What (starting/cranking) battery for a 2001 Maxum 2300SC

[SimonM]

I have two deep cycle batteries on my boat (both are 12v Deka Marine Master DC27 batteries)... one is much older than the other and is now struggling to hold a charge, so time for a replacement?... I thought I'd take the opportunity to buy a battery purely tasked with starting the engine (Battery 1) and have the Deep Cycle battery (Battery 2) to serve the "domestic" circuits when at anchor etc...

Assuming this is a sensible suggestion, does anyone have a recommendation as to what battery I should go for?

Thanks in advance,
Simon

[mmwjr]

Replacing the one you have with another deep cycle 27 series will be fine and that way when on the hook you will not have to touch the battery switch unless the battery is ran down from a long day on the hook.

Otherwise if you really want to go with just a starting battery get the largest one that fits.

[SimonM]

Thanks Mike... I thought there was a benefit to having a separate cranking battery and a seperate domestic battery (the two types have different characteristics)... ie start with the cranking battery, leave the engine charging it while I exit the marina, then switch to domestic for the day... that way the cranking battery will always have a charge?

Cheers,
Simon

[Phillbo]

Here is my set up and it works fine for me.

Batt 1 - Group 27 Starting Battery
Batt 2- Group 27 Deep Cycle Battery

Switch usage:
Batt 1 - Starting and leave in this position while cruising (both batts are being charged while engine is running)
Batt 2 - House battery while on the hook over night.

[SimonM]

Thanks Phill... so even with the batt selector on batt 1, both batteries receive a charge, or would I need to move the selector to "both"?

Cheers,
Simon

[mmwjr]

Originally Posted by SimonM

Thanks Mike... I thought there was a benefit to having a separate cranking battery and a seperate domestic battery (the two types have different characteristics)... ie start with the cranking battery, leave the engine charging it while I exit the marina, then switch to domestic for the day... that way the cranking battery will always have a charge?

Cheers,
Simon

Yes, just do not switch into the off position with the engine running as the alternator needs to see a load. Its ok to switch into 1- both -2 when running as the switch has a make before break design.

[mmwjr]

Originally Posted by SimonM

Thanks Phill... so even with the batt selector on batt 1, both batteries receive a charge, or would I need to move the selector to "both"?

Cheers,
Simon

For both to change by the engine the switch will need to be in the both position, however if one is lower that the other it will not get fully charged.