UPS Batteries

[S3rategos]

hi there, thanks for a great forum, I have following from the sidelines for a long time, and only registered to post now.

 

My question is around UPS units and Batteries.

I have 2x 120AH Deep cycle batteries.

Due to the current load shedding woes, I am battling to find another 120AH , so that I can build a complete 48V system.

 

Could I use 2x100AH or 2x135AH batteries instead?

[Guest]

Hi @S3rategos - welcome.

Don't mix and match batteries no. All must be the same age and amp hours. 

Obviously you can do what you want, but in mixing different batteries, the bank's overall life is affected, the smaller batts taking the biggest strain.

[___]

5 hours ago, The Terrible Triplett said:

Obviously you can do what you want, but in mixing different batteries, the bank's overall life is affected, the smaller batts taking the biggest strain.

I was about to say the same. Will it work? Yes. Will it last? No.

[S3rategos]

ha ha ha

 

thanks guys, got it!

 

so I'll go with 120ah all the way then.

 

I'm hoping I use different OEM batteries as long as the AH are the same? (does discharge rate etc need to be considered?)

[Guest]

59 minutes ago, S3rategos said:

I'm hoping I use different OEM batteries as long as the AH are the same? (does discharge rate etc need to be considered?)

Again, you can do that, but the chances are the chemistry and values differ between the makes, affect one make more than the other.

Rules of thumb for lead acid based batteries:
1) Use same make / model.
2) All the batteries must be aged within 6 months or less.