Charging an 800cca car battery

jbee55, Apr 24, 1:20am
hello,

have tried to use jumper cables to start it but it wouldnt work.

Have tried both a small car and a larger S500 as the "live" car to jump it from, but neither worked.

Have now taken the battery out and am using a 4 AMPS RMS charger on it, can anyone tell me if this is sufficient to charge it! It's been on charge for over 8 hrs so far and is still not indicating a full charge.

dyln.sampson, Apr 24, 1:23am
Check that the fluid inside the battery is just above the grill. U will see. If u have charged it for that long and haven't had any change. Then it's time for a new one

motorboy2011, Apr 24, 1:24am
it will charge it, eventually. give it another car or so.

dyln.sampson, Apr 24, 1:27am
Don't charge it through the car though. Use ur charger have it on 12volt and on minimal charge and leave it for a day

jbee55, Apr 24, 1:29am
it appears to be a maintenance free battery! i can't open it at the top.

jbee55, Apr 24, 1:29am
it appears to be a maintenance free battery! i can't open it at the top.

thank you both for your reply. i will leave it for another day and see what happens.

gmphil, Apr 24, 1:34am
a good battery with charger that size will take 24 hours to charge

n1smo_gtir, Apr 24, 1:36am
take it to a battery testing place if you still get no luck.

tmenz, Apr 24, 1:47am
An 800CCA battery will be about 90~100 ampere/hours.
If you charge it at 4 amps continuously, it will take around 30~35 hours to reach full charge from dead flat. (100/4 = 25 plus charging losses of about 10% for a good battery).
However, the el-cheapo battery chargers (Arlec etc.) do not charge at a constant 4 amps - they will manage 4 amps when the battery is flat but they taper off rapidly as the battery voltage comes up towards 12 and taper right off as the float voltage of 13.8~14.4 is reached.
The average charge current will more like 1/2~1 amp, which will mean a full charge time of something like 120~240 hours for a completely flat 100 amp/hour battery.
For a partially charged battery you can probably reckon on at least 2~3 days!

martin11, Apr 24, 1:51am
If it was dead flat its probably sulfated

tmenz, Apr 24, 2:34am
Quite right - if it's flattened completely, it has to be charged immediately or it's toast!
If the discharge is stopped at an acceptable end-point (about 1.7 volts per cell) then there shouldn't be any sulphating if it's recharged immediately.
If, however, it's allowed to over-discharge( to 1 volt per cell or less) then it will almost certainly not recover fully.

pup2, Apr 24, 6:45am
custy came in with a battery last week. Had -0.2volts in it (yes neg volts). He picked it up today. Has 400cca and 12.6v (Been sitting for 4 days after charging). Done quite a few like this now, must be due for a fail soon

kingfisher21, Apr 24, 8:09am
If it's a "maintanence free" battery, ie sealed top, it's more than likely a calcium battery and a normal charger won't charge it properly.

scuba, Apr 24, 11:23am
I've recharged my battery from dead flat a number of times - no problem.
just takes a bit longer.

snoopy221, Apr 24, 2:12pm
you can probably reckon on at least 2~3 days
Yip 800 CCA AND UNKOWN 4 Amp chrga.
give er a coupla days 4 sure.
Look at the numbers 800 (BIG ONE) 4 amps-(little one)-K

74nova, Apr 24, 10:10pm
If the car wont start after jumping off another car there must be something else wrong. Also If your battery is flat i'd take it to an auto sparky and get them to LOAD test the battery.