Can my OB be overcharging my batteries?

[nautihabits]

1992 250 hp Yamaha. Dual batteries. Starting (#1) and deep cycle (#2). Battery switch is off/1/both/2. Run boat on #1 only. Yamaha has second charging lead that is connected to #2 deep cycle for pumps, lights, gps, radio etc.
Batteries seem to be using alot of water and also heating up. Can the OB be overcharging these and what is the remedy. I see alot about ACR on posts would that help?
Also, should I have a breaker between the switch and the OB motor?
What is the best setup?

 

[bruceb58]

Re: Can my OB be overcharging my batteries?

What is the voltage at the battery measured with a hand held volt meter?

 

[nautihabits]

Re: Can my OB be overcharging my batteries?

Check that with OB running is suppose? What am I looking for? Would the rpm matter or should it charge at a constant voltage?

 

[Texasmark]

Re: Can my OB be overcharging my batteries?

When you charge them, the recharge rate can determine the temperature of the battery and whether or not you boil out water....the sulphuric acid electrolyte is supposed to stay in there. Additionally, if the recharge voltage is too high, the charger will continue to charge the battery and overcharging (at moderate charge rates) also boils the water out and heats the battery.

With alternators and voltage regulators, with a reasonably charged battery, being charged by the engine at around 1000 rpm's you should read around 14.5 volts (it has to be more than 12.75V to force current back into it and recharge). As rpm's increase it is the job of your regulator to maintain a reasonably constant voltage. If you are higher than that by more than .25 volts (Standard Temperature and Pressure) I'd be looking at a malfunctioning regulator.

You must have one or you wouldn't be doing what you are doing to your batteries.

Mark

 

[nautihabits]

Re: Can my OB be overcharging my batteries?

I will check the voltage and see if the regulator is failing me. Thank you.

Shouldn't go over 14.75 v.

 

[Boatist]

Re: Can my OB be overcharging my batteries?

I agree 13.8 to 14.8 normal.
Check at the battery with a good volt meter with the engine at 1000 rpms or more and everything off that you can turn off..
I like the regulator to be below 14.4 volts but even 13.8 is good unless you make short trips and need to charge the batteries fast.