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Everything posted by hobby16

  1. Most unicycles use bicycles' BMS which has a overdischarge cut-off circuit (Q1) to prevent the battery from discharging under the LiIon recommanded voltage. It's a feature usefull for off-the-shelf bicycles' batteries but for monocycles, it's 1) unecessary since the mainboard deals quite well with voltage warning 2) utterly, incredibly stupid since a cutoff by the BMS results in a faceplant for the rider. In other words, the wheel's designer prefers to protect the battery by hurting the user!!! Many many users have been harmed, especially when the wheel is cold (under 10°C), since the batteries' internal resistance increases and triggers the cut-off more easily. Of course, not all wheels are affected by such incredibly stupid "feature". AFAIK, Solowheel, Ninebot, Inmotion, ie reputable brands don't cut off. Gotway has early versions that cut-off but its recent BMSs don't, since the cut-off circuit has been removed. All others do, if not proven otherwise. So they are dangerous since the probability of cut-off will increase with cold weather coming and higher internal resistance due to natural battery aging. For prospective unicycle buyers, insist to have a safe BMS, ie without the cut-off. With enough pressure from users, the Shenzen genious will end up repairing this horrible blunder. For those stuck with an unsafe wheel, the BMS cut-off circuit MUST be shunted. When touching the battery pack, if you can feel under the shrinkwrap film the big mosfet transistors, it means the BMS must be shunted. The idea is to connect the battery's 0V (B-) directly to the power output (P-), bypassing the mosfets T1 responsible for the stupid cutoff : see the dotted green line in the schematics below. (B-) and (P-) are now standard markings on most BMS boards, so any BMS can be modified by laymen based on this principle. You can see immediately the improvement by testing the wheel with strong accelerations, no more cut-off, ever ! Enjoy and have a safe ride. Below are some examples of BMS shunt. Some remarks : - no need to disconnect the battery during the operation - for Airwheels, only dismount the half housing on the side of the battery (the side without the control panel). - T1 is usually composed of 2 or 3 or even more Mosfets, so it's distinctive from X1 usually made of just one mosfet. - On most boards' layouts, T1 is marked as Q1, X1 is marked as Q2 P.S. For more pictures and photos source credit of modders, see my original thread here : http://trottinetteselectriques.heberg-forum.fr/sutra13862_solution-probleme-bms.html#13862 TG BMS. The T1 transistors can be felt through the plastic wrap. The plastic is scapeled around T1. T1 is made of 3 paralleled MOSFET transistors. MOSFET's drain & source pins are shunted by a solder blob. Warning, avoid shunting X1 Mosfet. The plastic is closed by electrician tape. A smaller opening can be made, mine is unecessarily big. TG BMS, with CMS Mosfet Dolphin D5 BMS. 3 mostfets T1 are shunted. X1 at extreme right is NOT shunted. T1 and X1 are detected by measuring the mosfet' gate voltage (pin 1) : paralled mosfets have the same gate voltage.. Airwheel X8 BMS. T1 and X1 are not easily distinguishable. When in doubt, shunt the two middle Mosfets. Recent version Gotway BMS : no T1 circuit => no shunt to do. It's a safe BMS. Aliexpress generic battery BMS (Q1=T1 ; Q2=X1) Another Airwheel BMS, shunt directly B- to P- instead of shunting the mosfets Another generic wheel BMS. Shunt B- to P- SML160 BMS. Don't bother with shunting the mosfets. Shunt B- to P- instead. Firewheel BMS. B- shunted to P- by a big wire. Route the wire like in the picture to avoid adding thickness to the battery pack. Note that the B- wire here is red instead of the usual black color code for negative pole, an occurrence of lack of care (other Firewheel BMSs have the right color, ie black) which can be very misleading. Edit 2015/05/25 : Q1 & Q2 are ambiguous, replaced by T1 & X1
  2. Charge Doctor for INMOTION

