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Curtis B.
Curtis B., Other
Category: Electric Vehicles
Satisfied Customers: 28668
Experience:  Worked on fleet of various electric vehicles, golf carts, scissor lifts and electric booms.
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It is intermittent om speed. O replaced the MVOR Controller

Customer Question

It is intermittent om speed. O replaced the MVOR Controller & now it goes OK then slows down to a craw. Then back up, I have 50.4 volts across the batteries.
JA: Have you checked all the fuses? Do you have a wiring diagram?
Customer: Yes to both
JA: What is the model of your '50 electric?
Customer: DS, & that is the voltage across the battery set. each battery is 8.45V
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yes, replace the MCOR, cleaned the speed sw.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 11 months ago.
Category: Electric Vehicles
Expert:  Curtis B. replied 11 months ago.

Thanks for giving me the opportunity to work with you! I will do my best to help.

Expert:  Curtis B. replied 11 months ago.

Club Car, 48 volts. Do you have the speed sensor on the back of the drive motor? If you do, unplug the sensor and test drive, to see if sensor is giving false reading.???

Customer: replied 11 months ago.
Disconnected, went to play 9 holes of golf, hardly moved, rehooked sensor, did the same thing speed up, slow down.
Customer: replied 11 months ago.
You are already charging me $27, reply to my above message.
Expert:  Curtis B. replied 11 months ago.

No change with speed sensor disconnected. And the MCOR has been replaced. Only thing left , does it have OBC for charger? The OBC can be affecting operation and there is a rest for the OBC. Here is link showing ho t reset OBC.

Customer: replied 11 months ago.
Will try that & be back.
Expert:  Curtis B. replied 11 months ago.

OK>

Customer: replied 11 months ago.
Followed the instructions, Key/ off, f/r Natural, to/run to tow, disconnect battery, put tow/run to run, f/r switch to Reverse, key swith to on, lock throttle pedal down.
The reverse buzzer did not sound in 30 seconds, it has been down for 4 minutes now.What is next
Expert:  Curtis B. replied 11 months ago.

Try a different reset, and see it it will cycle. See the link above.

Customer: replied 11 months ago.
Followed the instruction on the buggies gone wild, charger did not start up, do you think I may have gotten a bad MCOR?
Customer: replied 11 months ago.
Please reply!
Customer: replied 11 months ago.
You did not answer my request, do you think it may be a bad MCOR?????
Expert:  Curtis B. replied 11 months ago.

I would try a second rest using the reset fro the Buggy s unlimited site and if no difference, then I would consider a defective MCOR.

Customer: replied 11 months ago.
I did try it, the charger did not come on, I will go ahead & file for a warranty on the MCOR.
Expert:  Curtis B. replied 11 months ago.

You say charger does not come on?

Customer: replied 11 months ago.
Correct, it did not come on.
Expert:  Curtis B. replied 11 months ago.

Batteries are no where near fulled charged, 48 volt system would be around 54 volts fully charged, I'm wondering if problem may be the OBC not letting charger work!

Customer: replied 11 months ago.
The batteries are 3 years old, did a individual check & each batter is 8.45 or better, it should allow the cart to run at first start up normal acceleration , and then slow down as batteries dis charge.
Expert:  Curtis B. replied 11 months ago.

Yes, but charger should come on, ??? Does the charger receptical show same voltage as battery pack?

Customer: replied 11 months ago.
Your saying that the charger should read 50 volts? Don't understand what you mean hear, I have not measured the volts out of the charger. Where would I do that? At the plug in?
Expert:  Curtis B. replied 11 months ago.

First ,I would like reading at the plug on the cart, where charger attaches, this is what the charger see's for voltage when plugged in. Then read the battery voltage after charger is attached. With charger running, voltage may peak well over 54 volts!

Customer: replied 11 months ago.
I will do that & get back tomorrow. Dinner time & still a broken cart.
Expert:  Curtis B. replied 11 months ago.

OK> I will be here in the AM.

Customer: replied 11 months ago.
Good Morning, spend yesterday following up with your suggestions, I had all the information you told be to go to, I'm a member of Buggies gone wild & they had sent me to Alltrax. I called the company I ordered the MCOR from & they are sending me another one, once I receive it I will replace it & see what happens. I was looking information from you of what experienced technician's have & that is to look at the unobvious problems. Could it be the brushes? How to check the controller out, could it be the f/r switch? Those type of things.
Expert:  Curtis B. replied 11 months ago.

