91 marathon, new guy trying to figure it out!

[jnmiller]

When I moved into my new house we were able to get the previous owner to throw in the golf cart, but she needs a little love. From the serial number I've found it's an 36 volt 1991 EZ-GO marathon, and I think I've deduced that it's a non-resistor series cart. This cart is a neighborhood cruiser and yard machine.

This will be the 3rd summer with it and the first summer i didn't do much, just charged it up, drove it and enjoyed it. Top speed with full charge was 8 mph.

Last year it was pretty unreliable for distance so we kept our trips short and charged it up every time we got back. Now she barely gets to the end of the driveway. I'm testing the batteries with a volt meter and will add that to the writeup here when I get home. I know I have 2 batteries that are toast reading around 4 volts and that the best route is probably to buy all new batteries. I know the previous owner would change batteries individually as they went bad and I never even thought as to check the water level or do any charging maintenance over winter.

Edit to add battery voltage

6.59
4.20
6.4
6.71
6.10
4.22


-What sort of top speed should I expect with a new battery pack? Is it stupid to keep the 3 seemingly newer and good batteries and add 3 brand new ones?

-Should I upgrade the charger? If not, can I overcharge the new pack if I charge it after each use/or monthly during winter? What is the significance of the amperes rating? I don't know how to read it and I don't have a manual. The charger is in the photo below, but I can't tell if it's timed or would float batteries in maintenance mode after full charge(if that's even a thing). I think it's timed due to the operating instructions but I don't know what implications, if any, would come of charging it starting at the "1" after driving it for say 15 minutes. I keep seeing recommendations to charge the cart after each use but I want to make sure not to trash the pack or the charger.

-Since I'm needing a new pack, should I upgrade to 48V? I think I'd need the 8 V batteries and a new charger. Anything else for the conversion? Not sure I need more speed, but the 8 mph top speed recorded a few years ago is pretty slow and I'd like to get more out of it. What kind of battery is a reputable one for my application? I'm a frugal guy so cheap is good if they work. Do I care about cold cranking amps? What other specs should I look for?

- I'd like to lift it with one of the budget lifts. probably just go with the 6" lift, what are my best options for tires? It runs on dirt/gravel and some sand, and maybe drive over the occasional log or small dog. I don't need blingy wheels so the black steelies are fine, but say I run a 22 inch tire, what are the advantages/disadvantages to running a 8 inch wheel rather than a 10 or 11.

-One of the batteries was reading 6.6 V, is there something I'm doing wrong here? I thought full charge was 6.37.


I think that's it for now, sorry for the novel!

[kernal]

Your charger operates as follows:
Operation: With the charger plugged into an AC source (wall outlet), turn the timer fully counterclockwise to the off position. Plug the cord into the cart receptacle and you should hear the charger "click". Now turn the timer fully clockwise to the start position and observe that the charger comes on (hums) and the amp meter jumps to approximately 20 amps. The amps will slowly decrease down to 1-3 amps as the batteries reach full charge. The charger will completely charge the batteries and automatically shut off when complete and the timer will stop indicating how long it took to charge the batteries. This is for info only but can help with trouble shooting. Normal charge time is 6-10 hours. If the charger runs the full 12 hours I would consider this abnormal and suspect a problem with the charger or more likely the batteries.
This is an automatic charger in that it senses full charge for the pack and shuts off by itself. It does not have a float/maintenance capability.

In general you should charge the batteries completely when you are through with the cart for the day. Starting the charge cycle over about once a month when in storage is appropriate. Keep water level at appropriate level with distilled (only) water.

This cart when new would run about 12-14 Mph with correct golf cart batteries.

For optimum performance you should have a matched pack of golf cart specific batteries. Matched meaning all six are identical by age, brand name and amp hour rating.

If you want to learn about batteries check this web site:http://www.cartsunlimited.net/How_Batteries_Work.html

[jnmiller]

Excellent thanks for the charger info. I think it's working properly, but it never shut itself off with the timer. I would suspect that it never reaches the shutoff voltage with the bad batteries. It also doesn't click when in you plug in the cable in the off position. Does it really matter which direction you turn the dial to start? I've always turned it counter clockwise from the off position I guess just due to the shortest path.

