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zlymex last won the day on December 10 2016

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About zlymex

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  1. Those are for charge protect synchronization. When a cell in one pack(the bad pack) is overcharged while the charging is in progress, the pack turn itself off, and tells the other pack to turn off as well by means of those wires. Otherwise the bad pack(although turned off from the charge port) will still be charged thru the output connectors which are connected directly all the time.
  2. First time see this. Looks to me that the battery pack/BMS is missing the balancing part. I believe I saw another E+ model with missing balancing components too.
  3. It's a very nice chart again especially some dynamic factors are introduced such as inclination and acceleration. I think the orange line(max speed) should be eliminated because the definition by GW is in a broad sense. I rather use something like 'rider's limit' to narrow the actual/physical limit incase riders make small 'mistake' just like the cordon on a cliff platform.
  4. I personally encountered many EUC riders but we normally just wave to each other when passing by if not familiar with each other. However afterward, we'll post a message in WeChat groups asking who is that that just encountered, and not surprisingly someone will always pop up saying 'that's me'
  5. I'm not sure about that being not very active for the last 6 months or so. I did put up the thermal photo(as above) for them but We didn't address that or asking them explicitly to modify the wire/connectors, that will sound like making a fool of them. I think Gotway is not encouraging people to use fast charger or external battery.
  6. I have partially tested that: I believe it's safe to pass 5A thru the SM2P connector and even a little higher current such as 6A/7A thru that 20AWG wire because it is silicone insulated(rated at 200C). The BMS of one battery pack can take 5A well because there is only one MOSFET sitting in between acting as a switch(and is always 'on' in normal conditions). That MOSFET is MTB55N06Z(55A, 60V, and with typical 14mOhm on resistance), which will dissipate only about 0.35Watt when there is a 5A charge current. Note too that there are two battery packs in parallel in many Gotway EUCs(such as 820Wh and up), the charge current will be shared making it possible to charge at 10A as far as the BMS is concerned.
  7. Thank you for the comments. We(the local team here) are actually having a good communication(over WeChat mainly) with Gotway and they seem well aware of the problems(from feedback of other areas as well). They were constantly modifying the hardware of ACM and V3, for instance connectors, MOSFETs, parallel resistors of the current sensors, apart from modifying the firmware. One thing for sure is that Gotway is never hesitate in sending us new boards for replacement in case of miss function of their EUCs, and they even send us several 84V version upgrade sets (board and thick covers, and directly by passing the dealers) for trial. Gotway is Guangzhou base(at first) where hills are few, and southern people on average are light in weight. There are a lot hills here and we have some heavy Gotway owners(110kg to 125kg), good for EUC testing.
  8. It is not necessary to open the battery. The path goes like this(for my V3 of 820Wh at least): The charge port --> 20AWG wires --> SM2P socket/plug --> 20AWG wires --> two soldered 'Y' joints --> two pairs of 20AWG wires that goes to each battery. Therefore, the replacement is necessary only to the 'Y' joints.
  9. Here is my IR photo when passing thru both wires of the GX-16-3 pair at 10A for some time. The ambient temperature is 24.8C, spot 1 is the plastic socket, spot 2 is the heat shrink tube wrapped around the metal case of the soket(metal is not good for temperature reading). The hottest spot is the 18AWG wires(40.8C) which is for test only. I actually use 16AWG and GX16-4 for my V3s+.
  10. This is not surprise to me at all as I had similar situation with my V3. - The charge socket(GX16-3) is of poor quality(the metal wall is thinner than usual and the plastic core is easily comes loose) -- I changed it - the solder joint is not good, too less time when soldering - the hot glue is not applied well, too cool and/or too less time. - the wires connecting the socket is thin(20AWG) -- I changed to 16AWG. - there is a plug/socket pair SM2P that is the bottle neck IMO that easily get hot if the charge current is large(as in the case of fast charger or external battery pack) -- I changed to GX16-4 pair. As for the max current of GX16, @esaj once said it is 7A. However, I've tested with 10A and monitored with my IR camera that the temperature rise is small(about 15C),
  11. This is nice. After I saw the measured 4,6kw, I realized that speed-torque curve of my preliminary chart should be much more steep, and should even be steeper than yours because the 4.6kW is just a sample, not the limit. If they repeat the procedure many times, it may well beyond 4.6kW. The limit chart of an EUC in some way resembles the SOA of a MOSFET, where there are many time dependent curves. The max power on the DC curve is similar to the rated power where the motor is allowed to run continuously without over heat. The peak power on the other hand is dependent on how short the period may be, and if the duration is short enough, the peak power may well reached to the max point on the speed-torque curve, which(in the case of V3s+ with full battery) is(roughly) 82V * 240A / 4 = 4.92kW, and this figure is very much dependent on the voltage.
  12. GL220 is able to read current at 100Hz rate(1channel), but Wheellog can't. It is very tricky as to how I motor is get, it requires a very high speed ADC because the analog output from the current sensor() is alternating very fast, and there are three phases. That is correct. May be it's better to allow users to enter kv value? Or just give an average kv, which is at least better than just power = U batt * I motor.
  13. I believe that the kv value(V/kph), as a parameter of the motor, can be regarded as a fixed value. The indirect measurement and calculation says otherwise, is probably because there are two much spikes(of current/torque) which in turn caused by the rough surface of the hill path. U batt * I batt = P motor, this equation is missing the efficiency of the main board, although may be as high as 95%, it may also be lower when hill climb where current is large. And the efficiency may be changed a lot because the current/torque spikes. The actual current/torque spikes may be larger than I've measured because the sample intervals(0.2 second by Wheellog and 0.1 second by GL220) are not small enough. I've once seen an ad saying that the adjustment speed(from the gyro input to the motor) top up at 100 times per second. Plus, how Gotway makes use the two current sensors and how gives away the current parameter remains a question mark. I guess a better way to obtain the kv is the later method you mentioned: by lift test. I've measure my V3/V3s+(same motor) to be 53.5kph and 68.6 respectively when battery is full. This will give roughly 1.2V/kmp if deduct 2V(presumed) from the battery as an dead zone. I actually plotted a preliminary limit chart for this, those green-dots part is the uphill data that I sent to you(but without averaging), and purple circles is the downhill part with regenerating(which should be bounded by the lower half of the orange line). http://forum.electricunicycle.org/topic/5915-is-there-any-other-app-i-can-use-for-my-msuper-v3-besides-the-one-on-the-app-store/?do=findComment&comment=71144 Wheellog btw is very good, I use 50A current warning(50A is the max., I hope more such as 70A because I always receive the warning when up/down hills while I know is quite safe), and 40kph speed warning. What Wheellog lack is the power warning(the so called 80% power warning is bu****it!) Apart from this kv value(which is a very nice parameter) that describe one very important aspect of the BLDC motor(back-EMF is proportional to the speed), there should be another parameter describing 'torque is proportional to the motor current'.
  14. Thanks. Since it is bump up, I'll add one more 'video' that was missing because the bad link, and two more photos of that time. mall pendulum 'S' curve Small radius 180 degree turn
  15. Awesome plan, but no news for sometimes and 3rd July has long passed. 100km to 150km per day is reasonable as I've once rode 200km a day(in the morning and in the evening) and still got the whole day for work.