Leisure Battery - accidentally drained, what next?

[interbear]

Hi all - need some advice please. We have an Autohaus Ashton T6.1 camper conversion, 2022. Having not used the Webasto diesel heater for months, I did a quick test of it a couple of weeks ago. It worked fine. I turned on the main control panel before testing the heater as I assumed the leisure battery had to be on to power up the diesel heater. All good. Turned the heater off. Walked away happy. Realised today, 2 weeks later, that I forgot to turn the leisure battery control panel off I checked late tonight on realising my apparent error. The control panel is beeping. Nothing showing on the control panel display. I fear the leisure battery is completely drained as presumably the fridge has been on all that time. It’s relatively new as a battery and has a 100w solar panel feeding it too. So perhaps it’s not been drained for too long. I have a couple of questions:

1) Is it survivable? Any tips on how I can revive it? Currently planning to take it on a drive tomorrow to see if that kicks it into action.

2) If I need to replace it is that easy, as in can I do it or will I need a specialist to do it? And can I get a bigger battery or does it need to be the same capacity?

Thanks for any guidance. This is the battery it has:

- Control panel with split charger system 100amp AGM leisure battery.​

 

[kipperman]

1) Quite possibly - the fact that the control panel is beeping means the voltage isn't 0 and the fridge will almost certainly have shut off after a certain low voltage has been reached. It's not as if there has been a dead short across the terminals. Assuming you can, use the EHU to charge it or as you say go for a drive, although that probably isn't going to charge it fully unless you are out for a while. Once fully charged, I'd switch on the fridge over a day or so and check that battery capacity is still acceptable.
2) As long as you know where it is ( probably in the boot) replacement is generally straightforward and might be as simple as quick release terminal clips or marginally more complicated by undoing the nuts that clamp the connection to the terminals. Capacity wise can be bigger - but sometimes the leisure battery "hole" is quite small, so make sure your new battery physically fits.

 

[Pete C]

Do you have a way of accurately checking the battery voltage now, before you start to recharge it ?

Pete

 

[interbear]

Do you have a way of accurately checking the battery voltage now, before you start to recharge it ?

Pete

Unfortunately not. Relied on the control panel display for that and have no other tool to measure it.

 

[interbear]

1) Quite possibly - the fact that the control panel is beeping means the voltage isn't 0 and the fridge will almost certainly have shut off after a certain low voltage has been reached. It's not as if there has been a dead short across the terminals. Assuming you can, use the EHU to charge it or as you say go for a drive, although that probably isn't going to charge it fully unless you are out for a while. Once fully charged, I'd switch on the fridge over a day or so and check that battery capacity is still acceptable.
2) As long as you know where it is ( probably in the boot) replacement is generally straightforward and might be as simple as quick release terminal clips or marginally more complicated by undoing the nuts that clamp the connection to the terminals. Capacity wise can be bigger - but sometimes the leisure battery "hole" is quite small, so make sure your new battery physically fits.

Thanks, I’ll do exactly as you suggest in (1).

 

[Drive Wayne]

Get yourself a multimeter, pretty cheap, I would be keeping a close eye on that battery with camping season already upon us!

 

[interbear]

Currently I have it plugged it in via EHU using mains power from the house so fingers crossed it’s charging. I checked and everything is working as it should - fridge, lights etc - but I’ve turned them all off in the hope that the EHU power will be focused on recharging the leisure battery. Time will tell. If not then that’s an expensive error I’ve made as the battery will need replaced

 

[Wills]

In my experience the battery was under 9v. The Ablemail wouldn’t operate under that voltage so the solar was out too. Driving wasn’t effective or EHU so I charged / reconditioned the battery direct with a smart charger. That was 2 years ago and it’s still going strong.

 

[Dellmassive]

Get it charged asap.... As above the charger may not pickup the battery if the volts are too low...

 

[interbear]

Current status after being plugged in all day yesterday and overnight - the beeping stopped, the control panel revived. I switched off the mains hook up to check the battery status. It's showing as 100% charged at 13.3V. For now I have unplugged the EHU and left the fridge on to see how the battery copes with that. I'm hoping any impact is limited and it won't drain too quickly, especially if the sun comes out to boost it via the solar panel. Fingers crossed.

 

[roadtripper]

Remember not to let an AGM drop below 50% for it's long term health

If you have a voltmeter you trust that's around the 12.0 mark.

