Search found 15147 matches

by fechter
May 25 2022 2:58pm
Forum: Motor Technology
Topic: Forum clean up ?
Replies: 5
Views: 151

Re: Forum clean up ?

It's easy enough to create a new category, but super time consuming to attempt to sort out all the old posts. I don't see that ever happening.
by fechter
May 25 2022 2:57pm
Forum: Battery Technology
Topic: 24 vdc-36 vdc-48vdc batterys
Replies: 7
Views: 75

Re: 24 vdc-36 vdc-48vdc batterys

Depending on the motor type, you may need a speed controller just to make it run. With a speed controller, you can lower the speed to anywhere you want, down to zero. At partial throttle, the motor will pull less from the battery.
by fechter
May 25 2022 2:47pm
Forum: Battery Technology
Topic: Should I replace a bent cell?
Replies: 12
Views: 160

Re: Should I replace a bent cell?

I've seen a dent like that cause an internal short and made the cell go off immediately. Like a little rocket motor. If the cell didn't go off, it was likely on the verge of it. Good idea to totally discharge it. I think you got lucky this time.
by fechter
May 25 2022 10:06am
Forum: EBike Technical
Topic: Throttle Master (Throttle Remapping and Filtering tool)
Replies: 6
Views: 125

Re: Throttle Master (Throttle Remapping and Filtering tool)

You want to be sure the output drops instantly if the input drops (for safety). I rode something one time that had a lag in the downward throttle action that I thought was going to kill me. Let off the throttle and the motor keeps going for a while.
by fechter
May 24 2022 5:55pm
Forum: EBike Build Threads
Topic: APL's V4 Cruiser Build.
Replies: 185
Views: 9053

Re: APL's V4 Cruiser Build.

I’m trying to think of an easy test you can do to determine if the controller or the motor is the limiting factor. If you watch the amps while increasing the load (brake?) if the controller is limiting you will reach the limit and stay there as load is further increased. If the motor is the limiting...
by fechter
May 23 2022 11:06pm
Forum: EBike Build Threads
Topic: APL's V4 Cruiser Build.
Replies: 185
Views: 9053

Re: APL's V4 Cruiser Build.

I put the Yawn-tan controller back on today, and gave it a voltage sag test, 66v to 58v at 1200w, roughly. Seems like a lot. That does seem like quite a bit of sag for 20A, but not so much that it would be your limiting factor. 58v is still enough to get some power. Is anything getting hot during t...
by fechter
May 22 2022 10:07am
Forum: EBike Troubleshooting
Topic: IR Camera enough. Or thermal camera necessary?
Replies: 8
Views: 102

Re: IR Camera enough. Or thermal camera necessary?

You can't measure temperature with a near-IR camera. Thermal IR cameras are expensive, but you can get IR non-contact spot thermometers for pretty cheap. These work like the camera, but only a single pixel.
by fechter
May 22 2022 10:00am
Forum: General Discussion
Topic: gas price thread
Replies: 1289
Views: 89351

Re: gas price thread

Unleaded regular is up to $6.29/gal at the "cheap" place near here. We are within 10 miles of several large refineries, but if you go inland, further away from the refineries, the gas is a lot cheaper. We are just getting ripped off in this area.
by fechter
May 21 2022 10:29am
Forum: EBike Build Threads
Topic: APL's V4 Cruiser Build.
Replies: 185
Views: 9053

Re: APL's V4 Cruiser Build.

The easy test is to measure the voltage sag on the pack going from no load to full load. This will tell you a lot about the pack.
by fechter
May 20 2022 10:22am
Forum: Motor Technology
Topic: How critical is magnet gap ?
Replies: 3
Views: 147

Re: How critical is magnet gap ?

The gap between magnet sections won't make much difference in performance unless it gets up to about the magnet thickness. Perfectly symmetrical spacing is more important. I've seen various recommendations for glue. You want something that stays strong at higher temps. Normal epoxy can get pretty so...
by fechter
May 20 2022 10:15am
Forum: Stand-up EScooter/ESkateboards
Topic: Hub motor magnets
Replies: 12
Views: 801

Re: Hub motor magnets

There is probably not much benefit to using magnets over a certain strength. With a higher flux, the hysteresis and eddy current losses will increase to the point of cancelling out the gain in torque. There are trade-offs in most aspects of motor design. Having magnets with a higher temperature rati...
by fechter
May 19 2022 11:12pm
Forum: EBike Build Threads
Topic: APL's V4 Cruiser Build.
Replies: 185
Views: 9053

Re: APL's V4 Cruiser Build.

