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gwhy

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About gwhy

  • Rank
    Advanced Member
  • Birthday 07/31/1964

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  • Bike
    E-sherco E-bmx

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  • Location
    Bristol
  • Gender
    Male

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  1. there was no need to disconnect the neg at the controller , should have just clipped the neg meter lead to the neg of the battery then carefully check on each pin of the relay. With key switch on yes you should have full battery voltage on 3 of the pins and 0v on the 4th relay pin ( black wire ? ). The relay ground goes directly to the controller ( on the oset diagram that i have ) so now if you still have fully battery volts on all 4 pins then now connect the meter neg directly to the black (thin ) wire connection on the relay then measure the the other 3 pins they should have fully battery voltage on each pin with key switch on.... with the key switch off you should only have battery voltage on 2 of the relay pins ( 1 red thick wire and 1 red thin wire) ... the fact that you had 36v on all 4 pins from your tests I would check connections and wires ( black thin wire ) from the relay back to the controller ( it may not be a black wire because you have upgraded the controller).
  2. connect the negative meter probe lead directly to the neg of the battery then the pos to each of the thicker wires on the relay, key switch on you should have full battery voltage on only 1 of the fatter wires on the relay (red wire), if you dont have any voltage then it could be the key switch itself , report back if you still have no voltage..
  3. have you checked the voltage at the relay when you turn on the key switch .. do the relay click on ?
  4. Also on a side note.. always put at least some charge back into a battery fitted with a bms after use especially if you don't intend to use it for a good few days, no need to fully recharge it .. charge for maybe a hour before storing it. and always disconnect the battery from the bike never rely on the key switch you fully turn the bike off especially if the bike has a pre-charge circuit fitted as this will drain the battery.
  5. li-ion and lipo cells have the same voltage so can be charged the same , to a absolute max of 4.2v per cell , lifpo4 is different and has a max absolute charged voltage of 3.7v per cell. the chargers are the same and the only difference is the total charge voltage need to be set at the correct output voltage for how many cells you are charging. if the charger states 54.6v and you have counted 13 cells then this is correct for lipo/liion 48v battery. ok now from what you have described my best guess is that you have a faulty cell which is bad news and the bms is shutting the battery down but it could be a faulty bms draining a cell down. can you get access to the bms ? there is a long connector with 14 or 15 thin wires on it .. unplug that connector from the bms then very carefully ( dont short any thing out !! ) measure each cell voltage, this can be done on the long bms connector . connect the neg meter lead to the main neg of the battery then start at one end of the bms connector plug measure each wire using the positive probe of the meter ( use a pin that fits into the hole on th econnector ) as you move along the connector measuring each cell they should all be the same difference between each one i.e a fully charged battery will be hole 1= 4.2v, hole 2=8.4, hole 3= 12.6 ect, and if you start from the other end it will be 54.6, 50.4, 46.2 ect a difference of 4.2v per cell. I think you have a very bad cell in the battery and this will show up if you test this way, as a good battery all the cells will be the same voltage. if there is a low cell then leave the bms connector off for 24 hours then measure again to see if the bad cells voltage comes back up and this will indicate that it is a possible bms fault. I have no idea what it would say 20s super charged on the battery if you counted 13cells ? ... any chance of posting up a pic? the charger will show a error because there is a fault with the battery. One thing you can test though with the charger is measure the output voltage as it should be 54.6v if its lower then this is what have dragged the battery voltage down.. post up results edit: if all the cells are the same voltage then you need to also disconnect the main neg wire that comes from the cells to the bms to stop the bms from doing any more damage.
  6. what battery is it ? .. I know you said its lipo but how many cells do it have ? ... normally a lipo 48v battery has 12 cells and this should be a max of 50.4v . if it is a battery with a bms then it may be 13 cells as this is the more nearer a true 48v battery but the voltage would then be 54.6v fully charged ... or is it a li-ion battery with bms .. basically what im getting at is do it have a bms and if so then there are 2 possible problems ( dependent on how many cells it has ) it is a faulty bms or the battery has a bad cell. what charger are you using for your lipo's ? a bms would turn the battery off if there is a fault with the battery or the rest of the wiring on the bike as soon as you put a load on to it. if there is no bms fitted then you defo need to know how many cells it has as 51v is way over the top for a 12cell lipo battery and could be dangerous on the other hand if its 13cell then its not charging at all and you still need to work out what is going on. you can test to see if its a bms problem just by connecting the battery directly to the motor wires ( wheel off the ground ! ) it will either spin the motor up full speed or not. edit: on the charger is should say the exact voltage output... is it the correct charger for the battery you are using i.e was it supplied with the battery .. common output voltages of (48v) Li chargers are 50.4v, 54.0, 54.6v, 57.6v this is the fully charged voltage of the battery that you are charging and should never ever be any higher thats why its important to know how many cells you have and what chemistry .. lipo4 is another common chemistry used for batterys but the cell voltage is lower than lipo. also if there is a bms fitted it could be that the battery is being turned off because there is a low ( bad ) cell in the battery.
  7. don't charge 3 batteries with a 48v charger , this will damage the batteries and may also over heat them and they may spit... you can charge each battery individually with a normal 12v car battery charger as long as its a slowish charger around 1A. The bike may work on 3 batteries but im not sure what the lvc is on the controller so it may not, but will do no damage to try.
  8. If you are carrying a spare battery on your bike then you just as well have it connected, no point in carrying it without making use of it.. :-) Just measuring the mileage and time is not a good indicator of how long a battery will last unless you are on flat ground and at a constant speed until the battery is run down to a set level, what is really needed for a more accurate reading would be a watt meter, as this will tell you how many AH's have been used on the discharge and also how many AH's the battery required to fully recharge with the information from a watt meter you can then also get the WH's for the battery, this will also give you a much better indication of how the battery is aging i.e if you are putting in 10ah and only getting 6 or 5ah out then you can safely say that that battery is getting a bit old and past it or the battery is not very good for a high drain application as this is what you will find if using sla batterys. I have a mechanical mod that I have developed that replaces a pure e-bike throttle with a cable throttle of choice and can also fit stiffer or softer springs to the mech so the feel can be customised so that it behaves 100% like that of a gas bike but also puts the sensor for the throttle well away of any possibility of getting damaged , I have never found a good ebike throttle that I have been 100% happy with thats why I designed my own :-) . This is v2 , and still being tested for reliability.
  9. 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 .
  10. 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 )..
  11. 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..
  12. 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 ?.
  13. 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.
  14. 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..
  15. 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.