1995 272 Sailfish Overcharging

[fellinger]

I recently replaced a bad house battery (3 battery system w/switches) on my 1995 272 Sailfish with 200hp Johnsons. It now appears I am overcharging. The battery I replaced it with is not the exact as the battery that was previously there. I have done some reading and it looks like some charging systems don't work well with maint free batteries. I can't find specifics on what should be installed on this boat.

Any ideas as to the problem or specific batteries that should be used?

Thanks!

 

[DennisG01]

What brand/model charger is on your boat? Forget about looking online or for specs/etc. Physically find/look at the charger. Often times charger can be have different settings for different types of batteries - but that's something like gel vs wet cell, not maintenance free wet cell vs a wet cell where you add distilled water once in a while. What type (size, style, group, etc) battery do you currently have and what is the new one? Have you checked the voltage at each battery while the engine is running? Is it the same? It's possible that while changing the battery some wires got crossed and possibly the engine's charging system got damaged. If you look in the service manual for your engine's, there should be test procedures for the different components.

 

[seasick]

Are you saying that the motor is overcharging or is it a charger that is overcharging.
Either way, why do you think overcharging is happening? Without measuring voltage, the only sign of overcharging would be cell boiling and you don't see that usually until the battery has been damaged.
The fact that a battery is sealed should not be an issue but the type of battery. AMG or standard lead acid might be.
If batteries are wired in parallel, then they should both be the same brand, type, size and age.

If the batteries you have are all the same type, and if connected one at a time they still overcharge, either the regulator or rectifier on the motor may have a problem

 

[fellinger]

Are you saying that the motor is overcharging or is it a charger that is overcharging.
Either way, why do you think overcharging is happening? Without measuring voltage, the only sign of overcharging would be cell boiling and you don't see that usually until the battery has been damaged.
The fact that a battery is sealed should not be an issue but the type of battery. AMG or standard lead acid might be.
If batteries are wired in parallel, then they should both be the same brand, type, size and age.

If the batteries you have are all the same type, and if connected one at a time they still overcharge, either the regulator or rectifier on the motor may have a problem

I know it is overcharging because while running both engine voltmeters read 15v - 16v. My GPS also displays voltage and it reads 15. At idle it is about 13 on the GPS. I did not notice what it was on the engine voltmeters at idle.

 

[seasick]

Are you saying that the motor is overcharging or is it a charger that is overcharging.
Either way, why do you think overcharging is happening? Without measuring voltage, the only sign of overcharging would be cell boiling and you don't see that usually until the battery has been damaged.
The fact that a battery is sealed should not be an issue but the type of battery. AMG or standard lead acid might be.
If batteries are wired in parallel, then they should both be the same brand, type, size and age.

If the batteries you have are all the same type, and if connected one at a time they still overcharge, either the regulator or rectifier on the motor may have a problem

I know it is overcharging because while running both engine voltmeters read 15v - 16v. My GPS also displays voltage and it reads 15. At idle it is about 13 on the GPS. I did not notice what it was on the engine voltmeters at idle.

If that voltage is correct, your regulator/rectifier is probably shot.
Switch off one engine at a time to see if the symptom is the same for both motors. Normally, I would not expect that to be the case. One will usually die first.
If both are bad, you need to see if you can find out why before replacing them. A bad charger could be to blame I guess and switching the battery switch from bat 1 to bat 2 by passing OFF with the motors running has been known also fry some inverters/regulators.
FYI, if you are really pushing 15+ volts, you could boil the electrolyte and kill your batteries.