Shoe73 Posted January 26, 2016 Share Posted January 26, 2016 5 hours ago, chriscalandro said: I'm assuming a lot here, and i could be totally wrong, but my assumptions are based on experience. It seems one day someone made the assumption that if their battery was full, and they went down hill, regenerative breaking would overcharge the battery. -which unless you have designed one of the worst motor controllers in the world, isn't the case. A lot of people like to just assume they know how things work, and that can be very dangerous... The thing is, it's not just an assumption. The energy has to go somewhere, either into the battery or into heat. Capacitors can store a little but no matter how you design the motor controller, I think the generated energy has to end up in the battery. Link to comment Share on other sites More sharing options...
Cranium Posted January 27, 2016 Share Posted January 27, 2016 15 hours ago, chriscalandro said: That chip looks like its a 3.3/5v chip. So that can't be right... Maybe I'm looking at the wrong one. (I had to Google it so I could translate the data sheet.) I don't have time right now to explain batteries and charging, and I don't have the drawing for the board, but you can bet there are some large capacitors to help control incoming voltage generated from the motor, and that probably goes into a voltage regulator... Most motor commercial motor controllers have regenerative circuits built into them, but I think ninebot has their own motor controller. It's probably built into it, but I don't know without the drawings. I'm assuming a lot here, and i could be totally wrong, but my assumptions are based on experience. It seems one day someone made the assumption that if their battery was full, and they went down hill, regenerative breaking would overcharge the battery. -which unless you have designed one of the worst motor controllers in the world, isn't the case. A lot of people like to just assume they know how things work, and that can be very dangerous... You weren't looking at the spec sheet close enough or you were indeed looking at the wrong one. Click on this link: google translation of the IC spec sheet Voltage of the IC is rated between -0.3V to 26V. Since the ground for each IC is relative to where it is placed in the string of batteries that are in series and it is capable of sensing 5 cells at a time, it has plenty of headroom for over voltage protection since 5cells X 4.2V/cell = 21V. The built in over voltage protection behavior is not able to be bypassed. You can only adjust the delay (slightly) before it triggers clamping down the voltage. Page 17 of the PDF version of spec sheet in my previous post shows a graph of over and under voltage behaviors of the IC. I would imagine the clamping down of voltage by the BMS would in turn cause a voltage spike on the controller side but they probably have a shutdown condition for this but perhaps you could explain what would happen better. Here are two versions of the Ninebot board being used in the E+ and P. Note there are no large caps AND no large heat sinks. Normal operation [by me] can get the controller to ~150°F. At 160° it has a built in thermal shutdown which I've experienced as well. Here is the Ninebot E+ BMS....it is very similar to the BMS that is used by KS. I haven't opened my Ninebot P battery yet but I expect it to be exactly the same as the E+. KS uses four SH367004 ICs since each one can only support 5 battery cells and KS uses 16s batteries (as do many others). A link to a picture taken by another forum member showing the KS18A BMS Here is a closeup of the SH367004 IC on the BMS Ninebot and KS have some of the better designs. But there is still a long ways to go for them to be really good designs. I think many experienced engineers may come to the EU world and asked WTF is this design?? Welcome to EUs. Link to comment Share on other sites More sharing options...
chriscalandro Posted January 27, 2016 Share Posted January 27, 2016 The very top of that first picture shows the motor driver fets attached to a large heat sink. (The metally bit at the top) Brushless motors generally are 3 phase, and there are sets of fets for each of these phases. Very close to them at the top you will see 3 caps. Those are to manage the back emf from the motor. I assume the 3 larger caps are filters into the battery controller but really, I have no idea. You are also correct. I had the wrong data sheet. That one looks much more reasonable. Regenerative breaking probably does not produce a whole lot of power. The motor controller I posted before can handle 15 amps and it is probably the size of a postage stamp * 1.5 Link to comment Share on other sites More sharing options...
chriscalandro Posted January 27, 2016 Share Posted January 27, 2016 Link to comment Share on other sites More sharing options...
esaj Posted January 29, 2016 Share Posted January 29, 2016 Split the braking- etc. discussion here and cleaned it up a bit (merging consecutive posts from same people): Link to comment Share on other sites More sharing options...
