Battery Charger Assumptions

Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
This will be simple.

I "assume" when a battery charger has three banks, and the charger is rated at 20 amps, that 20 amps is shared between the three banks, like 5/5/10. Would that be a safe assumption?

The reason I ask is Pro Mariner does not state that while other chargers do make that statement.
 
Sep 15, 2009
6,244
S2 9.2a Fairhope Al
my sterling is 40 amps when hooked up from one outlet but it loses that forty amps when split between the other two outlets in other words it divides the power between all three
 
Feb 6, 1998
11,759
Canadian Sailcraft 36T Casco Bay, ME
This will be simple.

I "assume" when a battery charger has three banks, and the charger is rated at 20 amps, that 20 amps is shared between the three banks, like 5/5/10. Would that be a safe assumption?

The reason I ask is Pro Mariner does not state that while other chargers do make that statement.
I would not advise any charger that divides your output two or three ways. The ProMariner chargers use a distributed by demand output. If the house bank needs 19A and the start will only take 1A then 19A will flow to house and 1A to start..
 
Jan 22, 2008
1,700
Hunter 34 Alameda CA
You are correct in the fact that the manual on my Xantrex 20 charger says "the total current into the batteries is a maximum of 20 amperes which is divided amongst the batteries according to their state of discharge." I don't know about your particular model, but it could be managed by connecting them all together (jumpering) to a single output and feeding a single bank, followed by charging additional batteries (same type only) via an ACR. That would at least balance out the loads on each individual output and not risk any one from overloading if that is possible on your particular charger.
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
I am in the market for a new charger. My Xantrex corroded and failed. That was several years ago and I have not put a new one in yet. I do have a Guest on my starter batteries. It is a Guest 16102, but I want to replace that and get something a little bigger. The Guest has two banks, 12 amps at 6/6.

With Maine's comments, I guest that is why there is not mention in the Pro Mariners Protech 1220i manual of shared current between the two banks.

Yes, I did see that one can strap the banks together for a single battery. I will keep that and the ACR in mind.

Thanks
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
So basically the battery bank SOC determines the amp flow and none of the advertisements to the contrary are going to change that. Physics still applies
 
Feb 6, 1998
11,759
Canadian Sailcraft 36T Casco Bay, ME
The Guest has two banks, 12 amps at 6/6.
This is a very, very cheap way of building a charger and you really get ripped off paying for a 12A charger because your second bank, usually a starting battery, is taking 0.5A or less and you are wasting the other 5.5A.... Witha distributed by demand charger none of the current you paid for is being wasted when it can be used.