Battery setup question

M

Matt R

New Member
Jul 22, 2008
25
Indiana
I'm working out some electrical gremlins on our new to us 2000 240DA. I've figured out that in order for either of the batteries to charge with the engine running or on shore power is to have the switch on BOTH. For example, if battery 1 is low, it won't charge if the switch is on 1; must be on BOTH. Does this sound right?

The other symptom of something not quite right is the refridgerator cuts out when the battery charge drops slightly. Still plenty of power to run the radio, start the engine, etc., just not running the fridge. If the engine is running slightly above idle (producing about 14+volts) or the shore power has been plugged in for a while, the fridge kicks on and will run the fridge for a couple hours after shutting off.

These are group 24 AGM batteries, new this season, pulled out of my old boat.

I'm not sure the batteries are hooked up properly. I'd really like to have the fridge running for at least 8 hours or so on the hook without starting every couple hours to charge the batteries; anyone have any thoughts?
 
The battery charger should have "independant" outputs. Two for a smaller charger, three for larger chargers.

On low cost chargers, these are "independant" by using diodes to isolate the output. But, many of these low end chargers have only one smart circuit.

It sounds like the multiple outputs in your charger are not properly connected.

Each battery bank should be connected to its own "independant" charger output. That would permit proper charging, regardless of selector switch setting.
 
I was thinking something isn't connected properly. Could this cause the fridge to shut off before the battery is further drained?
 
The engine charging circuit makes sense. It will charged based on what the switch is pointing at. Some people charge both, some people charge 1 and then switch to 2, etc.

It doesn't sounds like your shorepower charger is wired right? It should charge both batteries regardless of switch position? I'd follow those leads and assuming it is a two bank charger, you should see one lead to each positive post on the batteries. They may share a common ground, but something isn't right. And yes, you should be able to run more than 8 hours. I just bought new batteries (can't remember if they were group24's or 27!) and I easily get 24 hours before switching to the other battery. I could probably go longer but usually just switch them on Saturday night. That's running everything.
 
Matt

Do you know the actual voltage when your fridge stops running? I recently replaced my two year old Cranking batteries because they would not hold a high enough charge long enough on the hook. After an hour or two they would drop into the 10-11 volt range with the stereo and fridge running. But as far as I know the fridge didn't shut off.

Dave
 
Dave S said:
Matt

Do you know the actual voltage when your fridge stops running? I recently replaced my two year old Cranking batteries because they would not hold a high enough charge long enough on the hook. After an hour or two they would drop into the 10-11 volt range with the stereo and fridge running. But as far as I know the fridge didn't shut off.

Dave
Click to expand...

No, not sure exactly...I'm bringing a meter next time to find out actual voltage. I know that when the fridge cuts out, the battery still has enough juice to start the engine. If I run the engine at 1500rpm+ or plug into shore power for a while, the fridge will come back on. Dunno.
 
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