Isolation switch for 3 battery banks

[pappaecho]

My recently purchased Princess 33, has four batteries, two starter, for port and starboard engines, and 2 house batteries, and no less than four different isolation switches, which seems over the top.
What do forum members do with two engined rigs to isolate with either one or two switch arrays? It occurs to me that all batteries have a negative return which could be simply isolated via very powerful off/on switch, leaving the existing switchgear in place for individual isolation if neccessary

 

[Tranona]

BEP Marine do a very neat cluster that isolates each engine, the domestic bank plus a parallel switch to use the domestic bank to start the engines - and 2 VSRs to allow both engines to charge the domestic bank. Well worth fitting.

 

[PCUK]

You only need one engine start battery as this is the least used of them all. Change one of the engine batteries to an additional domestic and then switch between the three as required as suggested above..

 

[pappaecho]

Both 4 litre diesel engines require a lot of welly to get them started. I am not sure that one battery would be wise given the battery has to give a lot of amps and then a second batch a few seconds later as the second engine is started

 

[PCUK]

If the battery is man enough for starting the engine it should be man enough to do it more than once. In cold weather the engine may need to turn for a long period before it starts so the battery should be capable of this. Once one engine is running the volts are instantly raised and starting performance is enhanced. You can also jump from the domestics if there is a problem.

 

[blueglass]

If the battery is man enough for starting the engine it should be man enough to do it more than once. In cold weather the engine may need to turn for a long period before it starts so the battery should be capable of this. Once one engine is running the volts are instantly raised and starting performance is enhanced. You can also jump from the domestics if there is a problem.

Al the twin engine boats I have come across have a dedicated battery for each engine. I presonally wouldn't want to mess with that. Part of the security in having two engines is lost if you only have one starting battery.