of-batteries.html
> 
> ...


These 2 articles are really very useful thank you.

http://www.motorhomefacts.com/ftoptitle-65110-12-volt-systems.html

and
http://www.motorhomefacts.com/ftoptitle-65111-use-and-care-of-batteries.html


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## 747 (Oct 2, 2009)

richardsnow said:


> 747 said:
> 
> 
> > You should have a switch (usually in the footwell of the hab door). It cuts off the 12 volt supply in the van. Does this stop the battery drain?
> ...


Take a fuse with you to be certain that you are getting the right one.


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## denisl (Mar 16, 2011)

Just looking at your earlier comment:



> After driving 100 miles or so battery seems fully charged and after settling down it reads at 12.7v but within 24 hours has dropped to about 12.4v


How long a "settling down" period are you talking about. I believe a standard amount of time is 3 hrs to get a true value of the battery's state.

Is it possible that your battery really isn't fully charge. Driving 100 miles isn't that great a time if the battery is low. It may well show 12.7 after a few minutes - could 12.4 be the correct value?

If something is draining it, the voltage would drop quite quickly from 12.4


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