What engine starting batteries for ST44 D4-300

[boater3]

What engine starting batteries are folks in the USA switching to for the ST44 D4-300? I want to find something that takes the place of the 2x Exide Dual AGM, 450wh, 50ah, 750A, 12V, VRLA that are per engine (4 total) and fits in the existing battery tray/compartment. I cannot find these batteries in the USA.

Thank you!

[rslifkin]

I'd measure the space and see if you can fit a group 31 in there. Or based on the specs, a pair of group 34s would likely be comparable if they fit.

[DavidM]

The 3.7 liter Volvo D4 can easily be started with one Group 31 starting battery. The G31 is usually good for up to 6 liter engines. I used a single G31 as the starting battery for my 5.3 liter Yanmar with no problems.

David

[boater3]

Thanks. I will have to measure. IIRC I have space for around 9" height and I think the 31 are 9 3/8" ugh. I made MAJOR modifications to change my house bank and I don't wish to start doing that.

I got my hands on the shop manual. It says "Starter motor battery capacity 2x Ah 800 CCA"

What does that mean? I need 1600 CCA?

[Ski in NC]

Engine mfr's always like to spec high capacity batts in their manuals, partly to avoid complaints and also they don't know how cold conditions might be where it is operated.

I've seen the same CCA spec for a given engine in both the marine version and the standby generator version. The standby gen version could be used up in the arctic in sub-zero temps. The marine version, not so much. Takes way less batt to start at 40F than at -40F. Spec is the same for both.

In my shop, the go-to bench test batt is a simple grp 31. Starts every engine every time (unless 24v, then I need another).

On my personal boat which has an 8.3 liter engine, it starts also on a single grp 31, I think around 900 CCA. Starts fine down to 40F, which is the coldest engine temp I have run the boat. Spec for my engine is 1800 CCA. So I am at half spec and it is fine.

For your 3.7 liter engine, a 31 will be fine. Fitting it, I know those euro boxes can be a problem. You could go even smaller if needed to fit in the box.

[FlyWright]

I have a single Group 31 start battery (~900CCA) that I use to start both of my 3.7l Perkins 4.236 diesels. No issues with the setup.

[Bacchus]

Originally Posted by mystery

I got my hands on the shop manual. It says "Starter motor battery capacity 2x Ah 800 CCA"

What does that mean? I need 1600 CCA?

That makes no sense to me. But I've also looked up my Yanmar 6LYA starting requirementvand they spec it in AH which makes no sense to me. Starting should be CCA OR MCA not AH?

[DavidM]

Originally Posted by Bacchus

That makes no sense to me. But I've also looked up my Yanmar 6LYA starting requirementvand they spec it in AH which makes no sense to me. Starting should be CCA OR MCA not AH?

Absolutely right- mca or cca. Ahrs are irrelevant for starting.

David

[ranger58sb]

Originally Posted by mystery

What engine starting batteries are folks in the USA switching to for the ST44 D4-300? I want to find something that takes the place of the 2x Exide Dual AGM, 450wh, 50ah, 750A, 12V, VRLA that are per engine (4 total) and fits in the existing battery tray/compartment. I cannot find these batteries in the USA.

Is there no BCI Group info on those Exide batteries? Or on their website?

If the "750A" means cold cranking amps (CCA) and if they're smaller than Group 31s, I'd guess maybe G24, 27, 29, 34...

But you could also compare by dimensions, using website info from Exide, East Penn/Deka, Trojan, etc.

The Odyssey 34M-PC1500 (Group 34) AGM would make a decent start battery in a small package. 850 CCA. $$$ We use a single to start our genset, and our first lasted from mid-2009 through early 2020. (It was actually still working OK when we swapped it out for a new one... while we were troubleshooting a starting issue that eventually turned out to be the battery switch.)

-Chris

[boater3]

Thanks all. Anyone with a ST44 have any thoughts of what fits into the existing tray and compartment?