Same battery type with ACR?

[Berndahle]

I'm planning on running my two 4D AGM batteries in parallel as my house bank on switch #1 and adding a backup battery (Group 24) on switch #2. If I use an ACR to combine the two for charging the backup, does the backup battery also need to be AGM or can I go with something cheaper?

 

[Maine Sail]

I'm planning on running my two 4D AGM batteries in parallel as my house bank on switch #1 and adding a backup battery (Group 24) on switch #2. If I use an ACR to combine the two for charging the backup, does the backup battery also need to be AGM or can I go with something cheaper?

You should stick with the same battery type with an ACR. All an ACR does is basically a "BOTH" or "ALL" feature on a 1/2/BOTH/OFF switch.

AGM's accept current very differently than do wet cells and they should also have a slightly different charge voltage profile therefore not a good idea to mix. If you want to mix battery types across banks then an Echo Charger or Duo Charger is what you'll want to use as they never actually combine the batteries.. The Duo Charger would be the better choice because it can output a different voltage than it sees coming into it..

 

[Bill Roosa]

Mixing batteries

While I agree with mainsail that you can mix the batteries if you use the right charger, ask yourself how are you going to charge them when away from the dock?
If you have 2 alternators then you are set, just connect one to each bank and totally isolate each alt-bank via a switch. I'd not go for a 3 way as combining mixed types will cause problems with the different voltages.

 

[Maine Sail]

While I agree with mainsail that you can mix the batteries if you use the right charger, ask yourself how are you going to charge them when away from the dock?
If you have 2 alternators then you are set, just connect one to each bank and totally isolate each alt-bank via a switch. I'd not go for a 3 way as combining mixed types will cause problems with the different voltages.

Bill,

The Echo Charger and Duo Charger are made for charging when away from the dock via the alternator and also made for use with a dockside charger as well. I still think he should have all of one type or the other though when it comes to batteries.