Flavour Posted January 30, 2016 Share Posted January 30, 2016 On 25/01/2016 at 3:12 PM, DaveThomasPilot said: I have no desire to got fast or for long cruises. Bbut have a workshop located about 1500 feet from my house, down an 8 - 10 degree slope. I'd like to hop on the EUC to fetch something from the workshop, and return at something faster than a walk, maybe a jogging pace. What do you need to fetch that fast? 1 kg of sugar if you run out? I'm sure you can order a Tesco delivery or something Just kidding. I would recommend walking, seriously. I'm not rude, you'll feel much better physically and mentally. Ninebots are limited to 120 kg (according to the spec), however this is a margin to ride on flat. Some people ride short distances even with 160 kg, but on flat and with overheating. Cranium (you can high five him) is the only one with overheating issue on his P and it's because of weight, because he's son doesn't have this problem (but he will eventually, I bet his on the same diet ;-) ). I've never seen anyone else had overheating problems too. So the P model with more power will overheat, especially riding uphills, I think E+ might have a problems too. A horse is not an option either :-( Technology and the world is much better when we care about our health. To admins: I don't mind if you ban my account Link to comment Share on other sites More sharing options...
esaj Posted January 30, 2016 Share Posted January 30, 2016 1 hour ago, Bat said: What do you need to fetch that fast? 1 kg of sugar if you run out? I'm sure you can order a Tesco delivery or something Just kidding. I would recommend walking, seriously. I'm not rude, you'll feel much better physically and mentally. Ninebots are limited to 120 kg (according to the spec), however this is a margin to ride on flat. Some people ride short distances even with 160 kg, but on flat and with overheating. Cranium (you can high five him) is the only one with overheating issue on his P and it's because of weight, because he's son doesn't have this problem (but he will eventually, I bet his on the same diet ;-) ). I've never seen anyone else had overheating problems too. So the P model with more power will overheat, especially riding uphills, I think E+ might have a problems too. A horse is not an option either :-( Technology and the world is much better when we care about our health. To admins: I don't mind if you ban my account This is just childish. Did you get your feelings hurt over the braking-debate in the other topic and need to lash out? Arguing and debating is ok, but there's no need to be rude. I don't see the need to ban your account (at least just yet), maybe you're drunk right now or something Or it's just a case of John Gabriel's Greater Internet Dickwad Theory: Just kidding, don't take it personally Link to comment Share on other sites More sharing options...
DaveThomasPilot Posted January 31, 2016 Author Share Posted January 31, 2016 3 hours ago, Bat said: What do you need to fetch that fast? 1 kg of sugar if you run out? I'm sure you can order a Tesco delivery or something Just kidding. I would recommend walking, seriously. I'm not rude, you'll feel much better physically and mentally. Ninebots are limited to 120 kg (according to the spec), however this is a margin to ride on flat. Some people ride short distances even with 160 kg, but on flat and with overheating. Cranium (you can high five him) is the only one with overheating issue on his P and it's because of weight, because he's son doesn't have this problem (but he will eventually, I bet his on the same diet ;-) ). I've never seen anyone else had overheating problems too. So the P model with more power will overheat, especially riding uphills, I think E+ might have a problems too. A horse is not an option either :-( Technology and the world is much better when we care about our health. To admins: I don't mind if you ban my account http://forum.electricunicycle.org/topic/1189-regeneration-on-full-battery-bad-news/ Just now, DaveThomasPilot said: You should not make assumptions about peoples exercise habits. I hike 5 miles every weekday on a trail with lots of terrain. I do it at rate that keeps my at the top of the recommended pulse rate for my age. I get plenty of exercise, that's not why I want the unicycle. It's for fun! But, when I'm working on a project and need a tool, five minute walks back and forth to the workshop add up. Just something I'd like to have the power to do. Link to comment Share on other sites More sharing options...
