Fahrtwind Posted June 23, 2015 Share Posted June 23, 2015 Hello everybody,this is my first post, I just signed up to this community. My Name is Manuel, I am from germany. Two weeks ago, a colleague showed me his EUC and I was amazed in a second. I ordered one on the same day. It arrived yesterday. I am a lucky man: due to a lot of sport I guess (skiing, Inline Skating, running), I felt comfortable with the generic Airwheel within 30 Minutes. Today I trained mounting an d dismounting, curves. I did that in my big cellar riding slowly. I plan to get a high quality EUC later. My favorite is the 9B1 E+ at the moment...In the evening I went outside (no rain anymore) and drove on the sidewalk, got up and down. Then I just wanted to test, how fast it could be. Bad Idea. At maximum Speed, the device shut down. I lost it behind me, and started running as fast as possible, trying to decrease my "speed over ground". >15 km/h?? Well after 2-3 big steps I lost control and face plant it. Some abrasion at my elbow an knees. Of course I was not wearing any protection. Luckily nothing broken - and nobody saw my Unicycle-Dance...Well what happened? I guess it was a BMS shutdown due to high current. I would like to shunt it an had a look for the battery. The BMS-Pictures I saw here were a little bit different. The middle connector of the Mosfets is not connected. Can you help me? Thanks a lot!Manu Link to comment Share on other sites More sharing options...
esaj Posted June 23, 2015 Share Posted June 23, 2015 Hello Manuel, and welcome to the forums! Sorry to hear about your fall, luckily it doesn't sound that bad... The shutdown may have been caused by the BMS or simply overspeeding, but if the BMS has the overdischarge protection mosfets, in my opinion it's better to shunt them to be safe at least in that regard (do note that you'll be voiding the warranty on the battery, if not the entire wheel when shunting it!). But since it looks like you've already cut the battery pack open, it's gone already I think the best person to advice about the shunting is @hobby16. I recall him mentioning in some thread that you could find out the mosfets to shunt with a multimeter, they were the ones showing some certain voltage, but don't remember the specifics. Better ask our expert Link to comment Share on other sites More sharing options...
Fahrtwind Posted June 23, 2015 Author Share Posted June 23, 2015 Hey esaj,thanks for your quick response! Well I bought this wheel in China - I don´t care about the warranty I found some Things to improve. I 3D printed a cover for the charging port, sealed some holes in the housing etc. And I defenetly want to improve the safety of this EUC. I bought this as a training wheel. But the worst thing it could do is stop working on full speed. I´ll contact @hobby16 tomorrow! Manu Link to comment Share on other sites More sharing options...
esaj Posted June 23, 2015 Share Posted June 23, 2015 Here's the post, it was buried in vee73's "I plan to test"-thread:The 3 mosfets are paralleled so they must be shunted as shown by the big red lines.But first, check that they are indeed paralleled : mesure the voltage between the gates and 0V (black wire), you must have the same value (around 10V) gate1=gate2=gate3.Don't know if that's going to help you much, as there's only two mosfets on one side, two apparently missing and one on the other side in your picture, where as most of the shunting pictures I've seen, there's been at least 5 mosfets, out of which 3 are usually shunted... Link to comment Share on other sites More sharing options...
Gimlet Posted June 23, 2015 Share Posted June 23, 2015 Shunted or not they all stop working at full speed. That's why they all have warnings of some sort when you get anywhere near full speed.The main thing to remember is that it's not actually the speed that causes them to fail but the power draw. You can just as easily get any wheel to fail at low speed by leaning hard forward from a standstill or from going backwards. Link to comment Share on other sites More sharing options...
Fahrtwind Posted June 24, 2015 Author Share Posted June 24, 2015 Hi,when I think about my crash again, I changed my mind. I think it wasn´t a BMS cut off as I could continue driving immediately. I think it just was lack of power as you said and the wheel wasn´t able to keep me balanced. Good to know what happens if you reach the limits of the wheel. Well I think this is a reason why you should buy a wheel with a powerfull motor and a high capacity battery.So what do I have learned? Be carefull with speed on this generic wheel. Wear protections if you drive fast.I plan to get this bike to italy for holidays for the next weeks. If I am still alive and interested when I am home again, I will have a look for IPS Lhotz or 9B1 E+. I found a dealer for both in belgium close to our holiday Appartement. I´ll visit that shop on our next stay. Thanks for your posts! Manu Link to comment Share on other sites More sharing options...
Bigi Tum Posted June 24, 2015 Share Posted June 24, 2015 This exactly happened to me with my Airwheel clone. With the difference that I was able to avoid a face plant. I tried to accelerate to fast. That's why I changed to an EUC that better fits to my "dimensions" (details see below). It never happened again since. Link to comment Share on other sites More sharing options...
Jason McNeil Posted June 24, 2015 Share Posted June 24, 2015 The growing evidence seems to be the number of cells (also to a lesser degree their chemistry) is the most important thing for power safety margin:x16 (all single Wheel Airwheels + most generics) = Not good enough for Western ridersx32 >260Wh (two parallel packs offers 100% more power than 16) = Should be the minimum standardx 64 >520Wh (four parallel packs, loads of reserve power) = at this point the battery pack is typically not the bottleneck Link to comment Share on other sites More sharing options...
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