Mixing AGM & Flooded Cell Starting Batteries???

[RickO]

I'm on the road and having some electrical trouble I've documented on another thread here. I'm currently in Albuquerque and the Freightliner Oasis shop has determined that I had a broken post on one of my new starting batteries... as well as a defective alternator.

I installed the new batteries (multi purpose deep cycle marine 840CCA) Friday night when the trouble began. I got them at WalMart since that was all that was open around me that night I and felt it would get me going and probably last me a year or so.

Apparently I overtightened the cheap screw on terminal and the threaded post was spinning in place so Freightliner told me it needed replacing. I'm now back in the CG with the coach waiting for the alternator to arrive tomorrow but I just went out and saw that they have installed an AGM dual purpose deep cycle Aliance battery.

I've always read that batteries should be matched upon installation and questioned the tech (before I knew it was an AGM). He said that when using a deep cycle battery in a starter application it didn't really matter and that since the other battery was brand new as well all would be fine.

Now I find that it is an AGM. I know that's overkill in a starting battery application... at least some folks think so... but can an AGM be paired with a flooded cell battery without damaging the AGM???

Thanks

Rick

[wa8yxm]

IS an AGM overkill.. I don't think so but it is over priced. The only way I'd use AGM's is if there is a mounting issue (IE: Have to lay 'em on their side) Since they do not requrie "This side up"

As for the cheap wall mart battery.. Odds are you could have saved it, several ways.

When it comes to matching batteries: The difference between AGM and Flooded wet is very tiny.. I do not *THINK* you will have much problem.. The big difference is you need to equlize flooded wet more often.. However, ... THat said. Driving also de-stratifies and that's the equalazition feature mose needed.

[RickO]

Thanks John. That's the info I was looking for. I know I could have saved the cheap battery with a different kind of terminal adapter but I'm at such a point of frustration that I'm not going to split hairs with these guys about the cost of the new battery. What I DON'T want is to kill the new AGM by dragging it down with the cheapo.

Rick

[RJay]

Rick,
My concern was if there was a difference between the charging and equalization voltages between the two different types of batteries. I did some checking and there are none so you should be good to go.