Battery Charge time ?

6 replies [Last post]
silentguy
Offline
Joined: 05/27/2008
Points: 209

If the info. is in a FAQ somewhere please point me to it.

General charging question.

If I have a 12 volt 4.5 Ah SLA,
what is the charge time,
if I have a 12 volt 6 Amp charger ?

Is charging 1 hour enough ?

Thanks

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
fisher727
Offline
Joined: 06/26/2007
Points: 85
Re: Battery Charge time ?

If you try to charge your 4.5 amp battery with a 6 amp charger you will find that the battery will only accept maybe 3 amps if the battery is at 50% and taper off as the charge is nearing 100%. The charge time maybe about 3 hours or more for a full charge. That is based on your 6 amp charger and the battery at 50% discharge.

Eric Fisher
www.SiliconeBatteriesUSA.com

silentguy
Offline
Joined: 05/27/2008
Points: 209
Re: Battery Charge time ?

Thanks for the reply.

So is there any risk of overcharging a SLA ?

If I set the 12 Volt 4.5 Ah battery up on a timer for say 6 hours is that OK ?

Or should I be doing some calculations for the optimum charge time.

Unfortunately I only have a regular battery charger and a timer,
so I dont have a smart charger.

fisher727
Offline
Joined: 06/26/2007
Points: 85
Re: Battery Charge time ?

As long as the battery charger does not exceed 14.4 volts during charging,it will work fine. If you exceed 14.4 volts you could damage the battery because the boiling point on a gel cell is about 14.4 volts at room temperature. When the amp meter drops to almost zero the battery will be charged.

Eric Fisher
www.SiliconeBatteriesUSA.com

andrew
andrew's picture
Offline
Joined: 11/28/2006
Points: 1361
Re: Battery Charge time ?

Can you give us a better idea of the charger? By "regular" charger, do you mean just a transformer based power supply?

I would just get a smart charger. You are very likely to damage the batteries very quickly. To charge the batteries properly, you need a CV charger that holds the voltage constant. A constant current (CC) transformer power supply is really only suitable for a flooded battery, unless it is a very low current for charging a sealed battery, in which case it would take a long time to charge, and there is risk of damaging the battery if you don't take the charger off. I would go a maximum of .05CA, or .225 amps for your 4.5ah batteries. That 6 amp charger is not suitable at all unless you want your batteries to bulge up nice and big or explode. You would have to take the charger off long before the batteries are full charged to prevent the voltage going over 14.7v, and this would result in severely undercharging them.

Just buy a smart charger, and when or if you switch to another chemistry then sell it. It'll be much less of a headache and save the batteries.

dogman
dogman's picture
Offline
Joined: 04/29/2008
Points: 830
Re: Battery Charge time ?

Should be, but it will be kinda hard on it, charging so small a battery with a chager that big. a 1 amp for 5 hours would be better.

__________________

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

silentguy
Offline
Joined: 05/27/2008
Points: 209
Re: Battery Charge time ?

The charger I have is for a car or motorcycle battery.
It has 6volts/12volts and 6Amps.

The reason I am using it is to try and charge up 1 12volt battery,
that has gone out of synch,
out of a series of 2 or 3 batteries.

I have a 24volt 1Amp charger, and a 36 volt 2amp charger.

Thanks for everyones advice,
I ended buying a 12 volt 1 Amp battery charger off ebay,
as I was concerned about overcharging with the car battery charger.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Short URL

Customize This