I may be wrong on this. Looking at old info. My sticker says 1800A/800A. I saw other stickers say 1500 and the "track" (not race) version was 1800. But the stickers indicated that. I think this is a newer one and actually good for 1800. Check out the Pic and let me know if you free with that assumption.
Max Line and Phase Amps
- Thread starter tedo
- Start date
Here is where I saw the 1500a limit on the fardriver website;
Attachments
Nogasdash
1 µW
I am currently running that set up. Its quick, but because i have the FD 96 850 and i also use field weakening that I am missing some of that immediate torque.
Top speed is 106mph ..but that off the line should be a bit more punchy but that where those phase amps come in...or so I think from what I've read.
I had installed a ND72680 before. starting tourque was ok. Now with the ND721800 and 1400A I had the first time wheelspin. Now it starts like a mid sized motorcycle and exceeds 30kw at 30kph. With more battery amps I think I could raise power to over 40kw and get in under 6 seconds from 0-100kph with my heavy scooter.
j bjork
1 MW
What battery amps or watts are you using at top speed?
larry_says
10 mW
Max line current should be set lower then the BMS amperage by 5 to 10% so it won't shut off on you. Phase current can be set at whatever max line current is set at multiplied by 3. If you use boost you can set the value a little bit higher and run for brief moments. Use a momentary switch on the left side handlebar if throttle is on the right but boost only when it's needed for a minute or so. Brief boosts. Helps to have Temp working on motor and controller if boosting. Make sense?
Yes. Awesome info! Thanks so much.
larry_says
10 mW
It's in the motors windings. The phase amps can be up to 3 times the max line current. 3 phase. Make sense?
Why up to three times?
The extra current as such has nothing to do with 3 phase as extra current is also present with a single phase setups.
The extra (flyback or freewheeling) current occurs mainly at the lower RPM range and is a result of the pulse width modulation (pwm). The whole motor system could be said to work like a step down buck converter in producing extra current at the expense of lower voltage. The top mosfets is controlling the battery current by switching on and off rapidly thousands of times per second.. During the period when the top mosfet's are momentarily turning off the battery current, motor current continues to flow in the motor windings due to the motors large inductance as shown in diagram below as the bottom mosfets are not switched off. This extra circulation freewheeling/flyback current is shown in the thick lines below.
PS. I prefer to use the word 'flyback' current rather than the word 'freewheeling' as this term causes confusion when it comes to bikes and has nothing to do with whether the cyclist is pedaling or not.
The extra (flyback or freewheeling) current occurs mainly at the lower RPM range and is a result of the pulse width modulation (pwm). The whole motor system could be said to work like a step down buck converter in producing extra current at the expense of lower voltage. The top mosfets is controlling the battery current by switching on and off rapidly thousands of times per second.. During the period when the top mosfet's are momentarily turning off the battery current, motor current continues to flow in the motor windings due to the motors large inductance as shown in diagram below as the bottom mosfets are not switched off. This extra circulation freewheeling/flyback current is shown in the thick lines below.
PS. I prefer to use the word 'flyback' current rather than the word 'freewheeling' as this term causes confusion when it comes to bikes and has nothing to do with whether the cyclist is pedaling or not.
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Good question. There's the phase capability of the controller (relative to line current) and then there's the maximum requirement for the motor at a given line voltage, that occurs at stall. What the motor wants and what the controller can provide. I don't think there's a set rule, but there's an expected range, but let's hear from the poster.
Some observations based on playing with the Grin simulator. If you use the custom controller feature on the simulator, for a given motor at given voltage, you can choose a line current, then adjust the phase current upwards until the motor current maxes out (and the flat spot in the torque curve disappears). You can choose another line current and do the same steps. If you look at the ratio of phase to line current, this tends to happen somewhere around 2 to 3 times line current, but the motor may want more and If the controller is capable of providing the additional phase current it will get what it wants. More expensive and higher power controllers tend to have adjustable limits, to protect the investment. Cheap controllers don't limit phase current.
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Different motor, different voltage. 2.5X and 2.7X.
larry_says
10 mW
Because Spark Cycleworks says. Here's the video link.
larry_says
10 mW
You can start at 10:41
or
You can go to 15:41
or
Get right to the part where I quoted. 16:48
This is my source
He says 2.5 and it can be increased
I say 3
or
You can go to 15:41
or
Get right to the part where I quoted. 16:48
This is my source
He says 2.5 and it can be increased
I say 3
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I watched that video about 10 times. Went to do mine, LOL.... Not even close. There is a certain understanding experts like him have that us crayon eaters do not. So I was lost from the second I added power to mine and got the 7 beeps.
Ya I figured that out after reading it on google. My point was none of these videos mention this stuff in their "initial setup" instructions.
larry_says
10 mW
I hear ya. I was having trouble at first too. Hooked mine up and couldn't get the system ok to run auto learn. Mine was 4 beeps. I finally figured it out and was finally able to run auto learn. It's hasn't been a walk in the park but for you price these controllers aren't to bad. You have to learn what you can by trial and error but that's what makes it interesting and fun. For me at least. Sooo, you up and running now?
It's all good except the shutting off issue. No matter what I set max line amps to, when it hits that amount of line amps it shuts off the motor. Have to coast to a stop and then it will go again. Makes no sense.
larry_says
10 mW
Maybe the shut off is from your BMS protection and not the controller. I'm just throwing ideas out there.
The BMS is 400 continuous and 640 peak. I took it above and below the 400 on the controller. It ONLY shuts off when at the assigned max Line amps I put in. Weather put in as max or a percentage of max via the power in gears setting. I've made it shut off at 350, 40p and 470. So pretty sure it's the fardriver. It's probably one of those settings no one knows what they do. I asked the guys at SIA but no answer yet.
Sounds like a programmer failure....meaning, a failure of hte programer that wrote the controlelr firmware to understand what these things are supposed to do, and they thought they were making a BMS instead of a controller. 
...Because a BMS does just shut off when hitting it's limit, it dosen't have a way tod o anything else....but a controller is designed and built to limit current by lowering the draw on the battery once the "line amps" limit is reached, by reducing the average voltage provided to the motor which reduces the current to the motor, to keep the battery current below the limit.
If that's not happening, the controller is "defective", in that it isn't doing what it's supposed to. It's most likely a software (firmware) design problem rather than a hardware defect.
Even if the problem is that they are misnaming the setting that's doing this, it's still a defect.
...Because a BMS does just shut off when hitting it's limit, it dosen't have a way tod o anything else....but a controller is designed and built to limit current by lowering the draw on the battery once the "line amps" limit is reached, by reducing the average voltage provided to the motor which reduces the current to the motor, to keep the battery current below the limit.
If that's not happening, the controller is "defective", in that it isn't doing what it's supposed to. It's most likely a software (firmware) design problem rather than a hardware defect.
Even if the problem is that they are misnaming the setting that's doing this, it's still a defect.
It's just a coincidence. The motors used commonly fall into that range, but there's nothing that would prevent the phase current to be many times larger in appropriate circumstances.
It might work as a rule of thumb, but it's not a law - and that's indeed what the video says. And it doesn't directly come from the fact that the motors are 3-phase, like you seemed to suggest.
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