Electric Chopper Project

[Dui ni shuo de dui]

I am using the Chinese only BMS app since my BMS is from 2019. I cannot find a setting that is obviously the precharge current. Under "BMS hardware parameters" I have a "Starting current" setting with the unit "The A" and another setting "Quiescent current consumption" with the unit "MA". Is it anyone of these?

I'm using some very old version of the app and my interface is in english. I just checked on mine and it says "Pre-charge Current", the value is measured in A, not mA.

I suggest you try finding another version of the app, some work better than others.

 

[ecustom]

Yes, I have a wire coming directly from the battery positive to the key switch.
Then from the key switch I have one wire going to the controller ON/OFF wire, and another (thicker) wire going to the DCDC converter input in order to power all the other stuff.

Where did you find a key switch rated for this? All I find are 12V rated switches. I have been browsing through your roadster build. It really sets the bar high. Awesome.

 

[Dui ni shuo de dui]

Where did you find a key switch rated for this? All I find are 12V rated switches. I have been browsing through your roadster build. It really sets the bar high. Awesome.

I don't know where you live but here in China they are very common, pretty much every EV use them. Maybe try on aliexpress ?
You should look for key switches for electric vehicles, not regular motorcycles.
But they still tend to die after a few years, especially if you often turn the bike on while the light stich button is on.

One other way is to use the key switch to trigger a relay, but then the problem is that most relays will either have 12 or 24 V coils, meaning you'll need a power converter that will always be on. Meaning this power converter might discharge your battery after a while. Plus that creates new points of failures, because if this converter or the relay fails then you're stuck, just the same way if the key switch fails.

So my recommendation is to just get two key switches. One for now and one spare in case it breaks down in a few years.