Starter Battery for Manatee

[Wils]

Currently our house bank, consisting of 4-8D Lifeline AGM's also serves as the starter battery for the engine's (TMD30) starter motor which is rated at 2.2 kW.
No problem with current setup, but looking to replace batteries in the future and reviewing options including a dedicated start battery. Considering the starter motor rating it looks like the motor would only draw around 220 amps even if the starter battery was drawn down to 10 volts - I know this isn't the only consideration for sizing a starter battery so looking for some thoughts.

 

[DavidM]

It is always better to have separate and isolated start and house batteries for redundancy.

No matter the 2kW starter spec, I bet it draws as much as 400 amps when cranking.

Even though G24 or G27 battery might work I would go with a Group 31 AGM or FLA battery which will easily provide 400A with a CCA spec of 800+ amps.

To isolate the two systems use a Blue Seas ACR or similar.

David

 

[mvweebles]

I have a 75hp Perkins 4.236 in my Willard 36. Single AGM group 31 is my start battery. Isolated with an ACR as DavidM notes.

Pretty bulletproof setup.

Peter