Backup Battery



  • I ride almost exclusively on the beach. No random outlets along the way, thus my desire to develop a backup battery system I made good progress last night. I completely extracted the battery. This thing is well built! My original idea of using the charging port definitely will not work as a connection point for a backup battery. The battery reads 54.4v fully charged. This is baffling, as FM does say it is 48v and charger says 58v. The actual battery pack is composed of 4 12.8v battery packs (16 cells total) in serial which are labeled as being Li Ion (not LiFePo4 as they advertise). Perhaps they are the same thing, I'm not certain, and am just reporting what I see from the inside. Battery pack has a 3rd party part #266504S12 which I googled and came up with nothing. Here is a photo of the battery pack and cable: ![0_1464573825841_100_1894.JPG](Uploading 100%)



  • apparently I don't know how to post photos. Any suggestions?



  • Until I figure out how to post photos, I am going to make a NiCad battery pack to try as a test plug in backup battery pack. It should cost me below $50, as opposed to buying a $400 LiFePo4 pack only to find my idea does not work. I plan to run a pair of battery cables from inside the battery compartment through a cable gland similar to the one used by FM for the other cables which exit the sealed battery compartment. There is a perfect place for it opposite the location where their cable gland is, where the existing cable exits the battery compartment. From there I will be able to disconnect the stock battery, using the same connector types as they use, and connect my battery pack. IF that works, then I will refine it to perhaps an A/B switch which can switch between the battery packs, and/or ultimately contemplate connecting them both in parallel, making no battery switch necessary. Along the way I will be interested in observing how the iphone app reacts with my new battery connected.



  • @Count said in Backup Battery:

    The actual battery pack is composed of 4 12.8v battery packs ... labeled as being Li Ion (not LiFePo4 as they advertise). Perhaps they are the same thing, I'm not certain

    They are absolutely not the same thing! There are a mulititude of reasons that make LiFePo4 batteries far superior to Lithium Ion batteries, and advertising them as such would be pretty bad. So if these are indeed NOT LiFePo4, you've stumbled upon something pretty big. Are you sure that's what it says?

    Just the way they behave -- such as quick charging time, long life (in terms of how many times it can be charged before it starts to lose capacity), they stay cool while charging and discharging, they discharge at an equal rate all the way up until the end of each charge, etc -- make it difficult for me to believe that they're not the battery type Future Motion claims they are.



  • All I can tell you is what is on the sticker on the battery pack. The pack is 16- 2.5" green cells, shrink wrapped in a blue wrapping. On the pack is a sticker which reads:

    Li Ion Battery
    12.8V 6.9Ah 88.32Wh
    Part No. 266504S12
    Made in China

    I will try to remove some of the blue shrink wrap to reveal what is actually written on the individual green cells.



  • The individual green cells are double wrapped in reinforced strapping tape, and then blue shrink wrap. I am not willing to dissect the pack further to identify the cells at this stage as I am afraid I may damage it. Perhaps FM monitors these posts and will be willing to respond???



  • To upload a photo, upload it to a pic hosting site like photobucket or imgur or imageshack.us and then get the link but use the html code [img]url for pic here[/*img] just dont use the * and that should work

    Also if the battery isnt as advertised then this like Greck said is gonna be a huge huge deal.



  • I decided to try a YouTube video. It is my first one, so don't critique me! Turn the sound up some... link text



  • @count Am i the only one to be amazed that the battery is labelled 12.8v ? can you use a volt meter and check that?



  • @Tartopom The output of a fully charged battery reads 54.4v. The only thing I can think is that there are 4 battery modules, connected in series, within the battery pack. 12.8 x 4 = 51.2 volts, which falls between the advertised 48v and what I read, 54.4v. There are certainly some unanswered questions here!



  • @Count there is something wrong... because FM claims that the battery is around 116wh and I the sticker it is 83ish...



  • @Future-Motion Can you please chime in here? Lithium Ion is very different than Lithium Iron Phosphate, and it's false advertising if the type of battery in the Onewheel isn't what you've been claiming it is.



  • Possible explanation,
    usually it's 3.7V cells X 3, but they do make 4.2V Li-ion cells.

    4.2 X 3 = 12.6V X 4 = 50.4V , upward 54V when fully charged.



  • @thegreck - Im very curious to see what comes of this - I've been trying to understand the battery life difference between my two boards. With all other variables remaining constant (tire pressure, rider, route) I have a 10-12% delta on one board. I'm wondering if my 'shorter life' board has an imposter battery. Depending on what we learn from this discussion - I just might have to pull them apart to put eyes on...



  • @D-Wave @Future-Motion We hope to get a response quick since rumors(true or not)/reputation consequences might taint the company for a long time.



  • @DrN3RD - you're right. I certainly don't want to come across like I'm jumping to conclusions - or bashing FM, that is not my intent. I'm a huge fan and wouldn't give up my boards for anything...however - being a geeky engineering type - this has definitely piqued my curiosity...





  • @DrN3RD I believe I have fount the battery manufacturer... and although at first glance it portrays itself as li-ion, further reading is indicative of a LiFePo system

    http://www.a123systems.com/lithium-ion-cells-26650-cylindrical-cell.htm



  • @DrN3RD So after digging some more. I have found these patent related statements

    For example, power supply xxx may include sixteen (16) A123 lithium iron phosphate batteries (e.g., size 26650). The batteries of power supply xxx may be arranged in a 16S1P



  • @D-Wave Probably the delta come from the fact that the batteries capacity can vary from 6600mah at the lower range to 6900mah for best ones, so I guess it's where the delta come from...


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