Would you agree that #4 wire battery cables is sufficient for a Universal M25 Diesel with a total length of about 10' with no inverter installed?
Battery cables
- Thread starter simplicity
- Start date
In terms of starting the motor they "will work" but in terms of starting it well, with minimal voltage drop, they are undersized. Builders can get away with this because the ABYC does not address starter cable sizing. Some builders who installed that engine used 1/0 wire and others, on the same exact engine, used 4GA....
Morris Yachts for instance installs 2/0 wire on a similar sized motor. 1/0 or 2/0, depending upon length,would be my preference and the starting difference would be noticeable.
With your circuit I am guessing the 10' is one way? If so then your round trip distance is 20'. For a 3% voltage drop for a 160 amp starting load you'd need 1/0 wire.. 4GA wire is a 10% voltage drop or almost 1.3 volts on a fully charged battery. When you consider that the starting load can suck the battery well below 10 volts adding this additional 7% voltage drop is certainly not the best scenario. I tend to try and size wire for a 2-3% VD on starting circuits.
I had read somewhere that the starter on the M25 pulled about 50-60 amps and then read that you had done a bench test and it was more like 150 amps. Is that true and if so I will use the larger 1/0. Thanks
a gas outboard would do fine with a number two cable,but not a diesel,their high compression takes a lot of power to spin,going one size bigger then reccomended won't hurt any thing but one size smaller makes everything in your circut work harder.
Simplicity,
I have a similar but smaller engine, Universal M18 and had unreliable starts with the factory installed #4 cable. I parralleled the orginal #4 SAE cables with another #4 AWG cable to solve my weak starting problem, but if I had to do it over again I just replace it with a 1/0 with properly made up lugs and be done with it.
My M18 draws up to 111a for just a brief time... here's the video of the Victon Monitor on the start cycle if you are interested... http://www.youtube.com/watch?v=oJyaZcsXkwo
DanM.
I have a similar but smaller engine, Universal M18 and had unreliable starts with the factory installed #4 cable. I parralleled the orginal #4 SAE cables with another #4 AWG cable to solve my weak starting problem, but if I had to do it over again I just replace it with a 1/0 with properly made up lugs and be done with it.
My M18 draws up to 111a for just a brief time... here's the video of the Victon Monitor on the start cycle if you are interested... http://www.youtube.com/watch?v=oJyaZcsXkwo
DanM.