Fusing house and starter battery banks

[capta]

Off hand does anyone know the PERKINS 4-236 starter motor amperage draw for fusing the starter battery bank? Cable is 2/0 105c boatwire.
Also, it would be helpful if anyone knew the Onan MKDK 8 kw Kubota (3 cylinder) starter amp draw as well. Same cable, 2/0 105c boatwire.
If I were to parallel the house and starter banks in an an emergency to start either the ME or gene, would that mean the same fusing would be required, even though the max normal house draw is only around 155 amps max to distribution. Windlass is 1500 watts of 12 volts, or 125 amps which I believe is my largest single load. .
Lastly, is it necessary that these be fused or would breakers do just as well?
Thanks awfully,

 

[Charles Erwin]

For 2/0 cable 330A fuse outside the engine space 280A inside - assuming the cables are not bundled. These protections are sized to protect the wire. What is at the other end - stater motors in this case - is not considered. Also you can go to 150% of these values.

Fuses not breakers because breaker contacts can weld together at these levels of current which is not good.. And the correct style of fuses in addition.

Charles.

 

[Stu Jackson]

Engine Starting Loads - Amp Draw Data (by Maine Sail)

http://forums.catalina.sailboatowners.com/showthread.php?t=102027

Battery Fuse Sizing with tables (from Maine Sail)

http://forums.sbo.sailboatowners.com/showthread.php?t=130775

You don't want to combine in an emergency, bad to do, since either of your banks should start the engine, no need for both, you don't ant a good bank being drained by a bad one. The purpose of the crossover switching is to permit the house bank to start the engine or the start to run LIMITED house loads; a "just in case" scenario.