pendragon8000 said:
sorry to harp on about the fuse/ breaker but, if its 12v rated then the arc may not be broken as its what 6x16v=80 so 6 times more EMF making an arc welder from your breaker.
Listen to this guy, he does a few weeks at tafe and suddenly he's an expert
Yeah you're right, and I experienced very early on what happens when you try to use a switch even just a little above it's rating - one of the first bikes I built I used a 24v 30A switch on a 36v 30A controller and it welded shut after 3 actuations. I guess I could test this to destruction to find it's limits but for my application I dont plan to be using it as a switch as such - more of an emergency disconnect if I happen to need it. I think it's unlikely though, especially with everything protected inside the raptor frame. I'm also using heavy duty automotive wire which has much tougher and thicker insulation than the usual soft silicon RC stuff.
My other reasoning for not bothering with fuses is all they're really going to save you from is an accidental short of the discharge leads which in a properly built bike should be essentially impossible. Excessive current draw could then only come from a controller failure causing the main power leads to short, which is pretty unlikely. The huge current delivering ability of big lipo packs usually blows the offending part to pieces resulting in a nice clean open circuit :lol: I'm sure we've all accidentally bumped leads over time. I know when I was building a pack once I accidentally shorted the discharge leads while fitting the connectors. It vaporized a 4mm bullet down to a stub. There's your fuse
Rix said:
since you have to run an external shunt for your Sabvoton, is there a calibration process so the CA is accurately reflecting what the controller is getting? Is the Sabvoton set up for a CA to plug into or did you mod that as well?
The sabvoton doesn't use shunts to measure current and has no CADP connector so that's why I need to use an external one. So I'll need to make my own CA connector with the necessary connections - a sense wire at each end of the shunt plus connect up the other wires (battery voltage, speed and throttle) and then it'll work as normal. You just need to enter the correct resistance of the shunt in the CA rshunt value.
I really need to get this sorted quick as I'm blind without it. I only had a brief test ride and it's super smooth and quite rapid but it doesn't have quite the sting I was expecting. With the infineon it was pretty brutal if you grabbed the throttle - this one is nice and smooth but a little too much so - it wouldn't wheelie which I would totally expect at 12kw.
Going by the bum dyno it feels like it's only running around 80A and low (lower than programmed) phase current. I think the controller defaults to 60 or 80A so it may not have flashed properly. It certainly needs more tuning and I need the CA running to properly see the current etc in real time.
I gave it a good flog around the local back streets and though it wasn't a good way to test how hot it would get as it was only about 12 oC the motor and phase wires were cold to the touch (motor measured 20oC) so that's a positive sign! The phase wires on my batshit motor were super hot after such riding, though the controller phase wires were thinner so this may have been causing some upstream resistance and heating. But this further points to it not running as much current as I programmed. Needs moar laptop time
It is very quiet though unlike in the video. The first thing as I rolled away was the complete absence of motor noise and once you're moving it's nothing but tyre noise. You do hear it a little as the speed gets up but it's very minor.
Your build is....as usual, over the top. Neat and bad ass looking ride. Cant wait for the vids!
Cheers! I'm looking forward to giving it a proper run and make some vids too! The first opportunity will be the hunter EV festival so that'll be a nice christening for it
