Popular Post DebboR Posted November 21, 2015 Popular Post Share Posted November 21, 2015 Hi all! After getting annoyed by the "high" speed warnings of my generic wheel and destroying my BMS by trying to fix it, I decided it was time for an upgrade. I ordered the 14' 500W motor (http://wholesaler.alibaba.com/product-detail/2015-New-Products-500w-brushless-motor_60234663860.html) and the matching 30A controller (http://wholesaler.alibaba.com/product-detail/Electric-Scooter-controller-Self-balance-unicycle_60224721191.html) from Microworks. They are very friendly, and helped me during the ordering process. The components arrived in a few days, thanks to DHL Express shipping. Unfortunately, the package was held at the border, meaning €52 worth of import duties had to be paid. I am very happy about the build quality of the motor. The controller seems to be well designed, even using proper silpad under the FET's instead of the packing tape reported by some. The packaging around the controller however wasn't that good, which resulted in a few caps being damaged: Fortunately, I had some suited replacements lying around and replacing them was easy enough. Still something to keep in your mind if you order from Microworks and you're not that handy with a soldering iron. The nuts on the original EUC motor took a bit of persuading to get off, but after all it wasn't too much of a hassle. As the new controller doesn't have an integrated buzzer (and I don't have an active one laying around), I fabricobbled one together using a passive buzzer, a 555 IC and some discrete components. It works, but the volume isn't that good so I probably will get a proper active one. The first time I rode the wheel, I noticed the calibration was off by a lot, and the pedals had quite an odd angle to them while riding. Shorting the calibration contacts while holding the wheel upright and turning it on seemed to have helped, although the wheel didn't spin during this procedure and just started beeping and blinking the power LED. Haven't had the guts to try the top speed yet, as the buzzer sound is really quiet and I don't want to faceplant at 30km/h . I have rode it for at least 20km/h without any issues though, so it seems to have worked. The extra 150W also seems to help the riding over grass. About the battery: As some of you might know, my BMS didn't balance the individual cell voltages any more, and while trying to troubleshoot this, I might have shorted some pins on the PCB with my oscilloscope probe. Now it doesn't charge normally any more, as the charging FET just stays shut off. To test the wheel anyway, I override this FET and monitor all cell voltages regularly to avoid damaging them. I have ordered a new BMS (http://www.aliexpress.com/item/16S-15A-59-2V-li-ion-unicycle-BMS-PCM-battery-protection-board-bms-pcm-with-balancing/32414515852.html) and cells (http://eu.nkon.nl/rechargeable/18650-size/panasonic-ncr18650pf-3-7v-2900mah.html) with the U-tags welded on. The BMS really caught my attention, as each cell is soldered to it individually, which makes construction on my part a lot easier. I won't have to deal with spot welding at all. I already got the cells, but due to slow chinese shipping, the BMS is still in transit. I'll try to keep this tread updated on any progress / setback that is made, but for now I'm happy with the progress . 5 Quote Link to comment Share on other sites More sharing options...
Tom Posted November 21, 2015 Share Posted November 21, 2015 How did you purchase a single item from Microworks? They all seem to have 100 min order. Good luck with the project, will be closely watching Quote Link to comment Share on other sites More sharing options...
DebboR Posted November 21, 2015 Author Share Posted November 21, 2015 1 minute ago, Tom said: How did you purchase a single item from Microworks? They all seem to have 100 min order. Good luck with the project, will be closely watching You just have to contact them via alibaba. They will make you a personal order, in which they change the quantity. :-) Quote Link to comment Share on other sites More sharing options...
lizardmech Posted November 30, 2015 Share Posted November 30, 2015 Any chance of a picture of the two motors with the covers removed? Interested to see what is the different between the two in terms of winding and magnets. Quote Link to comment Share on other sites More sharing options...
DebboR Posted November 30, 2015 Author Share Posted November 30, 2015 14 hours ago, lizardmech said: Any chance of a picture of the two motors with the covers removed? Interested to see what is the different between the two in terms of winding and magnets. Hmm, might have considered it while changing out the motor, but now it's a bit too much work. Also, I doubt that the difference in the winding would be easy to see because of the large number of poles. I've been using the EUC for a few weeks now, so I'll update this thread with my experiences soon :-) Quote Link to comment Share on other sites More sharing options...
Jug Posted December 16, 2015 Share Posted December 16, 2015 On 11/30/2015 at 5:25 PM, DebboR said: Hmm, might have considered it while changing out the motor, but now it's a bit too much work. Also, I doubt that the difference in the winding would be easy to see because of the large number of poles. I've been using the EUC for a few weeks now, so I'll update this thread with my experiences soon :-) Hi, any news? Did you received BMS, is it good? Cheers! ;-) Quote Link to comment Share on other sites More sharing options...
