Inwo
10 kW
Will a 96v controller work from 72v to 100v? Or at least down to 84v?
large road legal electric go kart build. need help!
- Thread starter falshami
- Start date
torker
100 kW
Cool ride. Always want to build something like this. It might look wonky but what if you added a windshield frame from the top of the existing windshield and extend it to the front of the buggy. ? It would be really laid back. Oops ,looking it does go that way now. Does the windshield go all the way to the front?
Don't let my rendering skills scare you haha Maybe use the cage. The bottom section would not have to be clear.
Don't let my rendering skills scare you haha Maybe use the cage. The bottom section would not have to be clear.
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the controller i am hoping to get is a 96v controller. but from my understanding a controller basically ramps up the voltage from 0 to 96 to get rpm out of the motor. so if the controller is ramping up the voltage, my question is can i set it to simply stop ramping at around 60v. the controller i want is an HPC 500 at 96v. my hope would be that there will be no more voltage speed drop by doing this and i wont be over taxing my motor or controller, everything runs nice and cool and efficicent. is this how it works?
also as far as the windshield goes, that might be something to consider, id have to weld some metal as a reinforcement since any acrylic or poly-carbonate i place there would have some serious droop at 30-50 mph.
i am looking into transmission options now. a transmission would seriously help me, either a 2 speed or a CVT, i need something to get me going from 0 it would greatly increase acceleration. and maybe even drop starting amps .
also as far as the windshield goes, that might be something to consider, id have to weld some metal as a reinforcement since any acrylic or poly-carbonate i place there would have some serious droop at 30-50 mph.
i am looking into transmission options now. a transmission would seriously help me, either a 2 speed or a CVT, i need something to get me going from 0 it would greatly increase acceleration. and maybe even drop starting amps .
also as a further uodate, i insulated the rear hatch with carpet foam pad. and i will soon insulate the the new bottom floor i put in to keep things quieter im hoping that this stuff will quiet down the vehicle and help improve the aero dynamics
so i wasnt so happy with the acceleration even with the 12tooth. . i learned and noticed a feew things tonight. my thought process was , if i drop to a smaller gear i might draw fewer amps. and run the motor and controller cooler. hopefully giving me more range and a more efficient vehicle. i threw the 10t sprocket back on and took her for a drive. first thing i learned. my gear box reverse is geared higher than forward. our previous thought was they were the same. this is untrue. so i tested the reverse gear and forward gear. in reverse gear( driving forward) she still managed to get up to 46-48 mph. so not much change from the 12tooth, but she had more take off power and was honestly more pleasant to drive. though a bit louder. she seemed like she could keep up with traffic better, and regen does help. in forward gear she accelerated much quicker and got up to about 38 mph. that is a significant difference. i think i would be happy with my 10 tooth gear if it was sustainable. its like i have two modes now, quick mode and general purpose. now the problems
in 10tooth reverse gear forward moving we suck up amps. i mean we are doing roughly 280 wh per mile. which is a large increase from 220 it drops range significantly. my unreliable shunt/ bms also was reading 400 amps at times. which i trust it drew more amps. but i dont think that many more since the controller maxs at around 250a . still its a significant increase in amps. also to add to this the controller and motor get much warmer quicker. further confirming there are more amps being pulled. why is this? i assumed by allowing the motor an easier time to spin up she would draw fewer amps. to add to this the ambient temperature varied from the 60's to low 70's as i did this at night. my motor got hot enough that touching was uncomfortable. and controller easily jumped up to 110f. if i drove this in the day at 95f outside the controller would temperature throttle very quickly. and that motor would just cook. so im left wondering, do i need to reduce amps available from the motor? would this negate all my work with gearing?
it seems as if the higher the 12 tooth gear and 14 tooth sprocket with poor acceleration draw MUCH less amperage. but do manage to get up to speed eventually, and stay MUCH cooler. a quicker , easier to move car seems to draw a lot more amperage and heats up alot quicker. my range takes too much of a hit . i managed to drive 20 miles today on a charge. at about 15-16 miles the battery was low enough that usable speeds weren't really feasible. under 35 mph was what it would reach. i did manage to drive 20 miles though. with probably another 3 or 4 in the tank at sub usable speeds meaning under 35 mph.
