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About gwhy

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    Advanced Member
  • Birthday 07/31/1964

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    E-sherco E-bmx

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  1. Yes water can effect all the lower power side of things but the fault that is described with the startng to spin up then stop it is very unlikly to be caused by water, more like a diry/bad connection somewhere. And has already been said the fuse holder is a very good place to start. Sticking or worn brushes can cause these symptoms but that would not be the first place to look .
  2. water should not really effect the operation of a motor as water is conductive.. my best guess is that you may have a sticking brush in the motor or a bad connection to the motor ( from controller ) or a faulty throttle ... do it still cut out if you only twist the throttle less than half way ?. test the motor by directly connecting a 12v battery to the motor leads ( keep rear wheel off the ground )..
  3. There will be better traction for two reasons, bigger foot print ( tyre ) and less torque (to the ground due to larger wheel circumference ) so less likely to break traction. The battery, controller and motor will have a harder time with a larger rear tyre , so just keep a eye on the temperature of the motor that it do not start getting to hot..
  4. As it looks like the rear tyre makes the circumference a lot bigger you should also increase the gearing as this will put a lot more strain on the motor and controller. It will also give it better climbing ability. Out of intrest what was the size of the original tyre and what size have you replaced it with ?.
  5. I used to have the same problem with people grabbing the throttle .. I over come this by using a very short lanyard around my wrist ( throttle side ) so basically when my hand is not on the throttle then the bike is disabled. I have been thinking about doing it electronically with a proximity detector and a small magnet sewn onto a glove.
  6. there is no need for flywheels as a Electric motor can produce as much torque as you need ( unlike a ICE motor which has a peak torque plato ) as a instant hit ( within reason ) it will have to be limited pretty quick afterwards though for the motor to survive .. and the controller would also be able to handle the phase current from the motor. it should be fine for a trials application because there will be quite long periods where itsl not be needed..
  7. This is still not a truely progressive torque clutch as it has no torque feed because its only connected between the throttle and throttle input to the controller.. maybe one day someone will do it correctly :-). i.e throttle for speed and clutch for torque.
  8. yes 2x 6s 20000mah lipo's will be enough to run a oset 20.0 . a bms normally is fitted permently to the battery and protects ( prevents cells from overcharging 4.2v ) and balances the battery when charging AND it also prevents any cells from dropping below the safe level when discharging ( when in use ) a bms will also prevent the battery from charging if any cells are below the safe level (3v). if you have 12cell battery then you would need a 12cell BMS and you would treat and charge this 12cell battery as 1 battery ( 1x 50.4v li-ion charger ). so if the battery is fitted with a bms and wired correctly and using the correct charger there is no need for low voltage alarms or a balance charger as it becomes a Plug 'n' Play system that is 100% protected 100% of the time. when selecting a bms you need to make sure it covers the max charge current that you will be charging your battery with and that its for the correct chemistry of your batterys ... lipo is 3v - 4.2v the bms also needs to be correct for the amount of cells that make up your battery. 12s lipo bms's are quite hard to get hold of ( expensive a 12s bms's bms start @ around $50) 13s are more common ( cheaper ) .. normally the higher the discharge rating of a bms then the more expensive it is , it is possible to bypass the max discharge current limit of a bms.. i.e a cheap 13s bms @ $10.00 - $15.00 will do the job but it will only be rated for a max discharge of around 30A so the the max discharge will have to be bypassed .. but you can still have the bms protecting the cells within the battery by using the bms to turn off the bike should any cell drop below the safe level.
  9. this is one of the main problems with electric bikes... there is not a lot of room on a bike to put batterys. ebike batterys ( legal ebikes ) are only rated for a max of around (average) 500w ( these depends where in the world you are ) and all legal ebikes should do no more than a average of 15mph ( again depend where you are in the world ) now those batterys in the link will be fine for this sort of spec but once you start getting into higher power or higher speeds the choices are few... higher voltage runs a motor faster and the plus side to this that less discharge current ( from the batterys ) is needed for the same power .. . the big down side to this is that small motors ( the ones on bikes ) run way to fast to gear it down to a sensible speed if a high voltage is used so there is always a compromise between voltage and current. i.e the telsa indeed do run on laptop batterys ( well the very yealy models ) but they ran on about 350v so to get the power needed the discharge current will not have to be so much.. if you run a small bike (oset 16 ) on 350v (dont try it as the motor is not designed for that sort of voltage :-) ) then the speed will just be way to high and if the discharge current was adjusted down to i.e 10A max ( thats still a wopping 3.5kw) but the motor will not have enough torque to get you moving as it will be geared for around 200mph @350V .. i think the ktm runs around 350V but this is a motor designed for that bike ... personally 350v on a bike is way to high ( especially a off road bike ) and a bit dangerous . normally the bigger the motor the slower it will run per volt ( kv of the motor ) .. thats why cars can get away with it as they have much more room for the motor and batterys.. but bikes you are always struggling for space.
  10. just looked up the spec for these cells: ( as long as they are genuine cells then ) 10A max discharge for a single cell (3-4C) found some discharge graphs discharge @ 2C capacity drops to around 2000mah per cell so that then becomes a 8000mah pack is discharging @ 2C and from what i can tell in do not include a bms with that listing ... it should be ok for a small 36v bike that dont get taxed to hard ( much better with 2 packs) as long as a suitable bms is also installed, then the cost dont look so good . you would need a CC-CV charger to charge these batterys so the standard sla charger will not do the job.
  11. you connect the source side of the meter to the battery and the load side to the controller so basically it goes in between the battery and controller ( rest of the bike ) . because it requires full battery volts and current then its not ideal to run it upto the handle bars as this will involve quite long power cables, so i would try to mount it as close to the controller input as possible and as high up on the bike as possible ( as they are not very water proof ).. if you fit xt60's on the meter it can be easly taken out or put back in as it will only be really used to check stuff, as you will have your LV alarms on the battery to monitor the battery. if you want a perminant tank mounted voltmeter then get something like this .. that meter only reads up to 33v so keep that in mind if you go higher voltage on the bike.. but if you want a future proof voltmeter then this one reads upto 80v ..
  12. 8awg is way to thick for xt60's, you can get away with 10awg (just) but xt60's are designed for 12awg. the best way to make adaptors is using thick copper wire, hot glue and heat shrink. for a 3 way xt60 P adaptor set it up like this .... solder well ( no shorts!! )... then completely fill the gap with hot glue then cover with heat shrink.. the hot glue will make the whole thing rigid and insultat the connection from the elements then use heatshrink to make it look nice :-)..
  13. 8awg is way to thick for xt60's, you can get away with 10awg (just) but xt60's are designed for 12awg.
  14. charger looks ok, i have never came across one of those before... for 6s it will have a max charge current of around ~ 3.5A ( it says that it is a 90W charger )
  15. nope looks like you have it all covered . one very useful bit of kit to have is a watt meter, its great for a number of things ( fault finding ... motor , batterys, controller ) and it can be used as a fuel gauge : also get your self a 5 pack of xt60 plugs and sockets and some 8mm heat shrink .. they are always handy to have..