xyster
10 MW
What's the current limit on the stock controller?
.
- Thread starter D-Man
- Start date
What's the current limit on the stock controller?
Reid,
Xyster asks a good question. I think the controller current limit will increase with extra voltage but i'm not sure how much. If you want your motor to run more efficiently at 36 volts a simple method would be to reduced, (i don't know how easy this is) the current limit on your controller. Of course you'd loose torque and it sounds like your sorted with all your air cooling stuff anyway
Xyster asks a good question. I think the controller current limit will increase with extra voltage but i'm not sure how much. If you want your motor to run more efficiently at 36 volts a simple method would be to reduced, (i don't know how easy this is) the current limit on your controller. Of course you'd loose torque and it sounds like your sorted with all your air cooling stuff anyway
Reid Welch
1 MW
35 amps.xyster said:
But, guys, the motor is a current-driven device.
If I limit the current to a cool running 15A (that's the 24V power level, I mean), then then it goes only 17mph.
I'm not understanding something basic here... I'm not..e-smart.
Amps are amps here, inasmuch as the motor has the same winding as always, right?
xyster
10 MW
The current limit on my scooter's brushed controller remains the same 30 amps whether 36v or 48v. I've run my bike's 36-72v controller at many voltages between 30v and 84v and the on-board ammeter has never showed more than 35 amps.
At the lower voltages though, the ammeter shows the motor won't pull more than half the controller's 35 amp current limit.
In practice, voltage and electrical resistance sets a current limit without extra circuitry that is normally higher than a controller's current limit. But when running lower voltages, that voltage-set current limit comes into play because it drops below the controller's circuitry-set current limit.
Reid's mongoose I thought was sold as a 450 watt 24 volt bike, suggesting a 20 amp current limit. Did you upgrade the stock controller, Reid? How do you know the current limit is 35 amps?
Matt Gruber
1 MW
35 amps.Reid Welch said:
But, guys, the motor is a current-driven device.
*****************If I limit the current to a cool running 15A (that's the 24V power level, I mean), then then it goes only 17mph.******DID U TRY THIS? I BET NOT!
24x15=360w
36x15=540w will go much faster!
Reid Welch
1 MW
Xyster, the controller is labled "35 amps".
Thanks Nick and Matt and Xyster,
as I understand it, the motor know nothing of voltage,
only current...wait, that is until it approaches a running speed where the back EMF repulses the flow of additional current.
No-load current of this motor is small. It consumes 40W of power @24V.
Stall load current of this motor is large. It draws a bit over 30 amps of current, regardless of a 24 or 36V nominal supply. So, that is the controller's rating at work.
Xyster, the Currie folks, when it comes to the rating of this gearmotor,
are simply liars. A lie is a lie. The motor will develop more than 450W of -power-, even at 24V nominal supply. But not indefinitely.
The makers/designers of this motor (Unite Motor) rate the motor at 250W power output continuous. And that's because, we know, it's designed for the nearly world-wide speed limit for e-bikes. The motor surely will put out much more power, but... being well-designed to NOT be more motor than its design calls for, the result is
one hot little bastard.
:wink:
The main thing? Currie lies to puff the seeming-power of these bikes they're selling. The same bikes sold in other lands are advertised as 200W, and have a controller with a lower max current rating (so-labled, citing Lemmiwinks' bike in AU).
Currie=Lie-ee
Unite= Honest-EE
That is, the E.E.s at Unite present their motor honestly.
The P.R. pigs at Currie are whores, to put it delicately;
for I do not wish to sound harsh
Thanks Nick and Matt and Xyster,
as I understand it, the motor know nothing of voltage,
only current...wait, that is until it approaches a running speed where the back EMF repulses the flow of additional current.
No-load current of this motor is small. It consumes 40W of power @24V.
Stall load current of this motor is large. It draws a bit over 30 amps of current, regardless of a 24 or 36V nominal supply. So, that is the controller's rating at work.
Xyster, the Currie folks, when it comes to the rating of this gearmotor,
are simply liars. A lie is a lie. The motor will develop more than 450W of -power-, even at 24V nominal supply. But not indefinitely.
The makers/designers of this motor (Unite Motor) rate the motor at 250W power output continuous. And that's because, we know, it's designed for the nearly world-wide speed limit for e-bikes. The motor surely will put out much more power, but... being well-designed to NOT be more motor than its design calls for, the result is
one hot little bastard.
:wink:
The main thing? Currie lies to puff the seeming-power of these bikes they're selling. The same bikes sold in other lands are advertised as 200W, and have a controller with a lower max current rating (so-labled, citing Lemmiwinks' bike in AU).
Currie=Lie-ee
Unite= Honest-EE
That is, the E.E.s at Unite present their motor honestly.
The P.R. pigs at Currie are whores, to put it delicately;
for I do not wish to sound harsh
Reid Welch
1 MW
I did not have instrumentation on the bike when it was on 36V.Matt Gruber said:
After a spell of running a few hundred miles, the seatpost rack carrier of the extra brick busted.
I've not replaced it, being lazy, and so have been running on 24V since then (slowly, bah).
It was only after going back to 24V that I installed a Drain Brain.
So, tell me, if I feed 15A through the motor,
isn't that all the motor knows it is (15A), until such point as the back EMF limits the motor's RPMs?