[kernal]

Originally Posted by jnmiller

Excellent thanks for the charger info. I think it's working properly, but it never shut itself off with the timer. I would suspect that it never reaches the shutoff voltage with the bad batteries. It also doesn't click when in you plug in the cable in the off position. Does it really matter which direction you turn the dial to start? I've always turned it counter clockwise from the off position I guess just due to the shortest path.

If you read it again I think you will find we are in agreement.

Not shutting off would be in line with bad batteries.

[kernal]

Originally Posted by kernal

If you read it again I think you will find we are in agreement.

Not shutting off would be in line with bad batteries.

Sorry. I was quoting the manual which says to move the dial to "off" first. If you are saying you want to move the dial from wherever it stopped to the start position after plugging into the cart, thats probably OK but not what the book says.

[Sir Nuke]

jnmiller, you made mention that you are a FRUGLE guy....well if the 14 mph is good enough for you, there is no need for you to go to 48v, as that will be a whole lot more, as you would need a new controller, solenoid, F&R switch, all new cables, AND a 48v charger.

another thing, you mentioned lifting it...and going with larger tires....well, to properly do that and have the drive system have a happy life.....all of the above things, other than the 48v charger, would be needed....that is if you are going to stay with 36v.

[jnmiller]

Alright! this is the stuff I need to know thanks. Is there any guide or sticky that has this info? Sort if like a lift and tire central?

Can you explain a little more or point me in the direction of some info on what I need and why I need it? I'm not sure what a controller or solenoid does. Or why I would need to upgrade cable for a lift. Appreciate the responses!


I said frugal not cheap! I don't want to cheap out on parts but if Duracell is cheaper than Trojan and they have similar results then well....

[Sir Nuke]

Originally Posted by jnmiller

Alright! this is the stuff I need to know thanks. Is there any guide or sticky that has this info? Sort if like a lift and tire central?

Can you explain a little more or point me in the direction of some info on what I need and why I need it? I'm not sure what a controller or solenoid does. Or why I would need to upgrade cable for a lift. Appreciate the responses!


I said frugal not cheap! I don't want to cheap out on parts but if Duracell is cheaper than Trojan and they have similar results then well....

well I will attempt to explain some of it......for starters, a golf cart was/is designed for use in a stop and go mode for starters, with sort rests in-between on manicured fairways. The stock drive system had/has a controller which is rated at 275 amp, to flow to and from the batteries. also the flow of current will go through the solenoid, with was/is rated at 85 amp. The stock high current cables were/are 6 gauge.

Once you start putting more stress on that drive system, you need to upgrade it or it WILL fail, sooner or later, hopefully that failure doesn't include an electrical fire.

by putting larger tires, increasing the diameter, will cause some more stress, as it will require more torque/hp to turn the wheels/tires. more stress means more amperage flow, which will make more heat. now you can get away with putting larger tires, say up to about 20" with any harm....and that can be down without a lift as well.

so to ensure you don't have a failure as described above, you would need to up grade the controller, solenoid, f&r switch and cables, as these are the things that control and carry the high current from your batteries to your motor.

[fireboat]

I have a 92 Marathon that I am just about finished restoring. The only thing going for it originally was that it had 1 year old Crown batteries and was rust free. It would do about 12mph. My son welded a lift kit and I installed new 12" rims with 22" tires. The cart then did about 14mph but really labored on any sort of incline.
After that, I upgraded the motor, cables, controller, solenoid and F/R switch which increased the speed to 19mph. I then added two more batteries to get 48v and it now runs 24mph.
Its just a matter of money, lol.

[Sir Nuke]

Originally Posted by fireboat

I have a 92 Marathon that I am just about finished restoring. The only thing going for it originally was that it had 1 year old Crown batteries and was rust free. It would do about 12mph. My son welded a lift kit and I installed new 12" rims with 22" tires. The cart then did about 14mph but really labored on any sort of incline.
After that, I upgraded the motor, cables, controller, solenoid and F/R switch which increased the speed to 19mph. I then added two more batteries to get 48v and it now runs 24mph.
Its just a matter of money, lol.

BINGO!!

Like the sign in the speed shop states: " SPEED COST MONEY.... HOW FAST DO YOU WANT TO GO"