Leisure battery woes.

IanC · May 5, 2015

Hi All,

My van is T4 westy.

I replaced the leisure battery in 2012 with, like for like, Sonnenschein sl135. The old battery was manageable but we had totally abused it and thought we would have more fun with a new one.

The new battery was totally brilliant.

Until last year, we went to Germany and stayed on a camp site with no plug in. It's fine we thought, the van will cut out the fridge when it goes down to 10.5 volts. It'll get a good charge on the way home.

The battery is dead. But I don't know why. We haven't treated it any worse than the last on, in fact loads better, always removing all domestic fuses when not in use. I've checked the chargers, I've checked it cuts the fridge at 10.5 volts, I've checked there is nothing sucking amps, I've checked the voltage readout on the display is accurate. I've charged the battery for 3 and a half days, and it doesn't hold charge.

I'm on the point of buying a new battery, but I don't want it to go the same way as this one.

All help appreciated.

TwentyOneThirtyFive · May 6, 2015

Do you generally rely on the split charge to charge the batteries, only using the charger (hook up) when on campsites?

I believe that charging via the split charge relay (ie, diverting the output of the alternator from the cranking battery to the leisure battery) is not the best way to charge and never really gives as good a charge as using a battery charger. Repeatedly not charging fully will affect the life of the batteries.

Also, discharging the battery that low will not help, they shouldn't be repeatedly be discharged that low. The fridge cuts out not to protect the battery, but because it knows at that voltage it doesn't have enough power to run.

If it isn't holding a charge (what voltage are you seeing after 3.5 days of charging? What happens when you apply a load?) then it is unfortunately time to replace it.

Maybe they don't make batteries like they used to... I replaced mine around 2012. Sadly the van hasn't been used since last September, so I don't know what condition the batteries are in (mine is the older version with 2x80ah), but it's been on hookup pretty much all that time to keep them fully charged.

welshwestie · May 7, 2015

Is the charger set up for GEL batteries? They need a particular charge cycle.

Is the charger actually putting a charge into the battery?
I have read accounts where dead batteries have been resurrected by long charges of 7 days or more.

TwentyOneThirtyFive · May 7, 2015

Westies came with Sonnenschein Gel batteries, so unless the charger has been replaced with something different it should be okay.

welshwestie · May 7, 2015

I was thinking the op may have removed the battery. If it was me, I would remove the battery and try another charger.

IanC · May 8, 2015

Thanks for input TwentyOneThirtyFive and welshwestie.

Apologies for slow response.

After 3.5 days charge, I get 13 volts or so, can't remember exactly, then switch fridge on and within an hour it has cut out.

I have replaced the battery. This time Exide, Sonnenscheins unavailable.

It seems to me, and from some blog somewhere, that the new sonnenscheins are not the same as the old sonnenscheins. So my present assumption is, that taking it down to less than 10.5 volts once, was terminal for this battery whereas it wasn't for the old battery.. There is nothing in the handbook that says you shouldn't do this. But it seems to me you shouldn't go below 12.5v.

I have read also that batteries can be brought back from the dead, so I will put the old one on charge for a week or two and see what happens.

Re: Split charging.

My understanding is that you cannot charge a battery 100% without charging from the mains, the reason being that it is set to prevent overcharging the battery.

Both chargers are working. I have tested with a voltmeter. The split charge relay is clicking in and out, just as it should. Incidentaly the voltmeter readout on the van display is spot on.

The only things I haven't checked are:

1) the amps that the chargers are putting in (I have an inkling the alternator may be on its way out.)
2) the temperature sensors linked to the battery charging, one in the battery compartment and one under the bumper.

but I'm off abroad today, so fingers crossed.

If I come up with anything useful I will post it on here for others who pass this way.

Thanks again for input.

sidepod · May 22, 2015

Earth shunt? Earth leakage? Is something draining the battery? Best to leave the van plugged into the mains when not in use. Gel batteries take a good long time to come up to full capacity.

As already mentioned, it may be worth checking the DIP switch settings on the rear of your control panel to make sure it's set for single/Sonnenchein.

Good luck.

Pod.