Optibike Battery Pack Dissected

July 14, 2012

Here are pictures of an Optibike battery pack that was opened up by an Optibike owner in Thailand. The Optibike owner was getting half the expected capacity out of his 3 year old pack, and sending the pack to the United States was out of the question, so he had the pack dissected and repaired locally where skilled labor is cheap. What he found  is interesting and he photographed the results for posterity.

Optibike is using generic 18650 cells to make their packs. The highest quality cells are name brands made by Panasonic or Samsung and cost $10 each to buy (the packs consists of 100 cells).

Optibike is offering a 3 year warranty on their pack, but to get warranty service the entire bike needs to be hazmat shipped to Boulder Colorado at the bike owners expense. Therefore some Optibike owners are resorting to taking apart their Optibike and repairing their own pack by replacing bad cells..

This battery pack was epoxied and welded together in a way that it took hours of painstaking labor to tear and chisel the pack apart to get to the bad cells. This pack was obviously not meant to be repaired.


The “Boundless” battery pack fresh out of the downtube of the Optibike.


First the top cover was removed from the pack…an easy task:



Next the paper was peeled back, showing that the Optibike consists of 10 banks of 10 cells for a total of 100 cells (3.7 volts each, so 37 volts) to make up the 26-Ah pack.



Next the aluminum bottom case needed to be removed. Not easy, epoxy was used to bond the 100 cells to the Aluminum case. The case had to be torn apart to access the cells.



Next the metal tabs that are spot welded to each cell needed to be forced off with a chisel. Not easy work:



This is a 30 cell cluster that was broken off from the main pack to get to the two bad cells.



In the bottom of the next picture you can see two lavender cells which are brand new Samsung cells to replace the two duds.



Because the battery pack was torn apart to access these two cells, a new battery case had to be fabricated. Lucky this Optibike is in Thailand, and quality labor like this is very affordable:



Optibike has since changed the company that produces their packs (while still using the same lower quality cells), but now adds a carbon material to insulate each cell which reportedly increases cell life. Optibike calls this technology “cool carbon”.

We suspect it is the US battery manufacturer All Cell which makes the new Optibike pack. Here is an example of how an All Cell pack looks with the carbon insulator. All Cell makes custom packs for OEMs such as Optibike. They also make the battery pack for the Hanebrink and the Picycle.


Eric has been involved in the electric bike industry since 2002 when he started a 6000 square foot brick and mortar Electric Bike store in downtown San Francisco. He is a true believer that small electric vehicles can change the way we operate and the way we think.


  1. For $13,000, it should come with several battery packs.

  2. I agree ! Maybe a proper warranty too. Or even better, make work right
    before they sell them.. (CRAP)

    • Finally, I upgraded my NiMH optibike. The new battery I use is 15AH, 36v Li battery pack, with BMS board of course, with Samsung 18650s
      I also changed the controller to allow cruise control and power-cutoff-by-break-lever. The upgraded bike is much more powerful due to the new and better battery pack. If you want to upgrade or just replace the old battery pack. I am happy to help. Just send me a PM or email

      • hey just saw you replaced your optibike battery pack.. could you tell me more?

        • Hi, Dan:

          Order a li-ion pack ($400-500) and ebike controller package (<=$100) from ebay. Open your optibike, remove the electronics, brake lever. Put in your new electronics: the new controller, the new bike brake lever, connect them properly. Put the battery in, insulate it to prevent mechanical vibration from damaging the battery pack. Close the bike cover. Test. All this is not which
          is not easy because optibike is not designed to be openned and work with easily, due to its emphasis on beauty over maintainability. It took me about 3 month to finish the repair/upgrade, including what components, what tools, especially the size, the specs etc.
          But the much more powerful battery, the cruise control, the regenerative braking are worth the effort.


          • Hi Haito!

            Can you point me which battery fit easily into the Optibike frame? For the regenerative braking, does the new controler adds this option alone or the bike already have this feature?

            Thank you!


