36V run time/efficiency

jr.mnrd2184

Hello, all!

New to the hobby, I have built some classic "hot rods" and love projects! I originally bought this thing for my kids, and well that didn't last long!

So this was sort of a barn find, and this thing is in amazing shape. Besides a few rust spot the on the body, its a great staring point, and worth spending sometime and money on

I have been told by EZGO, that I a have 1983 Marathon(the SN was not being recognized). So for MY question, the cart runs great , and all works as it should. I have read a lot on the resistor style carts, and realize I am dealing with 1950's technology, but what is the "typical " run time on a cart this age?

I understand that the conversion must happen at some point, but for now, I would like to keep as much factory as possible(just like our classic cars). Any help would be greatly appreciated- and BTW this forum , has been a tremendous help thus far, lots of knowledge floating around!

BGW

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Sir Nuke

Hi....well to answer your question.....there are a lot of factors that go into the RUN TIME.
#1. The age of the batteries?
#2. what size (AH Rating) are the batteries?
#3. How have they been treated? (its a used cart so you might not know that answer)

One thing you should do is to go to cartsunlimited.net and read any and all things in the "battery info" section. This will give you all kinds of stuff to think about.

jr.mnrd2184

Thanks for you response,
#1. I replaced the batteries, after purchasing the cart
#2. I purchased Trojan T105s(new not recon)
#3. I have been following the "break in" instructions from Carts unlimited. so far so good

I guess my question is, how stock(or close to original) can I keep this cart, and still have decent ride time. I did install a jakes lift, and 23" tires, I am also satisfied with current speed and torque. I just want to make it as efficient(able) as possible with out converting to solid state.

hckymeyer

I have a 2006 TXT but same 36v system. I have the speed chip so does about 18mph. 12" rim with low profile tires.

I'm a golfer so can only relate the time/distance in that, but with fresh batteries driving on grass with a few rolling hills I can easily get 36-45 holes on one charge. That's with nice weather, as it get's colder that decreases.

I have an amp and speakers installed so I'm playing music the entire time, but figure that's 8+ hours of use and probably 10ish miles driven over that time.

coosa

I used an 84 Marathon for about 15 years as a work and hunting buggy and never did convert it. I would still be using it if the frame had not rusted in two. I have a couple of PDS carts now, and while they are much nicer to use, I don't think they have a lot more range than the old resistor cart. I had 22" tires on mine.

I tested the Marathon right after I got it by using it in a manner similar to how i would use it in the field. I ran it 3 miles every day and then tested the voltage to see if it was still above the 50% capacity level. It lasted 4 days, so about 12 miles before dropping below 50%. That test was probably hard on the batteries and shouldn't be repeated, but that was the way I was gonna have to use it. If you have read much here, then you already know to charge your batteries after every day of use.

Your resistor cart has decent efficiency only if you run it wide open. Run it half speed and the coils get red hot and are essentially wasting power to control the speed. But run it wide open and it's using that power to move the cart. I learned to drive mine by keeping the pedal down all the way, and letting completely off and coasting if the ground was too rough. If you drive it that way, I think your range will be good.

If you want a vintage cart, I don't see any reason you can't keep it like it is. The components aren't all that expensive and it's simple and easy to repair. Enjoy!

jr.mnrd2184

thanks for your response! A lot of good info, I am working through some wiring issues now(another thread lol) but once those are addressed, I will use your method to check my range. I don't plan on going down to 50% but at least I can have some sort of an idea.

JohnnieB

I find it amusing that you want to keep the drive train stock while bastardizing the cart mechanically and visually with a lift and tall tires. Of course the cars I built during my hot rod days were sleepers rather than all-show no-go.

Lifting the frame and body off the axles reduces the cart's stability by raising the center of gravity of a short wheelbase narrow track vehicle.
Taller than stock height tires reduce the amount of torque available where rubber meets road, so cart accelerates slower and slows more going uphill.

Fortunately, the taller tires have a greater circumference so the cart travels further for each tire revelation and the overall cart efficiency remains relatively constant.

While driving with your foot on the floor, there is little, if any, difference in cart efficiency between a resistor drive and a controller drive, however at anything less than WOT, the controller drive is far more efficient and the controller drive cart will travel further on a single battery charge under normal driving conditions.

JohnnieB

To get a reasonably accurate range estimate without unnecessarily aging your batteries by letting them sit overnight in a partially discharged state, measure the distance traveled with a GPS, wait half an hour after the drive to measure battery pack voltage and then crunch the numbers.

For example, when I was running a nearly stock PDS cart with T-105 batteries, my batteries started at 38.21V (100.0% SoC), I drove 12.7 miles over mixed terrain and surfaces, let battery voltage recover for 30 Minutes and measured 37.27V (74.0% SoC). So driving 12.7 miles reduced the battery pack's SoC by 26%, or 2.05% per Mile. We try not to discharge our battery packs below 50%, so 50 divided by 2.05 is 24.4 and my range estimate for that test run was 24.4 Miles on a single charge.

The only modifications to the drive train at the time were 2Ga cables and I was running in Mild Hill mode, so I had regen braking adding some energy back into the battery every time I lifted my foot off the pedal.

jr.mnrd2184

Honestly just not interested in spending $1200.00, on a cart that happeneds to be "all show and no go".

It will be used to ride around at UGA football games, no work, no long distances, basically a paved campground.

On the other hand , once I Get these things figured out, I plan on building something else

But as always thanks for your input, and the knowledge.

JohnnieB

Kidding aside, it sounds like you might be driving at something less than full throttle quite a bit due to being in congested areas. If so and the cart won't go as far as needed/desired, it can be converted to a 4 or 5-speed controller cart for little more than the cost of the controller and a few 1kΩ resistors.

An inexpensive controller with a 0-5K throttle input can be used and the existing wiper board and be modified to act as a 0-5K throttle, but in discrete steps rather than continuously variable. See attached picture.

Attached Images

Five-speed wiper switch.JPG (188.5 KB, 0 views)