Batts: Size 27 to 29?

[wufibugs]

Posted elsewhere but thought I would ask the Hunter focus group:
My 1986 Hunter 31 was fitted with 3 batts, all size 27. One went bad, and I am working through the rewiring to deal with that. But a friend has 3 size 29s that are nearly new that he is willing to donate.
1. Wondering if I can replace all my 27s with the 29s as long as I can make them fit properly. The 2 house batts were aft of the trans, I would say poorly mounted. I am looking carefully at Steve Dion's excellent mounting innovation in the Hunter Mod section.
2. None of the batts are in a box. Wondering how seriously I should pursue getting them all in boxes.

Richard

 

[Dan Johnson]

Don't recognize "29's" as a marine battery size...

but should be deep cycle recharging capable as well as being starting battery rated (two entirely different applications) if they are the only ones you intend to use.

The use of a battery box is highly recommended. It allows them to be tied down, the terminals covered to prevent inadvertent electrical terminal contact, and able to contain any "boil over" should they get overcharged. You don't want battery electrolyte sloshing about in your bilge! It also makes for handy carry containers if you remove them for the winter (not likely in Long Beach however).

 

[Claude L.-Auger]

Ditto Dan's comment. I have had 3 type 31 deep cycle batteries in my 34 for 5 years and they are still giving good service. 2 of them are hooked in pararell used for house bank power and starting. The 3rd one is a sparingly used spare, connected to the others through a 1-2-All switch. 60 amps alternator when running the engine and "intelligent" charger when plugged up on 110 provide easy recharging.

They are tight and secured in boxes. I check the electrolyte a couple of times a year besides having a voltmeter permanently connected. I rotate them every Fall so that over the last 5 years the batteries have had pretty much the same wear. I'll replace all 3 when they go bad.

 

[wufibugs]

Thanks, Claude. The suggestion about rotating the batts is a good one. I am not sure how much larger the 31 is than the 29, but batt space is a serious problem on the 31', which probably explains why the PO did not have the engine compartment bats in a box. Might consider relocating, bringing the cranking batt from the cockpit to aft of the engine where the house batts currently sit, and putting the house batts under the dinette seats. These are heavy units, and were I to relocate them I wonder how much thought I should give to putting one on each side of the centerline to distribute weight? This would also make it much easier to rotate. Removing the cockpit back involves squeezing myself down into the starboard compartment. I currently have a Newmar charger, and an older inadequate inverter. Thinking about replacing both with an inverter/charger but grappling with the expense.

 

[Steve Dion]

Richard: The reason I do not have battery boxes is because those batteries are Gel's. This lowers the profile so they will clear the cover over the shaft log/battery area. They are group 31's.

This is wired so these are our house keeping bank which was isolated from the starting battery.

Our new boat is a Hunter Vision 36 and we have a similar setup. If/when I replace my battery bank, I will probably add another G31 to the house bank for a total of 300+ ah.

 

[wufibugs]

If you care to hazard a guess, Steve, how do the dimensions of the 31 gel compare to the 27 or 29 lead/acid, sans box?

 

[Steve Dion]

Richard:

Check our a catalog for the exact measurments. The G31 is slightly longer (less than .25") and slightly lower (about .5"). The G31 makes the installation in the area above the shaft log a little easier.

The mount on my H31 was made from 1" or 1.25" plywood that was coated with epoxy.

 

[petersea]

OK here is my take on this. First you need to determine what your usage is. If you rarely spend overnight on hook where you will need a strong durable house bank or do you use a dock with 110 power available ? You may be able to use the regular batteries rather then deep cycle and since the batteries are "donated" how could you go wrong.So yes you can use the 29's just make sure to use all the same size (don't mix sizes) and they should be same (or very close) age.You could get two or three more years (maybe more) unless you are a heavy user away from shore power. A "smart" charger is the way to go regardless of what batteries you have also do a once monthly fluid check . I do agree you should have them in battery boxes no matter what type they are.

 

[wufibugs]

I think I would like to have the flexibility provided by deep cell batts. While docked, the boat is on shore power so the smart charger can do its magic. I think, however, that Steve's point is that almost irrespective of use, I can gain some space, particularly the scarce height over the shaft coupling, by using gel batts for which a box is not so critical. I will have to decide whether to turn down the free wet cells in favor of several hundred dollars worth of gels, which might require less work to install.
Steve, as you know there is already a dirth of height in the aft berth. I have never actually used that berth. If I were to raise that berth a couple of inches to raise the top on the shaft/batt area, would it render the berth unusable as a practical matter?