Hi, I have a Gtech Sport and want to replace the controller and battery , but keep the rear hub drive - can someone reccomend a suitable replacement that will allow better acceleration and slightly higher top speed? I know very little about ebikes. Thanks
Gtech Ebike sport - replacement battery & controller - advice needed
- Thread starter Wibbles
- Start date
A KT set up with a new lcd display might work, if wanting integrated controlle rto battery then one will have to buy from China @Topbikekit.com.
We need to know if the motor connector is 9 pin type, so some pics would help and also of the whole bike. We could look up the bike but hey if you want help you need to help us, instead of us doing all the donkey work.
After all all the advise is free.
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Top speed is dependent on the actual motor rpm winding, just replacing the controlelr kit doesn't mean one will gain much but 2 - 3 mph may be possible. As mentioned is really depends on the hub motor rpm specs.
We need to know if the motor connector is 9 pin type, so some pics would help and also of the whole bike. We could look up the bike but hey if you want help you need to help us, instead of us doing all the donkey work.
After all all the advise is free.
TopBikeKit-Electric Bike Lithium Ion/LiFePO4 Battery, Electric Bike Kit(Such As Bafang BBS Kits), Electric Bike Hub Motors, Electric Bike Charger, smart BMS, bluetooth BMS, Lithium battery BMS, Electric Bike Controllers, Electric Bike Meter, Electric Bike BMS/PCM, Electric Bike Accessories(Such As Bafang BBS Spare Parts, Bike Parts)-TopBikeKit Online Store For Electric Bicycle Parts-TopBikeKit.com.Electric bike parts and kits, electric bike controller, electric bike meter and display, electric bike BMS / PCM ( Battery Manage System ), electric bike charger, electric bike Bafang 8fun motor, electric hub motor, Bafang 8FUN BBS kits and spare parts, lithium ion battery and LiFePO4 battery-TopBikeKit Online Store For Electric Bicycle Parts-TopBikeKit.com.
Top speed is dependent on the actual motor rpm winding, just replacing the controlelr kit doesn't mean one will gain much but 2 - 3 mph may be possible. As mentioned is really depends on the hub motor rpm specs.
Thanks for the reply, as far as I know it's a Bafang 250w hub motor.
Would this be suitable for the motor:
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the connector to the motor is like a round Din plug with 9 pins I believe.
If you can reccomend something better then I would appreciate it - my commute is around 15 miles (round trip) so it needs to cover that.
Thanks
Yes that kit will be fine for the distance, the Bafang hub will use a std 9 pin julet layout. The battery 21700 is 360wh sp in low assist PAS 1 will see you 40 miles on flat terrain.
I use a 369wh 44v 8.4ah 21700 battery I spot welded and it easily does me 24 miles with my Kona Ute towing a trailer laden with upto 200lbs using a offroad trail for 70% of the route.
From the drop down boxes one will obviously need the inner controller.
9 pins : Either the 600 or 1000 9 pin so measure on your bike which one is needed from bat position to hub connector.
Charger : If your charger has the 5.5mm x 2.1mm single pin charge jack and is 36v rated, it wiil work ok so one can save a few quid and a bit weight on postage.
Display: If wanting minimalist then lcd4 is tiny if wanting a throttle then opt for lcd9 for less wires, other wise look at th options under meter on the header bar.
Cable : If opting for throttle then fit at least one brake cut out so one will need the 1T4 cable, if no throttle then the 1T2 is neater as one dosen't need a brake cut out.
(With KT one only needs a brake cut out when a throttle is fiitted in case of water ingress in throttle and malfunction, PAS run on is zero).
PAS: Opt for BZ10C or 8 pas, it depends on the bikes Bottom bracket fitted.
Throttle. Optional if not using lcd9.
I use a 369wh 44v 8.4ah 21700 battery I spot welded and it easily does me 24 miles with my Kona Ute towing a trailer laden with upto 200lbs using a offroad trail for 70% of the route.
From the drop down boxes one will obviously need the inner controller.
9 pins : Either the 600 or 1000 9 pin so measure on your bike which one is needed from bat position to hub connector.
Charger : If your charger has the 5.5mm x 2.1mm single pin charge jack and is 36v rated, it wiil work ok so one can save a few quid and a bit weight on postage.
Display: If wanting minimalist then lcd4 is tiny if wanting a throttle then opt for lcd9 for less wires, other wise look at th options under meter on the header bar.
Cable : If opting for throttle then fit at least one brake cut out so one will need the 1T4 cable, if no throttle then the 1T2 is neater as one dosen't need a brake cut out.
(With KT one only needs a brake cut out when a throttle is fiitted in case of water ingress in throttle and malfunction, PAS run on is zero).
PAS: Opt for BZ10C or 8 pas, it depends on the bikes Bottom bracket fitted.
Throttle. Optional if not using lcd9.
