openinverter forum

Hi
Im about to testrun my SDU and have setup everything to start it off, when supplying 12v I get access to the interface but when I start the inverter in manual mode opmode is still off. Version is 4.85.R-sine. Shouldnt opmode be showing something like ”on in manual mode”? I also try to start it with 12v pulse but nothing. I manage to get dir into fwd direction, status is UdcBelowUdcSw . I try ampnom up to 50 and fslipspnt to 1 but nothing. Im using a 40v kia soul module. The udc gets up to 39v. I have set Udcmin to 15, Udcmax to 45 and udcsw to 0. Is there anything else I have missed?
Thanks!

I should perhaps add that when I attempted a first precharge I could feel the resistor getting hot and So I closed everything down. I then found out the negative HV cable was in contact with the SDU cover so it was shortcircuited for some seconds apart from the resistor.. could this have harmed any components causing the inverter not to start? I only have 40v

The most obvious reason for precharge failing and the resistor getting hot is having the positive and negative connectors the wrong way round. In that case the whole inverter will act as a short circuit and the resistor will get hot. It won't damage anything if you only precharged, but will definitely cause damage if you closed the main contactor.

Shorting *both* cables to the chassis will also cause this, which is particularly easy to do if you accidentally crimp the cable shielding into your HV cable.

DO NOT RUN YOUR INVERTER WITH udcsw=0 This will allow the main contactor to close even if the precharge has failed, which is extremely dangerous.

Anyway, I'd suggest you triple check that your fuses are okay and that your polarity is correct. Set your udcsw to something just below your battery voltage, and then attempt precharge again and see what voltage the inverter reports as udc. If it looks correct (eg 39 and your battery voltage is 40), you should definitely be able to start the inverter.

Note: if you're switching on the HV manually, it needs to be switched on *immediately* after the inverter is powered, Te precharge starts as soon as the inverter is powered and will time out after a few seconds.

Then what happens when you apply the start signal? Do you still get UdcBelowUdcSw?

I'd stick with normal rather than manual mode.

I do the precharge sequence manually without the help of the sdu, measuring ghe voltage between the poles on the inverter. Will check again the shielding on the HV cables. Should I disable the prechargesequence in the inverter altogether?

ViktorT wrote: ↑Sat Aug 20, 2022 5:46 pm I do the precharge sequence manually without the help of the sdu, measuring ghe voltage between the poles on the inverter. Will check again the shielding on the HV cables. Should I disable the prechargesequence in the inverter altogether?

I don't know how to disable the precharge sequence. That's certainly an option if it's possible. The other option would be to just do the precharge *before* you power up the inverter.

I was just thinking there should be a way to disable it but realise the parameter I had seen was tripnode saying PrechargeOn. But that doesnt help.. the fuses I have is a 10A for the 12V and a 400A for the HV. Perhaps I should use a smaller fuse for the HV.. will try to do the precharge sequence via the inverter today, should the precharge sequence start when supplying 12v or when activating start?

Just a dumb question here catphish; you mean I should do a manual precharge sequence before I even supply the inverter with 12v ? Then I supply 12 v and press startbutton? When giving 12v I would still need to set udcmin to like 30v or so right? Any other parameter I need to set?

ViktorT wrote: ↑Sat Aug 20, 2022 3:27 pm when I start the inverter in manual mode opmode is still off.

Not sure if that version had this, but what is the value of "lasterr" after the failed start attempt?

Error message is Precharge. It was overcurrent after I did the first attempt when the neg HV cable was mistakenly in contact with the chassi

ViktorT wrote: ↑Sun Aug 21, 2022 9:27 am Just a dumb question here catphish; you mean I should do a manual precharge sequence before I even supply the inverter with 12v ? Then I supply 12 v and press startbutton? When giving 12v I would still need to set udcmin to like 30v or so right? Any other parameter I need to set?

That is what I meant, but I was wrong, and I don't recommend doing this. It can be quite dangerous to charge the HV when openinverter isn't fully booted.

With that in mind, I actually don't know how you deal with precharge if you aren't using openinverter to control the contactors, sorry

I did manage to precharge this last weekend. I opened the inverter and found a connector that hadnt clicked in properly. After that it was no problem. I supplied 12v, set udcsw and min dc voltage to 0 and did precharge msnually then started the inverter and testspinned. Such a great feeling