Electrical Control Module For Two Battery System 23'Venture

[Tim & Dave Kinghorn]

We built a current and voltage distribution module to fit in the stern lazarette.
The module is about 12 x 12 inches and about 3 inches deep. The start and the house batteries are housed in the same compartment to the right and left of the module. We ran two circuits forward to the helm using #6 wire to an off/on switch at the helm for each. One circuit we dubbed essential (wipers, vhf, running lights, etc.) and the second the house circuit (interior lights, fm radio,stove/heater, etc.). We ran two #6 grounds back to the stern (one essential--start battery, and a second for the house circuit--house battery). We built in CB protection for each battery, CB protection for the two circuits going forward to the helm, CB protection for the engine circuit, and CB protection for the aft fuse panel, and we connected a voltage sensing relay between the two batteries with a 3-way battery switch.

You can see photos on the Sound Venture photo album site.

Tim and Dave Kinghorn

[thataway]

Nicely done. Are you fusing or circuit breaking the engine start cable? I see both a circuit breaker and a fuse which seem to be involved with the engine.

[Tim & Dave Kinghorn]

Hi Bob,

Sorry to be late on the reply. I just checked in on this forum today. But notice, I got the reply on the right site!

As you saw, I used a 120A circuit breaker on the distribution module to protect the cable run for the two motors (Main and Kicker). As this was the biggest current draw, I also used a 120A circuity breaker for each battery primary line. I determined the amperage for the motor circuit based on the fusing for the engine of the Honda 90 (see manual or look inside the engine at the fuse size Honda puts in the circuit). I then ran a #4 wire to a fuse buss in the starboard lazarette from the top of the distribution module (this is the photo I think you're referring to). I then used a fuse to parallel from the main engine connection on this buss to a connection for the kicker. As the kicker pulls less current to start, I fused it separately at a lower amperage and taped a spare fuse to the cable. The main engine is on the hot side of the fuse and unaffected. It is protected by the 120 Amp circuit breaker in the module. The Kicker is by itself on the protected side of the fuse in the fuse buss.

I have two circuits going forward to the helm position (#6 wire) and one going aft to a switch panel in the cockpit. Although each of the two circuits going forward pull a max of about 25 amps each, I used #6 wire to minimize the voltage drop from the batteries forward and back.

One of the reasons, we chose the Honda 90EFI was the 44 amps usable output of the alternator compared to some of the other choices.

I did cover all the connections with liquid tape even though they are stainless and need oxygen, but each year I clean them and see no problem with the connection (no voltage drop or corrosion).

A major benefit of enclosing the major connections was keeping a pile of connections off the batteries and protected from damage.

Sorry to be late. I hope this answered your question. This was more of a pilot project and could certainly be improved.

Tim and Dave Kinghorn