Golf Cart Batteries

[esc]

I've had some experience with GC batteries in a renewable energy setting and believe that they are a very cost effective solution. I just installed a pair (2 x 6v x 220 amp hour=1 x 12v x 220 amp hour) I had laying around to replace the dead marine deep cycle batteries that my X had when I bought it. Right now I only have 1 battery bank for my off-1-all-2 switch, but I will fix that soon.

A good rule of thumb when evaluating batteries is to compare how much they weigh. The GC batteries I used (to replace the dead Marine starting batteries that were in my boat) weigh almost twice as much but have the same foot print and are only a little taller. The difference, as mentioned earlier, is in the lead. The more substantial lead plates will endure a lot more abuse over a longer period of time.

[Québec 1]

Are you saying that 2 six volt GC batteries can fit in the same spot as 1 12 volt battery?
Q!

[bartmac]

The ability to use or obtain batteries at a discount will obviously effect one's choice however the steering away from anything automotive and more deep cycle would have to be an overiding determinant.The choice of LED's in all lighting has reduced the load of one catagory,the other loads are similarly either intermitent or able to be minimised which just leaves refridgeration.....24/7 and obviously largely effected by load and ambient temperatures.
The view that a battery is a "tank" containing 12 vdc and that empty is 100% will quickly ruin all batteries other than some of the new fangled ones ie LI ion which are not yet available at reasonable cost for our application.

[esc]

Are you saying that 2 six volt GC batteries can fit in the same spot as 1 12 volt battery?

No, not at all.
I am saying that I placed two 6V GC batteries where two 12V Marine cranking batteries used to be.
Now I have one 12V battery bank, with almost 2 times the amp hours (220) of the previous two 12 volt batteries(~60 amp hours each,just a guess) combined.

I will soon be adding a second 12V circuit (probably 1 small 12V battery) for emergency engine starting power.

I will be using a combination of wind, solar and engine charging.

[seahouse]

Hi All-

As HaminX says, the term “Golf Cart Battery” refers to the external dimensions of a battery. It gives no indication of the density, alloy or thickness of the plates, or the robustness of the construction of the battery, which vary considerably. As you say seafarer, they tend to have a higher AH range ratings than regular deep cycle 12V batteries. So that's good advice to go by price (higher better) and name brand labels if buying these.

AGMs are recombinant batteries. They operate within a sealed case and the oxygen and hydrogen gases produced are contained within the battery and recombine into water during charging. This creates a small internal pressure which is valve-controlled and excessive pressure is released to the outside should unusual circumstances occur. Their lower internal resistance means they don’t heat up under high charge/discharge current, so the pressure buildup from heat is slight.

AGMs are also more robust, won’t freeze, and won’t leak even if the case is broken open.

I think the risk from a flooded cell battery in an enclosed living space is more from the acid vapours and fumes than from the hydrogen gas. Before you can actually smell them you will get a tickling in the back of your throat and then a dry cough. Had this happen once until I figured out what was causing the mysterious dry cough.

I concurr Norca - because of their high price AGMs are certainly not the economical choice when compared to the conventional flooded-cell batteries. But if you need/want their features they are the choice to make, and inside the living space such as in a Mac they are ideal.

Esc- I agree - good point, the weight of a battery will be greater if the plates are thicker and less spongy, which are both desirable characteristics in a deep cycle battery. Of course, not necessarily so in a starting battery.

There are batteries on the market that have a vent tube fitting built in for dispersion of gases/ vapours (I have one on my motorcycle, and one on my car), and car starting batteries, but I have not yet seen a deep cycle battery so equipped. Has anyone out there seen one?

Regards- Brian.

[ROAD Soldier]

Are you saying that 2 six volt GC batteries can fit in the same spot as 1 12 volt battery?

No, not at all.
I am saying that I placed two 6V GC batteries where two 12V Marine cranking batteries used to be.
Now I have one 12V battery bank, with almost 2 times the amp hours (220) of the previous two 12 volt batteries(~60 amp hours each,just a guess) combined.

I will soon be adding a second 12V circuit (probably 1 small 12V battery) for emergency engine starting power.

Dude you got more amps then my strictly 2 deep cycle 12 batteries hooked together to a 3rd purely start battery with a battery combiner. The combiner cuts the start battery out when voltage reaches below 12V and comes on when batteries are receiving a charge. The Wal-Mart Deep Cycles are 75amp/hr each. I hope you are not using those batteries to start you engine though. It is not good to make think lead plate batteries to discharge a large amount of current at one time like what is used to start an engine. That is where Cold Cranking Start Batteries come in with their thin lead plates that allow them to discharge quickly without damage.

[esc]

I AM using them to start the engine. Remember these batteries(+4 more just like them) are designed to run 8 to 12 HP electric motors all day long. So 2 of the 6 are routinely expect to power the equivalent of 2.6 to 4 hp electric motors for extended periods.

I would be surprised if the starter were more than 4 HP, but even if it were we are talking about VERY intermittent use, so I think it would be fine.

They are also great for a big trolling motor.

