Battery mounting in Mac Classic

An anonymous user · Aug 10, 2011

vizwhiz said:
Have a 1995 26S (the one where the galley top is flip-flopped with the sink against the wall...not that it matters) .
Anyway, moved the batteries from the lazarette up to the space under the galley...for several reasons...but anyway, wanted to know if any Mac Classic drivers out there have the batteries located there, and how you mounted them? What did you anchor them to, what did you do for a base, how are you strapping the boxes down, etc. etc.??

Thanks in advance for help. Pics would be awesome! (or point me to a thread you know about that already answered this?)

Thats where the PO installed the battery in my 26S (1991). I will try and get some pictures of it this weekend. There is a metal strap around the battery attached to the wall that seperates the galley from the head.

Cruiser1 · Aug 10, 2011

My battery is stored under the galley. Sorry I have not got a photo of the battery itself but the attached photo shows the access door, under the sink, through which the battery goes.

My battery is just held in with a stainless steel strap about about 20mm wide and say 3mm thick. The S/S strap goes across the front of the battery and down each side about 30-40mm and connects up with bolts (with nuts) that come through from the head wall. I am in the process of installing a longer battery so now have to move one of the bolts along an inch or so and make another, longer, stainless steel band to hold it in place.

The battery sits up close to the sink drain pipe, against the head wall and on the flat fibreglass area under the sink. The new battery goes in the same place but extends out over the dip in the hull so I will have to put a 5-ply board underneath to give full support to the base of the new battery.

MrBill_FLL · Aug 10, 2011

mine are there.

I put some 1/4" ply wood down, after fiberglassing it, then glassed some wood blocks (for a group 27 box), and set them (2) in place. drilled the wood and blocks for straps.

the only thing is because my sink is toward the center my batts are not centered and the boat tends to list to stb a little at rest...

had I do do over, I'd put them in the Vberth... (its also a little tricky to water the batts if you don't have access from the top.)

& I use a turkey baster to water the wet cell batts...

GL!

doehunter · Aug 10, 2011

I have a '93 S, and my battery is like the others, strapped to the head wall, under the galley.
I think the space would be better used for other stuff so when I get around to it, my battery is going to the V berth, maybe along with a second battery.

I keep seeing references to "group 27 " batteries.
I have been using a trolling motor battery, I don't know what group it would be. What are the group 27's and why are they so popular?
Jim

PuckandTitania · Aug 11, 2011

I also have a '95 S. The battery is under the sink strapped to the head wall. I removed the stock SS strap and bolts because it was too small to fit around a marine style battery box. Instead, I threaded a nylon battery strap thru the bolt holes in the head wall and easily cinch the battery tight. No more bolts to struggle with. It made it a lot easier to slip the battery in and out.

Sumner · Aug 11, 2011

One of ours is like the others under the sink and I decided to leave it there as it is about in the center of the boat and behind the sink drain. It would be hard to use that area for anything else, so the battery stays. We do have 3-4 removable plastic tubs under there for storage.

When we removed the head and...

http://purplesagetradingpost.com/sumner/macgregor/inside-5.html

...enlarged the V-berth I added a....

.... second battery ahead of the old V-berth.

When the batteries...

...are no longer good I'm going to replace them with two 6 volt batteries since we run them combined in parallel all of the time now and the two 6 volt batteries will give us more amp/hours,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

MrBill_FLL · Aug 11, 2011

group 24 is the standard (small) car size.

group 27 is a little longer, and bigger.

and IIRC group 32 are the big boys, until you get into the '3 men and a boy' size (t-105) *IIRC* that you find on the 30+' sailboats..

*it might be the 4 or 8 D that you see on the big boats....

http://www.windsun.com/Batteries/Battery_FAQ.htm

U1 34 to 40 Amp hours 12 volts
Group 24 70-85 Amp hours 12 volts
Group 27 85-105 Amp hours 12 volts
Group 31 95-125 Amp hours 12 volts
4-D 180-215 Amp hours 12 volts
8-D 225-255 Amp hours 12 volts
Golf Cart & T-105 180 to 225 Amp hours 6 volts
L-16, L16HC etc. 340 to 415 Amp hours 6 volts

***(pls correct me if I'm wrong)

doehunter · Aug 11, 2011

MrBill_FLL said:
group 24 is the standard (small) car size.

group 27 is a little longer, and bigger.

and IIRC group 32 are the big boys, until you get into the '3 men and a boy' size (t-105) *IIRC* that you find on the 30+' sailboats..

