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11-11-2014, 11:12 AM | #1 |
Not Yet Wild
Join Date: Nov 2014
Posts: 4
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Aging Batteries in a Golf Cart Fleet
We have a family owned golf course that has a fleet of older 2005 EZGO 36V golf carts. We are on our 2nd set of Trojan batteries. The current batteries are the T-105.
It has been close to 2 years now on the second set, and we are seeing some of the carts that die before 18 holes, while others will go 36 holes+ and seemingly never lose power. What causes this indiscrepancy? The funny thing, and one of my main questions this: the same carts, say #24 that will still go 36+ holes did the same thing with the 1st set of Trojans. It was like a "Superman" cart. While other carts, say #6, is a "Dog" cart with the 1st set and now also the 2nd set of Trojans. All of the carts are maintained the same way. They are rotated to different chargers. They are rotated into service. What can be causing these "Dog" carts to be draining/aging the batteries more quickly than the "Superman" carts. Are there any components in the motor or elsewhere that can prematurely age batteries? Thank you so much for your input in solving this issue. |
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11-11-2014, 12:26 PM | #2 |
Gone Wild
Join Date: Dec 2009
Location: Aiken, SC
Posts: 12,955
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Re: Aging Batteries in a Golf Cart Fleet
You could have some brakes dragging, lower air pressure in the tires, wheel bearing going bad, the list continues.. And sometimes you just get a bad battery.. Problem with that is that bad one can drag the others down as well. Buy yourself a load tester and a hydrometer and test the weaker carts..
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11-11-2014, 01:30 PM | #3 |
Techno-Nerd
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
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Re: Aging Batteries in a Golf Cart Fleet
Are the carts identical?
2005 EZGO carts came with two different drive system (Series and Sepex) and they came with three different type motors in each drive system (Standard, Hi-Speed or Hi-Torque), so there are six variants and each would use a different amount of energy over the same distance traveled over the same terrain. Roughly, how many miles are driven for 18 holes at your course? What are the pack voltages before they are sent out? |
11-11-2014, 01:58 PM | #4 |
Not Yet Wild
Join Date: Nov 2014
Posts: 4
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Re: Aging Batteries in a Golf Cart Fleet
Interesting info about the drive systems. That is the angle I was investigating. It can't be a coincidence that the same "dog" carts have become weakest first, with 2different sets of batteries unless for some reason they are using more energy over the same amount of time as the "strong" carts
To drive 18 holes would be approximately 4.8 miles. I will have to check with my car man to get the pack voltages. What reading should I be looking for there? |
11-11-2014, 02:10 PM | #5 |
Not Yet Wild
Join Date: Nov 2014
Posts: 4
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Re: Aging Batteries in a Golf Cart Fleet
How would I identify the drive systems and motor types? And where might I find out technical info for these systems like energy use?
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11-11-2014, 02:53 PM | #6 |
Techno-Nerd
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
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Re: Aging Batteries in a Golf Cart Fleet
If the F/R lever is by your right knee, it is a series cart (Series wound motor).
If the F/R selector is a rocker switch on the dash, it is a PDS (Sepex motor) For what type motor, you have to get the model number off the label on the motor. A fully charged 36V pack made up of T-105 batteries ought to read about 38.2V. Each battery ought to read about 6.37V and all six ought to be within 0.1V of each other. ------------ If you have an automatic battery watering system, that may be a source of some battery issues. Floats stick and cells get overfilled, effectively lowering the acid concentration in the overfilled cells. However, with a new set of batteries, both the dogs and the super-carts would run about the same distance until the batteries got overfilled repeatedly by a faulty filling system. So this probably isn't what you are seeing. ------------ Theoretically, all you cart should have a top speed of about 12-14 MPH and the battery packs should have a run-time of about an hour, so they all should travel about 12-14 miles, or 36+ Holes at 5 Miles per 18 holes. However, in the real world it is going to depend on how the cart is driven and the load they are carrying. Heavy loads and jackrabbit starts reduce the max range, as do hills and cooler weather. |
11-12-2014, 08:08 AM | #7 |
Not Yet Wild
Join Date: Nov 2014
Posts: 4
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Re: Aging Batteries in a Golf Cart Fleet
Thanks JohnnieB.
We usually get 3-4 years out of new batteries. These 2005 EZGO carts are averaging about 2 years on new batteries. Strange. |
11-12-2014, 10:29 AM | #8 |
Techno-Nerd
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
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Re: Aging Batteries in a Golf Cart Fleet
The two major factors influencing the useful lifespan of cart batteries are the temperature they are exposed to and the average SoC (State of Charge) maintained throughout their life. (There are other factors, but those two are the biggies.)
The temperature of the geographic area is outside our control, but the average annual temperature probably hasn't varied much over the last decade, so the difference in lifespan would probably be related to average SoC maintained and the number of charge cycles designed into the batteries at the time of manufacturer. Trojan undoubtedly will claim their newer battery designs will last as long, if not longer, than their older battery designs, so the average SoC the batteries is decreasing. SoC is the percent of the storage capacity of the battery less the energy removed from it and a battery's storage capacity decreases as it ages, so as battery ages, the amount the SoC drops on the same trip increases. For example: After being broken in properly, a new T-105 will have a storage capacity of about 225AH, and if 67.5AH are withdrawn, the resultant SoC will be 70%. However, after the storage capacity decreases down to 200AH through though the normal aging process, the same withdrawal take the resultant SoC down to 66%, so it ages faster. Another way of looking at it is that playing 18 holes and recharging the battery uses one charge cycle, while doubling the amount of energy used by playing 36 holes rather than 18, uses three charge cycles rather than just two. I have no idea of how your rental process is set up, but putting the batteries on charge (doesn't have to be a full charge) between rounds, will increase average battery lifespan for the fleet. ------------- There are differences in efficiency of the individual carts that may be mechanical related or electrically related, or both, and they need to be identified and addressed. I'm speculating, but I suspect if you tied a rope in the towing point on the front of the cart and connected something like a 100 lb fishing scale to the other end of the rope and then pulled the cart on a level hard surface, you'd see a considerable difference in how much force it takes to get the "Dogs" and the "Super-Carts" rolling. For the electrical part, note the SoC of each cart's battery pact before it is sent out on the course and after it is returned. That along with the number of holes played, will give you a rough idea of the electrical differences between the carts. |
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