Monday, Sep 12, 2011 at 10:44
Hi Craig
RE:"When installing batteries together in the one circuit it is ideal to have the same size, age & type to avoid one taking more charge than the other or a failing battery dragging the other down. This can be demonstrated particually with 24 volt systems on trucks where one batt drops a cell so you replace that one only to have the other fail a month later. end quote }
IN parallel:
Type can be more critical IF they have different charging requirements
such as max charge voltage or float voltage.
SIZE is not critical
Age can be a problem if the older battery has high internal leakage but this can developin relateively new batteries too
This will slowly pull both batteries down to the level of the faulty one
But unless left to continue long term will be unlikely to do any permanent damage to thev newer one
Peter's [of BW]suggestion of a regular check should find this problem & this SHOULD be done if battery capacity does not seem to be normal
Batteries in series :
Type & size is important as different types/sizes will charge @ different rates to a different % of charge
One can easily be over charged while the other may be left undercharged,
which also means one can be overdischarged
Age & resultant loss in capacity can cause similar effects to different sizes
If one developes a shorted cell the other will be overcharged
Overcharging can kill the good battery fast
Peter
FollowupID:
738757