BBS02 750w Issue

Adam648

Finding my (electric) wheels
Jul 26, 2018
13
1
28
Hi All,

Wondered if someone could point me in right direction.

Been out on the bike today - with what I thought was a fully charged battery.

Did approx two miles and the motor started jolting; I noticed the battery indicator was dropping fast then just turned to a red icon.

At first I assumed the battery; but this was showing 52V on the screen.

Peddled back home and charged battery up; fully charged and there’s still nothing on the e-bike.

The screen powers on no problem but there is a red battery icon in the corner - it’s had a few ‘jolts’ of power again but nothing normal.

Checked all wires and they appear fine.. what’s everyone’s thoughts on what could be wrong?
When I go into the battery info it says the voltage but capacity 0% on the screen - it worked for a brief second and showed 93% then back to 0%.

From what I’ve read it sounds like controller? Any thoughts?
 

Woosh

Trade Member
May 19, 2012
10,348
7,219
Southend on Sea
wooshbikes.co.uk
you may have a faulty cell in your battery.
Where did you buy your kit?
 

Tarka

Finding my (electric) wheels
Jan 29, 2019
12
8
Could be a poor electrical connection, not enough amperage getting through. Any error codes?
Also there is a troubleshooting guide, click here: Fault guide
 

Woosh

Trade Member
May 19, 2012
10,348
7,219
Southend on Sea
wooshbikes.co.uk
Anyway I could test for that?
PswPower.. only got it in September and done maybe 250 miles tops?
to test for this type of faults, you have to open the battery's case and check or imbalance between the 13 cell blocks. It's a no no from the customer because it will void the warranty. The indirect test is to use the battery on another bike, the same fault would happen. If I have your battery in the workshop, I can do a discharge test. Where do you live?
 

Adam648

Finding my (electric) wheels
Jul 26, 2018
13
1
28
to test for this type of faults, you have to open the battery's case and check or imbalance between the 13 cell blocks. It's a no no from the customer because it will void the warranty. The indirect test is to use the battery on another bike, the same fault would happen. If I have your battery in the workshop, I can do a discharge test. Where do you live?
Chesterfield. Unfortunately don’t have another bike to test on. Bike does show 54.8v but just a red battery icon.
 

Woosh

Trade Member
May 19, 2012
10,348
7,219
Southend on Sea
wooshbikes.co.uk
I would lend you a bike but it's a lot of miles from Southend.
maybe a member who lives near you and owns a bike running on 48V battery could help you check out your battery.

when the BMS detects a faulty cell, it cuts out the output to protect the cell pack. To test the cell pack, you can construct a simple discharge rig for your battery with four 50W 12V halogen bulbs connected in series. You need to prove that you can drain a fair bit from the battery without the BMS detecting any faulty cell.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,201
161
Basildon
It sounds like a blown MOSFET in the controller to me. have you got a wattmeter or ammeter to measure the current?
 

Woosh

Trade Member
May 19, 2012
10,348
7,219
Southend on Sea
wooshbikes.co.uk
It sounds like a blown MOSFET in the controller to me. have you got a wattmeter or ammeter to measure the current?
I would have thought a blown MOSFET would be found immediately by the power on self test and reported with something like current abnormality error.
 

Adam648

Finding my (electric) wheels
Jul 26, 2018
13
1
28
Sorry for the delayed reply guys; thanks for the advice so far.

Took the controller apart and have continuity between the negative & positive wires to the 3 phase wires. So I believe the controller might be ok.

Battery is currently at work with bulbs wires up to it to slowly discharge it - I’ll check it again in morning to see if it’s flat.

Question.. would using a different charger cause an imbalanced cell? I have one charger at work and one at home; the one at work is rated higher?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
7,126
2,712
55
West Sx RH
Charger only supplies voltage to the battery BMS, it is the BMS that controls cell balance by monitoring via the thin balance wires. The balance wires don't actually carry charge/discharge voltage , any unbalance is carried out via bleed resistors opening and closing dependant on what the balance wires read.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,201
161
Basildon
Sorry for the delayed reply guys; thanks for the advice so far.

Took the controller apart and have continuity between the negative & positive wires to the 3 phase wires. So I believe the controller might be ok.

Battery is currently at work with bulbs wires up to it to slowly discharge it - I’ll check it again in morning to see if it’s flat.

Question.. would using a different charger cause an imbalanced cell? I have one charger at work and one at home; the one at work is rated higher?
Continuity doesn3 tell you anything. You have to measure between the black battery wire and each of the three phase wires to get three readings that must be the same as each other in the range 7k to 14k, then repeat using the red battery wire.
 

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