id love some input friends!
what am i missing here?
in 10tooth reverse gear forward moving we suck up amps. i mean we are doing roughly 280 wh per mile. which is a large increase from 220 it drops range significantly. my unreliable shunt/ bms also was reading 400 amps at times. which i trust it drew more amps. but i dont think that many more since the controller maxs at around 250a . still its a significant increase in amps. also to add to this the controller and motor get much warmer quicker. further confirming there are more amps being pulled. why is this? i assumed by allowing the motor an easier time to spin up she would draw fewer amps. to add to this the ambient temperature varied from the 60's to low 70's as i did this at night. my motor got hot enough that touching was uncomfortable. and controller easily jumped up to 110f. if i drove this in the day at 95f outside the controller would temperature throttle very quickly. and that motor would just cook. so im left wondering, do i need to reduce amps available from the motor? would this negate all my work with gearing?
it seems as if the higher the 12 tooth gear and 14 tooth sprocket with poor acceleration draw MUCH less amperage. but do manage to get up to speed eventually, and stay MUCH cooler. a quicker , easier to move car seems to draw a lot more amperage and heats up alot quicker. my range takes too much of a hit . i managed to drive 20 miles today on a charge. at about 15-16 miles the battery was low enough that usable speeds weren't really feasible. under 35 mph was what it would reach. i did manage to drive 20 miles though. with probably another 3 or 4 in the tank at sub usable speeds meaning under 35 mph.
id love some input friends!
what am i missing here?
Something doesn't seem right. With lower gearing, the amps should be less but you're seeing more?
One test is to measure the amp draw at full speed, no load (lift the wheels or remove the chain). The amp draw should be minimal with no load.
One test is to measure the amp draw at full speed, no load (lift the wheels or remove the chain). The amp draw should be minimal with no load.
i will see if i can find a jack to get this tested. but yes, now that my gearing is 3:1 vs 2:1 my amps are insanely high, and draw is much more watt hour per mile wise. my question is what could be the issue shouldnt it be that if a vehicle is easier to push then then the amps should be low? it seems that when my vehicle gearing made it hard to move my amps were quite low
Inwo
10 kW
Just the reverse. Low gear = hard to push = easier on motor.
Inwo
10 kW
Could you be reversing numbers in gear ratio description?
How about a drawing?
Small gear on motor = low ratio.
When parking on hill you put car in low gear to keep it from rolling.
I never looked at your drive train. Is it a reduction Differential? Why not direct drive to that?
How about a drawing?
Small gear on motor = low ratio.
When parking on hill you put car in low gear to keep it from rolling.
I never looked at your drive train. Is it a reduction Differential? Why not direct drive to that?
Hillhater
100 TW
I Suggest you Clarify..
Harder to push ?.. Harder for the motor or somebody standing behind ?
I think you guys are confusing each other.
Harder to push ?.. Harder for the motor or somebody standing behind ?
I think you guys are confusing each other.
i think i need to learn to be more clear. and understand gearing terms! haha. the buggy is geared low. so the motor has currently a small 10 tooth pinion gear. the input to the differential box has a large gear of 31t . differential gear is welded and cannot be changed. so i was stuck either changing the pinion gear on the motor. or adding jack shafts to adjust ratios. i found that , the closer i got to 1:1 gear ratio the cooler the motor ran. as did the controller. BUT it struggled to do much of anything. my Goldilocks gear was that of a 12t on the pinion which gave me decent take off , good high end speed. and good temperatures. i figured that if i dropped two teeth. the motor would have an easier time getting the kart going, would increase acceleration, and the hope was lower the running temperature, since i figure that the amps wouldn't just be sitting in the motor struggling to get the motor turning . i really thought that if the motor had an easier time getting the car rolling.i would lower amperage and heat. in practice. my buggy did accelerate much quicker. and still managed a reasonable speed of 48 mph sometimes 50. however. it began drawing many more amps. and got everything hotter much quicker. my question is. now that the gearing was set to 3:1 which made the buggy quicker. why is it heating up much quicker and drawing much more power?
also the motor is direct drive to the differential via a gear box that selects forward or reverse for the old inferior engine. the reverse gear is geared in such a way that my top speed is quicker but lower torque. the forward gear reduces my speed and increases torque.
also the motor is direct drive to the differential via a gear box that selects forward or reverse for the old inferior engine. the reverse gear is geared in such a way that my top speed is quicker but lower torque. the forward gear reduces my speed and increases torque.
torker
100 kW
That is really strange. Just like a motorcycle, a larger sprocket on the wheel gives lots of torque for climbing which "should" take the load off the engine/motor. Why it runs hotter makes no sense to me. Unless the motor is running more rpm so the bearings are getting hotter and tightening up... ? :?
