Levo Gen 2 Bypassing BMS for Charging

[bigwaves311]

Good Morning,
I recently purchased a 2017 Levo and it wont charge past 78%. The battery health states 90% and i believe the firmware is old. I have tried charging several times with one time reaching 81% before the charger shut down. At that point the battery would only give 3 red flashing lights until it was ridden around the block, which seemed to reset the battery and was back down to 78%. Is this something that might be corrected with a firmware update? if not, has anyone attempted to bypass the BMS module for charging directly to cell groups? I have charged, balanced, and even saved several individual cells from battery packs I built for RC stuff but never an e-bike. From what i gather from this forum, the BMS seems to be very problematic for replacing/ balancing individual cells as it is directly integrated with the "Brain". Does the BMS recognize a bad cell and permanently disable it from the integrated pack? I understand the Job of the BMS is to protect overcharging/ discharging of cells, but if there are a few that are low voltage and might be able to be saved through a few balance cycles i would like to try and charge those within their individual groups. I have a 48v skate board which does 24mph with a true 26mi range that was begining to show poor range and not fully charging. I was able to save 7 cells by balancing it within their individual groups and it has ran through approx 20 charge cycles since with range and speed back to normal.

 

[Specialized Rider Care]

Hi @bigwaves311 - recommend you get a retailer to look at this battery on our latest diagnostic tool. If there's a cell imbalance that the BMS won't correct via charging (assuming an authentic Levo charger is being used and waiting until the charger LED turns green) then the diagnostic tool should pick this up. There's nothing user-serviceable inside and strongly recommend you do not attempt repair for your own safety - it could be that a retailer will offer a solution here. Will PM you to see which retailer you are nearest to.

 

[bigwaves311]

Thank you Specialized Rider Care. I emailed a local dealer to have it tuned up and checked out for updates/battery health, but have not received a response yet. Ill call them today on my lunch break since emails sometimes get lost or categorized as junk. The charger is the factory supplied charger. Another interesting development, I went on a 10-11 mile ride on eco yesterday starting with 78% battery. When i got home it was at 79% and about 20 minutes later said 80 percent.. The previous owner did not use the bike much and admitted to leaving it unattended for about a year and a half. I understand Specialized stance on discouraging people from trying to service the packs as they can cause fires or sever chemical burns, but having a B.S in electrical engineering and an A.S in electronic engineering i can only suppress my curiosity for so long.

On another note, it would be great if Specialized initiated a battery refurbish/ trade in program. Such as a battery with 90-80% health (verified at LBS) carries a return value of X amount. That amount is applied to the cost of a refurbished battery of similar watt-hour. This would greatly reduce the amount of service life/ charging anxiety on the consumer end and would further set Specialized apart from the competition. I can not speak for others, but if I were to be offered a refurbished pack for say $200-$300 in trade for a pack with 90-100 percent health it would be an every year purchase and regarded as maintenance.

 

[bigwaves311]

Wow, this took me way longer to get back to than it should have.. Either way guys i opened up the battery case and found several cells in a low voltage condition. Hooked them up individually to smart charger made for RC battery's and brought each cell in the pack to 4.2 volts. Ran it through 3 cycles from full to all the way dead and everything seems to be as it should. I might start offering this service for people who have the same issues. Also i am putting together a parts list for a higher AH battery pack with a more reliable BMS and un-restricted output, utilizing the same RoPD plug. I will start a new thread for the battery build.

 

[freerider85]

Hi I'm interested how did you fix your battery ? As I having issue with 3 blinking red LED I also found two groups were unballanced and charged them to 4.2V same with rest of cells but my battery is still blocked with shitty BMS . Also looking for unrestricted BMS but there will be issue with specilized as they using sensing wire (something similiar as dell use for computers) so if you connect non specialized bms motor will not recognize battery same for charger.

 

[bigwaves311]

try re installing the battery and riding it around the block a few times. Then see if it still flashes at you, you didn't push the button on the bms did you? that clears the bms software and essentially turns it into a brick. What i really need is to upload the software and read through the code. Since the batteries are interchangeable there needs to be a line in the code which is more or less a compatibility key for the motor to recognize. Two things i really need to get my hands on are a working bms/battery that i dont care about (it will be destroyed in the process of reverse engineering) and a broken brose motor for the same purpose. let me know if you end up getting rid of that battery

 

[freerider85]

I tried ride bike around block but no luck still flashes red. I didn't push switch what is on BMS but LED beside constantly blinking (not even code just blink every second). For me this battery is currently just brick all happened during charging proces , OEM charger cut out around 80% than battery turn in to failure before this charging everything was ok. Anyway good luck with reverse engineering this is what old type levos need .

 

[Chengsr]

Thank you Bigwave for the info​

I had a spare batter not used for over a year and now it drops power when it reach to the last 4 bar. I’m curious about using a RC car charger, can you elaborate on your steps and process? There are videos on taking part the gen1 battery and how to measure the voltage but can’t find anything on how to actually charge the battery bank independently. Thank you