Another question on Sealed Lead Acid battery charging

 I have four 7 amp/hr batteries, two 10 amp/hr batteries, and two 36 amp/hr
batteries.

My 12v charger has 3 amperage selections - 2,10,20.

I've been using the 2 amp setting but I was wondering if it would be safe to
use the 10 amp setting if I hooked the like batteries together in parallel.
i.e. first the four 7 amp/hr, then the two 10 amp/hr, then the two 36 amp/hr
batts.

As you know, they ain't cheap and I'm not sure they can handle that kind of
pressure so I don't want to experiment.

 

parallel.

The 7.2Amp hr SLA battery I use has a max charge current of 2.1Amp. So I
would say that 10Amps is to much for your 4x7Amp hr or 2x10Amp hr batteries.
I think10Amps would be ok for the 36Amp hr but if the price of the 36amp hr
batteries in au is anything to go by($300!!!) I would be looking for another
charger. Maybe a couple of 1amp charges for the 7 and 10 Amp hr batteries.
Here you can get 12V 1 Amp automatic chargers for $25.... the 7.2Amp hr
batteries cost $30.

 

Thanks for your response and recommendation.  I guess I'll stick to the 2
amp setting for now.

I got a lucky break when I went to the aluminum recycling place and the guy
gave me those 2 36amp/hr batteries.  They were almost brand new and in great
shape.

Oh, if you took a look at my bank balance right now, you would understand
why I'm not running out to buy another charger :-)

 More important than the current is the voltage on a SLA battery. Look
at the manufacturers specs for float voltage. Typically around 13.6
volts. Put a digital volt meter across the battery after it is charged
and you should get a good idea if you are over charging or not.

wrote:

 There are two ratings that I could find.  Cycle us and standby use.  Cycle
use is up to 14.5 on the larger batteries and 14.9 on the small ones.
Standby is 13.6 and 13.8.  I've been charging them to 14.1.  I'm trusting
half a volt or less is probably not enough to cause damage.