Hi fechter, thanks for the compliment. I wouldn't say the controller is getting excessively hot, I can just about keep my hand on it for about 15 secs after a full 15 mile run. The caps are all rated for 105degC so its well below that. I'd just like to keep it as cool as possible since heat stress will always reduce lifespan of components.
A Cycle Analyst is top of my wish list for the xmas stocking so we'll have to wait till then to get a reading on the current draw. The plan is definitely to increase battery voltage
My thinking at the moment is tending towards ~66v from 20s LiFePO4. The flat discharge curve and smaller voltage sag should get the scoot to much more where I'd like it to be. That said I'd have to have closer look at the controller to see if it'll take it without going fizz, bang, pop or something
Some of the caps in the controller are rated at 63v, some at 50v, one 25v and another at 12v. I may end up putting together a higher voltage Clite type controller with the rest of my FETs using plans from another ES member here in the UK. Then get the range from 15 miles up to ~50 and I'll have a really useful moped, especially if I can figure out how to rig up a method of getting at least a decent partial charge (~80%) in less then an hour whilst out and about, then balance off the cells when doing a full charge when back home. From what I've read here good quality LiFePO4 cells will stay in balance for a few charges without any problems. What do you think of
this as a method of providing 36v for the on the fly charging. There's a 36v version of this psu which should be able to put out 13-14 amps, so if I split the pack into 10s sub packs for charging on the fly then am I right in thinking this could work? Maybe the overvolt cut-off could also terminate charge?
This is how my ideas are developing but just for now I'm happy to scoot about town as it is. Even though the moped is bright red the total absence of motor noise when up to speed makes this a very stealthy machine indeed, I just have to ride it as I would a bicycle and assume that at any moment a pedestrian could step out into the road in front of me which is exactly what I'm used to on my pedal bikes anyhow.
I'm really enjoying riding this moped but I wouldn't recommend it to any one who wasn't prepared to sort out potential controller problems and be aware of the limited 15 mile range. The guy who sold it to me gave me a good deal and when I bought it the plan was always to use it as a platform for further developments. The dealer emailed me today asking me if I could fix another controller he's got which isn't working. I advised him that considering the amount of time it took me (over 6 hours) and the cost of the replacement components (£45) and their scarcity then he'd be better off contacting the Chinese manufacturer and resolving the issues with them. They've already said they've had a problem with the controller and have introduced a new one (for more money).
