Correct batteries?

[Polaris]

I need to replace the batteries in my 1999 270SD. I can't find information on what was the original battery configuration. My mechanic is telling me the prior owner used improper batteries and that I should NOT use a deep cycle battery.

Anyone know the answer to what should be the correct batteries - or where to find the answer?

Thanx.

 

[patokapirate]

Deep cycle batteries are normally for trolling motors and other applications where the batteries are constantly being recharged after being nearly fully discharged. I believe your manual would give the correct battery size but my guess is a group 31 marine starting battery at minimum. Group 34 would be better, and replace all the batteries at the same time. I put 3 of the diehard group 34 marine starting batteries on my boat about 2 months ago.

 

[insfnds]

I've always used deep cycle marine batteries in my boats (i.e your mechanic is nuts :grin:.)

I had a '96 270SD with a single 454 and had no starting issues with Grp 31 deep cycle batteries.

Also, Grp 34 are smaller (less capacity) then Grp 31 - I always go with the biggest battery that can fit.

You should verify that the batteries you buy have the minimum cranking amps for the engine(s) you have. AGM are the best but wet cells are fine if you remember to check the level periodically, at least monthly in the summer time. Also, make sure your charger can handle AGMs if you go that route.

 

[patokapirate]

My bad, "insfnds" is right on the group 31. Sears only offers a group 27 and 31 for the marine starting (what I actually have) in the series I bought. In fact I started a thread here about the deal when sears had the batteries on sale and was offering an online coupon. : )

The deep cycle part is confusing, there are straight up deep cycle batteries and there are deep cycle /starting batteries.

 

[Polaris]

Thanks for your information. I found the Owners Manual and Parts List from this forum but neither of them provides the specifics on the size/type batteries that were original equipment. My current batteries are one group 27 and one group 24 lead acid - both toast (that is another story.) My mechanic gave me the same story about only needing a deep cycle for trolling and is putting in two group 31 starting batteries.

 

[chpsk8]

Use starting batteries for the motors and a deep cycle for the house battery.

 

[ttmott]

To help need the configuration of the boat
1 or 2 engines?
engine size?
1 or 2 battery isolation switches?
battery cable configuration (each cable set up for one, two, or three

with a one engined boat there is typically one battery bank for the engine starting and house. In some cases two banks with an isolator one for engine and one for house.
Regardless these are typically group 27 batteries. Group 31 are perfectly acceptable alternatives if they will fit in the trays. Always use the same size and age batteries in a charging circuit.

With two engines there are two banks one for each engine and typically the port engine's bank powers the helm and NAV aids and the starboard engine's bank powers the house systems. Again these are typically group 27 batteries with an isolator between the banks. If there is an isolator all the batteries should be the same size and age. If the charger is an older multi bank unit (pre 2008, about) the batteries should be same size and age to ensure they are charged fully and with the same profile. If the charger is newer typically they can manage the banks individually. Again group 31's are acceptable.

group 27 and 31 batteries are hybrid starting / deep cycle. They have an acceptable CCA rating as well as an AH rating. For use as purely deep cycle house batteries they may fall short unless a lot of them are banked; this is where the 4D, 8D, 6 volt, and ( in our world) exotics come into play.

lastly, sizing your batteries depends upon the engines' alternator size(s) and the boat's charger. If the engine's alternator is (for example) a 35 amp unit and you have a 200 AH bank plan on a lot of run time to charge that bank. Same goes for the charger.

 

[Danny Troy]

I've been using Costco marine batteries in my last two boats. Before that I used Optima blue batteries, but switched to Costco after hearing good reviews, and hearing Optima's quality is not what it used to be. Easy to find the correct battery in Costco. Just look for the largest marine battery they have. Can't beat the price and so far they have been great. I use them for starting and house, switching them mid-season, to give equal wear and tear.

 

[my DOG HOUSE]

I just replace all 3 of mine with these http://www.amazon.com/dp/B00099DW6G Optima D31M's. Expensive, but last weekend ran the fridge, lights and stereo for 18 hours with no voltage drop. I was also surprised that there was also no drop in voltage while the windlass was operating.
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