That's interesting Alex, the bit about van batteries not lasting, I didn't realise that. Did you wait for starting problems before renewing or do you test your battery anyway?
I'm running off my Hiace batteries which are probably five years old (2) so it would seem likely I'll have trouble any day soon.
Here is how the last three years have gone for me on batteries.
Feb 2009 - Bought a brand new T5 transporter with second 85Ah battery and uprated alternator. For first year was very lazy and just ran the system straight from the van's primary battery via the 12v outlet (used to be called a cigarette lighter!).
Feb 2010 - After almost exactly one year and after three hours work in the day I went to start the van and it would not start! Jump-started the van from its own second battery and wired the pump to the second battery and continued working this way. The primary battery recovered enough during the days driving to continue in use as the vehicles battery until now. Standard driving puts most batteries under very little strain.
Jan 2012 - Went to wire in a prototype flow controller and this alerted me to the fact that the battery was running at under voltage at about 11.4 volts. I had noticed the pump was a little slow, but as I do not usually use a flow controller it had not alerted me to the the issue. Replaced this second battery with the Elecsol 110AH battery and immediate noticed how much stronger the pump was again! Lets see how it goes from now on.
The most I have ever previously got from a leisure battery that was charged daily was 18 months and about 14 months when using just the vehicle battery.
In answer to your question - I am very lazy and always wait for a problem! However I do always carry at least one spare battery and a set of jump leads and spare coils of wire and connectors. I hate having to give up a days work for a simple issue like a dead battery.
