# Have I knackered my leisure batteries



## skiboycey (May 21, 2009)

Hi

On a recent trip it got cold for the first time this year. Overnight my leisure batteries went down to 7 odd volts and the radio etc. lost it's memory. The leisure batteries were new last summer, 130Ah quality leisure specific batteries with small terminals on them (not starter type terminals), wet lead acid and about 200 euros each so not the most expensive but not cheap Halfords rubbish either. I have a 100w solar panel on which had been charging in the bright sunshine all day at 6 plus amps and the battery voltage before going to bed was a fairly healthy 12.7 volts.

On investigation both were low on water - very low. This has obviously been due to gassing which has depleted the water in each and, to my shame, I'd not checked them for a year. When the motorhome is parked up I normally don't plug it into the mains I just leave the solar panel to trickle charge the batteries via the Sargent control unit.

To cut a long story short I eventually ended up putting a bit more than 2 litres of distilled water into the two batteries - they really were that low. I've now left the van on mains charging for about 3 weeks and charge has settled to about 2.5 amps between the two batteries. They seem OK and worked for 3 days without hook-up recently. Before filling with new water the plates were visible well above the fluid level but didn't look particularly corroded though there was some sign of a blackish deposit on a few of them. I've not removed them again to see if this has disolved into the new water that's been added. To allow for further gassing I filled the cells to a couple of centimetres above the plates. As I never checked the batteries from new it's just possible they were not filled correctly when I bought them though this seems unlikely (unless this is deliberate to avoid spills and I should have been told to add water before use?)

I wondered if any battery experts might know whether running the water down this low has more-or-less knackered the batteries? Also is it possible to leave the van permanently plugged into the mains and charging via the Sargent Unit (EC-325)? Does this unit properly switch to bulk charging of the batteries or will it overcharge them and keep them gassing thus depleting the water again?

I understand how all this works from a physics/engineering point of view but lack experience dealing with many different batteries which other forum users may have. I also realise this has probably been coverd somewhere on the forum but I never seem to be able to get the search function to work properly!

Thanks in advance for any advice. Regards, Mark


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## inkey-2008 (May 24, 2008)

They sound like they have had it but you may be lucky. The plates in the battery buckle the easiest way to find out is to charge them up as you have said then put a load on them and see what happens.

If a cell has gone then the power will quickly fall away. 

When I bought my new to me motorhome the batteries would not hold a charge and like you I had to put nearly 5ltr of water between them but they never recovered.


Andy


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## pieterv (Feb 3, 2009)

You mention that after three weeks on mains the batteries are still being charged with 2.5A. This seems quite a lot to me, I would expect a small trickle charge of a few tenths of an Amp after a thorough charge.

Maybe this explains your water loss? You should check the voltage of your charger after it went down to trickle charge. Should be around 13.8V.

Pieter


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## CliveMott (Mar 10, 2008)

Very suspicious of your charger and/or solar regulator. The very high use of water suggests significant overcharge. Measure the leisure battery terminal voltage with an independant digital voltmeter directly at the battery terminals while it is on charge. Cover the solar panel when checking out the mains charger and similarly disconnect the hookup when checking out the solar regulator. If it stabilises over 14 volts after a night on charge then you need to get it sorted.

Lastly, have you checked that the starter battery electrolyte level is correct?

C.


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## skiboycey (May 21, 2009)

The voltage of the leisure batteries has stabilised at 14.72 volts on charge. The engine battery is at 12.40 volts. The charge going into the battery (on the Sargent digital display) is 3.1 amps. I could run an ampmeter across the leisure battery fuse to see the charge on my own multimeter but I don't want to pull the fuse if I can help it as I'll lose the radio memory and I've no reason to doubt the reading on the inbuilt display.

I can't currently check the solar charge because it's horrible and rainy. When it's charging it usually doesn't go above 14.3 volts on solar. On the mains charger circuit it's sometimes as much as 15 volts but I think this is because the Sargent unit 'lifts' the leisure batteries out of the circuit and conditions them independantly at a higher voltage than normal. It says something about it in the user manual. Maybe it's just that I should have kept a better eye on the water level? If the charge at the moment is 3 amps which is probably about 1 amp per battery (2 leisure and 1 engine) which doesn't seem very high to me...

I've not checked the starter levels but it always starts easily even in cold weather so no reason to suspect they are wrong as pulling 500 amps would show up a dud cell very quickly.

Thanks for the replies and any other input. Does anyone know if it's OK to leave the Sargent unit plugged in indefinitely? Perhaps if Ian Sargent reads this post he might have some input?

Cheers, Mark


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## sallytrafic (Jan 17, 2006)

14V is only a guide my charger and my panel will take them higher (just over 15V) especially when cold because both have temperature sensing. The lower the temp the higher the voltage before gassing.


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## pieterv (Feb 3, 2009)

If you mean that it has 14.72V after a considerable time charging (the weeks you mentioned) than that is too high, should be below 14V as a trickle/maintenance charge.


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## Sargent (Feb 1, 2008)

Hi Mark, sorry for the delay in getting back to you, I have been away on business.
There are a few checks that can be carried out, before we can establish all is well or not?? would you send our technical people an email or give them a call and they will talk you through the simple checks.

Technical support 01482 678981, [email protected]

Best regards

Ian Sargent


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