Popular Post DebboR Posted December 16, 2015 Author Popular Post Share Posted December 16, 2015 A quick update, as requested: The EUC upgrade is completely finished now and I'm really pleased with the end result. With the old battery in the EUC, it acted really strange, with several moments where it lacked power to accelerate me, resulting in me falling off. I believe this is due to the cells used in the old pack, since their C-rating was way lower. Once I received the new BMS and soldered it all together, those performance dips were removed completely. Here's a picture of the new pack installed: I used bubblewrap to keep the pack from sliding around and to absorb the vibrations. To make sure the cells wouldn't rattle individually, I used some kind of silicone in a tube I had laying around. When dry, it creates a nice celastic bond between each of the cells: I also applied this to all the big components on the control board (like the big caps, inductors, ...), to keep them from getting loose due to metal fatigue. About the BMS: I'm really pleased with it. The individual slots make it easy to solder on the cells with standard U-tabs, and the charging and balancing works well (all within ±5mV when the pack is at about 50% capacity). To prevent BMS shutoff, I did bridge the bottom 3 MOSFET's. With this pack, I get a range of about 10 km, which seems to be around average for this amount of capacity. I desoldered the buzzer from my old control board, and used that on the new controller. I haven't needed it yet, since I really don't dare to try out top speed. While using a GPS tracker on my phone, I have gotten up to 26.8km/h so far without any tilt back or beeping, but I'm not really confident with pushing it any further without proper safety gear. For normal day-to-day use, the speed is more than sufficiënt, and my averages are around 18-20 km/h for most trips. If there are any questions, feel free to ask . 4 Quote Link to comment Share on other sites More sharing options...
Jug Posted December 16, 2015 Share Posted December 16, 2015 Thank you for update I just ordered two same as yours BMS to make double battery pack Quote Link to comment Share on other sites More sharing options...
Tomek Posted December 16, 2015 Share Posted December 16, 2015 @DebboR great job. I'm planning to follow in your footsteps. Do you use your old battery in parallel with the new, or did you remove the old one? I was also wondering about the BMS specs. It says "Over current detection current 80A±10A", so it's a bit unclear if it cuts at 80A or 10A... I was considering using Samsung INR 18650-30Q batteries, which can handle sustained 15A and over 30A load spikes, so it would be a pity if the BMS shuts the current off below that... on the other hand, when using weaker batteries, isn't there a risk of overloading them if the BMS only cuts them off at 80A? any thoughts on that? Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 16, 2015 Author Share Posted December 16, 2015 4 minutes ago, Tomek said: @DebboR great job. I'm planning to follow in your footsteps. Do you use your old battery in parallel with the new, or did you remove the old one? Thank you! I like tinkering with stuff, so if you do too, I highly suggest trying this upgrade. It's well worth it in my opinion, and makes the EUC a lot more useful. I did not connect the old battery pack in parallel with this one, due to the fact that the old BMS was broken (see one of my other topics), and the EUC doesn't have any room left to put it in. Also, I mostly only do 2-3km a day, so range really isn't a problem for me. Just now, Tomek said: I was also wondering about the BMS specs. It says "Over current detection current 80A±10A", so it's a bit unclear if it cuts at 80A or 10A... I was considering using Samsung INR 18650-30Q batteries, which can handle sustained 15A and over 30A load spikes, so it would be a pity if the BMS shuts the current off below that... on the other hand, when using weaker batteries, isn't there a risk of overloading them if the BMS only cuts them off at 80A? any thoughts on that? 80±10A means that it is a cutoff of 80A, with a maximum fault of 10A (so effectively between 70 and 90A), so you don't have to worry about that. Also, if you bridge the MOSFET's, the output of the BMS is directly connected with the cells, so the over current protection is completely circumvented. When using weaker batteries, if the current is too high, the voltage of the battery also drops. If the voltage becomes too low (measured by the controller), it just shuts the EUC down, as it knows it no longer has enough power to maintain a steady ride. The over current protection will only be useful in the event of a short-circuit longer than a few seconds or so, as the cells aren't really happy with that. If you wire everything up correctly and make sure that the connections are nice and secure, there shouldn't be a lot of risk. 1 Quote Link to comment Share on other sites More sharing options...
Tomek Posted December 16, 2015 Share Posted December 16, 2015 11 minutes ago, DebboR said: 80±10A means that it is a cutoff of 80A, with a maximum fault of 10A (so effectively between 70 and 90A) Embarrassing, I wasn't thinking straight here... 32 minutes ago, DebboR said: Also, if you bridge the MOSFET's, the output of the BMS is directly connected with the cells, so the over current protection is completely circumvented. Not sure what you mean by bridging MOSFETs. The shunting hack? 14 minutes ago, DebboR said: When using weaker batteries, if the current is too high, the voltage of the battery also drops. If the voltage becomes too low (measured by the controller), it just shuts the EUC down, as it knows it no longer has enough power to maintain a steady ride. The over current protection will only be useful in the event of a short-circuit longer than a few seconds or so, as the cells aren't really happy with that. If you wire everything up correctly and make sure that the connections are nice and secure, there shouldn't be a lot of risk. Nice clarification! Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 16, 2015 Author Share Posted December 16, 2015 1 minute ago, Tomek said: Not sure what you mean by bridging MOSFETs. The shunting hack? Yes, connecting the base with the emitter. Quote Link to comment Share on other sites More sharing options...
