HPDI battery lead size?

[mitch184]

Hi,

So I've got a 21' aluminum jet boat with a 175 HPDI. I had one blue top optima group 27 (800cca I believe) installed into the bow storage of the boat. From there, the riggers ran AWG4 leads from the battery back to 2 separate 3/8" posts. This run is roughly 18-19 feet. The leads from the main motor were coiled up instead of being shortened (is this common install practice?) and run to the posts. Then all my electrical is also run to the posts. I do not have a large electrical load, (bilge, , washdown, 4 speaker stereo, 2 lights, 2 downriggers, Lowrance HDS8) and they are never all on at the same time. In addition I have a T9.9 kicker that provides a charge the entire time I'm *****ing, etc. My problem is that when I have my Lowrance on and go to start the main 175 motor, I get a low voltage and the lowrance resets. I went all thru Lowrance and there is no fix from their end.

I was thinking of shortening the battery leads from the motor (removing roughly 4 feet) and replacing the leads from the bow. I was hoping AWG2 would do the trick but wanted some advice. AWG0? AWG 1/0?

thanks
sean

[boats.net]

For the 175 HPDI battery cable size should be
up to 9ft use AWG4 cable
9-16ft use AWG2 cable
16-24ft use AWG0 cable

[mitch184]

Thanks for the quick response. If I still see a voltage drop issue that resets my Lowrance, is there something else besides moving the battery I could try? Bigger battery or adding a house battery?

[99yam40]

House battery would be the best in my opinion, that way start battery voltage drop would not effect electronics.

Most of the newer Yamaha motors have the second separate isolated charge wire I believe, but not sure which battery you should hook the kicker up to

[mitch184]

So here is something I just found while researching on this site. There is an auxilary charge lead on the motor? Is there not? Could I keep my blue top hooked to all my accessories and kicker motor lead and then get another, small starting battery and simply hook it to the main charging lead from the main motor? Smaller battery like an Odyssey PC1200. So basically the main motor battery leads only go to the starting battery. Then the auxilary charging lead from the main motor goes up into the bow (still using the AWG4 wiring) and will also charge the existing blue top optima.

[99yam40]

I think you could test it that way and see if kicker start drops voltage too far also