# Possible bad contactor?



## blondebikes (Dec 26, 2017)

Hi, I've had to out all my projects aside for some time mostly due to moving across the city, to be closer to work. 
Now that I'm slowly getting settled, and a little organised, the ekart has finally come back out. 

I've hooked up a temp 80v 4ah battery for the purposes of confirming operation. Then I can get to installing the perminate wiring. 

Here's the issue. 
I turn on the key switch, the 24v contactor engages I get a quick two flash on the sevcon powerpak then the contactor dissengages. 

Voltage with key off is 78v, key on is 0.4v 

Any thoughts?
Thanks


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## galderdi (Nov 17, 2015)

I am no expert. But I would do the following:



Double check that it is indeed a 48v contactor on the coil side. It is possible it is intended to pass 48v through the contact but may operate on a different voltage on the coil.
Check if your setup has the ability to disable the contactor. It is possible it is sensing a short or something similar and is disengaging the contactor as a safety measure. Maybe try disconnecting the traction battery from the contactor and see if it will remain engaged without the high voltage attached.
Make sure you are seeing the expected voltage on the contactor coil (probably while you have the traction battery disconnected from step 2). I know I had an issue where the voltage applied to the contactor coil was insufficient to operate the relay.
Check the current draw on the coil. While the power consumption is nothing like the traction circuit it is still significant. The available current may be insufficent to sustain the contactor operation. Although in this scenario I would expect you to be talking about blown fuses.
I doubt it is a bad contactor. A bad contactor would be unlikely to activate at all.


If I think of others I will update the post


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## blondebikes (Dec 26, 2017)

I've had it working in the past unfortunately. 
No blown fuse etc. 

Traction battery?


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## cricketo (Oct 4, 2018)

What Sevcon gen is that ? Some have an LED that will flash out diagnostic codes from which the malfunction can be determined. I'm especially suspicious about all those different voltages mentioned. Maybe an overvoltage protection kicks in ?


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## galderdi (Nov 17, 2015)

Traction battery is the higher voltage battery which powers your motor through the controller. As oposed to the auxilliary battery which powers your electronics including your contactor.


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## blondebikes (Dec 26, 2017)

Possible over voltage I guess. 
The temp packs are 36/40v for Ryobi 36v tools. Currently sitting at 76.9v 

Controller is powerpak pp784 (old school unit)
Contactor is white Rodgers type 586 (24v)


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## blondebikes (Dec 26, 2017)

I have only one battery pack specified in this wiring diagram?


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## cricketo (Oct 4, 2018)

blondebikes said:


> Possible over voltage I guess.
> The temp packs are 36/40v for Ryobi 36v tools. Currently sitting at 76.9v
> 
> Controller is powerpak pp784 (old school unit)
> Contactor is white Rodgers type 586 (24v)


Found the manual for that Sevcon unit, looks like it can really operate in 43-100v range. Still reading it to see what else could be happening.

http://www.thunderstruck-ev.com/Manuals/PowerpaK SEM & MicropaK_M.pdf


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## blondebikes (Dec 26, 2017)

cricketo said:


> blondebikes said:
> 
> 
> > Possible over voltage I guess.
> ...


Correct, that's why I wasn't too worried about the slightly over traditional pack voltage.


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## cricketo (Oct 4, 2018)

> 10.2.5 Diagnostic LED - This is mounted between the connectors on the front of the
> controller. It serves as a simple diagnostic tool as explained below:
> Constant illumination - No fault, normal condition
> LED extinguished - Internal controller fault
> ...


Do you have that LED ? I don't understand from the description if it's part of the wiring harness, or if it's built into the controller body.


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## blondebikes (Dec 26, 2017)

cricketo said:


> > 10.2.5 Diagnostic LED - This is mounted between the connectors on the front of the
> > controller. It serves as a simple diagnostic tool as explained below:
> > Constant illumination - No fault, normal condition
> > LED extinguished - Internal controller fault
> ...


It gives me 2flashes. But that could be partly because by the time the second flash occurred he contactor has already dissengaged


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## cricketo (Oct 4, 2018)

blondebikes said:


> It gives me 2flashes. But that could be partly because by the time the second flash occurred he contactor has already dissengaged


Controller is supposed to be wired with constant power to it, so it's the one that controls the contactor. There is more detailed diagnostics on page 21, with several conditions that would result in two flashes. Look through all the lines with 2F in them.


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## blondebikes (Dec 26, 2017)

What I don't understand, is that the wiring diagram I posted up earlier, doesn't show a secondary battery system. Or another way to wire it. 
It's all wired as per the diagram. 
That's why I'm confused, as I've had the system function. Just not engaged the motor. As moments into connection one of my BMS fried.


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## cricketo (Oct 4, 2018)

blondebikes said:


> What I don't understand, is that the wiring diagram I posted up earlier, doesn't show a secondary battery system. Or another way to wire it.
> It's all wired as per the diagram.
> That's why I'm confused, as I've had the system function. Just not engaged the motor. As moments into connection one of my BMS fried.


I don't know why another poster mentioned a second battery. The diagram you posted clearly shows contactor being powered from the controller. No other power source should be at play. Looking at the docs, this Sevcon has a feature called "contactor chopping", which ensures 24v contactor coil supply regardless the pack voltage. 

Like I said before, you need to go through those conditions and verify nothing is throwing it off. Simple things like stuck switches can prevent it from turning the system on.


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## blondebikes (Dec 26, 2017)

So, I managed to get a little more sense out of the controller. 
By disconnecting the 24v chopper circuit, the controller stays on (active) and cycles 2Flashes as I previously thought. 

Could it simply be a bad contactor?


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## cricketo (Oct 4, 2018)

blondebikes said:


> So, I managed to get a little more sense out of the controller.
> By disconnecting the 24v chopper circuit, the controller stays on (active) and cycles 2Flashes as I previously thought.
> 
> Could it simply be a bad contactor?


You mean you essentially disconnected the contactor ? It should then give you 4 flashes if that's the only issue - controller knows when contactor got stuck and/or fails to close, and will give a specific error condition for that.


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## blondebikes (Dec 26, 2017)

If I hold the regen switch (fs1) I get 4 flashes. 

My concern is if the MOSFET system is stuffed. I have no way to access the system.


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## blondebikes (Dec 26, 2017)

I really do need someone to physically help me. I know it hard diagnosing all the variables remotely. 
Especially when even I am not 100% what the issue is.


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## cricketo (Oct 4, 2018)

Well, take it to the dealer


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## blondebikes (Dec 26, 2017)

cricketo said:


> Well, take it to the dealer


Hahahha. Yeh tried that. They don't want to know. Old, dated unit.


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## cricketo (Oct 4, 2018)

blondebikes said:


> Hahahha. Yeh tried that. They don't want to know. Old, dated unit.


What vehicle is that ?


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## blondebikes (Dec 26, 2017)

cricketo said:


> blondebikes said:
> 
> 
> > Hahahha. Yeh tried that. They don't want to know. Old, dated unit.
> ...


The powerpak. Sem PP784


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## cricketo (Oct 4, 2018)

blondebikes said:


> The powerpak. Sem PP784


That's your Sevcon, but what is it installed on ?


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## blondebikes (Dec 26, 2017)

Sorry. 

15' Intrepid kart.


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## cricketo (Oct 4, 2018)

blondebikes said:


> Sorry.
> 
> 15' Intrepid kart.


Cool. You should probably share your location so if somebody is nearby they can let you know. There is always a small possibility that your controller went bad, so you can also consider unwiring it and sending it to for diagnostics to any place that services them.


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