Different Batteries

[slob02]

2008 210 .... I have a bad #2 battery. It is a group 24 deep cycle battery and I understand is not the recommended group size for this boat. The good battery #1 is its twin. I don't want to buy two new batteries. Any problem with making #2 a group 29 or 78and keeping the battery selector on 1&2?

[MLA]

Absolutely no reason you can run a group-29 on the #2 spot and retain a group-24 on the main cranking side. But where did you get that a group-24 deep-cycle is the recommended size for the boat? the "boat" really has zero to do with it.

[slob02]

Group 24 is NOT recommended. #78 is according to the cc sticker on the battery box. I just need to know if I can mix two different groups and run the selector switch on 1+2.

[MLA]

Not disputing that it has been stated, just curious as to the reasoning why a G-24 is not the right battery, but a 29 is ok to use? Also, you stated the good #1 was the twin to the G-24 thats bad, so I drew the conclusion that there was already a G-24 cranking there and you were retaining it. So i did not recommend a 24, just answered your question and asked one myself.

A 24 is: 11L x 6-7/8W x 9-1/2H

A 78 is 10-1/4L x 7-1/4W x 7-3/8H

A 29 is 13L x 6-3/4W x 10H

Theres a slight difference between the dimensions of the 24 and the 78, but if a 29 will fit where the battery goes, then those difference are irrelevant.

[slob02]

The cca's and mca's are different with the different groups....not just size. My group 24 is 500 cranking and I believe a group #78 is 1000. I am not a battery wize at all though.

[MLA]

That may be the case with a cranking battery, but when it comes to a marine deep-cycle for house loads, CCA's are irrelevant. Its all about Ah. Looking through Interstate's car/truck batteries, i see comparable CCA's between the G-24's and the G-78, but they do not offer a marine G-78. Quick google search and i did not find any G-78 marine cranking or deep-cycle batteries, so its hard to make an apples to apples.

For a cranking battery, theres nothing wrong with having a high CCA, especially as the vehicle/boat ages. On the same token, there are advantages to running a marine battery in a boat, over a car battery. They tend to be built more robust to withstand the pounding of the water and seasonal lay-ups.

[slob02]

Good info! I have been doing some research too... When the selector switch is on 1+2 the batteries are connected in parallel so it shouldn't affect the charging system either. So when I am done I will have a group 27/29/78 cranking battery and a group 24 deep cycle and both will be turned on.

[flyfishdelta]

I recently bought a 24MS Everstart at Walmart for the 93 SN, (you can see my project under 1993 SN parts) it's a 24 MS / 1000CA, well it blows the breakers when I try to start the motor. Have to use my old Batt with 650CA from my other boat. any ideas? too much CA for the boat to handle? I have a 1998 21' Monterey with the Volvo Penta 5.0 and it can use the 24MS- 1000 CA with no issues??

[MLA]

Funny thing is, batteries do not push current, but rather the devises draw from it, its just a storage vessel. A 25A pump will draw 25A whether the battery is a g-24 650 CCA or 1000 CCA. A starter motor should draw 250A no matter. A a 12 oz glass holds 12 oz no matter if being filled by a single can or a keg.

I would focus on what breaker trip and exactly when the trip. Battery switch on? Key to on? or key to crank? Sounds like some bad cables or connections, starter going bad, etc.