Also reading more. A 10 tooth sprocket is really small. I don't know, maybe someone like Luke might know. Does a small sprocket add a bunch of drag. If the chain has to wrap tighter that means the links are swiveling a lot more which would create a lot more heat/friction. Just an idea..
Also reading more. A 10 tooth sprocket is really small. I don't know, maybe someone like Luke might know. Does a small sprocket add a bunch of drag. If the chain has to wrap tighter that means the links are swiveling a lot more which would create a lot more heat/friction. Just an idea..
The sprocket theory might be valid. 10t is really small so the chain links have to bend further as they go around, which would increase the friction losses.
Another test would be to measure the full speed motor amps with the chain removed completely. This would give an idea whether it was the motor itself or something in the gearing.
Another test would be to measure the full speed motor amps with the chain removed completely. This would give an idea whether it was the motor itself or something in the gearing.
torker
100 kW
If this is correct then 2 speeds would be beneficial.
torker
100 kW
Any updates. I would love to build something similar. Video would be awesome. 8)
Hillhater
100 TW
falshami said:
Somewhere you have a major missmatch electrically.
1300 motor rpm is what you will get on those dia wheels , running a 1:1 transmission , and a 3:1 chain reduction from the motor...at 30 mph.
You are running the motor way to slow, hense the high amps and heat.
I dont know why it doesnt rev any higher when you increase the chain ratio, so my guess is it must be something in the controller, or the motor. Are you certain the phase connections are correct ?
sorry ive been gone a few days! ok let me answer these questions as well as i can.
latest update: i decided to insulate the rear motor area a bit more for noise. with carpet foam. we shall see tomorrow how it does. also add a VERY high CFM fan to my motor radiator and it seems to be cooling a bit better but is louder.
i managed to take me and my dad out for a ride for a pizza, on 70 percent charge it drove us just fine a round trip of 5 miles roughly and it even got us up the large hill we have , it did dip in speed from 40mph to 35 mph but to me that is still a win! a fully loaded vehicle and it made it up at safe legal speeds. this is in the forward gear which maxes at 41mph
starting from most recent to oldest.
Hillhater. how do i know for sure if my phase wires are correct? i wired them up directly as shown on GMs website. from what i have been able to HEAR. it sounds like it does rev higher now that i have gone to a smaller sprocket. so it seems to be hjitting full RPM of around 4000 rpm at full voltage which gives us about 41 mph in FORWARD gear , REVERSE gear gives us about 45-48 mph. however i do not know if it is revving lower. current ratio is 10 : 31 plus whatever ratio i slect on the gear box between fwd and reverse. i assumed it should lower heat. and it hasnt so far. i assumed that higher volts meant lower amps and visa versa. it seems to me the controller shoves out full voltage and high amps? which seems to make some sense i suppose?
torker. what kind of video would you like? ill make one! and yes , i am in talks with servo vision to see if we can do a dual motor transmission for the vehicle its a multi speed with planetary gears but mainly uses one motor to supplement the other through the speed range.
fetcher. the speed controller is torque vectoring so unloaded it draws maybe 10 amps. perhaps 20 if it feels like it. under some mild load close to 50 amps. you make a good point though the small sprocket may increase friction loss
a larger gear might reduce heat due to less movement?
latest update: i decided to insulate the rear motor area a bit more for noise. with carpet foam. we shall see tomorrow how it does. also add a VERY high CFM fan to my motor radiator and it seems to be cooling a bit better but is louder.
i managed to take me and my dad out for a ride for a pizza, on 70 percent charge it drove us just fine a round trip of 5 miles roughly and it even got us up the large hill we have , it did dip in speed from 40mph to 35 mph but to me that is still a win! a fully loaded vehicle and it made it up at safe legal speeds. this is in the forward gear which maxes at 41mph
starting from most recent to oldest.