A lot of folks find the basic BM2 monitors really handy for logging and keeping an eye on battery health, a lot of battery health background and use of it in a thread myself and @wallport had over here:

Newbie battery charger questions

Hi all, I'm new to forum and to campervan ownership. We have bought a new T28 conversion and would like to understand the battery and charging setup. The items which depend on the battery in our van from the top of my head are: Fridge; Heater (its run off diesel but has a fan); Lights; Water...

www.t6forum.com

 

[interbear]

Remember not to let an AGM drop below 50% for it's long term health

If you have a voltmeter you trust that's around the 12.0 mark.

A lot of folks find the basic BM2 monitors really handy for logging and keeping an eye on battery health, a lot of battery health background and use of it in a thread myself and @wallport had over here:

Newbie battery charger questions

Hi all, I'm new to forum and to campervan ownership. We have bought a new T28 conversion and would like to understand the battery and charging setup. The items which depend on the battery in our van from the top of my head are: Fridge; Heater (its run off diesel but has a fan); Lights; Water...

www.t6forum.com

That's useful, thanks. It's an AGM leisure battery so being 100% and 13.3V currently suggests all may be well.

 

[Wills]

Current status after being plugged in all day yesterday and overnight - the beeping stopped, the control panel revived. I switched off the mains hook up to check the battery status. It's showing as 100% charged at 13.3V. For now I have unplugged the EHU and left the fridge on to see how the battery copes with that. I'm hoping any impact is limited and it won't drain too quickly, especially if the sun comes out to boost it via the solar panel. Fingers crossed.

Worth leaving it connected to the EHU as the smart charger I assume you have with the LB will cycle and condition the battery too.

 

[interbear]

Well my earlier optimism appears to have been dashed.

At 1pm today the battery was at 100% and 13.3V

I switched off the EHU and let the fridge run to see if it drained the battery quickly or not.

At 3:30pm today the battery was at 22% and 12V.

As it should really last 2-3 days - especially with a solar panel - I am reaching the conclusion that my user error will lead to me needing to invest in a new battery.

I've switched the EHU on again for now.

 

[TallPaul_S]

Well my earlier optimism appears to have been dashed.

At 1pm today the battery was at 100% and 13.3V

I switched off the EHU and let the fridge run to see if it drained the battery quickly or not.

At 3:30pm today the battery was at 22% and 12V.

As it should really last 2-3 days - especially with a solar panel - I am reaching the conclusion that my user error will lead to me needing to invest in a new battery.

I've switched the EHU on again for now.

Did you check the voltage with the fridge still running? It'll show a lower voltage if there's any load - turn off the fridge and leave for 20 mins then take a reading to get the correct state of charge. Is it your control panel that's saying "20%"? If so, is that going off a shunt on the battery (measuring all current going in and out) or via a battery BMS? As if it's neither, it may be relying on the voltage, which as above - any load and it'll show lower than it actually is.

 

[interbear]

Did you check the voltage with the fridge still running? It'll show a lower voltage if there's any load - turn off the fridge and leave for 20 mins then take a reading to get the correct state of charge. Is it your control panel that's saying "20%"? If so, is that going off a shunt on the battery (measuring all current going in and out) or via a battery BMS? As if it's neither, it may be relying on the voltage, which as above - any load and it'll show lower than it actually is.

Oh - thanks for that advice. I checked the voltage (on the control panel, the only method I have) with the fridge still running. I'll do another check with it off.

 

[roadtripper]

Seconded, if you want to estimate state of charge in a battery from the voltage (any kind) it must be at rest - so no charge and no load. It's best to give the battery a while to settle if it's just been on charge or under heavy load before measuring.

 

[interbear]

Seconded, if you want to estimate state of charge in a battery from the voltage (any kind) it must be at rest - so no charge and no load. It's best to give the battery a while to settle if it's just been on charge or under heavy load before measuring.

I'll get it back up to 100% tonight then check again after a rest with no charge / load as you suggest.

 

[kipperman]

Depending on how much you are off grid and how much angst you will suffer from constantly checking the voltage ( Believe me, it's a thing) you might want to just replace and be done with it. Probably what I would do if I was in any real doubt. You don't want your Krug getting warm in the middle of summer..

 

[interbear]

Depending on how much you are off grid and how much angst you will suffer from constantly checking the voltage ( Believe me, it's a thing) you might want to just replace and be done with it. Probably what I would do if I was in any real doubt. You don't want your Krug getting warm in the middle of summer..

Yep I’ll be doing that if I am in any doubt. Will either take it back to Autohaus or a local specialist to get a replacement fitted. Unless it’s easy enough for me to do myself - the battery is fitted under the driver seat.