Flat Battery

[carlton23]

I have a small battery charger which I purchased many moons ago and I would like to know how long does it take to fully charge a flat battery at 5amps.

[gingejbee]

Depends on capacity of the battery eg 40, 60, or 80 Amphr. So could be 8, 12 or 16 hours.

[jaydah]

my Halfords regular car battery charger takes all night

[AlBags]

That's no good .. There are too many factors to calculate ..
Temperature ...
Antimony chemical balance quality and age
How discharged it actually is (SG)

If dead flat .. take off and put in the warm.
At 5A input it would take overnight.
If you can boost charge it a little first (no more than 25A) much shorter time. Do not put a flat battery on immediate high output boost charge .. It will damage the plates.

[razza]

Yes quite a while,some battery chargers have a booster setting which tends to damage battery in time,best to let it trickle charge overnight.

[carlton23]

My thanks to all, I let mine charge @ full charge overnight and about four hours also on trickle, so I`ve probably knackered it now, what do you think?

[razza]

No it should be ok,its if you use full charge every time.

[AlBags]

No .. That should be ok .. IF the battery cells are ok.
You can tell a lot if you use a Hydrometer and measure SG of the cells. Also a discharge tester (load type) will test output capability.

[carlton23]

Ta much chaps.