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The Best Battery Possible for Your BBSHD

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    The Best Battery Possible for Your BBSHD

    How would you like to increase the power of your BBSHD without any modifications to the motor?

    Very simple, just install a 15s battery...there are a multitude of benefits and I haven't thought of a downside at all.

    Why 15s...well the BBSHD will not operate on a battery above 60v without changing or modifying the controller. A 14s battery tops out at 58.8v and a 15s would go over 60v if fully charge but the benefits of only charging to 4.0v per cell or 60v are maximum voltage and wattage to the BBSHD as well as a lot longer battery life than if you charged a 14s pack to 100% pr 58.8v.

    Now with lithium batteries you don't want to charge them too high or discharge them too low so if you use a max charge of 4.0v per cell and discharge the pack to 3.49v per cell or approximately just about can't be any nicer to your battery unless you never use it. If you have a 15s8p pack and run it between 4.0v and 3.49v, you have about the same capacity or amp hours/watt hours as you would with a 14s6p pack running it from 100% to 25% or 4.2v per cell to 3.49v per cell. Just FYI, 3.49v is roughly 25% for a lithium battery and 4.2v is approximately 100%. The worst thing you can do to your lithium battery is charge it to 100%...well even worse is charge it to 100%, leave it there. In addition, the higher the temperature the worse it is for your battery...that is how I convinced my wife to let me leave my bike in the living room :D ...she is definitely a keeper.

    The optimum voltage for a lithium cell is 3.92v per cell so the closer you can stay to 3.92v, the longer your battery will last. Most of my battery info comes from this site:

    So no modifications to your BBSHD are required, just install your new 15s battery and get 1800 watts of power. Since the BBSHD is amperage limited and not wattage limited you want to run the voltage as high as possible without going over 60v to get the maximum power.

    Now just if someone would commercially produce a 15s pack....a 16s pack is available but remember you want to stay as close as possible to 3.92v and a 16s charged to 60v would give you 3.75v per cell. You also don't want to go below about 3.49v per cell...I am taking things to an extreme by the way with most of my recommendations. The number of parallel strings could be tailored to match the capacity you need, I just used an 8p pack because it will be real close in size and weight to a common 14s9p battery. The 14s9p has 126 cells (14x9) and a 15s8p has 120 cells (15x8)...the 15 is the number of series strings and 8 is the number of parallel strings. The number of series strings determines the voltage and the number of parallel strings determines the capacity (amp hours/watt hours).

    Yep, I am going to be first in line when there is a 15s8p pack available with 30Q cells. The 30Q cells are currently one of the best high power cells (high amperage) but that will probably change by the time I hit the "Submit" button with the way technology is rapidly advancing.

    I liked the article. Based on it, would this be a good project?
    BMS correct: 15S 48V 30A
    Number of batteries: 15x5 = 75
    Battery Suggestion: Sanyo 18650 GA 3000mah 10A (Red)
    Capacity: 3,000 x 5 = 15,000mah
    Correct charger: 58.8V / 1.5A (before the BBSHD limit, which would give 3.92V per cell)
    Maximum pack voltage: 63V (4.2V x 15S)
    I've read a lot about 18650 batteries, but I'm new to it. Can someone help me with this project?


      romarks...just saw your post. You need to match the motor, the controller, and the battery so everything works together well. Assuming you go with a BBSHD, the internal controller will not work with a battery above somewhere in the 60-62 volt range. Not sure exactly what the cut off is but it is above 60 a little bit. If you are running the stock controller for the BBSHD, it will only put out 30A and the cells you choose could be less expensive and have more capacity (Amp Hours) than the GA cells. The GA cells are relatively high amperage and they are good cells...there are just some that put out less amperage and have more capacity and cost less. If you build a 15s battery, you can NOT charge it fully and use it with a BBSHD...that is sort of the beauty, just charge it to about 60 volts and then you have more speed from the higher voltage than a fully charged 14s battery and your batteries will last longer because you don't charge them to 100%. See this article about Li battery life:

      Your capacity is determined by the total number of cells as well as which cells you use so a 15s may or may not have more capacity than a 14s all depends.

      If you are running a MAC or other hub motor, there are a bunch of controller options but two categories sort of divide a large portion of them....those that use 4110 FETs and can handle higher voltages and those that use 3077 FETs and are limited to about 60 volts. The 3077 FETs are more efficient...i.e. produce less waste heat but can't handle higher voltages so it just depends on what your overall objective is.

      Hope this helps a little :).