    I have added INMOTION to my list of wheels compatibles with the Charge Doctor. A summary of the specifics of Inmotion wheels, especially concerning fast-charging, is on my blog. Cut & paste of the blog's thread below: INMOTION unicycles have 20S batteries (nominal voltage 72V, charger voltage 84V) instead of the 16S classic topology on most other electric unicycles. Models V3 and V5 use the “square Lenovo” connector and model V8 uses the GX12-3 pin connector (same connector and same wiring as hoverboards). Charge Doctors for IMMOTION wheels are now available, in single-input or double-input versions. Warning, IMMOTION battery packs have less capacity than Gotways or King Song’s. So when using the CD-double-input, check that your setup does not charge at more than 1C (see article on “charge currents“). The CD’s usefullness is not only in allowing fast charging, it is mostly in the autocut function to automatically stop charging at 80% or 90% to preserve the the battery and considerably extend its mileage. INMOTION (72V nominal/ 84V charger) Connector Wh Ah Charge* at 1.5A (1 charger) Charge* at 3A (2 chargers in //) V3 Lenovo 144 2 0.7C 1.5C to be avoided!!! V5 Lenovo 288 4 0.4C 0.7C V5+ Lenovo 460 6.4 0.2C 0.4C V8 GX12-3 460 6.4 0.2C 0.4C *For a 2Ah battery, 1C charge corresponds to charging at 2A. On LiIon batteries, a <0.5C charge is considered a soft charge, a >1C charge is not recommended. Charge Doctor double input with Lenovo connectors, for INMOTION V3 & V5 Charge Doctor single input with GX12-3 connector, for INMOTION V8
  3. KS14C Battery Charge/Discharge Curves

    It's probably the 14C control board's voltmeter function which has not been correctly scaled. The difference is rather big and weird. Several causes : - charging has been terminated a bit early. As you said, waiting until current drops to 0A would add some Wh to the total - difference in discharge and charge currents accounts somewhat for the difference in Wh because energy loss (in the wires and inside the cells) is not the same depending on the current. I have seen it when comparing charges at 2A then at 4A. - when charging at high currents, expect that the battery needs some "relaxation" time. If you let it rest some hour and plug the charger again, you can put in some more Wh. The tilt-back threshold is probably not much usefull here because your board does not measure correctly voltage anyway. You can detect the tilt-back by discharging down to 56V then ride your wheel back and forth on the same place until the tilt-back occurs. As to the low voltage detection, from what I know on my wheels (GW, Firewheel, Airwheel), it is based on the instantaneous voltage, with no real filtering: a big acceleration (when the battery is small or near empty, that causes a rapid votage drop) is enough to trigger instantaneously detection (tiltback on firewheel, beeps on GW). The stop voltage is very dependent on how you ride. If you keep the speed low and constant, the wheel will have hard time detecting any voltage drop as low threshold so you can ride very long time. If the ride is fast and/or with many acceleration, the tilt back will occur much sooner. Riders with many hours on their wheels can easily sense when they need to reduce speed for more safety because when the battery is emptying, the wheel becomes less powerfull and less responsive to accelerations. Anyway, your 14C has a quite big battery so it should be easy to find the max & min voltage to ride safely while keeping a decent range.
  4. Inmotion V8 or Gotway Msuper V3?

    Thank you, it's good to know. More points to the Inmotion as my next wheel. A soft/wavy wheel is outright dangerous when riding at more than 20km/h or jumping curbs or hitting holes. Even on a low-speed historic Solowheel (v.e.r.y wavy), I find it scary. It's the "comfortable mode" on my Firewheel and I avoid it as pest : hitting a hole when the wheel is "wavy" means that I already fly while the wheels tries to get me back to vertical. The "comfortable" mode has failed me many times and it's not so comfortable since it stresses me out so much. I ride at 25km/h so I now systematically use the Firewheel's "sport mode", hard, ultra-responsive and safe.
  5. Charge Doctor for INMOTION

    @Bram, I totally agree. With a 1.5A charger, current cutoff gives a limited range : setting the threshold at 1.3A will probably cut at 90% but not lower (some lucky V8 users with a 2.5A charger have more leverage). Whereas with voltage cutoff, you have more resolution in the threshold and can autocut at much lower level, eg 80% or even 70%. As to the fluctuation, as hinted by @FreeRide, it is due to the charger which has some "hesitation" when passing from the constant current mode to the constant voltage mode. Maybe it's by (bad) design, maybe it's specific to your particuliar charger, to be determined by more data from other users. Anyway, not something to worry about, imho. I have added a line to my table to highlight the benefits of partial charges on extending the battery's mileage (table's second line, calculation method described at the end of the table). I didn't remember it's so substantial but it is, theorically! http://hobby16.neowp.fr/2016/12/01/voltage-threshold-on-charge-doctor/ Cells 0% 30% 60% 70% 80% 90% 100% Total discharge cycles* 1800-3600 1200-2400 950-1900 700-1400 500-1000 300-600
  6. Charge Doctor for INMOTION

