boats with 24 volt sytems

Well I learned something the hard way yesterday and am sharing it in case others don't know. My common rail electronic motors were balking intermittently at starting with an error code EXTERNAL LOCK OUT SWITCHING ISSUE. The first suggested culprit was the Fireboy system which eventually checked out Ok about $170. The next suggested culprit the glenndinnig SX cost not yet known. That checked out OK. Some where along the way I jumped my house and starter bank and zap both engines start no lock out. So with this information techs scratching their heads call in the company marine electrician. Electrician comes to boat with a sophisticated battery tester and I now own similar. Electrician dis-connects the two 12V starter batteries and measures each separately. Walla one has terrible test results particularly under load with very little CCA. and is pulling the other down with it. While they were connected the voltage was not great but borderline and this was confusing the previous none electrician techs by intermittently making the problem. Moral of story if 24 volt SX has problem check each 12 volt battery. Sounds simple dos't it so why did it stump 5 tech visits from firms with excellent reputations?

1. ALWAYS go for the simplest thing first
2. Its usually electrical

Glad you're sorted!

Shouldnt have confused the techs....a 12V system has the same probkem. Proper voltage showing but not able to put out enough cranking amps. Thays why load testers are used all the time.

Even 6V batts should be checked separately when in series for house banks for the same reason.

Did the first group realize that it was a 24 volt system? Did they offer you a refund?




BTW: There are some boats out there with 32 volt electrical systems.

In many substations in Asia and Europe there is a 108 to 110 cell lead acid cell battery system. All in series. Can you imagine these clucks trying to debug that?
Also, there is no need to disconnect the batteries just to do a load test. You put the resistor across 6 cells, measure the DC volts.