Search found 238 matches

by hias9
Jan 09 2020 12:23am
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

Thanks a lot. I will get some small capacitors and try it soon.

It behaves like this:

0 rpm, sensor voltage: 2.45V
Motor turning, no-load: 2.3V (with load it would be the same)
Motor stops turning: 2,2V for a split-second
0 rpm: 2.45V
by hias9
Jan 08 2020 11:17pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

Thanks, but this also happens when there is only a thermistor and no speed sensor at all.
I have this effect also on my direct drive motors.
Also it does not seem to be much related to how fast the motor is turning.
by hias9
Jan 08 2020 10:55pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

On all controllers with a temp sensor input I tried so far, the shown motor temperature was lower when the motor is turning. Could anybody explain why? Usually the temperature will not be more than 10 degrees celsius lower, but with this setup using a 5k or 10k PTC thermistor, the temperature would ...
by hias9
Jan 07 2020 10:11pm
Forum: Items for Sale - New
Topic: Compact Field Oriented Controller, ASI + Grin, limited run
Replies: 1272
Views: 282762

Re: Compact Field Oriented Controller, ASI + Grin, limited run

I have compared the noise of a Bafang G310 powered by an ASI BAC500 against a sinewave KT controller. The result was that both subjective and measured noise level was clearly lower with the KT controller. Measured (with an iPad, so don‘t take the values too serious) from about 70cm away at 200rpm: A...
by hias9
Jan 06 2020 7:21pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

Thanks. There are some 10k PTC thermistors available and these should do the job.
by hias9
Jan 06 2020 5:40pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

If the resistance (wired between signal and GND) of the thermistor is always higher than about 4kOhm, the speed sensor works fine. It should also be a thermistor which has increasing resistance with increasing temperature (like Kty, not like 10k ntc). Are there any thermistors that meet those requir...
by hias9
Jan 05 2020 10:52pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

Yes, the alternative if I cannot get it working is to use an external speed sensor and use the signal cable for the temp sensor instead of the speed sensor. Just wondering if it can be done without an external speed sensor. I have used kty and ntc sensors (resistances that vary with temperature) so ...
by hias9
Jan 05 2020 9:18pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Re: Common signal cable for both speed and temp sensor

On the ASI I have tested to wire a resistance in series with the signal cable. What happens is that while there is no speed sensor pulse, the voltage is the same as without the resistance in series (a bit less than 5V). While there is a speed sensor pulse, voltage is higher than without the resistan...
by hias9
Jan 05 2020 6:59pm
Forum: EBike Technical
Topic: Common signal cable for both speed and temp sensor
Replies: 13
Views: 573

Common signal cable for both speed and temp sensor

Is it somehow possible to wire a temperature sensor to a motor with an existing speed sensor without having to add an additional signal cable? So that voltage between signal cable and GND would be some voltage (maybe 2.5-5V) which corresponds to a certain temperature when there is no pulse from the ...
by hias9
Dec 29 2019 3:49pm
Forum: Battery Technology
Topic: Eltek PCBs
Replies: 4
Views: 464

Re: Eltek PCBs

Thanks, I will contact him.

On eBay I only found some bigger PCBs, not the compact ones.
by hias9
Dec 28 2019 4:57pm
Forum: Battery Technology
Topic: Eltek PCBs
Replies: 4
Views: 464

Eltek PCBs

I am looking for a compact PCB which fits the Eltek Flatpack S.
I have a PCB made by Energus PS called Eltek Power V1.0 (made for Flatpack2, but also fits the Flatpack S. + and - are reversed)

Does somebody have some of these PCBs left?
by hias9
Nov 15 2019 6:40pm
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

I would not say that these chargers on Aliexpress are compact, way bigger than the usual 4A charger and a 1800W Flatpack S.
Suitable for charging at home, but not so nice to put it in a frame bag if the bike should be stealth.
by hias9
Nov 14 2019 11:20am
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

10-30°C (50-86°F)

I think you wanted to say they should be warmed up before charging if it would be 10-30°F which I absolutely agree with.
by hias9
Nov 14 2019 8:22am
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