    The apps are not at all reliable, their soft are always sloppy. They take no data from the BMS (like eg the coulombmeter), only the voltage and deduce from it the % of charge, no wonder it's not a consistent value. As to the amps fluctuating, I have the same thing on one of my battery packs and it's a pack with a defect cell! Maybe your pack has the same problem, maybe not, hopefully (because 20S packs may have another behavior). As to the grapher KST, I don't know what's is wrong but I can say that Win10 is not the culprit. The problem may come from the config file, the path to the ascii datafile... KST may be hard to set up (some happen to get it work first time) and the interface is nightmarish but once it works, it works flawlessly.
  7. gotway mainboard in firewheel

    Horizontal and vertical correspond to the gyroscope's X and Y axis respectively. The board is programmed with a fixed setup for X and Y so the two axis are not permutable and what you need is not possible. You should probably have to remove a battery pack of the Firewheel to make room for the GW board. The problem is the FW battery system is such a mess (two packs sharing one BMS).
  8. Dead Ninebot One E+ due to battery issue.

    smallexis is ze reference as to Ninebot stuffs I made an error indeed, I wanted to say "to short the discharge mosfet" (transistor X1 in my link above). I know it has worked for at least one wheeler. The battery is not protected against overvoltage anymore but it works. The charger is voltage-limited anyway so the risk of overvoltage is zero if basic usage precautions are made.
  9. Dead Ninebot One E+ due to battery issue.

    @Dima Ninebot's people won't give you any relevant answer I'm afraid. They'll just tell you to buy stuffs. Your problem can have several causes, more info is needed to know which is the real cause : - Charger problem. It can powers up the wheel but still be faulty. Can you check it by the test above, yes, no ? - battery problem. Saying the "voltage is normal" means nothing unfortunately. The voltage of all the cells must be the same and in the range 3.3V to 4.2V per cell. What is the voltage of each cell and the total number? Without numbers, hard to tell. - BMS problem. There is a simple solution by shorting the BMS' charge mosfet (see schematics in my thread on BMS http://hobby16.neowp.fr/2015/07/21/bms-how-to-make-your-wheel-safer/ ) but the 2 causes above must be ruled out first.
  10. @Tilmann So bad what happened to you. I've heard the Germans are strict with rules but I didn't know they could be strict even when there is NO rule. What you have been submitted to is probably a world premiere. It's arbitrary and it sucks.
  11. Dead Ninebot One E+ due to battery issue.

    What do you mean by the sentence in bold ? The problem comes more probably from the charger. Connect the charger to a hair dryer (dumb load) then measure the current. If must be 2A, if not, your charger has a problem.
  12. Charge Doctor for INMOTION

    @nomad It's all sold out. I'll have some again only in 1 week or 2. Please, send me a MP so I'll remember to let you know when it's available. I'll also tell you the price and how to pay.
  13. Charge Doctor for INMOTION

    Discharging may refresh a battery only if it's NiCd or NiMH, not lithium batteries (LiIon, LiPo, LiPoFe...). When a lithium battery is dead, it's dead, unfortunately. I have implemented the discharge cut-off mode not for battery-refresh in mind but rather for testing purposes (for example for safely discharging to 0% without killing the battery in order to determine the exact capacity in Wh).
  14. Charge Doctor for INMOTION

    Yes. No. To store a LiIon battery, charge it to 30% (even 50% if stored for more prolonged periods, eg >1 year , to avoid reaching down 0% by autodischarge). For a 20S battery (Inmotion's battery), 30% corresponds to 72V so set the Charge Doctor to autocut by voltage ans set the threshold to 72V. For a 16S battery (most other wheels), 30% corresponds to 57V.
  15. Charge Doctor for INMOTION

    Good point. Yes, in the lastest version (2.04), the max cut voltage has been ported to 85V. Charge Doctors after october 2016 are with version 2.04. Most users prefer the autocut by current though, so it doesn't change much for them.
  16. Charge Doctor double input for IPS

