Golf Cart Batteries
Golf cart
batteries are one
of the most versatile batteries readily available
for either a small home, cabin or for someone just starting
to live off the grid. Some may think that this lowly
battery has no place in the real world of energy storage, but it
is applicable in some situations and can be relatively cost
effective.This battery is typically referred to as "golf car" or "golf cart" battery. We are not golfers so therefore do not know the intricacies that make the distinction between a cart or car so we will stick with "golf cart" from here on.
At first glance it looks like something you might pull out of an automobile or truck that is used for engine starting. The difference being it only has three cells as opposed to six in a starting battery. There is an 8 volt golf car battery but the vast majority are the 6 volt type. While an 8 volt battery may be an advantage in a vehicle to reduce weight, for renewable energy storage the 6 volt will be more cost effective.
Most likely if you have had any exposure to renewable energy storage, you already know that a car starting battery is an extremely poor choice for socking away those ampere hours for later use. But, if you have been hanging around the battery section at the department store, you may have also seen something that looks like a car battery, it's 12 volt, contains "deep cycle" in the description and sells for a reasonable price. You go home thinking that you have found the secret to the high cost of storage batteries. Before you decide to go back and load up your truck with this cheap solution, let's look at the drawbacks.
Why use Golf Cart batteries over a Marine Deep cycle or Auto battery?
We all know that the lead acid batteries are chemical storage containers and can exhibit different characteristic depending on how they are constructed. With the 12 volt car starting battery, there are twice as many thin plates in comparison to the 6 volt golf cart batteries. The starting battery has much more plate exposure resulting in it being able to give up a lot of electrons in short bursts. On the other side, heavy charge-discharge cycles for prolonged periods of time can distort and damage the thin, delicate plates. Furthermore, the positive plates will corrode much faster than a true deep cycle battery - which results in a very short lifespan.6 volt golf cart batteries, with its thicker plates, are able to endure long periods of deep discharging and recharging with less effect on its life span.
A product that can be tempting for a first-time battery buyer is the Group 24 or 27 RV or Marine deep cycle battery. These can be found at auto parts stores, department stores and discount warehouses. This particular battery comes up in discussions often enough to know that people are taking serious look at one of these for their house system. They are 12 volt batteries and it doesn't matter what "new" technology they advertise, they are still a cross between a starting and deep cycle design.
Power-Point |
To explain it in cost effective detail, let's look at how many ampere hours (AH) you can draw out of a Group 27, 12 volt dual purpose battery, versus a typical GC-2 golf cart 6 volt battery. As an example we will use a comparison of the West Marine brand to avoid mixing different brands and pricing structures.
The Group 27 battery cost $120, has an advertised discharge life cycle of 200 and is rated at an AH capacity of 80. The GC-2 costs $190, life cycle of 700 and is rated at an AH capacity of 215. We will use 2 Group 27 batteries connected in parallel to maintain 12 volts and provide a 160 AH capacity. Two GC-2's will be hooked in series to provide 12 volts and a 215 AH capacity.
Battery Type |
Amp Hour Capacity | Cycle Life | Total Battery Cost | Total AH's provided at 80% DOD* | Lifetime Cost per 100 AH's |
| Group 27 | 160 | 200 | $240 | 25,600 | $0.94 |
| GC-2 | 215 | 700 | $380 | 120,400 | $0.32 |
*The depth of discharge is not specified for either battery so the assumed 80% DOD is only for comparison purposes.
According to the spec's provided, the more expensive GC-2's will actually cost a third that of the cheaper Group 27. As far as comparing various brands, the plate thickness will be one of the top determining factors that you can use as a general guide. The only problem you will encounter is this number is not typically published in the spec's for the GC-2 type of battery.
Something else that will complicate matters is the variation in manufacturers with various "store brands". For example Costco, Sams Club and Walmart may carry the GC-2 but it will most likely have a store label instead of the company that actually made it. To compound this problem, the contracts for these batteries can vary from state to state and from time to time according to who has the lowest bid. This will mean that the Sams Club golf cart batteries your buddy purchased 3 years ago and is still going strong, may not be the same battery today. If you think golf cart batteries are right for you, several inquires might land you more specific and helpful information.
The problem that makes it hard to turn down the Warehouse Club golf cart battery is the price. We have found them to be the cheapest, by far, than any other source.
Our Experience with Golf Cart Batteries
The third set of batteries to store power for the Ranch was a set of Sams Club GC-2's. We had two sets of eight hooked in series and then each bank was connected to a buss bar for a 420 AH capacity. These lasted 12 months. Thinking that maybe we just got a bad batch, we tried the same thing again. Twelve months later we were again looking at 16 depleted little batteries.
We kept them charged, watered and clean and didn't abuse them with microwaves and such. The largest DOD they were subjected to was 35% with the average more like 20% - 25%. Even if you considered each day for a year as a "cycle" that would be only be 365 which is short of the average 500 which we see on a lot of charts. If we had been hammering them daily with high load devices, this might be understandable but the typical draw we have is in the 3 - 10 ampere range. One thought was that we should have added another bank of 8 the second time around, for a total of 24 to ease the average load per battery.
Do You Use Golf Cart Batteries?
What is your experience with golf cart batteries? Do you have a favorite brand or source you buy from? You can help others by voicing your opinion!
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Golf Cart Batteries in my camper
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I have had Golf Cart Batteries in my camper that I have lived in for 16 years. I tend to get 7 years of life or so from my 4 batteries. At one point ...
