Monday, Jun 01, 2009 at 00:24
G'day Bonz,
here is a quote from a reply I did to a different
forum. The difference was that the batteries in question were in a caravan, so when you see the word "van", substitute "car".
"The variables are:
What type of battery are they?
What is the quality of manufacture?
What have they been used for?
Have they been on float charge while the van has been idle?
How deeply have they been discharged?
How often have they been deeply discharged?
Have they been charged at the correct rate?
Have they been charged to the correct voltage?
Have they been given a boost charge and if so, how often?
Have they exceeded 40 degrees celcius and how often?
I can't even help you with a rule of thumb life expectancy without knowing the anwers to many of the above.
As a guide, AGM batteries, looked after optimally, will last about 7000 charge/discharge cycles if discharged by no more than 20% of their rated capacity. (That is, 80% capacity left after discharge).
However, if discharged to 50% they will last only about 2000 charge/discharge cycles.
If they are discharged by 80% (virtually dead flat) you would be lucky to get 300 charge/discharge cycles.
Not leaving batteries (except AGM types) on float charge while the van is idle is another killer. The batteries get a condition called Sulphation and this can kill them very quickly.
I think four years is probably on the money if you are not familiar with the principles and techniques that can extend their life." end of quote
Bonz,I got my figures from a webpage that went quite deeply into battery life and battery maintenance. I've changed PC's since then and I'll have to dig up the link when I get some time. I'll post it when I do, it's very informative.
Cheers
Russ.
AnswerID:
367855