F/R switch will always cause one direction failure only. Motor brushes can cause loss of speed, but typically either works or it doesn't. And motor would get hot and could smell burning from brushes arcing on the armature. But more times than not, speed drop is due to voltage drop. Have you checked the voltage on battery pack as you drive?

Customer: replied 11 months ago.
Not as I drive, I played 18 holes of golf yesterday & I checked it before I went out, it was 54.7, & when I returned 50.4, per my battery guy that is fine, if the batteries where bad it would just slow down not act like a variable resistor application, that is why I will be trying a new MCOR & we can move on from there. How do you check a controller? It is a Curtis PMC Model###-##-#### the one test from Buggies was to check the charger out, which I understand is the function of the computer.
Expert:  Curtis B. replied 11 months ago.

That is all I have and use. Buggy's unlimited is my first stop. I assume you did the OBC reset and did not help. But Running a couple of jumper wires from battery pack to test voltmeter is always good test, and can show things that you never see when cart is stopped.

Customer: replied 11 months ago.
I'll try that next, yes I did the reset, I did not get the reverse buzzer to go off at about 30 seconds, what I can't figure out is how will the buzzer go off with the negative wire unhooked?
Expert:  Curtis B. replied 11 months ago.

I wish I could tell you, but I am old school and this never made sense to me!

Customer: replied 11 months ago.
I'll call Alltrax & talk to them, will let you knew what they say, will try the voltage check when my wife gets back from golf. When I'm checking the voltage what should I expect to see? I have a amp meter on the cart & it shows about the same as before the problem, In the charge range, when acceleration it drops a little & then moves partially back to normal, just like before, when it is bogging down it does move.
Customer: replied 11 months ago.
The instructions to reset the controller are for a Alltrax control, I have a Curtis PMC controller.
Expert:  Curtis B. replied 11 months ago.

When checking the voltage, you want to see a constant voltage, with very little drop. If voltage does drop below say 48 volts, but recovers , seems all is well with batteries. If voltage drops but does nt recover, then I would want to check each battery under same type test.

Expert:  Curtis B. replied 11 months ago.

There are other resets, showing the Curtis controllers. I linked a second one on the Buggy's site.

Customer: replied 11 months ago.
Don't see a link?
Expert:  Curtis B. replied 11 months ago.

I am member so, I don't log in. so link pops up and I just scroll down to see the reset.

Customer: replied 11 months ago.
Thanks, ***** ***** get back with you when I check the voltage, check this reset procedure and when my wife gets back from golf. I hope the cart makes it around, if it would break make things easier, after 30 years being a field service engineer this type of problems drove me nuts, but once I solved it I was a little smarter on the next call that had the same problem.
Expert:  Curtis B. replied 11 months ago.

!! really! I was field service engineer for Clark Equipment in the early 70's now you know my secret!

Customer: replied 11 months ago.
I was with Signode, we did large packaging equipment, that's the strap & streach film around shipped packages & then was Corp manger in the Midwest, 44 locations, now retired. Took a look at the tread, tried that & it showed everything was OK.
Expert:  Curtis B. replied 11 months ago.

oK Let's see if voltage test revels anything. Thanks.

Customer: replied 11 months ago.
She finished playing, When she got back: 50.8 v--starting 45.5, shortely 48.5, stayed around the 48.5, went up the steepest hill we have here in FL I didn't get it back down to 45.5 starting up the hill but when right back to 48.5. When charged it is 54.7
Expert:  Curtis B. replied 11 months ago.

Was it still acting up with these voltages?

Customer: replied 11 months ago.
I'm still stuck on the MCOR, should have a new one within a week.
Expert:  Curtis B. replied 11 months ago.

OK>

Customer: replied 11 months ago.
Called a dealer bout the controller, he had me check the Omhs on the MCOR, he thinks like I'm thinking, it is bad, did some checks & everything points to the MCOR, just wait until a new one comes in.
Expert:  Curtis B. replied 11 months ago.

OK, It is suspect, but when it acts same as old one, makes you wonder.

Customer: replied 11 months ago.
It operated a little different as on slow speeds it was jerky, if you got to higher speeds it operated ok, being jerky when my wife is backing out of the garage is what I needed fixed, we will see, I will let you know when I get the new one & install it.
Expert:  Curtis B. replied 11 months ago.

Sounds great! Thanks