Hillhater. how do i know for sure if my phase wires are correct? i wired them up directly as shown on GMs website. from what i have been able to HEAR. it sounds like it does rev higher now that i have gone to a smaller sprocket. so it seems to be hjitting full RPM of around 4000 rpm at full voltage which gives us about 41 mph in FORWARD gear , REVERSE gear gives us about 45-48 mph. however i do not know if it is revving lower. current ratio is 10 : 31 plus whatever ratio i slect on the gear box between fwd and reverse. i assumed it should lower heat. and it hasnt so far. i assumed that higher volts meant lower amps and visa versa. it seems to me the controller shoves out full voltage and high amps? which seems to make some sense i suppose?
torker. what kind of video would you like? ill make one! and yes , i am in talks with servo vision to see if we can do a dual motor transmission for the vehicle its a multi speed with planetary gears but mainly uses one motor to supplement the other through the speed range.
fetcher. the speed controller is torque vectoring so unloaded it draws maybe 10 amps. perhaps 20 if it feels like it. under some mild load close to 50 amps. you make a good point though the small sprocket may increase friction loss
a larger gear might reduce heat due to less movement?
torker
100 kW
Maybe get an infrared thermometer and shoot that gear after a run. Awesome you took your dad for dinner ..
Hillhater
100 TW
If your motor was to rev at 4000 rpm, with the 3:1 chain reduction, you would be travelling at near 100 mph !
So either your motor is running too slow still , or your differential housing gearing is not 1:1 as you think.
Try to get an accurate rpm measurement from the motor, and recheck that transmission gearing ratio.
Sorry, but i can only suggest you buy a phase tester if GM is not helping
So either your motor is running too slow still , or your differential housing gearing is not 1:1 as you think.
Try to get an accurate rpm measurement from the motor, and recheck that transmission gearing ratio.
Sorry, but i can only suggest you buy a phase tester if GM is not helping
falshami said:
That seems pretty high to me, but I have no experience with that motor. If the controller is going into field weakening to get the higher RPM it might make the efficiency drop.
The thermal imaging idea is good. Anything that's getting hot is wasting energy. Poor man's approach is to do a hard run, stop, and use your hand to touch things to look for hot spots. Check everything, like brakes, tires, drive train, bearings.
torker , thank you! my dad loved the trip, we would both just love if it was a bit quieter, its a work in progress. I will see if i can use my infrared thermometer in a video
hillhater:i wish i could read my RPM from the motor i dont really know how to go about that. my gear ratio in the diff i will have to remeasure. i do think that this motor should be able to push more out of itself but i am trying to figure out how. a phase tester is an interesting thing ill have to look into this.
galderdi: i will do a walk around video soon then!. i can to an internal acceleration video, external if i can get someone to help me.
Fechter: i dont know what field weakening is? i will be doing a thermal check in the next few days or so. so far the poor mans way of checking ha told me that only the motor and motor shaft get really hot. other than the controller. im kind of concerned as to why it gets so hot, i also wish i could rid myself of the chain. chain drive is so loud and to me inefficient.
hillhater:i wish i could read my RPM from the motor i dont really know how to go about that. my gear ratio in the diff i will have to remeasure. i do think that this motor should be able to push more out of itself but i am trying to figure out how. a phase tester is an interesting thing ill have to look into this.
galderdi: i will do a walk around video soon then!. i can to an internal acceleration video, external if i can get someone to help me.
Fechter: i dont know what field weakening is? i will be doing a thermal check in the next few days or so. so far the poor mans way of checking ha told me that only the motor and motor shaft get really hot. other than the controller. im kind of concerned as to why it gets so hot, i also wish i could rid myself of the chain. chain drive is so loud and to me inefficient.
Hillhater
100 TW
There are smartphone apps that let you measure rpm using the flashlight as a strobe light.
Manually comparing the input turns on the transmission to the output axle turns is the most reliable method.
Manually comparing the input turns on the transmission to the output axle turns is the most reliable method.
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