SlowMo Posted December 16, 2015 Share Posted December 16, 2015 (edited) Did you solder the batteries by spot welding? Edited December 16, 2015 by SlowMo Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 16, 2015 Author Share Posted December 16, 2015 1 hour ago, SlowMo said: Did you solder the batteries by spot welding? They are spot welded, but I didn't bother to do this myself (I would have had to make the welder first), so I ordered them pre-welded (for €0,40 per cell extra). 1 Quote Link to comment Share on other sites More sharing options...
Jug Posted December 27, 2015 Share Posted December 27, 2015 On 12/16/2015 at 10:42 PM, DebboR said: They are spot welded, but I didn't bother to do this myself (I would have had to make the welder first), so I ordered them pre-welded (for €0,40 per cell extra). Can you please share where did you do spot welding or where to find U-tabs, i cannot find anywhere here in Belgium :-( I still waiting my BMS... Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 27, 2015 Author Share Posted December 27, 2015 1 hour ago, Jug said: Can you please share where did you do spot welding or where to find U-tabs, i cannot find anywhere here in Belgium :-( I still waiting my BMS... I ordered them on www.nkon.nl. With most of their cells, you can select the optional U-tabs while ordering. They do all the spot welding for you . Quote Link to comment Share on other sites More sharing options...
Jug Posted December 27, 2015 Share Posted December 27, 2015 Just now, DebboR said: I ordered them on www.nkon.nl. With most of their cells, you can select the optional U-tabs while ordering. They do all the spot welding for you . Well, the problem is i already have batteries, i just need to find someone to do spot welding or to find those tabs to solder myself, but i cant find that in Belgium! Weird Thanks anyway Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 27, 2015 Author Share Posted December 27, 2015 7 minutes ago, Jug said: Well, the problem is i already have batteries, i just need to find someone to do spot welding or to find those tabs to solder myself, but i cant find that in Belgium! Weird Thanks anyway You don't have to buy the tabs. Just cut some copper (or other metal) strips, they'll work fine. Making a small spot welder to do these kind of welds isn't very easy, but certainly doable with a microwave transformer and some electronics knowledge. I've read about welding tabs, and supposedly it happens in 2 pulses. The first pulse is the shortest, and takes care of softening the metal to ease the actual welding. The second pulse is a bit longer (a few ms), and actually does the welding. I suppose it would be possible to put a relay in series with the transformer input side, and controlling it with an arduino or something similar. I might actually try to build one myself some day. Quote Link to comment Share on other sites More sharing options...
Jug Posted December 27, 2015 Share Posted December 27, 2015 Lol, I was also thinking about that to build from old microwave, but it will take some time to do that so maybe 29 minutes ago, DebboR said: some day. like you Thanks for clearing that for copper or other, i was thinking that is maybe weak for the current or something Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 27, 2015 Author Share Posted December 27, 2015 1 minute ago, Jug said: Thanks for clearing that for copper or other, i was thinking that is maybe weak for the current or something Copper is one of the best conductors, so that won't be a problem 1 Quote Link to comment Share on other sites More sharing options...
Jug Posted December 27, 2015 Share Posted December 27, 2015 Can i use this? http://www.amazon.de/MISOL-tabulation-bricolage-Solarpanel-Solarzellen/dp/B00F9TCCMQ/ref=sr_1_1?ie=UTF8&qid=1451246871&sr=8-1&keywords=SOLDER+Tab+WIRE Quote Link to comment Share on other sites More sharing options...
DebboR Posted December 27, 2015 Author Share Posted December 27, 2015 2 minutes ago, Jug said: Can i use this? http://www.amazon.de/MISOL-tabulation-bricolage-Solarpanel-Solarzellen/dp/B00F9TCCMQ/ref=sr_1_1?ie=UTF8&qid=1451246871&sr=8-1&keywords=SOLDER+Tab+WIRE Seems like tis is only 2mm wide. That's a bit too narrow I'd think. Quote Link to comment Share on other sites More sharing options...
Jug Posted December 27, 2015 Share Posted December 27, 2015 Hm yes, something about 5mm would be better.... Quote Link to comment Share on other sites More sharing options...
SlowMo Posted December 27, 2015 Share Posted December 27, 2015 I got these nickle strips from Ebay: http://www.ebay.com/itm/272035339960?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT Quote Link to comment Share on other sites More sharing options...
Jug Posted December 27, 2015 Share Posted December 27, 2015 Thanks SlowMo but this i will wait till february with my luck and i need something fast! Quote Link to comment Share on other sites More sharing options...
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