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  #21  
Old 04-06-2017, 11:02 PM
Karter2 Karter2 is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

if you want to see what good data instrumentation can show you , take a look at this typical record of a 10 sec run from John Metrics DC Plasma EV racer...
Note how the motor voltage increases as the battery voltage sags to peak output
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  #22  
Old 04-14-2017, 02:38 AM
falshami falshami is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

are any of you familliar with the vec500 by golden motors do you know if a cycle analyst can hook up to it? maybe this will help? also does it seem that a higher voltage is what may be needed?
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  #23  
Old 04-18-2017, 02:46 AM
falshami falshami is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

so latest update.. i put in a jack shaft, i got a gear ratio from 10 teeth to 21 , attached to a 10 tooth to a 31, so roughly a 5:1 ratio, and now she does 24 mph... also the power wont go past 6 or 7 kw, i am quite confused. any ideas guys? i was really sure that with my size wheels at 5:1 i would have at least 50 mph?
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  #24  
Old 05-08-2017, 04:05 AM
Killzilla Killzilla is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

Any updates? Running into a similar problem.
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  #25  
Old 05-08-2017, 12:26 PM
falshami falshami is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

so i did have an update. a 5:1 ratio with a wheel of around 21 inches tall , did not work out, good acceleration but she got to a top speed of 24 which wasn't what we wanted. i next tried a ratio of 18 teeth to 31 and that worked for a top speed of almost 40 ish mph. take off power was abysmal it would struggle to start up any hill. i then dropped to a 14 tooth to 31 and got spectacular results, up to 47 mph depending on the grade of the road. take off power is still weak but not as bad. i am moving to a 12 tooth to 31 which i think should be my magic numbers i may lose a couple miles per hour but im hoping i can make up for it with better acceleration . next issue is it draws a lot of amps. i had originally planned my buggy to have a range of nearly 60 miles, she does around 20 now with this gearing, which is problematic, since the final 7 or 8 miles arent as usable as the first 12 especially with the said lack of power on take off. i have raised the starting phase amps to help to 350, but that isnt sustainable. I am going to activate regen soon and have added 240w of solar to the roof to help a bit. maybe this may add an extra mile of usable range.. unsure still. i have calculated that my vehicle uses 7.5ah per mile or roughly 360 watts per mile, which is atrocious efficiency. i think that part of this is due to poor aero dynamics, since this is the realistic range at higher speeds. also the fact that the gearing is set so high, i am thinking that when i drop to 12 teeth my draw should drop a bit. if i could get the draw to around 240w per mile id be in much better shape, although that's still quite inefficient. but it would up my range to about 30 miles which would work for my commute needs. any ideas to bring my efficiency up would be wonderful!
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  #26  
Old 05-08-2017, 11:07 PM
Killzilla Killzilla is offline
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Unhappy Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

Have you played around with the controller settings? I had a 3 KW motor from golden motors, initially it was terrible, played around with the settings a bit and it improved. Not dramatically, but it did improve. The 3 KW motor takes 3840 W of power for us (48 V x 80 A) so we are maxing it out almost. We also used a 5 KW motor and got quite a decent range. We were drawing 1 Amp/hr per Km so approx 48 Wh/km. Only issue was gradeability and top speed. All this was on a flat road though (the range test).
Only difference between our vehicles is I have a three wheeler (reverse trike), and probably thinner or less wider tires than you. But that shouldn't give such a dramatic difference in numbers.

Vehicle Weight = 500 kgs
Drive wheel radius = 24 inches
Motor = 3 and 5 KW.
Transmission = CVT
3 KW gave us top speed of 35 kmph, and lousy to OK acceleration.
We wanted to go ahead and buy a 10 KW and hook it up with a gearing of 4:1 or 5:1 (similar to yours) and hope to get to at least 50 mph. However a little underwhelmed after hearing your situation.
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  #27  
Old 05-09-2017, 01:49 AM
falshami falshami is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

I am simply astounded that you got such an efficient run out of the vehicle, although at 35kmh i only draw about 80 to 110 amps as well so we are about as efficient as each other there. and my vehicle weighs about 400kgs. roughly. i can no longer dead lift the rear end my self, it originally weighed around 650 but motors and batteries add up. im thinking i simply need more volts which is unfortunate. sicne that means upgrading my controller and battery setup which will confuse me quite a bit, my suggestion is sell your 48v stuff and use 96v. thats what i should have done. from my experience a 10kw motor will not get you to 50 mph especially at a 4:1 ratio or 5:1. that actually got me speeds of only around 18 to 22 mph, it ripped though, it really hauled! i have settled on a gear ratio of 2.58 to 1 that should net me a top speed at full voltage of around 43 to 45 mph with one occupant. and hopefully give me a range of hopefully 24 miles? thats at 150ah. i tried a cvt at first to no avail. it was incredibly loud , unreliable and just didnt work , especially with reverse. a cvt would have been a dream. i have messed with that controller a ton as well, i have it damn near maxed out on settings. starting amps are at 350, peaks at 350 battery amps . again this was using a 3:1 ratio . my 2.58 to 1 should be my golidlocks gear or a 12 teeth to 31 . what i need to do is drop my amps consumption and maintain speeds of around 40 to 45 mph. im hoping my new gear will arrive soon. also adding another battery will really help . i sometimes push betwen 9600 and 12600 watts . my biggest accomplishment so far is keeping my controller super cool! i only wish i could improve the take off torque. it concerns me since it may not be able to get up inclines with two passengers. its only funny since while moving it accelerates just fine. so i am bewildered.
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  #28  
Old 05-09-2017, 01:57 AM
falshami falshami is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

one big thing i am doing is trying to see if there is a way to add a 2 speed or 3 speed transmission to my vehicle.
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  #29  
Old 05-09-2017, 02:39 AM
Killzilla Killzilla is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

Maybe my vehicle is slightly more efficient as I only have three wheels! And one driven wheel. So with my current set up being useless, I am probably going to buy a 10 kW motor from GM and use a final drive ratio somewhat similar to yours (3:1). However I cannot use a 72V system as my budget is stretched to the limit. So I am stuck with 48V. Also acceleration is not a top priority if I can reach around 40-45 mph. Do you think such an effort is even worth it? Would said 10 KW motor be able to reach the requisite speed even if I sacrifice acceleration instead?
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  #30  
Old 05-09-2017, 06:50 AM
Duncan Duncan is offline
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Default Re: stuck on my build need help with BLDC setup 10kw on my buggy urgent!

Why not buy a Forklift motor and a Paul & Sabrina controller

75Kw!

I paid $100NZ for the motor and $600US for the controller

You will also need more volts with only 130 I struggled to reach 100Kph

NOTE pay no attention to the nameplate power on the motor - mine is 10K
But I'm putting about 300Kw into it
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