Andje wrote:?
I don't even know where to begin
. The 18650v's come in 5s2p, so at .5c the 2p should give me 3200 mah; mine are testing around that at .5c, and at 2 c they are showing between 2500 and 3000 mah; this is expected.
Your second comment is based on what? I know that I was putting 8500 watts into my hs30; I know that I was close to saturation since I couldn't go faster with more amps and through LFP's own experiments on his hs30. I know that my Kelly should be more efficient then the Infineon. I know that I'm using 18 gauge wire with high temp insulation to rewind the motor and increasing the copper fill. I know I'm running much heavier phase wires on this bike. Over all, I expect the bike to be able to handle 17kw of actual output power at the motor. This would mean that at say 85% efficiency I would need 20kw going in with about 3kw of heat. So, my original estimate was high, but there is a lot of leeway for the numbers to be off up or down. The motor will not cook in seconds at all, and I certainly wont see less then 50% efficiency to generate 15-20kw of heat. Only if I stalled it.
that makes sense now with the cells, 2 in parallel, sweet.
please dont get me wrong with motor power etc -like i said im a fan of your plan to double them up for one of the most powerful hubs around, but i just think the two melted motors were trying desperately to tell you something..
my comment is based on the physics, dyno testing, and LFP's testing of all of these brushless motors.
doubling up the hs30 is roughly going to have double the power (and torque) of one, there are a few adjustments like less end turn losses (good), and not double the surface area for heat shedding (bad) but for now we will keep it simple and say times 2.
so a double hs30 has (from my dyno testing etc) the ability to produce around 60NM of torque continuously (64NM according to justins simulator for a hs35), holding 150deg c winding temp and is able to dissipate the 580w of waste heat (578w according to justins sim).
so you would be putting in your 30kw at say 100kph (800rpm for your 26' wheel) in order to push through to 150kph?
its easy to calculate then, double the 30NM (for your big motor) times 800 times .1047 gives power out of 5.026kw -this would be the ballpark max continuous power out
and corresponds pretty well with peak efficiency like you thought of around 85%. all good!
when you go to double the power to 60NM per motor you now have 4 times the loss (losses are squared for increasing torque) ive measured 1790w of loss, justins sim 1780w, and you will now have the motor at its max winding (and hall) temp by flooring it a quarter of the time and getting off the throttle for three quarters of the time. but yes you have about 10kw output.
if you go to double THAT then my testing has shown 8860w of loss, (prolly saturating) and justins sim shows 7120w lost, my test motor went from 20deg c to 160deg c within 16 seconds and i shut the test down the temp still overshot to 175deg. the attempt is to make 20kw output but over a third is now going missing to heat, and the effect is squared as you push upward so either way you can hopefully see the difficulties involved with an attempt well above this.
all of this is backed up by LFP dyno run with the same hs35 motor showing a total max of 7.5kw out no matter what power he put in, from memory (up to 40kw)
and the motor up in flames.
now you may see what the 2 melted motors were trying to say during their last moments..
i am sorry if i have caused offense in this or my last post, that was honestly not my intention, but their are certain realities involved here that we will all benefit from being aware of.
and now i can't do photos till I get it back.