# HELP! DCP Controller Problem?



## Bill()C (Aug 3, 2007)

Even though I have owned this car for a while I classify myself as an softly educated newbie. I did not drive this car over the winter and broke it out of slumber this spring. However I'm unsuccessful as the car will not move.

It has a 144v pack (18 x 8v), with a DC Power systems Controller (TREX-600?). Much to my dismay it appears this company has long ago ceased to exist. Since I did not do the wiring on this vehicle I'm a little at a loss trying to figure it out, but I understand many of the concepts of how it operates.

The basic problem: The car does not move.
It appears both contactors (negative and positive) respond to the "ignition" key and close supplying the controller with current. However the controller then appears to cycle through on/off supplying the motor with current momentarily, then opening the circuit, then closing the circuit, then opening, etc, etc, etc.

I have uploaded a short video of my problem on Youtube:

http://www.youtube.com/watch?v=6qWS9GfKaPE

The video shows the output of the controller in volts DC. Currently the battery pack is low, about 130v or so. You can see the meter rise to 130v or so then instantly start falling. You can also hear a click of some sort of transformer / contactor apparently internal to the controller.

Is anyone familiar with this controller? Does anyone have trouble shooting suggestions for me to pinpoint / confirm the problem as the controller or trouble shooting to determine if the controller is fixable? I would be willing to attempt myself.

I can't find any reference to this controller on the forum here.

Thanks,
Bill


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## Tesseract (Sep 27, 2008)

I am just barely familiar with this controller and it is an oldie, for sure. That said, it sounds like you might be running into low voltage cutoff for the battery pack. Try charging up the pack *first* then trying the controller. Right now your pack is pretty much dead.


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## Powered By DC (Jan 3, 2009)

Id have to agree it looks like a low voltage issue .

Dave


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## EVfun (Mar 14, 2010)

Your pack is dead. Really, REALLY dead. You are at about 1.8 volts per cell. You need more voltage to test the DCP. 

The contactor is controlled by the DCP but is external and installed in the positive power cable between the pack and the controller. The way this controller handled giving emergency shutdown authority to both the controller and operator is by having the ignition switch circuit supply power to the coil and the controller supply the ground so long everything was fine. The controller had to precharge before it would pull in the main contactor, so it appears that is happening.

I would pull one of the cables off the motor before continuing to test. You can safely read voltage off the controller output without a load connected. I'm concerned about the pull in of the contactor followed by sag. It hints of the possibility that the controller has died with shorted MOSFETs. It is impossible to know for sure until you get a working battery pack.


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## Bill()C (Aug 3, 2007)

I'm not THAT dead. I have 135v in the total pack. You don't see it in the video because the voltage cycles so fast, my meter can't follow it. I've had the pack lower. I've never had the controller cut out without any call for power either.

I can't get the charger to charge right now and I don't particularly like the way it's wired up. But it's been raining and I can't do much about it at the moment. It will likely sit until good weather at the end of the week.

However I'll take the advice, rewire the charge leads so that it makes more sense to me and charge her up and try again.

SIDE NOTE to EVFun: I don't see how the contactor is controlled by the controller. It reacts to the ignition switch through convoluted, poor unprofessional wiring. Unless you are talking about an internal controller contactor. I apologize because I'm having trouble following you and I'm NOT saying that's your fault. I have to reread what you said a few times for it to sink in.

Thanks,
Bill


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## EVfun (Mar 14, 2010)

A 144 volt pack at 135 volts is *REALLY* dead. It is likely you cannot get even 20 amps from the pack to spin up the motor without the pack voltage crashing. That kind of pack voltage is equivalent to finding your cars 12 volt battery resting at 11.25 volts. It won't start your car, in fact the dome light is likely to go out when you try!

It is not about how low you can take a pack under load, it is about the low voltage reading without a load. I've pushed a 120 volt pack down to 80 volts, but when the load was removed it popped right back up to 115 and after 20 minutes without a load it was back to 120 volts.


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## EVfun (Mar 14, 2010)

I think I found some additional documentation that may help. 
From the EVDL.org document library:
DCP wiring diagram
DCP installation instructions

If you have a motor rpm sender input to the controller it frequently causes problems as they get old. Disconnecting it from the controller gets around that problem, but disables rpm limiting of course.

All the DCP controller have basically the same instructions, just differing on peak volts and amps. A few early DCP controller had different connections for the small wires. I installed a rare (I think less than a dozen where built) DCP 450 in a VW Pickup around 1998. They are generally a good controller but they have had some issues as they get older. I think the main problems are with the connection between the power and logic boards inside. They will be happier if kept clean and dry.


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## Bowser330 (Jun 15, 2008)

EVfun said:


> A 144 volt pack at 135 volts is *REALLY* dead. It is likely you cannot get even 20 amps from the pack to spin up the motor without the pack voltage crashing. That kind of pack voltage is equivalent to finding your cars 12 volt battery resting at 11.25 volts. It won't start your car, in fact the dome light is likely to go out when you try!
> 
> It is not about how low you can take a pack under load, it is about the low voltage reading without a load. I've pushed a 120 volt pack down to 80 volts, but when the load was removed it popped right back up to 115 and after 20 minutes without a load it was back to 120 volts.


nicely said...


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