Solenoid or controller?

[qhcrazy]

I need to reclarify some things according to my son: The 4 green lights come on when it is NOT charging, it was never hooked up to the charger when the lights came on. To answer your question, Johnnie B, yes, it clicks when the pedal is pushed and unclicks when the pedal is let up. Yes, after the solenoid clicks, the LED flashes green 4 times and then goes to a steady green.

[JohnnieB]

Originally Posted by qhcrazy

I need to reclarify some things according to my son: The 4 green lights come on when it is NOT charging, it was never hooked up to the charger when the lights came on. To answer your question, Johnnie B, yes, it clicks when the pedal is pushed and unclicks when the pedal is let up. Yes, after the solenoid clicks, the LED flashes green 4 times and then goes to a steady green.

That's good, it means the problem is in the high current circuit.

Jack the rear wheels off the ground and put on jackstands, so the half ton cart doesn't take off unexpectedly and run over someone or something.

Connect a voltmeter between the B- and M- terminals on the controller.
Push pedal just far enough for solenoid to click.
You should read FULL battery pack voltage.

If you don't get full pack voltage, use the test probe that was on the M- terminal to check the voltage on the four studs on the F/R switch assembly. They should all read FULL pack voltage. If not, the switch needs to be repaired, replaced, or adjusted.

If you do get full pack voltage between B- and M-, push pedal slowly to floor,
The voltage should smoothly decrease to zero.

If it doesn't, measure the voltage between the black and white wires on the 6-pin connector on top of the controller. Should be 10V when pedal is pushed just far enough for solenoid to click and 6V when pedal is on floor.

Let us know what you find and we will go from there.

[qhcrazy]

What is full pack voltage?

[Sir Nuke]

Originally Posted by qhcrazy

What is full pack voltage?

the TOTAL (FULL) Voltage after you have complete a charge cycle and waited 12 hrs. you have a 48v cart.....so it should be in the neighborhood of 50.9 volts

[JohnnieB]

Originally Posted by qhcrazy

What is full pack voltage?

Full pack voltage is whatever the voltage between the main negative and main positive terminals on the battery pack is at the time.

As Sir Nuke mentioned, if your battery pack is fully charged, it ought to be somewhere in the neighborhood of 50.9V roughly 12 hours after the charger shuts of. However, as long as it is above 48V (50% SoC), it is adequate for troubleshooting.

The important part is that the voltage at the test points stipulated is identical with the voltage at the main battery terminals at the time of test.

IE: If the pack voltage measures 49.5V, the voltage between B- and M- should measure 49.5V.

[qhcrazy]

Thank you for the explanations!! Update: My son pushed the accelerator and it moved, although very slowly, so we thought that it needed to be charged, so we charged it. He was able to get it to move again and it accelerated normally. However, he tried to move it again, and nothing. He said it wouldn't go in reverse...?

[JohnnieB]

Originally Posted by qhcrazy

Thank you for the explanations!! Update: My son pushed the accelerator and it moved, although very slowly, so we thought that it needed to be charged, so we charged it. He was able to get it to move again and it accelerated normally. However, he tried to move it again, and nothing. He said it wouldn't go in reverse...?

Do the tests I outlined in Post#12.

Chances are the high current contacts in the F/R switch assembly are not making good contact.

[qhcrazy]

Update: It was running well, then my son said he heard sparking and now we're back to melting of the main charging battery post. The charging wire goes to the post that melted completely. I know most have said it's because there's a loose connection, but the connections weren't loose...? I don't want to go and keep purchasing used batteries to replace this "problem battery". The guy at the golf cart place said that we didn't need the fuse that was attached. It's a converted 36 to 48V. So, what's making the same terminal melt over and over? Grrrrrrrr....frustrated Mom!!!! I don't want my son and his friends to be in danger. Help!!!!

[JohnnieB]

There is the possibility the nuts securing the cables on the studs are being overtightened.

Your batteries most likely have either EHPT or ELPT (Embedded High or Low profile Terminal) and the torque specs on those are 95-105 In/Lb (7.92 - 8.75 Ft/Lb), so they can be unknowingly overtightened.

See page 6 of attached Trojan user's guide for terminal type and page 11 for torque specs.

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The stud is actually a hex head bolt with the head embedded in lead. Lead is a soft metal and if too much torque is applied to the nut, the bolt's head will twist in the soft lead. When that happens, the connection between the flats of the hex head is lost and only the six point are touching the lead, so the contact area is greatly reduced and the current density is greatly increased. The amount of heat generated increases exponentially as current density increases linearly (W = 1² X R) and the melting point of lead is only 621.5°F, so battery posts are fairly easy to melt.

[cgtech]

The main positive cable lug at the terminal could have a "not-so-awesome" connection internally. Bad cable from battery to solenoid?