battery boiling

[greg@sierra]

battery boiling

I have a 1985 Merc 90 I-6. I have installed a new stator a new rectifier and a new battery. The original problem was rectifiers getting blown. I replaced the rectifier. But now I have a battery that is boiling. I have done the standard test on the rectifierwich tests closed one way and open the other. But the ohms readings seem awful high. I am reading 4.6 megohms. This is baffling me. Where should I turn to now.

 

[12Footer]

Re: battery boiling

Re: battery boiling

The rectifier tests ok.<br />Some old outboards are not equipped with a regulator from the factory, and are notoriously rough on batteries,sometimes, delivering 18VDC or higher. Yes, this will fry the battery. An old trick is to (other than retrofitting a regulator module from another outboard or ridin lawmower), is to discharge the battery by running all your accesories.<br /><br />Sometimes the motor HAS one, but it is cooked. Measure DC voltage at the battery. If it climbs-over 14VDC, chances are the regulator needs attention.

 

[ob1jeeper]

Re: battery boiling

Re: battery boiling

Ditto to 12 Footer's remarks... Either:<br /><br />A- Too much charge voltage and/or amperage from the charging system...<br />OR B- Possible internal short in the Battery<br /><br />If you are not using a Marine Battery, there is a higher risk possibility that the plates may be contacting each other during bouncing...<br /><br />FYI... Batteries made for "high vibration" service (like marine & agricultutral units) have the internal plates "anchored", and/or insulated/separated by "non-conductive" materials to prevent the opposite charge plates from touching, when the battery is being bounced... Another good reason to NOT simply try to get by with an automotive battery...<br /><br />I gotta believe there are voltage regulators available to fit the marine application you are working with... Check with your local marine dealer, and there are SEVERAL sites on the web to research as well...<br /><br />AND... Be sure to use a Marine battery...<br /><br />GOOD LUCK... Obiwan Jeeper