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Peter Le Lievre

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About Peter Le Lievre

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  1. Look through your garage to find that old Rockwheel GR16! I have a project where I am after a geared EUC wheel as a basis.
  2. If you still have your GR16 let me know. I am after one for a project of mine. alive or dead. I am based in Sausalito.
  3. Working or not. I am researching geared EUC wheels and wanted to rebuild/ride a geared GR16. I normally ride a Gotway ACMs+ but am interested in the geared alternative. Will pay cash if you have the wheel.
  4. If you run a low tire pressure with all that power, the tube will wander around and break free of the stem. Even though its a pain its worth checking your tire pressure at least every other month. Otherwise its an even greater pain to split the wheel to change the tube. I find my ACMs+ is a totally different ride with 60PSI than with 30PSI. Fast, responsive and better range. However it is also more bumpy and a little twitchy at speed so adjust to suit. Unlock your 'other' wheel and pump up your tires please!
  5. My bad, LiOn is constant current charging like you say. Further, a 5amp 'fast' charger is not exactly high power loading for any mosfet. The only issue is that 84V is kind of up there so any internal unexpected Mosfet resistance is going to lead to a fritzed part way quicker than the good old days when 36V was 'high power'. I haven't seen the BMS design but if that is an 84V board and the gating voltage for the mosfet uses a resistor to drop the voltage, if that resistor fries and goes closed circuit and that gate gets even close to seeing 84V then its bye bye Mosfet. So if your fast charger has any DC ripple due to dead/dying caps or bad rectifier then that could kill the mosfet gate resistor/mosfet gate pretty quickly. So I take back what I said about the charger not being to blame. Looking more closely at this issue, I suspect the charger for sure. I see crappy capacitors all the time in Chinese electronics so I would replace the BMS mosfets then certainly buy another charger. Or if you decide to keep the charger, put it on a scope so any DC ripple can be checked.
  6. Guys, The charger is most likely just fine, however it's important to note that a 'quick charger' will pump more amps through the input mosfets of the BMS. No surprise is that they get hotter. And its not hard to imagine that when the input mosfet fries on one side that ALL the current will attempt to charge the other side and then fry that too. I bet the OP's input mosfets fried as he plugged the 'fast' charger straight after a long ride? When the battery and BMS were already hot? When battery volts were so low that the fast charger amped up to max? Below is a typical BMS (36V) which shows the single input mosfet which regulates the high voltage charge cutoff. Its the single INPUT mosfet on the bottom right. Not the same as ours but principle is similar. The input mosfet handles all the input power (charge). This BMS also has 3 OUTPUT mosfets which regulate the output low voltage cutoff. They handle all the output power. I haven't seen a Gotway BMS but most likely the output BMS mosfets are omitted as the wheel control board probably has a low voltage cutout of its own. However the input mosfets (x2 in our case) will be still there as pictured below. The input mosfets should easily be able to handle a fast charger current however until I can see the part number of them it's hard to know. Perhaps they are bad parts. Whatever the case it pays to be kind to your charge mosfets and use a 'fast charger' only when battery is cold, or even better use the normal charger routinely unless you have a special need to get back on the wheel more quickly. Remember, all the power that goes into your wheel first has to pass those input Mosfets and in this BMS design they are not actively cooled like the output ones are. We are so focussed on the insanely high amperage output mosfets that we forget the much lower rated input mosfets that must first accept all the power we put into our wheel.
  7. OK Marty. So I took the covers off my ACMs+ and found everything looked pretty good. No burnt wires, no nasty corrosion (from those wet rides) no nothing..................except the 6 screws holding the case to the pedal hangers were loosened on each side. About 3 or 4 had backed out quite a few turns. So I tightened them and check the tightness of the main axle bolts (21mm) which were TIGHT. I put her back together and HEY PRESTO! No more shudder on takeoff. Smoother than new. Turbine smooth. Smooth as a baby's...... How smooth?? So 2000KM and only a couple of loose screws. Still happy. THANK YOU MARTY!! You nailed it. Now ready to join you all for a ride .
  8. My ACMs+ is approaching 2000KM now and also zero problems. Its been a great wheel which has done a lot of mountain climbing and trail work without any complaint. As a newbie (2000km ago!) I am so glad I picked a 1600WH ACMs+ as the 84V power and range have been very rewarding. Lovin it. The only issue lately has been a slight shudder during starts (high torque) which feels like a soft mosfet or voltage sag but I really am not sure. At speed and on hills at speed she is as smooth as silk. I'd appreciate any feedback from others whom have shudder during starts as that first 10 feet doesnt feel as 'secure' as it used to.
  9. I have a Gotway ACM and it has a black rubber paint finish on the wheel. Duct tape will not stick to it!! Any ideas on how to protect?? I am looking for a tape or film that will stick to the rubber paint. I dont fall off anymore on tar but on the dirt trails I have been knocked off a few times now by bumps/rocks etc.
  10. For those in the Bay Area i was riding back across the Golden Gate Bridge last night after 9PM. The cycleway is closed then and the pedestrian pathway has a security gate after 9. I pressed the intercom but they refused to open the gate. I was told that 'motorized' devices are not allowed on the either the Cycleway (west side) or Pedestrian way (east side) . So I was totally stuck. You just cant take the roadway as it is too dangerous. After a 'discussion' security sent a patrol car whom offered me a ride. The pickup was in the east car park. So an OK outcome but food for thought for any one contemplating a bridge ride. My own take is that if you cross before 9pm then the cyclway is pretty much OK and although technically EUC's aren't allowed, you can go across mixing it with the bikes as long as you don't bring attention to yourself. My only recommendation is that it sure is windy up there and the path is narrow so make sure you are confident on your EUC before attempting. Longer term, I guess we need to lobby about this issue as its nuts that EUC's are banned when they are both safe and practical and in the future I expect we will see a lot more of them. Unlike the bikes whom all seem to think faster is better and travel at dangerous speeds the whole time on that cycleway. Its just a matter of time before someone is knocked over the edge!
  11. The ACM hasnt beeped once yet. The only thing I notice is that it does tilt back probably at a little less than 20mph. But no beeping. I did go up a very steep dirt trail and the ACM basically got so slow that I had to hop off. However it didnt beep and it was still trying to do this hill, just ran out of speed. I logged on to the ACM using the app and I havent touched any settings yet,. I see it is in 'soft' mode still and alarms are set to 'default'. However there is no tilt back speed selected at all, which makes me wonder why it does tilt back like it does. When I get a bit more experience I will try the other modes.
  12. Another way to get better range is to upgrade the standard Gotway battery backs for 3500mah cells. The new 1600wh packs use these cells. For the same weight and size you get 20% more range. These are standard 18650 cells supplied in Tesla battery packs and are available on eBay if you look. However only buy genuine LG or Panasonics otherwise less range may result
  13. Just took delivery of my own ACM 1300WH and have two days riding so far. As a newbie (never ridden a EUC) I started s-l-o-w-l-y and never busted 10mph. I also COVERED the ACM in duct tape to handle the inevitable crashes. Now after 50 miles I am very comfortable on the wheel and starting to make longer trips. Its really great and the power of the ACM seems a safety bonus to me. The wheel always has the oomph to keep you upright, even up and down inclines which were probably 20%. I am based in Sausalito (California Bay area) so happy to meet up with other EUC riders to compare notes. There are a lot of trails in the Marin area which seem ideal for a powerful EUC. The ACM seems perfect and I am very happy with it so far. Scared of 84V? Not me. Just take it easy and life is good.
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