Starter Battery for Yanmar 4JH2E

[JebLostInSpace]

I'm replacing my start battery to (hopefully) improve my issues with getting the engine started up. The problem is, I can't seem to find the correct battery. The owner's manual calls for a battery with at least 660 Cold Crank Amps / 780 Marine Crank. The manual also specifies at least 120 Ah. The manual does not specify a reserve capacity figure. My current house bank, start battery, and generator start battery are all AGM, so I'm sticking with that.

Now, the batteries I can get my hands on locally don't seem to fit the bill. I can find lots of options that meet the CCA requirement. 700-1000 are available at various price points in AGM batteries. The Ah spec is where I get into trouble. The highest Ah battery I've found hits 105 Ah. My currently installed battery is also 105 Ah, so that's probably good enough. However, this is the most expensive battery by far at $320.

It seems to me that the spec on Ah is much less important on the dedicated start battery. Literally the only thing this battery runs is the Yanmar's starter motor, so I don't see any reason that it should need so much capacity. However, I also don't know much about batteries, so I'm asking the experts here. I can get a 750 CCA battery with 90 Ah for $150, which seems a lot better. Plus, it's a smaller box which is always nice. Is there any reason to think that one won't work?

[Wotname]

The $150 battery will do the job for all the reasons you mention. It probably won't last as long as long with a higher Ah but being much cheaper, this isn't a huge issue.

[tkeithlu]

Jeb, your being lost in space makes this a more difficult question - it costs bunches to get something as heavy as a battery up there, and then NASA has to find you to deliver.

That said, take a look at the Sam's Club prices on Duracell AGMs. They've been recommended as a best alternative to a person not wanting to invest in a Lithium system. We went with their floodeds and are happier than we were with Interstate.

[JebLostInSpace]

Thanks for the Sam's Club tip - got a Duracell that fit the bill for barely more money than the 95 Ah one. Had to drive an hour out of my way to get it, but this is a rare week when I have access to a car, so I could do that!

Unfortunately, I installed the new battery and the engine continues to struggle to start

New thread upcoming where I'll ask for all y'all's help figuring this one out

[tkeithlu]

Is the engine spinning well but not starting or is the engine struggling to turn despite a new (and charged?) battery?

[JebLostInSpace]

Just posted a new thread to try and troubleshoot this with more information:

https://www.cruisersforum.com/forums...38#post3245038

Figured it was better to start with a fresh thread that's not focused on the battery.