New Ebike Built with Bafang 750w Question my first bike ever

Hello everyone. This forum is awesome i've reading it for the last 2 weeks, but im having some difficulty knowing if the buy im buying will actually fit the Bafang mid drive motor.

So the bike i wanna get is http://www.chainreactioncycles.com/us/en/vitus-bikes-sentier-275-hardtail-bike-2014/rp-prod107035

by email CRC back and fourth that bike has BSA threaded 73mm bottom bracket which are Shimano Hollowtech II bottom brackets and they say that the inside diameter is 36mm not the 35mm that i keep on reading with all of the requirements about bafang motor setup.

I've emailed CRC back asking if they're sure that its 36mm inside diamter and they confirmed. So i don't know if this bike will work for the bafang motor.

Sorry im a complete newb with Bicycles and have absolutely no idea... but i built things all the time so as soon i have things on hand i can pick them apart and put it together without a problem.

Ok and the next thing i've bought the bafang kit from http://www.greenbikekit.com/ and they said that the kit they ship doesn't have the longer bolts or bolt that is needed for 73mm.

What is the exact part that i need to buy to be able to install it on a 73mm bottom bracket

Guys thank you so much into looking for this and for your help as soon as i can have this figured out im going to buy the right bike (i've already bout the motor kit as well as the battery)

It will fit straight onto that bike BUT you won't be able to fit the locknut on it.
All you need do is use thread locking compound on the one nut instead.

Thank you, finally got to installing it last night but ran into some trouble. and so i have one question (not regarding the trouble)

Will the stock chain work with the larger front chain wheel?

this is the bike i bought
http://www.chainreactioncycles.com/us/en/vitus-bikes-sentier-275-hardtail-bike-2014/rp-prod107035 and the bafang chain wheel is quite larger then stock.

Or do i need a larger chain?

Thank you!

As your chainwheel is 12 teeth less than the Bafang thats a 6 inch difference in length so I think you will need a new chain.
Plenty of 10 speed ones on ebay,just count up your links and get one with at least another 12 and you will be sorted.
What batteries will you be using?

I am using http://www.ebay.com/itm/161417958605?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

from electrictronic store.

Guys i need help once again. I installed everything today , made custom wooden enclosure for the battery, everything is just was just perfect and awesome. Rode it great for 1.5 miles was so happy. Parked it for 2 min, when i went to ride it again the lcd was off. Trying to turn it on is useless, it won't turn on..... so to make long story short i got it to work by disconnecting power wires (red/black from the battery to the motor, then i put put the charger on the battery, charged it for 1 min, connected the wires and and got the lcd/motor to turn on. Went for a ride and this time it worked only for about 100 yards before completely shutting off and unable to turn it on.

So the only way im able to turn on the lcd/motor is by connecting the charger to the battery/disconnecting charger and then bafang will turn on/off.... But when you go for a ride it lasts between 50-100 yards before completely shutting down. LCD is showing fully charged battery btw.

Can anyone please help? I don't know where to proceed. Obviously i've made sure all connections are very good, is it a bad battery or bad bafang? What do i check next?

thank you guys. Im sorry for being such a newb.
Please guide me i have no idea what to do and how to get it to work.

Measure your battery voltage when your motor has cut off. It should be about 53v.

Did you mess about with any of the parameters in the LCD other than wheel size?

d8veh said:

Measure your battery voltage when your motor has cut off. It should be about 53v.

Did you mess about with any of the parameters in the LCD other than wheel size?

Click to expand...

I didn't even mess with the wheel size yet. Only set time and selected miles. Do you guys think its the battery?

Don't guess. Measure it!

Hello guys. reporting back. So went out and got my volt meter. Here is what it reads.

bafang turned on = 53volts
when i take a ride the voltage falls down to 49volts
then all of the sudden voltage falls to 7volts.... and everything shuts down. the only way for the battery to start showing 53volts is by pluging it into the charger and then its back to normal 53volts/49volts when riding.

so it seems that its the battery that is faulty? I don't thing bafang has anything to do with it?

Thank you, let me know what you think and thank you again for helping me out d8veh!

Hello guys, seller has told me to charge the battery for 3-4 days to balance all the cells in the battery and everything should be fine then. Does it really take 3-4 days to balance the cells? and would i have to wait that long again in the future for the battery to fully charge?

Last night after charging battery for about 20 hours i went for a ride. Battery lasted for 2 miles before it shut down... Is that normal to charge brand new battery for 20 something hours and only have 2 mile range? Thank you for help.

Your battery is not working as it should.
Some of the cells inside goes below treshold point and batterys BMS cuts the power for the whole pack to protect the cells do go beyond their limits. This happens when you see your 7 Volts.
It could take 1-3 days to balance out the cells. Normally this is one time procedure.
If it still does not work for you, you should get a new battery, because yours is faulty -nothing to do with your motor.
Where did you buy it and what kind is it?

Hello. im coming to the same conclusion Allex. after 4 days of balancing the battery it lasted me 10 miles with me assisting id say 75% of the time. So it did do a lot better. im wondering if i keep on doing charge/recharge the battery can fix itself??? Or does that not happen?

I already did email the seller about not being happy and that it is underperforming. i got it from http://stores.ebay.com/electronicstore

Its interesting since i've bought the battery, he revised the listing and now the battery is a bit heaving and its dimensions have increased. so basically he's selling same capacity but at different weight/size.

is there any tool that i can buy that i can connect it between the battery as well as the motor to have it measure perhaps volts,amps, but most importantly so it could measure AH (size of the battery)

Thank you!

I would have expected the seller to check and balance batteries before sending them out. Yours must be a long way out. Balancing does happen very slowly. I have some BMSs with 390 ohm bleed resistors, so that's about .01A balancing current or 0.03 watts. Each cell contains about 47wh, so it could take 1566 hours to balance in the worst case if I've done my math correctly. The big question is why it's out of balance in the first place.

I think your best course of action would be to get back to the supplier and tell him that charging hasn't sorted it. In the meantime, keep it on charge all the time to see if it continues to improve. I'd expect a minimum of 20 hilly miles, but if it's flat and you pedal, something like 30 miles or more

As it's getting better, we can assume that it's a balance issue. If it were mine, I'd open it up as far as the BMS, where you can check the cell voltages on the multi-pin connector. You can also charge the individual low cells through the same connector if you have the right equipment. Obviously, you'd need to agree that with supplier first.

another day of charging and then riding. got 9.3 miles range today with average speed of 16.5mph. Seller telling me to keep on charging the battery for more then 4 days to balance the battery.

Once again guys do you know of any meter that i can connect to this 48v battery that will measure the watts of this battery? is this something what im looking for?

http://www.powerwerx.com/digital-meters/dc-inline-watt-meter-power-analyzer-powerpoles.html

Thank you.

Frustrated a bit cause the bike and everything is awesome but range

Keep it on the charger, without riding it a couple days. If that doesn't fix it, get a new one.

Dan

Plug it in for 96hrs. Where do you live ? Saler S.F. .

Cheaper if you are in US
http://www.hobbyking.com/hobbyking/store/__55323__Turnigy_130A_Watt_Meter_and_Power_Analyzer_US_Warehouse_.html

Request the money back and get a proper pack from him:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=50015

Thank you all for the help. Seller sent me a new battery pack which worked fine right after the first charge. I'll post some pictures in a bit of my bike and setup. appreciate to the members that helped me in the right direction. Thank you

There are no specs as to what kind of charger it is too.
Most lipo chargers switch off once they hit a target voltage so the balance charging time is quite short.
Glad to hear you got it sorted tho. Thats quite a reasonable price for that amount of batteries.