If possible, stop working on the second pack, before you clear up what cells are suitable. Would be nice if the first battery could be dedicated to the slower bike. You need another charger for this pack, 1C charging is definitely no way for GA. Even 0,5C is too much. GA cells are good for the mild...
by hias9
Nov 13 2019 6:47pm
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

My question is very general, not about my specific case. One battery is finished and will probably be used on two bikes. The faster one will have about 3500W peak (7A per cell), 2000W continous. The slower one only about 1000W peak (2A per cell), about 600W continous. If 1C charging does not complet...
by hias9
Nov 13 2019 3:42pm
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

If you could do such an analysis, that would be really great.
Just use whatever is most comfortable for you as parameters.
If it does not matter, I would say 1C constant discharge and 70% DoD.
by hias9
Nov 13 2019 7:58am
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

It's a bit off-topic, but what I am curious to see would be a diagram how quick-charging affects cycle-life. Something like the following: The first graph using normal charging current (for GA: 0.3C), the second using quick charging current (for GA: 0.5C) and the third using an unhealthy quick charg...
by hias9
Nov 06 2019 3:59pm
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

I plan to quick-charge two 14S10P packs in parallel with a 1800W Flatpack S when making a break. Current would be around 0.45-0.5C. When riding alone, charging a single pack at 1800W would mean 0.9-1C which will probably have a significant negative effect on cycle life. Are there any numbers for the...
by hias9
Nov 06 2019 6:11am
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

I don't know exact values, but I think the resistance of the other parts could be less than 100mOhms, so it would be safer to calculate with a low resistance. Why would you not go over 0.3C maximum charging current? The current we are calculating is only a peak value, so I think a bit more than the ...
by hias9
Nov 06 2019 1:29am
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Re: Max safe Voltage Difference when connecting two Batteries in parallel

Cells are 3500mAh GA Cells which have an internal resistance of 50mOhm according to the sheet. BMS allows 60amps continuous discharge and 50amps continuous charge. If we ignore the wire resistance, it would be 2x70mOhms for two 14S10P packs. So if we don't want to exceed a charging current of 1C, th...
by hias9
Nov 05 2019 2:56am
Forum: Battery Technology
Topic: Max safe Voltage Difference when connecting two Batteries in parallel
Replies: 54
Views: 4650

Max safe Voltage Difference when connecting two Batteries in parallel

What would you consider the maximum safe voltage difference when connecting two 14S10P 18650 batteries in parallel?

Is it possible to calculate the maximum equalizing current? ( maybe U(difference)/(Ri1+Ri2) )
by hias9
Sep 22 2019 2:07pm
Forum: EBike General Discussion
Topic: Axle trying to leave Dropouts when Tightening
Replies: 14
Views: 764

Re: Axle trying to leave Dropouts when Tightening

I am trying to fix this. Where do you upload your pictures?
edit: It should be working now.
by hias9
Sep 22 2019 2:02pm
Forum: EBike General Discussion
Topic: Axle trying to leave Dropouts when Tightening
Replies: 14
Views: 764

Re: Axle trying to leave Dropouts when Tightening

I design them using a 2D CAD software and have them water cut out of 10mm stainless steel.
On the left side it´s fixed to the IS2000 brake mount. On the right I drilled a hole and cut a thread.

Here is a picture of the left side:
Image
by hias9
Sep 22 2019 9:29am
Forum: EBike General Discussion
Topic: Axle trying to leave Dropouts when Tightening
Replies: 14
Views: 764

Re: Axle trying to leave Dropouts when Tightening

For my fast bike I have 10mm thick stainless steel torque arms on both sides water cutted. No problem at all at 22S and 200/450A. This is just for a 2KW (14S, 40 battery amps) city bike, which I used to ride without TAs. (only TA washers) Motor was overheating when riding hills, so I went to a sligh...
by hias9
Sep 21 2019 10:34pm
Forum: EBike General Discussion
Topic: Axle trying to leave Dropouts when Tightening
Replies: 14
Views: 764

Re: Axle trying to leave Dropouts when Tightening

Yea, that‘s exactly what happened. And it also happened on my other bike, but at higher tightening torque and the axle did not move that much. Maybe it happened because I could not hold and tighten at the same time cause I have a broken arm at the moment. Instead I was putting my weight on the saddl...