          • Use 18650 battery with continuous discharge current>=10A. I used 60 of them arranged in 3*20 shape, connected as 10S6P. This size barely fits in. It will be easier if it is shorter, such as 10s5p which can be arranged in 3*17 rectangular shape. With today’s 3000mah battery, the battery size is 3*5 = 15 Ah ( 3.5*5 = 17.5Ah if use 3500mah battery) which is already much better than the stock Nimh battery. Also, I do not know your bike’s size. Mine was 2009-2010 Nimh OptiBike. So it is better to get your old battery out and measure the size. The controller for brushless motor you buy should come with new brake lever for regen braking and cutting off power and cruise control when breaking. The cruise control is automatic set when you stay at the power level for a few seconds.

      • can you share your battery upgrade experience so I can do it?? Thanks alot, Bruce in CA truemanbruce@gmail.com

        • Over-voltage to 75v: If the hall sensor is not designed for this voltage, I guess misreading of sensor may happen, resulting in a stalled motor. Some controller can “learn” the motor phase positions and do not need hall sensors’ feedback. Will that kind of controller solve the problem? Maybe worth trying.

      • Haitao,
        Do you have any pictures of your battery retrofit? The new battery is a simple drop in?
        What controller did you use? Are there many differences? I heard someone modded their bike to be 72V with a backpack battery but he had some stalling issues. Any sense in trying to use the stock controller with a battery retrofit?

        • You need to have these

          1. a bike rack to hold the bike in any direction you want.

          2. a sel of long allen tool to open the cover.

          3. Solder, and related consumables, heat shrink tubes.

          4. Multimeter. and other small things common for electronics engr.


          1. If you want to use new electronics: 36v 500w ( or more depends on your model ) brushless dc motor controller, that can work with hall sensor or without. Optibike is known to have unreliable hall sensor or hall sensor wires. So, be prepared to use the motor even without hall sensor wiring.
          2. battery: 10S6P li-ion 18650 pack that can provide at least 40A continuous discharge amp. Use reputable batteries to avoid fire. I forgot the size spec. But I remember the size barely fits.
          A smaller size is better.

          3. Charger. wires, connectors.


          WARNING: There is a risk of doing electronics yourself, including a big spark damaging your eye, fire hazard, exploding battery, property damage. Faulty installation may cause accidents.
          The following description is only about what I did. I am not giving advises to anyone. If you repeat what I did as described below, you are responsible for anything that results from it.

          1. hang you bike up. remove some nuts to move the back wheel+motor assembly back to expose the bottom cover.

          2. open the lower cover to show the battery. Be careful here as it may drop out.

          3. pull the battery out. Note where the charging and discharging cable goes
          4. I tries to use the old electronics, but it fried the circuit board.
          5. So I used new electronics. I disassembled old electronics.

          5. Put new brake lever, speed, cruise control/brake interrupt cables etc into the body. Connect them to the controller.

          6. Connect motor wire, hall sensor wire to controller.

          7. connect the charging wire to new battery. WARNING: polarity must be right, or you may get a fireball.

          8. Connect the power from the battery to the controller.

          9. Test run the motor, test charging.

          10. if 9 passed, then put controller into the body. cable, battery pack, insulation of battery especially at the bottom where the weight of the pack rests on.

          11. Close the cover, put the bike parts back.

          12. test run.

          If the above is too much trouble for you and you are in US, then you can send the bike to me for upgrading at a cost of parts+shipping+$799 for labor.

  3. I understand how Optibike would want to keep some things a secret, but the least they could have done is to have the battery pack user removable. Then only the battery pack has to be Hazmat shipped instead of the whole 60 lbs bike. Even then, it would still be expensive to ship the battery.

  4. I’m having the same problem with my battery pack
    At this point i am building my own new and improved

  5. I need to change the battery (NiMH) on my optibike (4yrs old).
    I called Optibike, the customer services guy said that optibike does not service bike with NiMH battery any more. They offered me a $500 to trade in my bike ( bought at >$6000 4 years ago ) to get a new bike at $8000. Wow, a $6000 bike only lasts 4 years!

    So, I have to replace the battery by myself. Please help me by telling me how to open the bike, get the battery out, change to Li battery if possible.

  6. Since Stealth Ebikes have come, & HPC ..opti has gone south..in sales..its no more opti!

  7. What happens. .if u just throw the old..& buy..new..battery bank & connect?? U could get for 4-500$..

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