marathon resistor cart questions

[paulss]

I've been looking for something for my BIL. He had a stroke 8 months ago and is starting to come around but has challenges ahead. He lives on about 15 acres and needs something to help him with chores and just give him some mobility and freedom. Reliability is a priority but he doesn't need a lot of range or speed.

I ran across a neighbor that had an EZGO marathon that appears to be a resistor cart (the tag # is 9801890 if that gives anyone a clue). The batteries are about 5 years old and it appears to be in good shape. He replaced the battery tray when he replaced the batteries and all connections are tight and look to be sprayed w/anti-corrosion spray. The only thing he's replaced other than the batteries and the cables connecting them is the solenoid. The brakes are a little weak but it runs great and he just used it for 18 holes of golf a month ago. The top is shot but my wife has recovered the seat and backrests.

As I mentioned, reliability is important as my BIL lives 100 miles from me and knows nothing about carts. I know a little about the solid state controller carts but nothing about the resistor variety. Is there anything I need to be looking for or checking? It appears to have 6 gauge cables on it. Would it create any problems to replace them with 4 gauge? Since it appears to be running good, would I be better just to leave it as is?

Any thoughts/suggestions will be greatly appreciated.

Thanks in advance

Paul

[JohnnieB]

I have no personal experience with a resistor cart, but I can read schematics and wiring diagrams quite well, and I've pick up some info reading posts here and other places. That said, here are my thoughts.

1. The resistors get red hot when cart is driven at anything other than max speed.
(Throttle position 4 connects the battery directly to motor, the rest go through the resistors)
That means your BIL will have to remember not to stop cart in tall grass after driving slowly, or risk starting a grass fire.

2. I'm an efficiency nut and a resistor cart can be very inefficient or very efficient depending on the throttle position.
Upgrading the cables between the throttle switch assembly and the resistor box to 4Ga won't produce any noticeable increase in speed or torque because the difference between the resistance of 6Ga an 4Ga cable is relatively small when compared to the resistance of the resistor coils that are intentionally being placed in series with the motor. Of course, if those cables are in bad condition, they need to be replaced.

However, upgrading the seven cables highlighted in the attached schematic to 4Ga might increase the speed and torque in throttle position 4, but only slightly if the original cables are good and more if they are bad.

3. How long a set of batteries will last depends on a ton of variables and the fact that the battery terminals have a protectorate on them indicates the previous owner knew something about battery care and maintenance, but 5 years is approaching the upper end of life expectancy for cart batteries. They might last another year, or two, maybe more, but they might fail tomorrow.

Hope this helps.

[kernal]

I have both a solid state and a resister cart as shown in my signature. Both carts have Trojan T105 batteries (36volts). If we take these carts on a cruise with one following the other the battery usage will be very close to the same as measured by a digital meter. Under these conditions the solid state cart is considerably heavier with rear seat and more passenger weight plus it has a hotter motor and bigger than stock speed control and still uses slightly less battery than the other which attests to its better efficiency. Either cart will run 20+ miles (paved paths) on less than 50% SOC under optimal conditions.

The resister cart has been very reliable for me but it is looked after, garaged and only subjected to the relatively mild Atlanta weather. Last I checked parts were readily available and comparatively cheap. The wiper switch is the only thing I have ever had to replace.

In my cart the coils are in the box between the batteries as pictured. They certainly get hot but I have never seen them get RED hot. Older carts may have the resisters behind the batteries in front of the left rear wheel (I think) and are more exposed, probably, making it more risky in tall grass. Just a guess on my part.

[paulss]

Thanks to everyone for their help. I'm in a little of a time bind on this and think I'll just double check all connections and do whatever maintenance I can see that needs to be done. I hate to mess with something that is working fine and has been for a while.

The charger that came with it is an EZGO but has a timer on it and doesn't appear to be solid state. If I set it for 6 hours and it fully charges the batteries in 3, will it drop back to a minimum maintenance charge or will it keep charging and hurt the batteries?

Thanks again for all your help.

Paul

[kernal]

Mine is a '91 and the charger that came with it has the timer but it is in fact automatic.
While plugged in to wall, plug the charger into the cart. Turn the timer all the way clockwise to start. The amp meter should jump to about 20 and slowly decrease to about 1-3 amps as batteries reach full charge. Charger will shut off when batteries are charged and the timer will stop indicating how long it took. Typically 6-8 hours. If the charger is really old or malfunctioning it may not shut off automatically. A picture and/or model no. of the charger would help.

[JohnnieB]

Look at the timer knob/dial.
If the first digit clockwise from OFF is a "1", it is a manual charger. If it is an "11", it is an automatic charger.

Even if it is the manual type (Runs for the amount of time set on timer), there is little, if any, danger of overcharging the battery pack.

Lets us know what type you have and we'll run through a checkout procedure with you if you want.