Carlos E Rodriguez Posted April 16, 2017 Share Posted April 16, 2017 16 mph is about 25 kph which looks to be advertised top speed. The going up hill. then 200Lbs load. Then 50% battery. All sound ok until you try to go up hill. I believe going up hill at max speed is not a good practice. I always slow down. I have to do some look up but maybe one of the other members can do a power calculation and it will show that you went wayyyy pass the capabilities of the motor/battery/mass combination. I always slow down. My rule is at least slow down to 50% of max or even more on a large grade. Like walking speed on big grades. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 16, 2017 Share Posted April 16, 2017 I'm no expert, but I believe part of the problem may be that the temperature reading is read at the MPU's (motion processor unit) internal sensor rather than read at other critical components like the MOSFETs. The MOSFETs could be heating up faster and fail earlier than what the MPU acceptable operating temperature is set at in the firmware temperature warning subroutine. Looking at some of @Cloud's modifications to his wheel the heatsink is not well cooled in the KS14 so that may be why it fails earlier than other wheels on climbing. Keep in mind I only have a Ninebot One E+ and a generic wheel so I'm basing my conclusions on what I have read on the forums and theorized from putting all the clues together. Maybe if the KS14 had a temp sensor right at the MOSFETs it might be able to issue a warning or tiltback in time before the failure point. That still wouldn't prevent BMS shutdowns from over-taxing an already drained battery pack with a current draw spike. I would recommend everyone to log their rides using 9Bmetrics, Wheelog, or similar to record the riding data so it's easier to review any points of failure and have some hard crash data. Think of it as a black box recorder. I log every ride I take, and I can see the power spikes and battery level at each point in my trip. Thanks @Paco Gorina! Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 16, 2017 Share Posted April 16, 2017 This might be handy if someone wants to do some logging as well... I saw that ElectroBoom guy use one: https://moosh.im/mooshimeter/ Link to comment Share on other sites More sharing options...
MaxLinux Posted April 16, 2017 Share Posted April 16, 2017 3 hours ago, Carlos E Rodriguez said: I always slow down. My rule is at least slow down to 50% of max or even more on a large grade. Like walking speed on big grades. That's excellent advice, in my opinion. I always try to stay well below max, especially on hills. When climbing, I don't try to force the wheel to maintain the same speed. I allow it to slow down. Sometimes on very steep hills, the wheel is barely moving, but I'd rather climb slowly than overwhelm the wheel. Link to comment Share on other sites More sharing options...
esaj Posted April 16, 2017 Share Posted April 16, 2017 12 hours ago, Christoph Zens said: So the assumption is that it was a BMS shutdown? If that's true, then I would say the motor controller is not working properly. The firmware has to know what the systems hardware limitations are, and must not exceed them under any circumstances. Why on earth would the firmware decide to overload the power supply and cause a complete and sudden loss of power with the rider definitely flying off the wheel, instead of just letting the wheel lag behind while pumping all AVAILABLE power to the motor to keep up as much as possible? This would cause the rider to tilt forward as the wheel under his feet lags behind, but it would at least give him a chance to react and ride it out. If there is no more power to be had, it's no use to stick to the simple control loop and overload the system up to a complete failure. Controller software needs to allow for errors in wheel balance, in favor of staying within the safe operating area of all its components. Battery voltage and current is constantly monitored. It should be no problem to limit motor power output when battery voltage drops too low or currents are too high, approaching BMS limits. Many (especially cheaper) wheels use off-the-shelf battery-BMSs (I think hobby16 or someone mentioned they're mostly e-bike BMSs), that have no datalines or such, so the actual wheel firmware has no knowledge of what's happening in the BMS. Some (like older Firewheels) have dataline to the mainboard (it still cutout unless the BMS was shunted, but the mainboard warned of cell failure with a recorded voice-message if it was left unconnected, so it did do some monitoring on the pack), and at least some IPSs apparently have the BMS built directly into the mainboard, so in those cases the firmware could at least theoretically get some data from the BMS-side. Of course they could check the BMS specs and program the values into the firmware, low voltage detection is already there, as that seems to be what the firmwares use for "guessing" the battery level, but it can drop very fast on high current demand when the battery is close to empty. There probably is current detection in the firmware, but what they use to decide on the current limits is anyones' guess. It could also be that the BMSs might be different between different batches, in case they found a better (or cheaper but matching the specs ) BMS, and want to avoid the hassle of having to match mainboards and battery packs with specific BMSs... Quote Under normal situations, it is of course better to warn the rider upfront by doing the opposite, which is to drive the motor even harder to overtake the rider and cause the pedals to tilt back, since this will safely slow him down. But if things got bad all of a sudden, there is no more power reserve for tilt back, and no