21ec Battery Replacement

[JFisher]

Hi There, Just joined Tugnuts after purchasing a 2007 21ec. I want to replace the 2 batteries and having read previous posts am still confused as what type to purchase. I am thinking I will keep the battery switch set to both batteries for starting, running and for house power when moored or at anchor. I came to that conclusion after reading previous posts and also considering the limited amount of power I anticipate I will use at anchor. Assuming my plan is OK my questions are 1). should I purchase two of the same kind of batteries and 2). what type should they be. Any advice on this would be greatly appreciated as I am still trying to understand the subject of batteries in general. (All my previous boating experience has been with runabouts with outboard motors).

 

[lproulx]

I just bought two new batteries for my 21ec. I really haven't researched the gell versus conventional flooded acid batteries, so will just give a couple of thoughts on the regular flooded acid kind.

First - It seems that "deep cycle" marine or RV batteries now have terrible warranties - West Marine and Wall Mart both have one year free replacement. Whoopee! They basically guarantee them for one season. Wall-Mart gives a free replacement for three years on its top line CAR batteries. One of your batteries - the engine starting battery - sees essentially car type service. I say hands down buy a Wall Mart car battery for engine starting. Car batteries are not "optimized" for repeated deep discharge, but hey - Wall Mart doesn't ask how you use the battery. Buy one of those for your house battery also.

Note that you need group 24 batteries. There are two kinds - 24 and 24F. They are identical size, but the positive and negative terminals are reversed. I don't remember which the 21ec uses, but just make sure you get the same kind as in the boat now so the cables will reach.

Larry

 

[Fisho]

I have a 2012 21EC and replaced both batteries recently. Both the same. Sealed calcium marine deep cycle/start batteries. CCA 600 and 82 Ah. Model SMFDCM24. Absolutely no problems. BTW I have also added another house battery (same) and a spare dedicated start battery (that is kept charged and I can switch over if the other one fails, since I regularly anchor over night). The spare start battery is a Calcium 7601 85 Ah and 720 CCA. Both in the rear storage area in front of the fuel tank. All good. No issues. Of interest I have changed all lights and globes to LED to reduce current drain (except the searchlight) but have added an LED flood light for rear cockpit. The only serous drain is from the fridge and the Fusion stereo.

 

[Catch22]

Pay attention to CCA ratings when selecting new batteries. Price point batteries will often have lesser ratings. Example...even Wal-Mart offers group 24 marine cranking batteries in group 24 ranging from 650 to 1000 CCA.

The OEM Centennial brand cranking battery in my 21EC was 1000 CCA and replaced with same rating.

The limited warranties on deep cycle batteries are generally attributed to premature failures of those units due to deep discharge followed by improper recharging. Immediate recharge is important as is off season battery monitoring.

Also be sure your shore powered charger is set to the correct battery selection if so equipped.

 

[JFisher]

Thanks for sharing your battery know-how, that's a big help and much appreciated.
Cheers, John