Replacement Battery Needed

[saltyfish]

New to me 2002 21 SE with 150 HPDI, 2nd battery was "missing" when I bought the boat, the previous owner did not use a backup. All I see in the online Yam owners manual for 150 HPDI is "Min cold crank performance 512 Amps, Min reserve capacity 182 minutes". Revealing my ignorance here...but is this the only relevant info for purchasing a battery?

Also, no idea how much life is left in the current battery, but engine starts fine. Thought I would simply buy one deep cycle interstate marine battery that exceeds the 512/182 specs, and "take turns" on the two batteries until the original battery craps out. Should the specs on the the two batteries match if both are deep cycle?

Any incorrect assumptions/weak spots in my logic?

THANKS

Bryce

 

[markman03]

I think the 150 hpdi minimum battery is a group 24. I have a starting battery and a dual purpose. They were like that when I bought the boat. I am thinking about going up a size. Not sure on the configuration. I am going to replace them both so the will be the same age.

 

[ATBob]

If you EVER put the 2 batteries in parallel, they must be the same, including size, age, and I suggest manufactuer. Any differences will result in the weaker battery failing.

Unfortunately I have proved this two times with the back-up sump pump in my cellar.