*it might be the 4 or 8 D that you see on the big boats....

http://www.windsun.com/Batteries/Battery_FAQ.htm

U1 34 to 40 Amp hours 12 volts
Group 24 70-85 Amp hours 12 volts
Group 27 85-105 Amp hours 12 volts
Group 31 95-125 Amp hours 12 volts
4-D 180-215 Amp hours 12 volts
8-D 225-255 Amp hours 12 volts
Golf Cart & T-105 180 to 225 Amp hours 6 volts
L-16, L16HC etc. 340 to 415 Amp hours 6 volts

***(pls correct me if I'm wrong)

This forum is so educational!
I would guess my current battery is a group 24.
I bought a another trolling motor battery and found when I tried to put it in that it was bigger so I didn't install it. It comes along on overnighters if the kids are there. It must be a group 27.
When I get around to it, it's going under the V berth, but for now it runs my trolling motor on my fishing boat (that I haven't used since I got the Mac!)
Dang, so much to do, and only so much time and money...

Sumner · Aug 11, 2011

doehunter said:
...When I get around to it, it's going under the V berth, but for now it runs my trolling motor on my fishing boat (that I haven't used since I got the Mac!)
Dang, so much to do, and only so much time and money...

If you are going to mix the two batteries it isn't going to be a good deal. Our boat came with an older battery under the sink. Then I put in the second battery that was a Walmart RV battery that was a couple years old. I'd kept a trickle charger on it and it hadn't been used that much. The two batteries were different sizes and types and ages and usually showed significant different voltages. I would use one or the other with the A-B-Both switch and charged them separately with the gen-set. Walt got me to realize that I could charge them more efficiently if I charged them at the same time. That was fine, but I also needed to pull them down together and they just weren't matched so that didn't work well The oldest just didn't want to take a good charge.

So I replace the oldest with an Interstate RV type. Things were better, but now the Walmart battery was the old/different one. I finally gave up and bought a second Interstate like the first one. One does have an addition month or more usage on it. They will usually show the same voltage or at least within .1 of a volt.

When you get ready for the second battery install I'd try and put two new ones of the same type in or like I'm going to do use the golf cart batteries, they are not that expensive, $80-$100. Walt how do you like the two 6 volt setup? I believe that is what you are using and what influenced me, plus most larger boats that have 'house' battery banks use the 6 volt batteries,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

walt · Aug 11, 2011

I have never had a "battery switch" only one big battery that is on a charge monitor so I know what my single battery is doing rather than having two batteries that I sort of know the state of charge- so this has somewhat influenced what I’ve got.

Originally the one "big battery" was two 12V group 27 batteries which were always in parallel. I abused them pretty bad by not checking the water often enough at first but did check the water later and always found that one battery took WAY more water than the other.

When I replaced the 12 volt batteries, I went to two six volt in series - still 12 volts. I’ve had this now for almost two years and now when I check the water level, both batteries use just a little water and also take about the same amount of water..

Good or bad... don’t know but this did seem to solve the problem of one battery having the water boiled out of it.

FYI, my two six volt batteries are as far forward under the Vberth as I could get them. I cut some access hatches to try and make it easy to maintain the water (since I was SO bad about this the first year I had the boat)..

doehunter · Aug 11, 2011

Hmmm,
I got so used to assuming that all the new batteries were "sealed" that it's been a really long time since I tried checking the water. Aren't all the new trolling motor batteries supposed to be "maintenance free, and sealed" ?
I only checked them after they were a few years old and didn't seem to work very well any more. Usually they would be low.
If they are low, I have been told to use distilled water, and I didn't bother with that either! If I do it right, do I use distilled water, and what about the acid?

timebandit · Aug 14, 2011

Distilled water will make your batteries last longer.

Durring the charge and discharge hydrogen and oxygen are released so that all you need to replace is H2O.

I use a turkey baster because if you over fill you can remove some.

doehunter said:
Hmmm,
I got so used to assuming that all the new batteries were "sealed" that it's been a really long time since I tried checking the water. Aren't all the new trolling motor batteries supposed to be "maintenance free, and sealed" ?
I only checked them after they were a few years old and didn't seem to work very well any more. Usually they would be low.
If they are low, I have been told to use distilled water, and I didn't bother with that either! If I do it right, do I use distilled water, and what about the acid?

Battery mounting in Mac Classic

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