Sevcon Gen4 "Capactior Precharge Failure" Help!

[bastens_com]

I am stumped and hoping someone out there has seen this issue before. I am building my third conversion using a Sevcon. I have a Gen4 Size4 80v 350A model but I bought it used. I didn't have a chance to use it to now. When I turn on the system the capacitor recharges but stops at a low voltage (not always the same) but around 10V and throws an error "0x51C2 Capacitor Precharge Failure" I look at the capacitor voltage with DVT and it just stays at 9V (I have a 100V battery). DVT shows the main voltage to be 100V from the key switch, I confirmed it with a volt meter. If I turn it off then on with only 1 second pause it moves up to around 20V, then if I do it a third time it will go to around 50V then finally the fourth time it is charged all the way and matches the input voltage and turns on the main contactor. It seems like the Sevcon gives up on precharge.

* I have nothing else on the key switch input, I disconnected the DC/DC to be sure and the error still occurs.
* I thought I could turn off the "Capacitors charged check" 0x4650 but no joy

Is there a setting I am missing?
How can I tell the Sevcon to continue precharge longer?
Is the capacitor bad in the Sevcon?

Any ideas would be appreciated.

Cheers,
Patrick

I have been making a video of my project build if you want to see what I am building. I have released two videos so far. After I figure this part out I will make a final video.
Part 1 video: https://youtu.be/Tffr7h9A8Mw
Part 2 video: https://youtu.be/MHFZ84tD98o
Part 3 (final) video: will release after I figure out this bug :wink:

 

[amberwolf]

Best guess is the precharge system in the Sevcon is not working--the resistor could be damaged or faulty connection (internally, perhaps), or whatever it uses to switch the precharge on/off has failed (FET, relay, etc).

 

[bastens_com]

UPDATE: the controller died. I did buy it used and it seem to have a lot of hours on it so who knows what caused the issue. I hope my two other Sevcon controllers in my SXS and my other ATV lasts much longer than this one did. Anywho, now the controller says the contactor is welded but it is working, just to be sure I swapped the contactor out with a new one and tested the old one. The controller is making a high pitched noise so it literally sounds like capacitor is bad.

Cheers,
Patrick