Battery life

[Lyn and John]

Hi everyone Having slight trouble with our batteries. Even with full sun we are only topping 12.9. Van is 4 years old. Can anyone comment on the expectant life of the batteries and if they require replacing has anyone got the best supplier. Regards Lyn and John Mooney

[RussnSue]

G'day Lyn and John,

this is like the old "how long is a piece of string?" question.

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?

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 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.

Cheers

Russ

[gypsy2]

Hi Lyn and John, I think some of that FNQ sun on your panels would do the trick. :biggrin:

Talk soon, Rael & Sue