Mismatched batteries?

[willp2]

Hello. I have a 12v dual battery setup with an A/B/ALL switch. I need to replace one of my lead acid batteries and I?d like to upgrade to an AGM battery for the new battery and keep the newest lead acid battery as the second unit.

I?ve read and heard that you should not mix battery types like that. But the only time I ever use the ALL switch setting is as a last resort start up, which has only happened a couple of times and will probably happen even less with the new AGM battery. So does it really matter that they are mismatched? And if so what is going to happen when I do run them together?

Eventually I?ll have them matched, but for the time being I?d really like to avoid spending the money.

Thanks!

 

[drewpster]

Re: Mismatched batteries?

AGM or Absorbed Glass Mat batteries typically function the same as wet cell batteries. So mixing an AGM with a conventional wet cell battery should not give you any problems. AGM batteries normally store better and last longer than wet cells by design. The charging profiles are generally the same.

Where you could come into a problem is if you parallel a new battery with an old sulfated battery. Given that two paralleled batteries become one bigger battery, the sulfated cells of the older battery will adversely effect the performance of the combined battery bank.

If you leave the two batteries "un-paralleled" for the majority of time and you recharge both of them in a timely fashion you should be fine until you get another AGM. I have been saving my pennies for a set myself.

Mixing Gel cell batteries with AGM or conventional wet cell batteries is where you can run into real problems as the Gel cell will have a completely different charging profile than an AGM or a Wet cell.

 

[willp2]

Re: Mismatched batteries?

That's the answer I was looking for. I think I'll be picking up a new battery for the weekend.

Thanks for the very fast reply!