More ER space needed

I have a 1976 Gulfstar with the fiberglass fuel tank. I need space to mount a large house battery bank. I was thinking about glassing a thick sheet of marine plywood painted with bilge coat gray to the top of the tank towards the front of the boat. Then using 5200 and short screw that would not penetrate the fuel tank. Has anyone done something similar? If you have done something different or similar please tell me what you have done. I will be mounting one double 8D battery enclosure made by AC DC Inc. They have some unique good marine products. I just purchased their 2 bilge pump switch assembly that includes a counter to see if there is an increase in bilge pump operations over a time period indicating a potential problem.
Thanks for any input on mounting the house battery bank.
Bill

Maybe examine the possibility of using AGMs and installing in unorthodox mounting orientations?

I'm also considering multiple 6V AGMs when we eventually need to replace one bank... 'cause I can't deal with the weight of 8Ds.

-Chris

I am using AGM batteries the DEKA Unigy1 series 105AH 12VDC version. I want the weight to be in the center of the vessel. 4 of these batteries are the similar to 2 8D batteries. Hence the reason I bought the AC DC Inc 2 8D battery box. I have 8 of these batteries they are new.
Since I will initially start out with 200 watts of 24-28VDC solar and an AIR-X 24-28 wind generator into smart controllers to charge a 12-14VDC house bank. I figure I might be able to use a small 420AH house bank. However I'm prepared to go as high a 840AH's if needed.
Bill

So a typical 8D box holds two Group 31s? Or the AC DC box holds two 8Ds or four Group 31s?

-Chris

Bigger boat, Bill- bigger boat

Chris the Deka Unigy1 105AH cells are narrower compared to a group 31. The AC DC dual 8D box dimensions are the same as 2 8Ds side by side.
Bill

Pau Hana said:

Bigger boat, Bill- bigger boat

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I'm downsizing.
Bill

Chris I can't answer your question I haven't tried to install any group 31's in this new battery enclosure. All my 31 series batteries in my Mainship 40SB are all in individual battery boxes sized for group 31 batteries. Since I'm using DEKA Unigy1 105AH 12VDC cells they are narrower then a 31 series battery.
Bill

Chris here's the DEKA spec for the house batteries I have. Mine are the gray top flame retardant version.

http://www.apeximg.com/spec/31HR4000S.pdf


Deka/Unigy 31HR4000S UPS Battery (12V, 105AH)

Thanks. Given the 105 Ah, I just assumed Group 31s. Useful to know yours are narrower...

I've been eyeballing the space where my starboard bank lives -- 3x Group 31s -- in peaceful coexistence with my genset battery (1x Group 34), and 4x 6V deep cycles will fit there without displacing the genset battery. That would increase that bank from 300 Ah to about 450 Ah... and maybe more if I have enough clearance to use the slightly taller 6Vs.

I also confirmed that new 6V bank would still supply enough CCAs to start that engine...

Don't actually need to do anything until that bank goes south, but we're starting our 9th season on 'em... so I've been shopping for battery boxes, too

-Chris

Chris, I found AC DC Inc on EBay but I believe they have a website. They have all kinds of unique marine products.
Bill

ranger42c said:

Thanks. Given the 105 Ah, I just assumed Group 31s. Useful to know yours are narrower...

I've been eyeballing the space where my starboard bank lives -- 3x Group 31s -- in peaceful coexistence with my genset battery (1x Group 34), and 4x 6V deep cycles will fit there without displacing the genset battery. That would increase that bank from 300 Ah to about 450 Ah... and maybe more if I have enough clearance to use the slightly taller 6Vs.

I also confirmed that new 6V bank would still supply enough CCAs to start that engine...

Don't actually need to do anything until that bank goes south, but we're starting our 9th season on 'em... so I've been shopping for battery boxes, too

-Chris

Click to expand...

To further complicate this DEKA calls these 31 hour batteries in some of their marketing....
Bill

That's a strange looking battery Bill with odd ball terminals for use as a UPS battery replacement. What made you go with those? They are about the same price as the tried and true Sears Platinum marine AGM made by Odyssey with similar specs.

caltexflanc said:

That's a strange looking battery Bill with odd ball terminals for use as a UPS battery replacement. What made you go with those? They are about the same price as the tried and true Sears Platinum marine AGM made by Odyssey with similar specs.

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I got 8 brand new ones for FREE George, so the price was right. Also if I remove the top caps it has a larger conductive surface with a large headed machined hold down nuts on the + and - terminals. These are used in Alcatel Lucent NV MMBTS battery back up systems.
Bill

Free is good! So what type of terminal do you use?

caltexflanc said:

Free is good! So what type of terminal do you use?