[DaveB]

I have two Walmart group 27 Marine deep cycle batteries for house and a 24 group starter with a combiner. Charging I have a automatic 10 amp built-in that will charge the house and starter batteries separately and have it hooked up to AC when on trailer. I like this system and have only topped off fluid once in two years.
I had a Compac 19 with two golf cart batteries and I also liked that.
I work in a water park with 2-golf carts, one with 24 volt (4 batteries) and one with 36 volt (6 batteries) the life guards beat these cart up by using them as a toy and many times become air born slamming to the ground breaking steel battery boxes and going thru mud and water soaking batteries. They also often forget to plug them up for recharge every night. (charge at 22 amps than dropping down) I top the fluid off every month and usually get 3-4 years use out of the batteries.
The Golf Cart batteries have thicker lead plates and will stand up to abuse longer than the Walmart ones and the costs are about the same, the warranty is usually longer with the golf cart batteries.
Make sure you always have fluid over the plates, don't discharge over 50% and recharge as quickly as possible for long battery life.
Dave

I've read several threads that have mentioned using Golf Cart Batteries but haven't seen any that dealt directly with this topic.

In addition to the "start" battery I was planning on installing a pair of Walmart Group 24 or 27 "house" batteries as the Admiral expects many of the comforts of home on our . (She still thinks it's a trailer! ) I've ordered an "Add-a battery" switch and combiner (and new distribution panels, a solar panel, battery charger and shore power inlet) but now I'm reconsidering my battery choice.

Pros-Cons?

Any advice?

Thanks,
Russell

[hoaglandr]

Thanks for all the feed back.

Sounds like I can get more amp-hours with GC batteries. I think it will come down to price.

Either way I go I should get good results as long as I take care of my batteries.

Question - Do I need to use a battery box and if so, how does that allow for the ventilation I need? The existing start battery is under the step and has no box. Shouldn't it have been ventilated?

I am planning on putting my batteries, charger, combiner, etc under the step compartment and the adjoining dinette seat. Is this an acceptable location on the M or do I need to put it under the vee? My thought was to keep all the cable runs as short as possible.

Thank Bartmac for the comment about the LED's. I will add that to my list as I begin the upgrade of the electrical systems. Reducing demand is certainly an important part of the equation.

Russell

[March]

The batteries breathe through the caps. If you could find an adequate container to keep them together and connect them in series (as Catigale duly pointed out) that'll keep them in one place, rather than having them strapped separately. That shouldn't be an issue as long as the container has no top.
If you use battery-gauge wires, it shouldn't matter too much if you put them under the step or under the V berth. One of my batteries is under the starboard seat, but it has a long cable which goes all the way to the v-berth and then back to the port, under the galley, where I have the combiner and the electronics. It's been working just fine.
People put the batteries under the v-berth for a better balance. Whatever works for you, and gives you easy access.
I am curious about your setup. Still not convinced that the GK 6 volt combination (in series, as duly pointed out) is the way to go--

[DaveB]

My WM group 27 are 105 amp hrs each. A 6 volt GC battery is usually the same but the size of a group 24.All depends on the battery you buy as they differ in amp hrs in price and quality. two WM group 27 equals 210 amp hrs. two GC batteries equal 210 amps. the GC batteries are in series, the WM 12volts are parallel.
Another option is a gel battery that is deep cycle and can take longer discharge than a wet cell battery and can operate at any position and no gasses.
I had one on my Potter 19 and can withstand deep discharge for long periods and still come back to normal.
Most people prefer the GC or WM wet cells as they are much less cost and under normal condition and care will give you 4-5 years or more service.
Both WM Group27 and a middle grade 6 volt GC will cost $80.
I have both my house batteries centered under Vberth for weight balance on boat,and would recommend it highly for heavy loads aft. (larger engine,fuel etc.)
Dave

Thanks for all the feed back.

Sounds like I can get more amp-hours with GC batteries. I think it will come down to price.

Either way I go I should get good results as long as I take care of my batteries.

Question - Do I need to use a battery box and if so, how does that allow for the ventilation I need? The existing start battery is under the step and has no box. Shouldn't it have been ventilated?

I am planning on putting my batteries, charger, combiner, etc under the step compartment and the adjoining dinette seat. Is this an acceptable location on the M or do I need to put it under the vee? My thought was to keep all the cable runs as short as possible.

Thank Bartmac for the comment about the LED's. I will add that to my list as I begin the upgrade of the electrical systems. Reducing demand is certainly an important part of the equation.

Russell

[hoaglandr]

March - thanks for the clarification on the battery box. I keep picturing the one on my trailer that has a lid. I guess the main goal here is to contain any spills?

I haven't really gone shopping for the batteries yet. Just trying to consider all the options before I started shelling out the money. AGM's sound great but might not be in the budget. (Not that I've really stuck to it thus far). I'll have to price out all the options and then make a decision based upon all the great advice I got here.

Dave and March - thanks for the advice on the forward location. I think I've read other posts that had indicated the weight forward was a better choice. With the gas tanks and motor and all the other stuff stowed aft that makes a lot of sense.

Hopefully I can get started on this project soon. I've purchased most of the stuff I need and the batteries are one of the last pieces of the puzzle.

Russell

[Catigale]

Iirc my mercury bf 50 starter pulls about 150 amps on starting

That would make it a 2.5 HP device, tops ... And probably less than this

[esc]

Iirc my mercury bf 50 starter pulls about 150 amps on starting

That would make it a 2.5 HP device, tops ... And probably less than this

That's about what I expected. I think that the GC batteries would burn out the starter before running out of juice or suffering any harm themselves. But I'm sure that everyone knows better than to run a starter continuously for any length of time.