How much is too much for lead acid?

[ed6269]

Hello
I am setting my system up to work on 2 -6 volt 232 ah interstate batteries after returning my Lion energy batteries to Costco the other day(long story) and I need to know if I need to lower the charging amperage from the outback SCC for the lead acid batteries that I am now using.
Before it was charging 700 watts at 40 amps for the Lion energy batteries, I am pretty sure that will boil the lead acid and I'm thinking of lowering the amperage of the SCC down to 25 amps , is that too much or can I go higher?
Any opinions appreciated
Thanks

 

[chrisski]

I would say check the spec sheet for a max charge rate and I bet you did and there is no spec sheet for max charging rate.

I had four Trojan solar 6 volt Batteries similar to what you got. My Spec sheet said charge no more than 1/8 the C20 rate. I might back that to 1/10 so 23 amps, but I would first check the 232 ah rate to be sure that is a 20 hour rate and not the 50 hour rate. I seem to remember the COSTCO batteries being 180 ah At 20 hours. I could easily be wrong.

 

[grizzzman]

The Costco CG2 I have are 208 AH at the 20 HR rate.

 

[acdoctor]

Most deep cycle FLA charge rate minimum 0.1 and max of 0.2 of C. If you are connected series to get 12 volts 232 AH would be max of 46 amps. I recommend using the battery specs though of specs from a very similar format. Water loss comes from charging at higher voltage through not amperage.

 

[ed6269]

Most deep cycle FLA charge rate minimum 0.1 and max of 0.2 of C. If you are connected series to get 12 volts 232 AH would be max of 46 amps. I recommend using the battery specs though of specs from a very similar format. Water loss comes from charging at higher voltage through not amperage.

So you are saying that because the batteries are the C20 rate which have a max amperage charge of 23 amps if they are hooked up in series that I will be able to double the amperage to 46 amps , correct?

 

[timselectric]

No
Voltage, adds up in a series connection.
Amperage, adds up in a parallel connection.

 

[ed6269]

No
Voltage, adds up in a series connection.
Amperage, adds up in a parallel connection.

Ok thanks

 

[sunshine_eggo]

Most deep cycle FLA charge rate minimum 0.1 and max of 0.2 of C.

Strong statement. If you had indicated AGM, I would agree. I own too many FLA with charge limits < 0.2C to agree (Trojan and Rolls).

If you are connected series to get 12 volts 232 AH would be max of 46 amps. I recommend using the battery specs though of specs from a very similar format

The exact battery manufacturer specs are the best recommendation. If you can't get them, 0.1C.

. Water loss comes from charging at higher voltage through not amperage.

Higher voltage is worse, BUT high current at the absorption voltage contributes significantly. Many 0.3C rated AGM/GEL batteries restrict that current rating to 13.8V max for that reason.

 

[ed6269]

Strong statement. If you had indicated AGM, I would agree. I own too many FLA with charge limits < 0.2C to agree (Trojan and Rolls).



The exact battery manufacturer specs are the best recommendation. If you can't get them, 0.1C.



Higher voltage is worse, BUT high current at the absorption voltage contributes significantly. Many 0.3C rated AGM/GEL batteries restrict that current rating to 13.8V max for that reason.

If I use a .1C rate as a default because I can't find the manufacturers charge rate what would you recommend for a amperage setting and voltage?

 

[sunshine_eggo]

If I use a .1C rate as a default because I can't find the manufacturers charge rate what would you recommend for a amperage setting and voltage?

0.1C is 10% of the C20 capacity, i.e., if you have a 100Ah battery, 0.1C is 10A.

 

[Wellbuilt]

I charge at 10% battery amp hours
So 23 amp or a little more
Maybe 13%
Start at 10% and watch your water
If you are not lousing water every month
You can go up .
I charge with more power when it’s cold
It’s hard to over change and damage
Flood battery’s .
Check water and feel for heat .
As they age they will use more water

 

[Wellbuilt]

I charge at 10% battery amp hours
So 23 amp or a little more
Maybe 13%
Start at 10% and watch your water
If you are not lousing water every month
You can go up .
I charge with more power when it’s cold
It’s hard to over change and damage
Flood battery’s .
Check water and feel for heat .
As they age they will use more water

 

[ed6269]

I charge at 10% battery amp hours
So 23 amp or a little more
Maybe 13%
Start at 10% and watch your water
If you are not lousing water every month
You can go up .
I charge with more power when it’s cold
It’s hard to over change and damage
Flood battery’s .
Check water and feel for heat .
As they age they will use more water

Oooh , thank you , I was looking at settling on 23 amps after all the input from others but this cinches it , 23 it is.