battery charge question

[raggie33]

battery charge question

i have a 12 volt 4.5 ah/20hour battery its lead acid how long will it take to charge with a 12 volt 1 amp charger? please help im new to this i dont want to kill battery

 

[Brock]

Re: battery charge question

Technically it would take 4.5 hours from almost dead. That is a pretty fast charge rate for a battery though. I would suggest 500mA or .5 amp for about 8-10 hours. If the battery were sealed I would charge it at even a lower rate for longer.

 

[raggie33]

Re: battery charge question

kewl ty sir.

 

[Floating Spots]

Re: battery charge question

If its a battery tender that automatically floats the battery, you shouldn't have any trouble. Thats not a horrible rate.
Most don't put out that much power at the top end anyways.
The problem comes when the charge should terminate.
If the charger doesn't turn off, you can "boil" the water right out of the battery.
So if its a dumb charger, just put a resistor in series to cut the current.
If its smart (has a charging light) it won't cook the cell much at all....

 

[BatteryCharger]

Re: battery charge question

Most lead acids require 110% of the amp hours used, put back in to fully charge.

 

[raggie33]

Re: battery charge question

whats the max volts i can use?

 

[RussH]

Re: battery charge question

Most manufaturers recommend 13.6-13.9v for float charge. They allow about 14.4v for a faster charge, usually with a current limit. Take a look at what Panasonic recommends:
http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_VRLA_ChargingMethods.pdf