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The KT display will if the motor winding allows it, one expects you should be able to gain 2 - 3mph at least even if the hub is 201 rpm wound. If it is a 270 rpm you should get about 23mph but with speed comes range anxiety as the battery will deplete quicker.
The Motor is a Bafang 250w 36v unit - Model Number: BFY1812H17686
Is it ok to use a higher voltage on this unit? I'm looking for better acceleration, higher top speed and a bit more assist up some steep hills on my commute.
If I need to change the wheel, I don't mind but I want the conversion to be reversible in case I want to sell the bike at a later date.
If you could tell me the exact thing I need to buy then I would be most grateful.
My bike comes with a charger but it is specific to the GTech battery
If you run 36v at 48v then one theoretically gets 33% more speed & torque from the hub for the same current, the controller may overheat if one can't maintain good speed on hills.
One will need a controller of about 17a if wanting 48v and a battery that can discharge ideally 25a continuously so the cells aren't stressed.
The hub numbers mean nothing apart from it being 36v, tbh one is best sticking with 36v and using a 20 - 25a controller. Any battery needs to have a continuous current rating greate rthen the controllers max rating.
One will need a controller of about 17a if wanting 48v and a battery that can discharge ideally 25a continuously so the cells aren't stressed.
The hub numbers mean nothing apart from it being 36v, tbh one is best sticking with 36v and using a 20 - 25a controller. Any battery needs to have a continuous current rating greate rthen the controllers max rating.
I don't advise on items to buy to go fast above the required limits, all I do is theortically say what may be possible with any given info.
In #6 I have given what I think the motor is capable of at 36v, use a 17/20a controller KT kit and one should get the min speed I mentioned. If the motor is a faster winding then it will maybe reach the upper speeds I mentioned.
One can't be more precise as the motor winding RPM isn't know, it how ever will be in the range of 201 rpm - 270ish rpm.
In #6 I have given what I think the motor is capable of at 36v, use a 17/20a controller KT kit and one should get the min speed I mentioned. If the motor is a faster winding then it will maybe reach the upper speeds I mentioned.
One can't be more precise as the motor winding RPM isn't know, it how ever will be in the range of 201 rpm - 270ish rpm.
Given that you reccommend a 20 - 25a unit, would this be better:
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No the battery is only 20a continuous so idealy for a 15/17a controller
For 20 -25a controllers one needs very good higher rated cells with 21700 or 18650 cells.
The continuous discharge rating means the battery can run at the rated current without damage to the cells, in this case 20a. The other rating of 40a peak discharge is a temporary 10 - 30 second usage that the cells can sustain but prolonged usage will result in capacity loss and range loss, this will lessen the battery life.
A battery cell has a max cuurrent rating but this rating if used will result in cell damage and loss of performance and early aging. A recommended rating for life cycle and good use is approx. 50/60% of the current rating.
For 20 -25a controllers one needs very good higher rated cells with 21700 or 18650 cells.
The continuous discharge rating means the battery can run at the rated current without damage to the cells, in this case 20a. The other rating of 40a peak discharge is a temporary 10 - 30 second usage that the cells can sustain but prolonged usage will result in capacity loss and range loss, this will lessen the battery life.
A battery cell has a max cuurrent rating but this rating if used will result in cell damage and loss of performance and early aging. A recommended rating for life cycle and good use is approx. 50/60% of the current rating.
This one with 30a BMS would work but is china cells.
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You are best sticking to max 17a controller for nearly all the batteries with internal controller.
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You are best sticking to max 17a controller for nearly all the batteries with internal controller.
how about this one: http://www.topbikekit.com/hailong12-battery-36v21ah-panasonic-ncr18650ga-battery-pack-for-ebike-p-1095.html
That has a 25a discharge.
alternatively I can go for the one you suggested - is there anyway I can use the built in PAS that comes with the GTECH?
I am super grateful for all the help, I'm a total noob when it comes to this stuff - I got the bike super cheap and I am ejoying using it but I just want a bit more out of it without breaking the bank.
If you think I would be better off selling and buying a different bike then I can do that but I would need to probably modify that one too as they are all limited to 15mph.
If you want to ride fast buy a lightweight rode bike and pedal harder.
The only thing holding back the Gtec is the electronics software, stick to the KT items listed earlier in the thread and you should have little issue managing 18 or 19mph with good rider input.
If wanting more you are definately on the wrong forum.
The only thing holding back the Gtec is the electronics software, stick to the KT items listed earlier in the thread and you should have little issue managing 18 or 19mph with good rider input.
If wanting more you are definately on the wrong forum.
I've already got a Specialized road bike but I don't use that during the winter and it's not really a commuting bike.
I'll order the kit you reccomemended - the bottom bracket on my bike has the PAS sensor built in, it's got a similar plug to the motor - I will count the pins - can I use that or would I be better off getting a different PAS from the same place as the battery and a throttle of some kind?
I'm not looking to beat any land speed records, just improve the performance a bit.
I hope I am on the right forum and appreciate your patience with someone that has zero knowledge in this area but is willing to learn.
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