Posts: 2754
Location: Mauston, Wisconsin | I agree w/Shep. 0.08V isn't much drop in a 14 hr period. You probably have a cracked inter-cell weld inside of the battery. This can cause exactly the symptoms you describe- random dead battery syndrome- not able to start the boat motor. yet voltage looks OK. A little vibration is all it takes to make or break the connection. It may run the electronics just fine, then not start the motor. The battery in a boat can go through some pretty high shock levels in traveling to & from your fishing hole's, there are no shock absorber's on boat trailers.
Take the battery into a battery shop and ask them to do a cold cranking amps (CCA) test on the battery. Be sure to tell them you suspect a cracked inter-cell weld so they can take appropriate safety precautions. It could explode if it was recently recharged. If its a wet-cell they will probably remove the vent caps to allow any accumulated hydrogen gas to escape.
If that's not the problem, it could also be a intermittent fault in the wiring - much harder to find.
Good luck!
Al |
