Golf Cart Stops in the middle of driving

[Kolassus]

Hello all. I have a 96 CC 48v DS. I heavily modified the unit with 6” lift kit, 23” tires, new batteries, HD F&R switch, 400a solenoid, Alltrax 500 controller, an A1 Admiral motor, and replaced all the high amp wiring with 2awg wire.

The cart has been running awesome. Average speeds of 22mph and over 16 going up some decent size hills. I use the cart just for my and adjacent neighborhoods for rides with my kids as a fun past time. It is almost always on pavement, albeit some of the pavement is rough. Yesterday during one of my drives, coming to a stop after coming down a hill, I hit the break. Came to a stop. And then hit the pedal and had nothing. Solenoid was clicking, but no movement at all. Batteries were freshly charged when we started and we were only about 3 miles into our ride (have gone over 10 with no issues). I checked everything and nothing seem unusual. The motor was hot, but I could touch it for a few seconds with no issues. Not sure what is normal tho on motor temp, never really checked before. After a few minutes of looking and not finding anything. I got back on the cart and the cart took off like there were no issues. Was able to make it back home (2 miles) up and down hills with no issues. Any ideas on what could have caused this?

As a side note, I did change a few things on the controller. Mainly I just added “Peak Amp Mode” toner some more juice. And I adjusted the throttle for more acceleration. Could this affect anything?

[NoleFan4Ever]

Which solenoid do you have? MZJ-400's have been an issue for several of us sticking over the last year. I have had numerous as has other members.

You can tell if it does not move and you got the click w/o the cart moving and then you test the large post and can verify the current is not going through it. If this occurs, a tap a few times with the but of a hammer handle or back and forth attempts will usually do it.

[Kolassus]

Yes, I do in fact have a MZJ400A solenoid. So is this something I can expect to happen routinely? Should I keep a hammer in the cart in case it sticks again in the middle of a ride or is this a one time kind of thing.

Everything but the v-glide and OBC is brand new. I love the cart and want to ensure it’s alway at maximum performance with the cargo I am carrying (kids).

One other thing, the back up buzzer doesn’t consistently buzz. I’m not a big fan of it so I haven’t looked to fix it. Is that connection anything vital that could affect the cart?

[NoleFan4Ever]

I have had one that did it repeatedly and I removed it. The others have continued on after once or twice occurring.... I use to replace them each time, but figured out after a few taps it quit.

We have speculated it was the coil weakening or the bridge sticking. Maybe a combination of both. If that is your problem and it occurs more then a couple times, I would go ahead and replace it.

[R&TBabich]

Originally Posted by NoleFan4Ever

.... We have speculated it was the coil weakening or the bridge sticking. ....

Could a contributing factor be the length of run and gauge of the wire for the solenoid coil?
- solenoid to Tow/Run and 2 feeds tapped off to the Controller
- key Switch with 2 more feeds tapped off to the Controller
- Lt Blue back to the solenoid, then on to the Controller
That is around 15ft of wire.
My OEM solenoid activation coil measures 190 ohms and the MZJ400A solenoid measures 16 ohms.
That would be a .25A draw for the old coil and 3A for the MZJ400A.

[Kolassus]

So what would you recommend as a replacement for it?

[Sergio]

The MZJ400A has two separate coils, when the Solenoid is OFF, only coil L1 is in the circuit and it provides a strong pull.

When the Solenoid is energized and the plunger arm moves, there is a second set of contacts attached to the bottom of the Solenoid and activated by the same plunger that open and add another coil (L2) in Series to reduce the current consumption.

The contacts on the bottom sometimes get stuck and it never removes the second coil when it turns OFF which causes the solenoid not to close some times.

When that happens the resistance of the Solenoid coil when measured is around 300Ω when off.

On the other side if that coil does not get added in series when the Solenoid turns ON, the 16Ω will dissipate 150w and the Solenoid will soon burn.


Edit: I have the same Solenoid and never had an issue, I have mine mounted horizontally as some manufactures of similar designs recommend.

[R&TBabich]

Originally Posted by Sergio

The MZJ400A has two separate coils, when the Solenoid is OFF, only coil L1 is in the circuit and it provides a strong pull.

When the Solenoid is energized and the plunger arm moves, there is a second set of contacts attached to the bottom of the Solenoid and activated by the same plunger that open and add another coil (L2) in Series to reduce the current consumption. . ....

Is the L1 coil that provides the strong initial pull the one I am reading 16 ohms?
This makes sense to bring in another coil L2 to help hold the contacts closed with a lower current because this thing can be on a long time.

[Fairtax4me]

Alot of high current solenoids have a separate pull-in and hold-in coil. The pull-in coil always has a lower resistance, it has a higher power than the hold-in coil so it will quickly overcome the spring tension that holds the bridge away from the contacts, and quickly force the bridge closed to help avoid arcing, and also to allow that impact to help clean the contacts.

Does your controller have a fan? Did you touch the controller to see if it was hot?
Did you check all of the main cables to see if any ends were hot?

[Kolassus]

Are there any “how to’s” or a link to this horizontal mounting bracket? I must have missed that step in the directions. I installed the solenoid in the same orientation as the stock unit was. The contacts are facing the roof. How can I prove that this is the cause to my problem?