time for beeping, any wheel should keep going at maximum permissible power output and hope for the rider to correct his balance. Exceeding BMS limits is a software error and must be fixed. There is no excuse for this behavior and I don't see how a sudden power loss due to the BMS shutting down could be preferable to any other option. The discharge-side protections of the BMS can be bypassed ("shunted"), hobby16 wrote an article on it a couple years back: http://hobby16.neowp.fr/2015/07/21/bms-how-to-make-your-wheel-safer/ (The post is in the forum also, but most of the image-links don't work there anymore) Quote Also, overheating is no reason for a sudden shutdown. I used my NB1 at 35 Celsius outside temperature climbing a steep hill in the woods until the overheat warning kicked in at 70C system temperature. The wheel did not shut down on me while I was riding. Just started beeping and kept going until I stepped off to let it cool down. That's correct behavior. Same thing with trying to climb faster than the wheel can handle. On a very steep hill I climb almost every day, I can go like 7-8kph. Pushing it harder causes it to beep as it approaches its 1.5kW power limit. So the beeps we can configure as a speed warning are one thing, but any wheel should beep by itself regardless of current speed, when power output approaches critical values. It appears that many wheels use either the CPU (Central Processing Unit) or MPU (Motion Processing Unit, ie. the gyro/accelerometer -chip) internal thermal sensor for detecting the temperature (to save costs, I think?), although that's speculation, and the only reason I think so is that when reverse-engineering the old Gotway-protocol, I noticed the temperature in Celcius is calculated exactly the same way as the MPU-6050 (the 6-axis gyro/accelerometer used at least in the older wheels) datasheet states the chip reports the temperature. https://www.invensense.com/wp-content/uploads/2015/02/MPU-6000-Register-Map1.pdf (page 30): The temperature in degrees C for a given register value may be computed as: Temperature in degrees C = (TEMP_OUT Register Value as a signed quantity)/340 + 36.53 Please note that the math in the above equation is in decimal. Parameters: TEMP_OUT 16-bit signed value. Stores the most recent temperature sensor measurement. I see no other reason for using that "complicated" way of calculating the temperature in the app-side other than that they're directly dumping the MPU register-value into the data going to the app. The problem is, it might be (relatively speaking) far away from the hottest parts, ie. the mosfets of the half-bridges. If the heat rises fast enough, the thermal resistance of the air / distance in the mainboard between the mosfets and the part actually measuring the temperature might cause that the temperature that the firmware is "seeing" is much lower than what's actually going on at the mosfets. I'd prefer to see a heat sensor attached directly to the heatsink next to the mosfets, as that would react much quicker. Also, on the more powerful wheels, they might be pushing the highest allowed temperature too high, so the mosfets could overheat. There have been lots of mosfets destroyed over the last couple of years, but whether it's just due to overheating or something else (bridge shoot-through, gate breakdown?), again we don't know. Link to comment Share on other sites More sharing options...
Rehab1 Posted April 16, 2017 Share Posted April 16, 2017 2 hours ago, esaj said: . I'd prefer to see a heat sensor attached directly to the heatsink next to the mosfets, as that would react much quicker. Also, on the more powerful wheels, they might be pushing the highest allowed temperature too high, so the mosfets could overheat Hopefully the wireless temperature data logger mounted next to the Mosfets of my ACM will be sending back accurate evidence base data about the Mosfet surrounding temperatures. I cannot mount the logger directly over the Mosfets due to space restrictions but it is in close proximity. Link to comment Share on other sites More sharing options...
Marty Backe Posted April 16, 2017 Share Posted April 16, 2017 On 4/14/2017 at 7:10 PM, abinder3 said: Just did some searching on the internet and supposedly, the 14C has a max speed of about 15mph. You stated that you think you were going 16mph uphill. Sounds like you may of encountered 'tilt back' or it shut down because you were pushing it too hard. (again, just a thought) Allen I own a 14C. The maximum speed is 19mph. Actually, I think there are two versions of the 14C. The one that has the >800wh battery has the more powerful motor and goes 19mph. The other one is less powerful. Link to comment Share on other sites More sharing options...
Marty Backe Posted April 16, 2017 Share Posted April 16, 2017 12 hours ago, MaxLinux said: That's excellent advice, in my opinion. I always try to stay well below max, especially on hills. When climbing, I don't try to force the wheel to maintain the same speed. I allow it to slow down. Sometimes on very steep hills, the wheel is barely moving, but I'd rather climb slowly than overwhelm the wheel. I second this. The 14C is a great little hill climber but I don't push the speed when climbing or descending. Even with my more powerful wheels I usually don't accelerate into the climbs and descends. Link to comment Share on other sites More sharing options...
Marty Backe Posted April 16, 2017 Share Posted April 16, 2017 On 4/14/2017 at 6:57 PM, abinder3 said: Agreed. KS14s will overheat going up too steep of a hill and just shut down. OP; was there any beeping while going up the hill? Allen The KS14C does not shutdown when it overheats. It starts beeping and tilts-back. Link to comment Share on other sites More sharing options...