Either the controller isn't allowing more current, or the motor winding resistance is doing it. At near zero RPM, the motor resistance will be very low, so shouldn't be the limiting factor, but hard to say. If you are at the limit over a fairly wide RPM range, it would indicate the controller. Tryin...
by fechter
May 19 2022 10:42am
Forum: EBike Troubleshooting
Topic: No-com error
Replies: 3
Views: 95

Re: No-com error

It looks just like the A2B Metro motor but with a different controller board. A comm error would indicate a problem somewhere between the controller and the display. I would carefully trace the entire cable that goes to the display and look for possible damaged spots. Also unplug any connectors and ...
by fechter
May 17 2022 10:17am
Forum: EScooters/EMotorcycles
Topic: Rebuilt kids electric cross to 3000w
Replies: 60
Views: 1016

Re: Rebuilt kids electric cross to 3000w

The CA has several connections it needs to work. Power is pretty straightforward. It needs a current sensor input that is a shunt either inside the controller or an external one. In your case, you might want an external one, but you'd have to buy one. There is also a speed input, either from a wheel...
by fechter
May 16 2022 1:38pm
Forum: Battery Technology
Topic: Bms discharged completely parallel cell
Replies: 1
Views: 79

Re: Bms discharged completely parallel cell

It is not uncommon for many models of BMS to blow a shunt transistor. These are incredibly small, surface mounted things. Unless you have the skill and equipment, replacing it is very difficult. I would recommend replacing the entire BMS unit. You might be able to get one under warranty if you ask t...
by fechter
May 16 2022 12:31am
Forum: Motor Technology
Topic: Combining 2 hub motors into one?
Replies: 11
Views: 224

Re: Combining 2 hub motors into one?

Cool. So assuming I grab 2 phases at random to do this test. The positive and neg from my DC source makes those 2 phases unique and the 3rd phase is not used in the test. So does this mean all the info I need to parallel them is all gained from just one test? So just to check my understanding here....
by fechter
May 15 2022 10:19am
Forum: Motor Technology
Topic: Combining 2 hub motors into one?
Replies: 11
Views: 224

Re: Combining 2 hub motors into one?

As long as the rotors and stators are aligned properly, you can parallel the windings and just use one of the hall sets. You can put the rotors as close as you want. Just make sure the rotor magnets are aligned the same before joining. One way to do this is to apply a steady DC (like 12v) to a pair ...
by fechter
May 15 2022 10:14am
Forum: Battery Technology
Topic: Paralleling batteries, separate charging ports & BMS
Replies: 8
Views: 171

Re: Paralleling batteries, separate charging ports & BMS

If both batteries are connected at the discharge port, only the one getting the charger will be protected during charge. To charge safely, you need to disconnect the packs from each other and charge separately. This will be sort of a pain and if you forget something and connect them when the voltage...
by fechter
May 15 2022 10:03am
Forum: Stand-up EScooter/ESkateboards
Topic: gogotops help rear motor shut down
Replies: 1
Views: 62

Re: gogotops help rear motor shut down

It sounds like there's a short in the phase wires somewhere. To test, you need to disconnect the motor from the controller and see if the drag goes away. If the motor spins freely when the controller is unplugged, then most likely the controller shorted. If the motor still has drag, then the problem...
by fechter
May 15 2022 9:58am
Forum: Battery Technology
Topic: Coulometer blues
Replies: 9
Views: 250

Re: Coulometer blues

Thanks again for posting the instructions. It's been a long time since I installed mine. I typically charge my pack to 58v and had the "full" voltage set to 58v. But over time, the voltage reading had drifted upward so when it was 58v, the TK15 was reading 59v. I didn't see a way to calibr...
by fechter
May 14 2022 9:47pm
Forum: EScooters/EMotorcycles
Topic: Rebuilt kids electric cross to 3000w
Replies: 60
Views: 1016

Re: Rebuilt kids electric cross to 3000w

One thing you might consider is looking for a motor sprocket with more teeth. The one that's on there is extremely small and that can't be good for noise and wear. By going to a larger front sprocket, the motor will be geared higher, so more likely to hit the current limit and less likely to wheelie...
by fechter
May 13 2022 10:25am
Forum: EScooter/EMotorcycle Build Threads
Topic: Nova Cruz Voloci Scooter/Bike Info
Replies: 236
Views: 50148

Re: Nova Cruz Voloci Scooter/Bike Info

So how's the acceleration? That is a big controller, but there is plenty of room for it. I think you're going to want bigger batteries :wink: Looks like you could possibly mount the controller between the frame and the seat cushion if you needed a higher (and warmer) seat. Is there a way to re-insta...
by fechter
May 10 2022 2:24pm
Forum: EBike Build Threads
Topic: APL's V4 Cruiser Build.
Replies: 185
Views: 9053

Re: APL's V4 Cruiser Build.

Pack output is up to 1300w, and the fact that it's climbing tells me that there isn't any hard current restriction from the controller or system components. However, it occurred to me that the 18" 8awg battery wires might be sucking up some watts. (36" round trip.) Putting the BMS in the ...
by fechter
May 09 2022 10:37am
Forum: Large EV General Discussion
Topic: 4x4 Transport Kart from scratch
Replies: 18
Views: 1566

Re: 4x4 Transport Kart from scratch

Excellent work! Thanks for sharing it here.

I don't think I've ever seen hub motors like those. Are those geared? Most of them are made to go too fast.
by fechter
May 08 2022 4:28pm
Forum: General Discussion
Topic: Ideal Household Electrical Standards?
Replies: 31
Views: 931

Re: Ideal Household Electrical Standards?

The main reason AC is popular is you can use a transformer. Transformers are needed for long distance transmission lines to get the voltage very high. Otherwise, you'd need very fat wires to carry the current or have huge resistance losses. I guess the other reason is you can run a 3 phase induction...