    The Charge Doctor with double input for IPS (Holtz, Zero...) is available. You can order it on the "Buy" page of my blog : http://hobby16.neowp.fr/buy/ I've also had questions about the IPS chargers, so I have posted a how-to mod a generic charger to make a customized charger with the right connector : http://hobby16.neowp.fr/2016/11/20/charger-customization/ The how-to is posted below as a backup : Charger customization Most e-wheels have settled for the GX16-3 connector. Some though use a different format and the corresponding charger may be difficult to find and are mostly more expensive. A customized charger with the right connector can be made from a generic 2A charger with the wiring instructions below. Various ewheel connectors, size and pin comparison Most frequently found connectors e-Wheel Socket Wiring Voltage Topo* Remark Most e-wheels GX16-3 1: V+ ; 3: 0V 67.2V 16S connector for Solowheel, Airwheel, Gotway, Firewheel, King Song… Gotway MSuper3 84V/1600Wh GX16-4 1: V+ ; 2: 0V 84V 20S other MSuper3 with battery <1600Wh have GX16-3 connectors IPS (Holtz, Zero…) GX16-4 2: V+ ; 4: 0V 67.2V 16S warning, same connector as above but different wiring! InMotion V8 ** GX12-3 1: V+ ; 2: 0V 84V 20S same connector & wiring as hoverboards InMotion V3,V5 Lenovo Int:V+ ; Ext: 0V 84V 20S Lenovo square socket, originally for Lenovo laptop power supply Ninebot One*** Lemo 63V 15S see photo for wiring*** Ninebot Minipro, Xiaomi ** GX12-4 1: V+ ; 4: 0V 63V 15S *16S = 16 LiIon cells connected in series, total voltage calculated using battery full value = 4.2V/cell ** important, the numbering order on GX16-3 connectors is totally different from the GX12-3 : from left to right 3-2-1 for GX16-3 compared to 1-3-2 for GX12-3 !!! Likewise for GX12-4 and GX16-4 GX12 and GX16 plugs, note the difference in pin numbering *** Wiring for Lemo on NinebotOne Beware of the charger For this mod, I recommand using the fanless 2A generic chargers. Even if they tend naturally to warm much more than a (noisy) charger with integrated fan, they have many great features: availability for various voltages, noiseless, compact and transportable… They allow fast charging at 4A by a parallel connection with the original charger using a Duo Charge Doctor (or even at 6A with the Triplex CD). Warning though, some 1.5A chargers are sold as 2A chargers. They have a smaller housing and are very hot when charging, thus unreliable in the long term. When buying it online, the vendor never details the housing dimensions and count on the buyers not to check the actual current to sell it. Without stated dimensions, the difference can still be made looking at the distance between the rectangle and the grooves (see arrows on the picture). Any vendor with such dubious practices should be avoided anyway. So don’t be misled, buy only the 2A charger with the bigger housing. Chargers 2A and 1.5A, size comparison
  17. Charge Doctor double input for IPS

    Oh, great idea. Such ready converter don't exist of course. But I can sell you the required connectors (if you know how to solder) or I can make the converter for you, just ask me when you order the Charge Doctor.
  18. Charge Doctor double input for IPS

    @Cloud, @swvision MSuper3 84V with battery not at 1600Wh have connectors with 3 pins ! Only the model with 1600Wh battery has 4 pins, go figure... No, there is no problem using a Gotway 84V charger on Inmotion wheels and vice-versa, I can certify that, having made a mixte Charge Doctor allowing such setup, see more details about the battery topology on different brands here The precaution needed though is to avoid a high charge current that will reduce the battery's lifetime, "high" depending on your wheel's battery capacity. See my post on "What is the recommended charge current". In a nutshell, when you want to know if your wheel can be fast-charged (eg at 4A, by connecting two 2A-chargers in //), the first thing to know is the battery's capacity in Wh.
  19. Charge Doctor double input for IPS

    No and no, sorry. 84V chargers are indeed not generic and hard to find. Gotway has used a 4 pin connector probably to let the customer stuck with its charger. But you can probably count on Gotway not to sell its chargers at racket prices like Ninebot. An Inmotion V8 charger can also be changed to a GW charger by soldering the 4 pin connector, it would widen somehow the sourcing. Inmotion has generally quite good prices too.
  20. Charge Doctor double input for IPS

