Paul & Sabrina's cheap DIY 144v motor controller

[jedsmd]

Originally Posted by MPaulHolmes

The throttle sensor ground is the control board ground, which is a filtered version of the output ground of the isolated dc-dc that's bolted to the roof of the controller.

Thanks that is what I figured - keep it isolated from chassis ground.

[jedsmd]

Originally Posted by Astro

Sounds like the pack is being grounded to vehicle ground through the remote sending unit. In the PDF they say that "If you need galvanic isolation between pack negative and your 12V supply ground, then you must use optional isolated DC/DC converter as shown on the wiring diagram."

I have an older version and the documentation for the current version does not apply.

The old sensor board has a dc-dc built in. The pack is and always has been floating. The voltage between pack negative and chassis is ambiguous. I just measured it as 72 volts. If I measure it again it will be something else.

Maybe also put a meter between the pot box ground wire and its casing to see if they are internally connected. I would have expected there to be no connection between the hall sensor and the casing but you never know till you check.

The hall sensor ground is isolated from the potbox. I opened it up before installing it (mostly because I wanted to see what was inside).

[jedsmd]

Originally Posted by MPaulHolmes

Do you have the isolated dc-dc feature? Or is the EV Display ground the same as the pack ground?

Paul ignore my previous answer to this question. The design of the 'EV display has changed significantly since I bought mine. Mine has a built in dc-dc and does not require an external one.

[jedsmd]

Originally Posted by MPaulHolmes

I just love mysteries like this. I'll do that now... new software sent!

I installed the fixed frequency software you just sent and the meter is no longer going bonkers. The spread spectrum must generate a little more noise.

I prefer the spread spectrum. When the parts arrive I will install the filter and switch back to the spread spectrum

[MPaulHolmes]

We could try a higher frequency spread spectrum. Like 7-12khz or something. The problem may be from the low frequencies of the spread spectrum. the battery bank experiences the largest surges at low frequencies. Maybe that's affecting the meter. I'll change it and we can see if it gets better.

[MPaulHolmes]

Holy cow, your spread spectrum frequency range was 3-5kHz. Oops... No wonder you were having problems with that monitor.

[jedsmd]

Originally Posted by MPaulHolmes

Holy cow, your spread spectrum frequency range was 3-5kHz. Oops... No wonder you were having problems with that monitor.

No wonder I liked the way it sounds

[flores]

I was browsing the mouser site, and found an IGBT that is fairly priced and has a high continuous current (840A)..

FZ600R17KE3 Infineon Technologies | Mouser

And was wondering if we could use it for the controller?

[MPaulHolmes]

I think you would still need an external freewheel diode though. The dual igbts have the low side IGBT's diode acting as the freewheel diode.

[flores]

Hmm yes.. in de mouser description it says DUAL.. but based on the schema it clearly isn't