Leisure battery slow discharge under load, then recharge!

[cubensis]

Hello all, we have a 65ah leisure battery in our t25. It's been registering as empty a few times on the Zig unit after a short amount of use. I put a meter on it and got a reading of 12.01v (Is this a little low? I think it should read more like 12.7v?) I then kept the meter on and switched a light on. The battery slowly discharged below 11V, I then turned the light off and the battery started to recover back up to 12v again.

So my main question is; is this normal? I understand the load of the light should offset the voltage of the battery but the slow coundown of voltage seemed unusual and then the slow recovery back upto 12v.

Any advice would be great, cheers.

[lloydy]

they do recover after a load has been put on them. But 12.01 is pretty flat, sounds like new battery time or at least check your charging system is working correctly. What voltage is the battery when the engine is running?

[cubensis]

Hi, thanks for your reply. I have it disconnected from everything on trickle charge via a solar panel and it's currently reading 12.49 after 3 days in the glorious sun.

I haven't checked the voltage directly after the engine charged it but i'm thinking the battery is going to max out at around 12.5 volts.

Does this sound low to you?

Thank for your reply

[ghost123uk]

Check your charging circuit. With the engine running you should see between 13.6 and 14 Volts on the leisure battery. Any less and summat is not right.

What rating of solar panel have you got ? Unless it is one of those useless little ones your battery should be well charged and reading at least 12.8 after 3 days in sunny conditions.

My bet is on the battery being foobarred. (has it ever been allowed to go flat ?)

[kevtherev]

Don't flog a dead horse... it is no more

[cubensis]

Hello all, thanks for the advice, yes it's been allowed to go flat during the winters for about 5 years. It's something I know I should have not done but didn't get round to sorting anything over the winters.

i've just been out now and checked the leisure disconnected from anything other than the solar panel (it is just a small crappy one but it's giving of 10 - 15 v consistently) and the battery is now showing 12.2 v, it was showing 12.49 a few days ago.

I've just checked with the engine running and the split charge is giving 14.8 v to the leisure battery so no issue there, unless this is a little to high? I replaced all the connections coming from the alternator a while back so it's probably a very clean / efficient supply.

It's sounding like i'll be getting a new one if you lot agree?

[ghost123uk]

Yes, get a new one. See http://wiki.club8090.co.uk/index.php/Ca ... s_that_fit" onclick="window.open(this.href);return false;

Also that solar panel does not appear top be doing much. Those small ones have been discussed on here recently. They are often next to useless I am afraid.

And when you get your new battery, don't let it drop below 11.5 Volts as this damages them.

[cubensis]

Thanks to all for your advice, I have my new battery ordered, I won't let it got below 11.5v

If i was to install a decent solar panel and fix it to the roof would it be okay to charge the van battery and the leisure battery of it? I'm guessing it'd be best to do this in parallel rather than series?

Thanks again.

[ghost123uk]

Most definitely parallel !!!!!!!!!!!!!!!!!!!

Mind you, I would not recommend you do this. Reason = if your leisure battery is low, it will sap power from your main battery = not a good thing. Plus, why would you need to charge your main battery ? (unless stored unused for long periods, in which case bet to take it off and charge it at home once a month).

If fitting a decent panel to the roof, you will need a solar panel charge controller. There are some around (and have been mentioned on here) that have a low voltage cut off system, to prevent your leisure battery going too flat

[cubensis]

Most definitely parallel !!!!!!!!!!!!!!!!!!!

Mind you, I would not recommend you do this. Reason = if your leisure battery is low, it will sap power from your main battery = not a good thing. Plus, why would you need to charge your main battery ? (unless stored unused for long periods, in which case bet to take it off and charge it at home once a month).

If fitting a decent panel to the roof, you will need a solar panel charge controller. There are some around (and have been mentioned on here) that have a low voltage cut off system, to prevent your leisure battery going too flat

Nice, i'll look into that. The reason for the solar panel is because we use the van once a month / 2 month and it'd be good to keep the batteries trickle charged. I'll be taking them out for winter and using a plug in trickle charger, maybe that will do to be honest.

Thanks.