Charging Problem

[Clutch87]

I've got a 1963 17 ft Starcraft with a 75hp Johnson outboard. My question to anyone who might know, is that it doesn't charge, only discharges. I have checked all the connections and fuses. I bought the boat from my son-in-law and wasn't sure if he had connected the batteries back up right but they look fine. everything worked before he got it from his dad. Would appreciate any help on the subject, Thanks

 

[dkondelik]

Re: Charging Problem

first, let's confirm your daignosis. use a voltmeter, read battery voltage with the motor turned off. should read at about 12.8V. Now start the motor and re-read battery voltage. should read a good volt higher then when the motor wasn't running. This delta in the battery readings will let you know if you're charging.<br />we'll go from there.

 

[Clutch87]

Re: Charging Problem

OK The battery reads 12.89v with engine off and with engine running will start dropping. Got down to 10.23v when I shut it off then started coming back up.

 

[NathanY]

Re: Charging Problem

Sounds like you are pulling an excessive load somewhere. I dont know anything about those old Johnsons, but if it has a rectifier, I would check that.

 

[Clutch87]

Re: Charging Problem

Nathan, <br />I really appreciate the response. Thanks I will check that out.

 

[Yepblaze]

Re: Charging Problem

Also sounds like you may have drained the battery pretty well. The battery may not have enough capacity and might be about time for replacement.<br /><br />Not all the older motors even had a charging system. Many had the battery for starting but required it be charged at home from a battery charger.<br /><br />Perhaps if you look under the hood and see a belt driven generator, you can assume it does have a charging system.<br /><br />Next if it has a generator, it should also have a regulator/ relay box. Perhaps the regulator or wiring might be suspect.<br /><br />But like I said many older motors had no charging system and a good quality marine starting battery should last you a couple of days of boating before recharging. Don't run the battery too low as it can be detremental to it'ds ability to take a charge afterwards.