Cloud Posted January 31, 2016 Share Posted January 31, 2016 No need to justify yourself @DaveThomasPilot. We all know how convenient eucs are to go back and forth. Noone here should be criticising your weight or physical shape and make allegations that you are just being lazy. What Bat said was totally uncalled for. Link to comment Share on other sites More sharing options...
dpong Posted January 31, 2016 Share Posted January 31, 2016 I don't think we need to stay strictly theoretical in discussing the possibility of a cut-out (on Ninebot One, at least) from regenerative braking on a fully charged battery. One can theorize about the exact mechanisms involved, but we have empirical reports from the field of people experiencing face-plants from this exact maneuver. Link to comment Share on other sites More sharing options...
chriscalandro Posted February 1, 2016 Share Posted February 1, 2016 Where. If you have a definite example, please post it because I have missed it. Link to comment Share on other sites More sharing options...
dpong Posted February 2, 2016 Share Posted February 2, 2016 On February 1, 2016 at 0:13 AM, chriscalandro said: Where. If you have a definite example, please post it because I have missed it. @chriscalandro In this post, @mengke who has worked with the Ninebot company, explains that this can happen and why. Here is what mengke said: If you fell but the Ninebot One is still powered(red flash led lights) then that is bad luck occasionally. But if you fell and Ninebot One is shut off and the battery was full then you need to contact Ninebot Inc. You battery, control board or charger has a minor issue maybe. It will stop working when you regenerate power charge back into your battery when it is already full. So going downhills or quick slowing down from high speed when it is fully charged will trigger the "shutting-off". It could be surprising in some cases to shut off power with no alert. Basically if you can, you need to try to charge your unit with another charger from your supplier or buy another one to see if the problem persists. Or just change your battery with Ninebot Inc to eliminate the issue for good. Why this is happening? basically it is because the charger over-charge the battery by a small voltage offset, so when you ride and regenerate power into battery while the voltage is still higher than standard, the over-charging protection function kick in and shut off your ninebot one power supply. (Yes it is supposed to be a self protect function for the battery.) So it is an issue with battery power management system and the charger. Change either of them would be able to fix the problem most likely. It is a BMS issue but it only happens when it is fully charged. if you carefully use some power to take it off the peak, it is trouble free with the rest of the power supplying until you charge it fully again. Contact your dealer see if they can help you with at least a new charger to start with. If not, just contact Ninebot Inc. to describe the issue and ask for a battery replacement or at least the new charger. Unfortunately, it is not something that can be fixed by firmware update at this stage. So change charge to try to have a quick fix or change battery to fix it for good. Here is how you contact Ninebot customer service: https://plus.google.com/+MengkeLi51/posts/eJPUMdRRf1F Why I know all this? I have seen this happening before and tested one Ninebot One with this issue myself. It shuts off as we anticipated rapidly slowing down from high speed when it is fully charged. At last, it was resolved by changing another battery. I do care when there is some minor issue with Ninebot One(regardless if I sold it or someone else did) and I dig out the root cause with Ninebot Inc to figure out the best solution. The Ninebot One E+ I am offering is most likely the same as any other dealer but the service I am offering should be much better. I offer the best deal and service for Ninebot One, as well as the best collection of Ninebot One accessories. Find the offers at: wheelyouride.webs.com or the Ninebot One community on Google+ at: https://plus.google.com/u/0/communities/103704604858097234749 Mengke from wheelyouride.webs.com Link to comment Share on other sites More sharing options...
Jason McNeil Posted February 2, 2016 Share Posted February 2, 2016 On 1/30/2016 at 4:40 PM, Bat said: I've never seen anyone else had overheating problems too Ninebot themselves have acknowledged that the 'P' is not yet ready. Link to comment Share on other sites More sharing options...
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