House Batteries over heating and engine battery only 340 c amps

[psolie]

Put in a new set of batteries 1.5 years ago from Battery Systems Seattle. In the last 2 months both house batteries, 2 weeks apart ,over heated bad and were smoking and the engine battery had only 340 cranking amps. Went back and got a new set, I have the new ones installed, charged them for less than 1 hour and meter showed the top line flashing on the meter and on the charger display it read: 14.4A, 21V, so I turned off the charger.
If the charger is working OK what read outs should I see on the charger and meter? Or do you suspect a problem with the charger?
Also What does the remote switch do?
Is there a battery temperature sensor installed on my boat, 2016 R 23 OB?
Thanks in advance, Paul Solie

 

[Jared Dunning]

There is no battery temperature sensor installed on your 2016 R-23 OB.

A few things to check:

• What type of batteries did you install (AGM, Flooded, Gel, etc.)?
• Are all the battery and charger connections clean and tight?

If the battery type was changed—for example, from deep cycle to AGM—but the charger settings weren’t updated to match, this can cause overcharging, overheating, and ultimately damage to the batteries. The charger must be configured correctly for the specific battery type you're using.

Also, what brand and model of solar charger is installed on your boat? I’d recommend checking its output voltage. If the solar controller is faulty, it could be sending an overvoltage to the batteries, which can also cause overheating.

Regarding your readings—14.4 amps and 21 volts—that’s an unusually high voltage for a 12V system and could indicate a charger malfunction or misconfiguration. For a properly working 12V system with fully charged batteries, you should generally see:

• Around 13.2V–13.6V in float mode
• Up to 14.4V–14.6V during absorption (depending on battery type)
• No more than 14.6V for extended periods, and definitely not 21V

The remote switch is typically used to turn the inverter/charger system on or off remotely.
Based on your description, I’d strongly recommend:

1. Verifying the charger settings match the battery type.
2. Checking for any wiring issues, especially reversed polarity or crossed battery leads.
3. Testing both the AC charger and the solar controller for correct voltage output.