hi-all Could anyone tell me what to do with my car battery while the car is off the road for 6 months. Should I drain the battery with a small bulb and recharge at regular intervals. Or will the battery be ok if I do nothing? Its only a few months old and I dont want to ruin it. Thanks Jacko

In ascending order of usefulness:

1. Leave it in the car, disconnected. It will lose some charge and may get sulphated (not good).

2. Discharge and recharge (as you said) - better, but no need for a bulb, as it will discharge by itself anyway. Just charge it up with a decent charger every few weeks.

3. Charge it normally, then put a trickle charger on it (about £10 from Halfrauds). Slight risk of overcharging, but works for most people.

4. Get a posh charger that monitors the voltage and charges when it goes below a certain level (£30 - £40). These give a short charge a couple of times per day. Best option, but not cheap!

rgds,

David

A lead/acid battery shall be kept fully charged at all times for longest possible life time.
A self discharge is always present, so charge at intervalls during the winter (every 6 weeks or so).
Every dischagre "use up" some of the life time. The deeper discharge, the more of the life time wasted. Example: a 5% discharge is possible about 1000 times, while a 25% is possible about 250 times, before reaching a specific performance reduction. Valid for automotive batteries.

So for the best "winter rest" keep it fully charged and stored cool and dry since this minimizes the self discharge.
/Hasse

In the end I decided to buy one of these things:

Oxford Oximiser

I have just bought one - not received it yet so obviously not tried it, but I have seen many people praise it. Time will tell!

I could have built an equivalent (see Rob Lane's pictures for a construction article) but in the end I couldn't be bothered. I'll let you know how it works out...

rgds,

David