    @Cloud Where can't see the pictures, on my blog or on this forum ? Yes, the CD with double input GX16-4 for Msuper3 1600Wh has been recently added on my blog's "Buy" page : http://hobby16.neowp.fr/fr/buy/ Charge Doctor V2 double input for GOTWAY Msuper3 84V/1600Wh. With GX16-4 pin connector. See pinout 32.10 €
  21. hmm, this probably means that the battery (B+ & B-) supplies directly the wheel, without passing through the BMS protection circuit (P+ & +-), meaning that the pack is in fact already shunted. The BMS' protection circuitry is just there for window dressing (and wired-on only for regulatory purpose when needed). So you do NOT need to shunt. BTW, Tishawn, don't you have a Ninebot One ? If yes, since it is powered with 15S packs, putting a 16S battery means you made an overdrive mod. Wouldn't that be nice ?
  22. IIRC, to have a high torque motor, all is needed is to have a higher number of poles (eg 60 poles for high torque, 30 poles for high speed), the length of wire for windings remaining roughly the same. Since the winding of such motor is made manually, the production is quite flexible and can be easily adapted to demand. BTW, does anyone has the pinout of the 4 pin-connector of the Msuper3-1600Wh 84V, please ? Maybe it can be found on the label on the back of the charger. I would like to make a Charge Doctor-double-input for the Msuper3-1600Wh and an adaptor to use the Inmotion V8's charger (also at 84V). It's the same GX16-4 connector as on the IPS Holtz but I don't know if it's wired likewise. Hope so. Here is the IPS's connector pinout :
  23. Not having much more than 320Wh means 1) your battery has decreased in capacity because of ageing (mine has lost nearly 20% after one year) 2) and/or the battery was not empty when you start charging. On some wheels, it's very hard to discharge near 0% because the tilt-up occurs quite early. On the Ninebot battery (15 cells instead of 16 cells on most other wheels) the nearly 0% voltage must be around 51V, look it up with the Charge Doctor when you start charging. Not sure I understand your question about "2 chargers" but YES, you can connect a generic charger on the second input of a CD-mixte (with the first input connected to a Ninebot charger), I've tried it and it's ok, you'll double the charge current and divide by 2 the charging time. But be aware that the generic charger voltage is 4V higher so you may have a problem of overvoltage during the "constant-voltage phase" of the charging. Overvoltage on LiIon batteries means overheating, possible explosion or fire, burning down the house, cat and stepmother. Normally, the BMS should prevent it. But to be 100% safe, set the autocut of the CD to "voltage mode" and set the threshold to 60.5V, as soon as the voltage reaches that value, the CD will end the charging session. Then when you charge with a single charger, switch back the autocut to "current mode", since the current threshold and the voltage threshold are stored in two separate memory, switching from one mode to the other is just a matter of 2 or 3 button clicks.
  24. It's normal to get 199.7Wh by the Charge Doctor on a 320Wh battery. It means 1) your battery was not empty when you begin charging (ride until empty if you want to check your battery is really 320Wh) 2) the Charge Doctor's auto-cut occurs at 90%, meaning that you can charge 32Wh until full (if auto-cut is disabled). About KST not displaying "log.txt" : it is because KST has detected a Deutsch computer and has switched to German language => the config file "session.kst" is not understood anymore that's why you see nothing. Solution : "session.kst" is a text file, open it with an notepad and change all instances of "Colonne" to its translation in German (which I don't know). As an example, you can see that "Colonne" (French) in "session.kst" has been translated into "Column" (English) in "session_EN.kst"
  25. Once again, you are making hypothesis instead of checking. Pictures of Gotway BMS can be found everywhere, look at them, there is no mosfet to cut power. There is only one small mosfet to cut charging current to protect against overcharge, that's all. And I repeat, it's the only sensible thing to do, whatever you believe or not. It would be totally crazy to let the BMS cut power on a wheel that can go up to more than 30 km/h. Maybe you don't mind faceplants but you are the exception, not the norm. Any normal person would prefer to be protected against the certainty of faceplants than against the hypothetical and near zero risk of battery fire. End of debate.