ORIGINAL: Popriv
ORIGINAL: psuguru
You really don't want to be trickle charging at above 70mA, once the battery is fully charged.
Lead acid batteries are finnicky animals. A good start would be to ask the supplier for charging recommendations.
Cyclic charging requires different characteristics in the charger to float (or trickle) charging for the best and most efficient battery charge and life-time.
There are motorcycle chargers that would do a really good job on any small battery; 'trouble is they are about $60.
Instructions are to charge with 12V 500mA charger for 10 hours.
I'm thinking I could use the .3 amp wallwart I have and charge for 13-14 hours????
I'm thinking: .5 amps = 10 hours so .25 amps would be 15 hours so the the .3 amp I have would be about 13 - 14 hours.
what I need to know is at what voltage should I stop charging this 12 volt battery?
Just trying to get the best life without buying another charger?
steve
I don't know the battery, so these are generic recommendations; I still advise obtaining charging information from the manufacturer.
The instructions are indicating an initial charge of 5.0AH, so at 0.3A you'd need a 16-17 hour charge
at constant current.
Do not, under any circumstances, allow the terminal voltage to rise above 14.4V, because all Lead Acid batteries will gas at that voltage. Hydrogen gas is explosive and I have seen a Panasonic 12V battery used in a Telecomm application blown out like a balloon! Acid release from a venting battery will destroy anything nearby and may cause personal injury.
For cyclic charging, I recommend a peak termination voltage of 13.8V and trickle or float charge at 13.2V
constant voltage. (at 25C. decrease by 13.2mV per degree C above this temperature )
Make sure the voltages you read are the actual voltages at the terminals and that your readings are not affected by voltage drops along leads and connectors.
The battery chargers in the post above are good stuff. I use the Optimate on my bikes.