On Mon, 24 Dec 2012 13:02:57 -0800 (PST),
andrew_...@yahoo.com
wrote:
>I have a 12 Volt battery, 9.5 Ah that uses a 12 volt charger 1.0 amp.
I'll assume that it's an SLA (sealed lead acid) or AGM (Absorbed Glass
Mat) battery. Makers and model numbers are a good thing to disclose.
>Assuming the battery is completely discharged, is there a way to determine how long to charge ?
Yep. Math.
Incidentally, if your battery is completely discharged (i.e. zero
volts), it's probably dead.
A new lead acid battery has a Coulombic Efficiency of about 75%. That
means for every amp you feed the battery, only 75% of it stays in the
battery.
12v * 9.5 Amp-Hr / 0.75 = 152 watt-hrs
will be needed to recharge the battery. If your charger actually
delivers 1 amp, it will take:
152 watt-hrs / (12v * 1 amp) = 13 hrs
This is under ideal and simplified circumstances. Coulombic charge
efficiency varies from 50% to 98% depending on battery type and age.
Your battery may not be completely discharged. Your 12v 1A charger
(maker and model please?) may be capable of delivering a 1 Amp
maximum, but will probably deliver much less while charging. SLA
batteries just hate going over their rated maximum voltage. So, it's
likely that the charger is set to a conservative voltage, that may not
fully charge the battery. The charge current is also not constant
over the entire charge cycle. Lots of variables, potential errors,
and guesswork here.
My wild guess(tm) is about 8-10 hours will be about right. Better to
undercharge than to go over. I can make a more accurate guess(tm)
when you find the makers and model numbers.
--
Jeff Liebermann
je...@cruzio.com
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS
831-336-2558