Cranking battery

[HTC33]

Hey guys….I’m sure this has been discussed, but couldn’t find it during a quick search. I need to replace my cranking battery. I’m not going lithium (yet). What are the battery specs I need to adhere to? I think I need a group 31 battery, right?

[jc2bg]

Matt, your question is best answered on the Mercury 4-stroke forum, as they are the experts over there on your engine’s requirements. However, if the cranking battery is also to be used for powering all of the other electrical components of your boat, then the issue is much more complicated.

If I recall correctly, Mercury recommends a minimum 1000 cold cranking amps for starting that engine. But what electronics and other components you are powering, plus how many hours you fish and how much you run during that time, etc., all should be factored in. Definitely a high-cranking capacity 31 series battery, but which one and so forth depends on several factors. The electrical/wiring/trolling forum also might have some clues for you. Hint: if you are running 3 or 4 big graphs, running livewells all day, and sometimes don’t run the big engine enough to garner replacement charge, you might need even more than a group 31 battery.

[paulrodbender]

https://www.bbcboards.net/showthread.php?t=20671

[paulrodbender]

Happy Monday Morning John..... 100 might be a little low....

[jc2bg]

Happy Monday Morning John..... 100 might be a little low....

Only off by one decimal place! Good grief. Had been reading posts about minimum amp hours for bass rigs and forgot to make the conversion to cold cranking amps. Not the same thing.

[apenland01]

LOL, that was funny...

It looked fine to me, then noticed it was edited for clarity hahaha...

[jc2bg]

I know, right? Sometimes my brain is seeing one thing and my fingers are typing another. Oof!

[HTC33]

Thanks everybody! This info is exactly what I was looking for.

[jc2bg]

Glad you got it, Matt. If you are a tournament fisherman, livewell operation will have a substantial draw on your cranking battery, as will multiple large graphs, when active. For this reason, it’s considered prudent to not only meet minimum engine cranking requirements [at least *1000*] but also have decent reserve capacity for the other electrical components. A strong dual-purpose battery, preferably AGM, is a popular choice for tournament anglers, and even then sometimes there’s a problem with starting the engine at the end of a tournament day. As a final piece of advice, lithium jump-start packs like the Noco GB40 are worth their weight in gold and take up very little space. You might not need to buy the highest-priced cranking/dual battery if you have one of those on board. Good luck and happy fishing!

[paulrodbender]

Only off by one decimal place! Good grief. Had been reading posts about minimum amp hours for bass rigs and forgot to make the conversion to cold cranking amps. Not the same thing.

I was just being a wise guy......... I knew exactly what you meant.

[jc2bg]

The “good grief” was directed at myself, Paul. Your reaction was spot on, very funny indeed. Glad you could read between the lines. Keep me on the straight and narrow, if possible.

[cmbtvet]

Hey guys….I’m sure this has been discussed, but couldn’t find it during a quick search. I need to replace my cranking battery. I’m not going lithium (yet). What are the battery specs I need to adhere to? I think I need a group 31 battery, right?

I was using an X2 AGM until it crapped out and they wouldn't honor the warranty. Now I use a Duracell AGM and no issues so far.

[HTC33]

Thanks again John!

[Pulsare2020]

I was using an X2 AGM until it crapped out and they wouldn't honor the warranty. Now I use a Duracell AGM and no issues so far.

I have a group 31 X2 AGM (1150 CCA). Did you have a group 31 X2? Which group and CCA size Duracell did you switch to? I am just asking as I do not have that much confidence in the X2.

[Mark Wendler]

I have been using the Vmax XCA31-1400 for almost 2 years now and am very pleased with it's performance. (I was previously running the Duracell AGM) The only side note is that the mfg recommends charging at 20 amps minimum.

[mikesxpress]

The benchmark Group 31 AGM battery. This battery exceeds the Mercury Marine requirements for the V8 four strokes.

ODYSSEY Extreme Battery
ODX-AGM31M
(31M-PC2150)

https://www.odysseybattery.com/produ...y-31m-pc2150st

[cmbtvet]

I have a group 31 X2 AGM (1150 CCA). Did you have a group 31 X2? Which group and CCA size Duracell did you switch to? I am just asking as I do not have that much confidence in the X2.

It is the group 31 AGM Duracell that I currently have, not sure of the CCA. Yes I had the grp 31 X2. The X2 worked great until it didn't. No warning signs whatsoever...just dead and wouldn't charge.