Oh, wait... I recall how the bike on 36V felt like: like a slingshot stretched and released by Hercules.
It accelerated hugely better.
See, I told you guys I am stupe id.
Matt Gruber
1 MW
Watts = power
Amps times volts = watts
calculate watts to get performance
Amps alone while helpful, is only half of the data.
Amps times volts = watts
calculate watts to get performance
Amps alone while helpful, is only half of the data.
TylerDurden
100 GW
test
Reid Welch
1 MW
Here's where I get mentally stuck in stufumode:
Resistance:
When current flows relatively freely through a heavy copper wire,
then no power is developed. Factor in copper resistance, and there's that heat developed, useless heat, thermal power we can't use.
When current flow and lines of magnetic force develop, there's no power developed, only force, if something attractive is nearby.
When current flows and lines of force develop, angled to attract to a magnetic target, power may be extracted from the turning of these lines of force upon a rotating axis.
If the motor is stalled, or nearly stalled, how do 15A with 24V of battery make any less force than 15A (throttled) from 36V of battery?
See, counter EMF is absent in this 'example'.
What am I missing above my brainstem, Matt? :wink:
Whatever it is that's missing, I find it does not hurt a bit
until I look around (like now) trying hard to find it!
ouch
Resistance:
When current flows relatively freely through a heavy copper wire,
then no power is developed. Factor in copper resistance, and there's that heat developed, useless heat, thermal power we can't use.
When current flow and lines of magnetic force develop, there's no power developed, only force, if something attractive is nearby.
When current flows and lines of force develop, angled to attract to a magnetic target, power may be extracted from the turning of these lines of force upon a rotating axis.
If the motor is stalled, or nearly stalled, how do 15A with 24V of battery make any less force than 15A (throttled) from 36V of battery?
See, counter EMF is absent in this 'example'.
What am I missing above my brainstem, Matt? :wink:
Whatever it is that's missing, I find it does not hurt a bit
until I look around (like now) trying hard to find it!
ouch
Matt Gruber
1 MW
IF U Think volts don't matter,
stick your finger in an electric socket.
Stalled? how do u ride stalled?
stick your finger in an electric socket.
Stalled? how do u ride stalled?
Reid Welch
1 MW
I didn't know that. .....Ah,TylerDurden said:
Fu....man..chooo
Pardon me.
I sputter half-oaths and sneeze when rattled.
Maxwell Smart
is never ever unnerved, almost.
Most controllers limit the battery current.
If you run a higher voltage, the battery current will be limited to the same value, but the motor will see much more current at low speeds becasue of the "current mulitiplication" effect of the controller.
Another way to look at it is if the controller is limiting the battery current and you increase the battery voltage, the limit occurs at a higher power level (power= volts X amps).
Try putting an ammeter between the controller and the motor and see what happens.
If you run a higher voltage, the battery current will be limited to the same value, but the motor will see much more current at low speeds becasue of the "current mulitiplication" effect of the controller.
Another way to look at it is if the controller is limiting the battery current and you increase the battery voltage, the limit occurs at a higher power level (power= volts X amps).
Try putting an ammeter between the controller and the motor and see what happens.
Reid Welch
1 MW
When the ride starts, if full throttle is applied, that's a full power stall. And max current, limited only by the controller, or by the battery's voltage -pressure- is seen, right?Matt Gruber said:IF U Think volts don't matter,
stick your finger in an electric socket.
Stalled? how do u ride stalled?
Volts matter as a matter of push, but current here is current.
Now I just read fechter's (as usual perfect) tutorial,
and I see better. Still looking for my bwain, but
what the hell, what the hell; I don't need it when Richard Fechter is around
(nor hardly, when you're nearby, thanks Matt)
--
weid
Matt Gruber
1 MW
stalled is, say, stuck in a ditch.
being stopped is not usually stalled. i've NEVER stalled my mbike, but my 250w psev easily stalls like on a door threshold. it just won't move, as the CT limits amps to 9 or 10.
mbike can pull out from stopped using only 1 amp. i do this in stores. thresholds pull ~3 amps.
moral: small motors suck at low amps and burn up at high amps
being stopped is not usually stalled. i've NEVER stalled my mbike, but my 250w psev easily stalls like on a door threshold. it just won't move, as the CT limits amps to 9 or 10.
mbike can pull out from stopped using only 1 amp. i do this in stores. thresholds pull ~3 amps.
moral: small motors suck at low amps and burn up at high amps
Actually a clamp-on inductive pickup should work since it's AC. I'll have to borrow the one from work and try it
baltipower2
1 µW
Brett White did open heart surgery on an avanti motor, his photo report is here:
http://www.users.bigpond.com/solarbbq/avanti.htm
It's an interesting design, quality looks very good, but power is severely choked. It might go well with a decent battery and controller.
Mick Sheehy
http://www.users.bigpond.com/solarbbq/avanti.htm
It's an interesting design, quality looks very good, but power is severely choked. It might go well with a decent battery and controller.
Mick Sheehy
That's pretty interesting. The copper looks beefy.
The controller looks very similar to the Voloci controller.
It's hard to guess what the efficiency would be just from looking, but it should be decent.
The controller looks very similar to the Voloci controller.
It's hard to guess what the efficiency would be just from looking, but it should be decent.
Similar threads
