After 30 years, the EZ-GO was ready for the new Century.
Our 1994 EZ-GO Marathon has been a fun and interesting project. We bought it in the fall of 2006 for $300 and it needed some work. Like most golf carts, it only went 11 MPH on stock wheels, and that was slow enough to be dangerous. The previous owner had used it on a farm, towing an old bed frame behind it, to "grade" his gravel road, so it was pretty beat up.
We found the roof for it (the owner said it was buried, literally, behind his garage) and installed that along with a tinted windshield. Mr. See put on a lift kit and I bought my first set of "Seely" Chinese off-road tires. It was a 36V cart and we added two more batteries to it along with a bypass switch and a diode (suggested by an online source). That boosted it to nearly 17 MPH, but when you hit that switch, it basically rocketed off.
Yes, it is a 36V motor running 48V and has been for over eight years.
I got tired of the diode thing and frankly, I think it fried the Curtis solid-state controller. 1994 was the first year for these - they are pretty standard on the newer EZ-GO TXT models, which were introduced around 1995 and are still in production. Those, of course, have a steel frame and a fiberglass "body." Our 1994 Marathon is all-steel and enameled like a brooch.
My neighbor moved away, leaving behind a broken aluminum folding yard cart, sans one wheel. I took it apart and cut it up and riveted it together to make a cargo box for the back and it has served us well for nearly a decade - but may go away soon.
It is a bit of a "found object" work of art. Mark won a Karoke machine at Bingo at a gay campground and I riveted it under the roof - it even lights up to the music. Of course, I added undercarriage chaser lights (132 different patterns! cheap on eBay) and a FIAMMA air horn, turn signals, and a brake light switch. A friend sold us a set of seatbelts for cheap. It was a rocking buggy!
After the controller died, I bought a new Curtis controller online for cheap. They showed a generic controller on the eBay listing but when it arrived, I was shocked to see it was a genuine Curtis (or a fake knock-off). It has worked well. More modern golf carts have electronic throttles, where the "gas" pedal sends a signal to the controller. Our cart has a Rube Goldberg linkage that disengages the brake and connects to a potentiometer (0-50 Ohms or something) to control speed. I ended up buying a new potentiometer as the old one broke. Thirty years is a long time!
Along the way, I made various small repairs. Last year, I put a new wheel bearing in the rear axle (which was harder than it sounds - stuff sticks together after 30 years!). Along the way, the new Seely tires went bald and I found a new set online - alloy wheels this time - for cheap. Nice street tread, too - no more noisy tires!
By now, we had over $2000 into our $300 cart and the original batteries, which the previous owner claimed were "nearly new" (suspiciously, one was an oddball battery) went South. Lead-acid batteries don't die all at once, but the range gets less and less and the cart gets slower and slower. We bought new "Duracell" 8V batteries (six of them) at Sam's Club - 12 month batteries. They lasted five years. This year, they barely were able to carry us to the historic district and back. And they started using a LOT of distilled water. It was time to move on or move up.
The local "buggy" place wants $14,000 for a de-luxe cart. Lowe's was selling Chinese-made carts with hydraulic disc brakes (!) for $9000 or so (probably ten grand when done). I thought about this but was wary that parts for a Chinese-made cart might be hard to come by.
New 12-month Duracell batteries, which were $89 apiece were now over $130. Fancy AGM batteries were close to $200 - a $1200 investment in a 30-year-old cart! I was aware of the "sunk cost fallacy" involved. Should I throw money at this three-decade old machine, or just junk it and start over?
I looked online and saw that Lithium-Ion batteries were not much more. You could buy four 12-volt Lithium-Ion batteries for under $1000. Or, you could buy a huge 48V battery pack with smart charger for about $1400. I thought about it and talked with the seller and decided to do it. The 12V batteries sounded like a better option, but they explained that I would have to charge them in parallel before connecting them in series so they would "learn" and I thought that was too complicated. The 12V batteries were slightly larger than the stock 8V batteries, so it would have involved some rearranging of the battery trays. So I went with the 48V pack and charger which arrived within a week.
The first step was to remove the old batteries - what a mess! Over the years, they spilled acid, needed water, and out-gassed hydrogen. One of the "repairs" I made over the years was to cut away the rusted-out battery brackets and bolt and rivet in new ones. I was going to have to clear some space for this new battery pack. Also, I wanted to seal up the compartment better, so road dirt wasn't being slung into the battery compartment. With lead-acid batteries, the whole thing is open to the road below and it gets filthy. They make these carts in a gas version, so I guess the open-ness works well for that - you need some air cooling.
A friend came by and was throwing away a set of shelves, so I took this as a sign from God and cut them up and filled in the battery trays. I added a thin piece of plywood (pilfered from a dumpster in the Historic district) to make it all nice and level. Then I put a thicker piece of plywood on top of that to make a nice flat load floor. I painted it all white with enamel paint so it would be easy to keep clean.
Nice clean work area now!
I did some measuring and realized that the new battery pack would not fit unless I moved three things. First, the Curtis Controller would have to move over. I puzzled about this for a while and realized I could rotate it 180 degrees and mount the potentiometer on the outside of the mounting bracket. That didn't take too long. The forward/reverse switch was a bit of a beast as its mounting bracket is welded in place. I used a cutoff saw to grind down the welds (sparks a-flying!) and mounted the bracket where the "ignition" switch was (riveting and bolting it in place). I put the ignition switch where the forward/reverse switch was - so no need to drill new holes in the body.
I cleaned all the connections and the components and used the larger gauge wires I bought for the batteries to replace some of the controller wires. I used my label maker to label each wire. It took some time, to say the least. I used some old PVC trim to enclose the center section. I will use some PVC flashing to seal off the side compartments, which I will use for the "smart" charger as well as the 12V power supplies for the accessory items (lights, turn signals, horn, stereo, etc.)
I hooked it all up and it worked. But first I charged the battery - it arrived 66% charged, which I know because THE BATTERY HAS BLUETOOTH!!! I wasn't expecting this but it really is a nice feature, as it the "smart" charger which is smarter than I am, as I hooked it up backwards and instead of exploding, it said "error!" I was pretty tired at that point - this has been a four or five day project and there are more days coming.
There is still some things to do. I need to secure the battery pack so it doesn't slide around. I also need to install the 12V power supply (on order) and wire that. AND.... I bought a back seat for the buggy as they were on sale for $270. Folds into a cargo platform, too! For years I wanted one, but since the Marathon is so old, they wanted $350 for them while TXT seats went for $275. I guess they decided to get rid of the Marathon seat inventory while they still can - not many of these buggies left on the road!
So there is still a lot to do. I just "finished" the install an hour ago and took it for a test ride around the block. Before, with new lead-acid batteries, they would charge up to 52 volts and at open throttle, it would be running at 48V tops - usually far less. Well, this thing charges up to 53.5 Volts and runs at 51 Volts! So it probably is going faster (I did not set up the GPS to check, I will update). Best of all, with Lithium-Ion, the voltage doesn't drop off as it discharges (as much as Lead-Acid does) so you don't have the "slower and slower" feeling.
Did I mention the battery pack weighs less than half of what the Lead-Acid batteries weigh? No water to monitor or add. No acid staining the floor or eating through metal. So far, at least, this has been a very good upgrade to the old buggy!
Which probably has over $4000 "invested" in it by now. Sunk cost fallacy strikes again!
