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Windlass suddenly tripping main breaker

Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
Here is the electrical diagram for the new and installed Lewmar V2 windlass. Everything is wired according to the diagram (Contactor setup), with the exception of the battery isolator. The windlass is currently wired: Windlass>Bus>isolator switch>100amp breaker>battery + terminal.
View attachment 196028
No, it is not wired correctly. The windlass load is going through the C-Series breaker and it CANNOT pass through this type of breaker!! It needs to go through an ON/OFF siwtch then a 285 Series or similar breaker. The house battery needs a fuse regardless of the windlass stuff. You don't want to know what happens if a wire shorts between the battery and the 100A breaker. The house bank fuse is an ABYC requirement for safety.

If the wiring between the Blue Sea 8080 panel and the battery is not sufficiently sized for the windlass then the windlass wiring would start all the way back at the battery at the house bank fuse.

This is what correct wiring would look like.
 
Feb 16, 2021
89
Hunter Legend 35.5 Bellingham
I will rewire the windlass positive directly to the combiner switch, bypassing the 100a C Series breaker. As an interim workaround, I have been able to use the windlass by combining the batteries.
 
Feb 16, 2021
89
Hunter Legend 35.5 Bellingham
The house battery needs a fuse regardless of the windlass stuff. You don't want to know what happens if a wire shorts between the battery and the 100A breaker. The house bank fuse is an ABYC requirement for safety.
Thanks for that. I have two sets of "in series" 235Ah 6V batteries that are run in parallel to provide 470Ah 12v. The two sets are on either side of the helm and separated by ~4'. I assume I should attach the fuse at the positive out from the combined bank? What fuse would you recommend? Right now there is a lug on a terminal, and it seems ideal to insert a fuse inline with the positive coming off the bank, correct?
 
Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
Thanks for that. I have two sets of "in series" 235Ah 6V batteries that are run in parallel to provide 470Ah 12v. The two sets are on either side of the helm and separated by ~4'. I assume I should attach the fuse at the positive out from the combined bank? What fuse would you recommend? Right now there is a lug on a terminal, and it seems ideal to insert a fuse inline with the positive coming off the bank, correct?
Each side of the positive parallel jumper needs a fuse. 250A is the bare minimum we advise for any bank that could be called on the start a motor. We strongly advise 300A and the wire to support it. MRBF fuses are excellent
 
Feb 16, 2021
89
Hunter Legend 35.5 Bellingham
Each side of the positive parallel jumper needs a fuse. 250A is the bare minimum we advise for any bank that could be called on the start a motor. We strongly advise 300A and the wire to support it. MRBF fuses are excellent
I don’t quite understand the location you describe for the fuses. The wiring diagram you provided shows a fuse at the house bank out as well as at the house bank in from the alternator. Is this what you mean by “Each side of the positive parallel jumper”? Or are you saying a fuse should be on the battery side of the parallel jumper positive cables running to both the house and starter bank? Should the fuse be as close as possible to the banks?
Thanks
 
Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
I don’t quite understand the location you describe for the fuses. The wiring diagram you provided shows a fuse at the house bank out as well as at the house bank in from the alternator. Is this what you mean by “Each side of the positive parallel jumper”? Or are you saying a fuse should be on the battery side of the parallel jumper positive cables running to both the house and starter bank? Should the fuse be as close as possible to the banks?
Thanks
Bank fuses need to be within 7" of the positive battery terminal on each bank, when the banks are in different locations..
 
Feb 16, 2021
89
Hunter Legend 35.5 Bellingham
Will do. Makes perfect sense.
Is a fuse advisable to have within 7” of the positive terminal of the starter battery as well? I assume all positive connections to either bank should be downstream of the fuses, correct?
 
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