# Help! Wiring



## Dr. Bill (Oct 17, 2008)

I wired my pack up today and it is showing a ground to the frame of the Jeep. I have rechecked all of the wires and can't find anything that could be causing it. I have unhooked the pack and double checked all wiring. It does this with the contactor open so it can't be feeding back thru the brushes on the motor. CONFUSED AGAIN.....Bill


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## Dave Koller (Nov 15, 2008)

Interesting, if you have eliminated the motor then suspect leakage to the frame from one of the batteries. when you say ground do you mean it is common with the 12 volt chassis ground? if you remove both + and - of pack are you still showing leakage? AND is it of low amp? Even a small bolt can poke into a battery and cause it to short to frame.... I guess I would like to hear more on what you mean...
Dave


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## Dr. Bill (Oct 17, 2008)

The multimeter I am using is a new digital and not an analog that I am used to using. Loaned it out and it didn't come home. I just tried to light a light bulb with the + from the pack and the frame and nothing happened. With the pack + and - it lit brightly. The 12v doesn't come into play because it is not hooked up. The interesting thing is that the body is fiberglass and 15 6v batteries are hanging in the back box of the Jeep body and not yet bolted to the frame at all. The frame holding 9 6v batteries under the hood is welded to the crossmember that holds the motor and the front of the frame is mounted to the front of the Jeep frame with 3rd. member ends with rubber bushings in them. It may be touching the frame somewhere, I don't know. As for the batteries having a bolt thru one or something it is highly unlikely as this vehicle has not been out of the shop yet and they are setting on hard rubber in their frames....STILL CONFUSED.....Bill


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## Dave Koller (Nov 15, 2008)

Ok now all that would be left would be to see if acid has spilled (or was spilled) it can act like a resistor with dust to the frame... it is more like the frame that you have bolted - start disconnecting each in turn to see... AND get a cheap led test light as they will light at low current and voltage. I have seen a battery Led test light glow from oxidation on top of a dirty battery....

From what you are saying it is NOT high current... What is the actual reading on the multi in OHMS?

Dave


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## CPLTECH (Sep 14, 2007)

Just a thought that some hook the battery pack to chassis to avoid purchase of DC to DC converter to run the 12V items. This can not be done. The battery, controller, and motor are totally isolated circuit from the chassis. 

Is it possible that the motor or controller is shorted to the chassis in some manner? Of course the case of the motor is attached to the frame, but not the wires. My controller sits on a fiberglass board.


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## Dave Koller (Nov 15, 2008)

CPLTECH said:


> Just a thought that some hook the battery pack to chassis to avoid purchase of DC to DC converter to run the 12V items. This can not be done. The battery, controller, and motor are totally isolated circuit from the chassis.
> 
> Is it possible that the motor or controller is shorted to the chassis in some manner? Of course the case of the motor is attached to the frame, but not the wires. My controller sits on a fiberglass board.


All true - but I think he has the pack completely disconnected ! So this will be a puzzle till we find out..
Dave


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## EV-propulsion.com (Jun 1, 2009)

Dr. Bill,
did you find a solution to you problem?
I have a customer with the same or similiar problem-with the most positive cable to the controller disconnected, he can read sequential high voltage from each battery positive to chassis. The battery negative is still connected to the curtis 1231 controller. I think there is leakage through the controller negative-but it is from a charged capacitor or equivalent since it can be discharged by grounding a battery positive to chassis. This can really only be read with a digital voltmeter, an analog will not read a voltage. If an ohmeter is connected between the chassis and the controller B- terminal, it reads 4M ohms, reverse the terminals and it reads infinity (open). Curtis' answer is the case is isolated from the internal components to 500v, so it shouldn't be that........
Once again this is a new construction, with all wiring checked multiple times, and clean batteries....
A big problem arose when he went to charge the pack for the first time-This time there was highvoltage _and _current-lit a 100 watt bulb no problem. His only answer became to install a contactor in the negative line also, which helped in charging but not in normal operation-he still has the high voltage, low current issue.......


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## Dave Koller (Nov 15, 2008)

What else is connected between that neg side ? DC/DC? got a wiring diagram? 

Dave 




EV-propulsion.com said:


> Once again this is a new construction, with all wiring checked multiple times, and clean batteries....
> A big problem arose when he went to charge the pack for the first time-This time there was highvoltage _and _current-lit a 100 watt bulb no problem. His only answer became to install a contactor in the negative line also, which helped in charging but not in normal operation-he still has the high voltage, low current issue.......


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## EV-propulsion.com (Jun 1, 2009)

This is actually a basic system, there is not a dc-dc,etc. Aux 12v battery not connected to pack battery.All other items have been disconnected at the batteries to find the source,(volt meter, ammeter shunt,paktraker, charger) with the battery pack _supposed_ to be isolated.
So basically its a battery pack, one kilovac contactor & fuse on insulated holder and board,curtis controller, warp 9 motor. I am assuming its leakage through the controller then thru the motor to ground. Like I said it is a low current. I am checking with the charger manufacturer to see if there is any way there could be a leakage to ground when charging(after it's reconnected to batt pack), because then there is a higher current.


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## CPLTECH (Sep 14, 2007)

My thoughts of the possibilities (IF battery wiring is not compromised in some way):

From the schematic, I doubt the controller is the issue. Look elsewhere.

If a 100 watt (.8A) bulb can be powered, that’s a hefty voltage & current you are dealing with.

I am guessing that there is nothing internally that is grounded to the chassis, in fact my Curtis is on an insulated mounting board by previous owner. That being the situation, does the motor have an internal short to the grounded case? At no time does the battery pack voltage + or - leads come in contact with the chassis!!!

