Mercury pro xs 250 cranking battery???

[mbfuhr]

So, the local parts store has a M24-3 which will work for cranking the boat. They do not stock the 27M6 anymore . However, My big question would be has anyone ever used a farm and commercial battery as a cranking battery? They are used to crank semi's and tractors and to take a beating in rough conditions. I just am not sure if they are built to withstand the boating atmosphere. The battery would be a 31s30 which is essentially a dual purpose battery built to take discharges from a tractor whose alternator does not completely charge the battery constantly. Much like a boat running a lot of electronics with the motor not running. The 31 group battery would have 950 cca which is 150cca higher than the m24 marine battery and a reserve capacity of 175 which is 45 higher than the m24. Any information or thoughts on this would be greatly appreciated.

[Jim Dunn]

Might check the 3.0 ltr Mercury forum. There is a ton of good info on batteries. Bottom line bigger is better.

[CatFan]

A commercial battery will do the job and many people here use them. Consider a 31 series for running electronics. Internally there is nothing special about marine batteries. If there was, commercial batteries would be tougher because they are used in equipment on hard ground with no suspension so they take a pounding. The distinction is the threaded posts.

[mbfuhr]

Well the good thing about the battery I am looking at is that it uses threaded posts. Sounds like thats the way I am gonna go then.

[catdude28]

If I am looking at the correct 31S30 battery from Advanced/Carquest, then it is a very nice battery. Napa carries it too. It is made by Deka/East Penn, and has 950 ccas and a RC of 175 minutes, and is very reasonably priced around 120 dollars. Many, including me, use commercial batteries as they seem to be the only wet batteries available with high ccas and good reserve for an Opti and accessories. Some claim that because the lead alloy is different in a commercial battery that they are not suitable for bass boats. But many, including me, do very well with them in our boats. I am going into year four with mine, the Canadian version with nearly identical specs. My previous boat also had a commercial battery, but the Interstate version. BTW, it you look around hard enough, that 31S30 is also available in a post version as opposed to threaded studs if you wanted.

[mbfuhr]

I ended up getting the 31p30 from advance auto and just used marine terminals. First trip out and it worked flawlessly, Online discounts of 25% plus speed perks from there made the battery cost only 80$. Hopefully it will last as long as yours has.

[4 Buck]

Can you add water to these? I have a NAPA one and it worked great last year but the caps are covered up like they don't want you to remove them?

[CatFan]

Can you add water to these? I have a NAPA one and it worked great last year but the caps are covered up like they don't want you to remove them?

Your battery is likely made by East Penn. Their commercial batteries are maintenance free, meaning you shouldn't open the caps.

[catdude28]

Can you add water to these? I have a NAPA one and it worked great last year but the caps are covered up like they don't want you to remove them?

When used in a typical commercial scenario (ambulance, truck, heavy equipment), these Deka batteries are intended for short term usage, and basically are throw away after a certain time and replaced on a regular basis. Levels are not intended to be monitored and they are labelled as "maintenance free". However, when used in our bass boats, we are looking for some longevity. I believe that we will only get that from these flooded batteries if we monitor water levels and fill accordingly. Those with your same battery pull the sticker off to reveal the caps, and monitor water levels. If it were me, I would do that.

I have a very similar Deka commercial battery, with almost the same specs, and it came with caps that were not sealed up, and I do monitor levels. Year four for me.

[4 Buck]

Thanks, I will take a look.

[JamesfromID]

Get a Cat marine battery from a Cat dealer.

Cranking: 8C3638
Trolling: 8C3639

Super awesome batteries and easy on the wallet!

[eliteangler]

I bought this battery: https://www.napaonline.com/en/p/NBP7236. I am pleased with it so far. However, some are going with the 7234. It is a commercial battery and has a 3 year warranty. Plenty of CCA for the motor and good reserve minutes for the accessories/electronics.

[eliteangler]

Also... here is the battery thread from the Mercury 3 liter forums: http://www.bbcboards.net/showthread....batteries+meet