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I will be using Anchor 3/8ths single hole lugs using #2/0 tinned stranded wire. My inverter will be less than 6' round trip. The inverter is a 2000 watt pure sine wave ProMariner that also has a 70 amp smart charger. The DC house primary panel (<60 amps) is within 8 feet round trip and a high current (<60 amp) sub panel will be 20 feet round trip.
Bill

I got thrown off because the specs and pics indicated a female terminal on the battery; so you thread a stud in there?

caltexflanc said:

I got thrown off because the specs and pics indicated a female terminal on the battery; so you thread a stud in there?

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Yes there is are female threads on the top of the battery under a safety ABS cap it has a knurled fitting about .7" in diameter with an Allen key used to remove or tighten it. These hold L backets that can be removed that have 1/4" threaded posts on the front side of the battery. The 1/4" threaded posts would only be good for a medium/ low current ( like my Balmar Battery Smartmeter) connections these studs come with black and red protection caps.
It's a bit difficult to describe.
Bill

Billylll said:

Chris, I found AC DC Inc on EBay but I believe they have a website. They have all kinds of unique marine products.
Bill

Click to expand...

Thanks, I'll check that out.

-Chris

I'm in the process of turning the aft bench of the dinette on my 36MKII into a battery box. I took the top off and made a hinged lid that seals with a gasket and vented the area through the bulkhead into the ER. Am now glassing the inside of the bench. I can get 6 or 8 golf cart batteries plus switches and busbars in the space.

On The Rocks said:

I'm in the process of turning the aft bench of the dinette on my 36MKII into a battery box. I took the top off and made a hinged lid that seals with a gasket and vented the area through the bulkhead into the ER. Am now glassing the inside of the bench. I can get 6 or 8 golf cart batteries plus switches and busbars in the space.

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What about the gasses that lead/acid batts give off?

N4712 said:

What about the gasses that lead/acid batts give off?

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Vented into engine compartment per OP

boatpoker said:

Vented into engine compartment per OP

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Oh ok, that makes sense.

On The Rocks said:

I'm in the process of turning the aft bench of the dinette on my 36MKII into a battery box. I took the top off and made a hinged lid that seals with a gasket and vented the area through the bulkhead into the ER. Am now glassing the inside of the bench. I can get 6 or 8 golf cart batteries plus switches and busbars in the space.

Click to expand...

Are you talking about the dinette seat that is in the forward cabin across from the galley? I assume the one that backs up into the vertical raised floor where the engine room is?
I guess this could be a good alternative but I wanted the weight centered and lower above the belly diesel tank forward near the ER's bow facing wall.
Bill

Bill,
I used 5200 to attach a 2' length of 2x2 spruce to the side of my aluminum fuel tank. This 2x2 supports a plywood shelf on which I often stand while climbing in or out of the cockpit locker. Mounting your 3/4 ply baseplate to the top of your fiberglass tank is easy. You won't need the screws. Just be sure you want that ply there FOREVER.

richterpooh said:

Bill,
I used 5200 to attach a 2' length of 2x2 spruce to the side of my aluminum fuel tank. This 2x2 supports a plywood shelf on which I often stand while climbing in or out of the cockpit locker. Mounting your 3/4 ply baseplate to the top of your fiberglass tank is easy. You won't need the screws. Just be sure you want that ply there FOREVER.

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Thanks Mark, I agree now I'm wondering if I can 5200 the dual 8D battery box directly on top of the FRP belly tank? I wanted the 3/4 marine plywood to spread the load out. I may have answered my own question....
Bill

Billylll said:

Are you talking about the dinette seat that is in the forward cabin across from the galley? I assume the one that backs up into the vertical raised floor where the engine room is?

I guess this could be a good alternative but I wanted the weight centered and lower above the belly diesel tank forward near the ER's bow facing wall.

Bill

Click to expand...

Yes that's the location I chose. You are correct that it isn't on the center line. I'll put the batteries as close to center as I can. It is about the same level as the top of the fuel tank. My generator is mounted on top of the fuel tank.

Interesting my generator is mounted at the rear wall of the ER against the bulkhead to the aft cabin, locker and aft head. It's mounted sideways with the weight on dead center.
Bill

BillyIII

Do I understand this correctly? You are thinking of mounting two 8-Ds on top of a fiberglass fuel tank.

If that is correct I am concerned that the tank is not designed to hold that amount of weight on its top, and second that by putting that amount of weight above the hull level you may affect the stability of the boat.

Can you move something else to the top of the tank, say fresh water pump, racors, anything that wouldn't have the weight of a battery bank?

The weight would be spreadout using an oversized 3/4" piece of marine plywood painted bilge coat gray. The tanks very thick there's no way 4 DEKA Unigy 1's spread out over a large area could compromise the thick FRP belly tank. I'm also told by another owner of the same model that there is a thick FRP cover over the area I want to install the battery bank on. I want the weight dead center of the boat. Another Gulfstar owner has his generator mounted where I want to put the house bank. It's a relatively small house bank 420AH's but because I'm using solar and wind alternative charging I shouldn't need a larger house bank. The cover over the tank is where everyone stands who has ever worked in the ER.
Bill