US69 Posted April 16, 2017 Share Posted April 16, 2017 @fourthewin From my experience (owned a 14c 680wh myself) and especially all i heard from a very big rider group in asia with very much! Ks14c owners: The 14c is known to be not able to go 30kmh over its complete batterie life! or better say...if you draw to much power in the second half of batterie...a cutout CAN happen...if really all negatives comes together(weight, hill, batterie percentage, wind etc etc) As you are speaking of a uphill AND accelerating...this seams to be thecase here! IF you have a newer version of 14C, which is with upgradeable firmware, do yourself a favor and update to latest firmware 1.25!!! This firmware will prevent you from speeding to high on a certain batterie percentage! If it is not upgradable...dont go higher than. 25-27kmh when50% and below, and dont do hard accelerations! AND yes...some here have never got problems with it...but believe me...its a known fact..... Link to comment Share on other sites More sharing options...
KINGKONGSONG Posted April 19, 2017 Share Posted April 19, 2017 Watching that video is painful after having the KS16S for a last few weeks. I can zip up and down the steepest hills San Francisco has to offer. The medium sized hills are a piece of cake. I never realized just how powerful my particular wheel is in comparison to other ones. Link to comment Share on other sites More sharing options...
Smoother Posted April 21, 2017 Share Posted April 21, 2017 OP welcome to the face plant club. Membership is free but the hazing is hell. I have little to add. Others have told you what went wrong. NO WAIT! I do have something to add. For you newbies, you can't treat an euc battery like a gas tank in a car. It won't provide the full power all the way to the last drop. You can cane a tiny car with 6 of your closest friends, up a hill, with your right foot buried in the shag pile carpet, and it will either make it or it wont, but no one will fall out and roll down the road. Ask too much of a half full euc battery and once it hits " no reserve left" you better start flapping, I know I do. So,it's official, not enough battery, too much speed, too much hill, accelerating as well, a heavy rider and loads of spectators, place all ingredients in a bowl, stir vigorously, et voila, face plant brownies. I've eaten quite a few, following this exact recipe, and a few variations to boot,. Still makes the same delicious, gravel filled brownies. i won't ride my 14c close to 15mph, because it tried to throw me off once around 16 mph, WITH a full battery. If I want to go 15mph, I'll pony up for a wheel that will comfortably do 25mph (40 kph). I keep it around 12mph (20kph) and slower on hills. I know other like Marty say it will do 20 mph, but I'm pain averse, and don't want to go where I know pain is lurking. Link to comment Share on other sites More sharing options...
dpong Posted April 21, 2017 Share Posted April 21, 2017 1 hour ago, Smoother said: OP welcome to the face plant club. Membership is free but the hazing is hell. I have little to add. Others have told you what went wrong. NO WAIT! I do have something to add. For you newbies, you can't treat an euc battery like a gas tank in a car. It won't provide the full power all the way to the last drop. You can cane a tiny car with 6 of your closest friends, up a hill, with your right foot buried in the shag pile carpet, and it will either make it or it wont, but no one will fall out and roll down the road. Ask too much of a half full euc battery and once it hits " no reserve left" you better start flapping, I know do. So,it's official, not enough battery, too much speed, too much hill, accelerating as well, a heavy rider and loads of spectators, place all ingredients in a bowl, stir vigorously, et voila, face plant brownies. I've eaten quite a few, following this exact recipe, and a few variations to boot,. Still makes the same delicious, gravel filled brownies. i won't ride my 14c close to 15mph, because it tried to throw me off once around 16 mph, WITH a full battery. If I want to go 15mph, I'll pony up for a wheel that will comfortably do 25mph (40 kph). I keep it around 12mph (20kph) and slower on hills. I know other like Marty say it will do 20 mph, but I'm pain averse, and don't want to go where I know pain is lurking. Well stated, sir! I'm with you on this. Link to comment Share on other sites More sharing options...
fourthewin Posted April 22, 2017 Author Share Posted April 22, 2017 Thank you all for the help? How do you upgrade the firmware when my app doesn't provide the option? All it says is "version 0.00" Link to comment Share on other sites More sharing options...
Smoother Posted April 22, 2017 Share Posted April 22, 2017 2 hours ago, fourthewin said: Thank you all for the help? How do you upgrade the firmware when my app doesn't provide the option? All it says is "version 0.00" Can't help you with that one. Mine (iOS) says 1.23 and 1.25 is available for download. I might bite the bullet tonight and download it since answers to my question about 1.25 seem favourable. To be honest I'm not expecting miracles. I doubt I'll even notice the difference, Link to comment Share on other sites More sharing options...
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