Is it possible the 12V muffin fan mounted on the Curtis has one of its power leads pinched to ground or designed to have the frame & negative lead grounded.

At this time, I would see if the charger is somehow grounded, engineered that way or not. In fact, my K&W’s GFCI will trip if the key is on.

Former Electronic tech


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## tj4fa (May 25, 2008)

What charger do you have?


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## EV-propulsion.com (Jun 1, 2009)

The charger he is using is one that I sold him see http://www.ev-propulsion.com/chargers.html , I have used many of them without this problem, but I am going to check it over again when the owner brings the car in again, tuesday or wednesday.
Also, the 1231c curtis does not have cooling fans on it, response to previous post....


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## tj4fa (May 25, 2008)

Because of this thread I started checking for a ground fault and it appears I am getting a ground fault problem as well between the negative lead of my battery pack at the battery side of my primary negative contactor and to the chassis (over 140V of the 153V battery pack). 

I took out the charger, unhooked the negative off the accessory battery, and started unhooking all the 12V components one-by-one to isolate the problem until my cheap peace of crap chinese Greenlee LED multimeter shit the bed....

It wasn't the charger, because I removed it completely from the vehicle and still was getting the ground fault.

Once I get a real multimeter (hopefully later today), I plan on rechecking again by disconnecting the 12v grounds for my control board components one-by-one at my common chassis ground point and rechecking to see if it's a particular device.

If I still have the battery pack to chassis fault after disconneting all the grounds of the control board components and to the accessory battery completely, I will have to look for the problem elsewhere.

As a note, my drive motor is hard mounted to the frame through the motor-mount bolts (no stock rubber motor mounts).

I'll keep you posted...


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## EV-propulsion.com (Jun 1, 2009)

It also appears that your curtis controller is mounted on an insulated board-correct? That would eliminate leakage through the controller case to ground-doesn't leave much else except the motor. or?


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## tj4fa (May 25, 2008)

EV-propulsion.com said:


> It also appears that your curtis controller is mounted on an insulated board-correct? That would eliminate leakage through the controller case to ground-doesn't leave much else except the motor. or?


Tracing this down is some wild stuff. 

Here's where I was at until the lightning and rain drops drove me inside:

After disconnecting about every frigging wire on my control board components, it seems there may be a ground fault through my Westburgh and digital guages to chassis somehow. When I totally disconnected the 150+ pack voltage wiring to them, the 150+ high voltage to chassis went away (I still may have a volt or three).

During that process, I had also disconnected the DC-DC converter from battery pack voltage and the accessory battery but when I reconnected, I got ~24-30V volts reading from negative pack wiring to chassis.

Next time out in the driveway, I plan on totally disconnecting the DC-DC wiring and see what I get...


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## tj4fa (May 25, 2008)

Well my amp gauge isn't a problem but I'm thinking there must be something I did wrong with the wiring to my analog and LED voltmeters inside the car.

I think I may rewire the gauges to work in a simpler manner than coming on when I turn on the ignition switch and the primary negative contactor closes and completes the circuit.


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## Guest (Sep 10, 2009)

I had a simalar problem when I was building my first ev. The first mistake was trying to save a couple of dollars. I used some old heater hose to insulate battery cables. I found that all rubber is not equal. The hose had conducting properties (grafite ?) Luckly there was enough resistance to keep the volts down enough that all I got was a little nip. God I hate getting shocked! So maybe you should check for continuity on the rubber mounts. After straightening that out every once in awhile I would still get a reading between the batts and frame. very low but still it botherd me. After days of taking things of and putting them back on for no particular reason I put one probe on a battery and the other in the air. I do not remember the exact reading but it was close to 20 volt. Then I checked the humidity. It was like 75 or 80.


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## danimal (Apr 24, 2009)

You know what might come in real handy here is a "clamp on" low amp current probe. I use this for tracing down current draws on cars and it sure beats the hell out of disconecting everything.


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## EV-propulsion.com (Jun 1, 2009)

In this case the amp clamp won't work as the current is very low, unreadable actually-once a circuit is formed from pack + to ground, the voltage drops to zero.

After disassembling the car, here are the findings. He basically has a slight leakage through the B - terminal of the controller to the chassis.I get a full voltage reading from the battery pack + terminal to the chassis, when only the battery pack - (negative) is connected to the controller B - terminal with no other connections. Battery + is not hooked up to the battery pack, and the motor is not hooked up at all; just the lead from the battery pack (-) to the controller B-. I have to add this is a very small current, I cannot even read it with the meter, but there is pack voltage.(120vdc). I also took an ohm reading from the controllers B - terminal to chassis, and got a reading of 13M ohms. Quite a bit, but I guess enough to get a volt reading with the digital meter. I guess some leakage can be expected, and at this very low current not a problem as long as it stays low.
As an aside, I checked the battery pack to chassis while it was disconnected from the controller and got less than 1/10 of a volt
Also, while the motor was disconnected, I took some ohm readings between the motor terminals and its housing, there was infinity ohms-no connection to chassis, no leakage through the motor.
And, I checked the other controller terminals to chassis and the other 3 were about 6M ohms.

As far as the higher current reading between the pack + and chassis with the charger on, it is because the charger is a non isolated transformer type, and the neg of the battery is basically the neutral in the input 120v.
And as the neutral is grounded at the service of the house, the case of the charger is also now connected through the ground in the cord. If I disconnect the cord ground in the charger or insulate the charger case from the chassis, this problem disappears, will advise to definitly use a GFI then.


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