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Luna softpack batteries basic FAQ

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  • Luna softpack batteries basic FAQ


    There are two connectors on the battery, one is for charging the other is the discharge connector. The small one (XT60) is for charging. The large one (XT90-S) is the discharge connector, this connects to your controller.

    If your kit has integrated controller such as a BBSHD or Magic Pie 5, then you would go from this XT90 to the motor, by cutting off whatever original connector was on there and putting on a matching XT90.* If your kit has external controller you would do the same but put the connector on the controller, and leave whatever wiring you already use for the connection between controller and motor. To make the connection you either crimp or solder the connection, or use heat shrink solder sleeves. Tools needed may include heatshrink, soldering gun/solder, crimper, lighter, and butt splices or solder sleeves.

    Crimping instructions

    Further crimping instructions

    Using heatshrink solder sleeves
    *(Alternately if your BBSHD comes with Anderson power connectors you can use our anderson-xt90 adapter for plug and play connectivity)

    You can use these butt splices to match the XT-90S large 12 gauge wire to a wire that is a bit thinner. These are known as step-down butt splices, and are specifically made for connecting different sizes of wire securely. It already has heat shrink tubing on as well, so afterwards just use a hair dryer and the connector will form a nice shrink seal on the wiring. For crimping the BBSHD motor to the XT-90s: use 12 gauge to 12 gauge butt splices if, because these are the same size wire. These also have shrink already on them, make sure to heat afterwards to seal it.

    The same basic idea applies to wiring up all batteries and kits, just make sure you have the right splices for the right size wire. If one set of wires looks bigger than the other use a step-down butt splice, if equally sized use a regular one, and if possible use the heatshrink type that already has shrink on it for the best seal when heating it.
    In a pinch you could also use wire nuts and wrap in electrical tape but this is not a reliable long term solution.

    Note: You cannot just twist the wires together and leave it wrapped in electrical tape, to do so is dangerous and may damage your battery by tripping the BMS as well as causing all sorts of potential performance problems. Fine for a quick test but do not leave it that way. If you choose not to use proper connections then in the very least use wire nuts along with dielectric grease.

    Notes: BBS02 kits have bullet connectors by default on the power cables from the motor. These need cut off to install the XT90 that matches your battery (or any other matching connector to the battery you have). Newer BBS02 kits may have Anderson connectors instead here, in which case you can use our xt90-anderson adapter. When using butt splices, you need bare wires on both the cradle and the motor, so make sure to cut off the bullet connectors if your kit has them, so you have bare wires.


    Sizing batteries for your frame

    It is important to ensure that you will be able to fit the battery into the frame before you buy it. It is recommended to create a cardboard mockup of the battery you are looking at ahead of time by taking the detailed dimensions available in the photographs of each battery listing, then putting that mockup within this space available on your frame and seeing if it fits, while also making allowances for whatever enclosure you are putting the softpack in, whether that is a battery bag or custom built hard case. If you buy the pack anyway and it does not fit, Luna can take a battery back if it is completely unused, recently bought, brand new, and you pay for the shipping. After processing and inspection of the battery to ensure that it is new and unused you would then get store credit to buy whatever you need.

    Basic info:
    How long should i leave the pack plugged in?
    Well you should leave it plugged in until it is charged or maybe a little bit before it is fully charged, optimally you want it to be within a range of voltage/charge percentage equaling something like 80 to 90%, perhaps a bit lower if storing for a long time such as over the winter. This will optimize it for the longest amount of cycle life. You can still charge to 100% right before a ride though as this does not negatively affect the cells much, it is more about not leaving the cell at 100% for a long period of time than about never letting it reach that charge level.
    How do i know when it is fully charged? Are there things I can do to best care for the battery and prolong its life?
    If your battery has a voltage display on it then you can tell that is fully charged based on the voltage readout, we have charts on every listing for each type of battery pack showing what voltage equals what the charge percentage. You can also test the voltage with a multimeter directly from the discharge connector. You can best care for the battery by not running it all the way down to zero, for the best use of it you really want to keep it above 20%.
    Why does my charger have a different voltage than the battery listed on the label?
    The voltage listed on your battery is just the nominal voltage, it actually goes higher and lower depending on the charge. The charger outputs at the highest voltage that the battery would reach when fully charged. See the chart on the listing for your particular battery and look at the 100% voltage level, that is about the voltage it should be charging at.
    Using multiple batteries in parallel?
    Parallel batteries means having two of the same battery joined together with an adapter to double your capacity. While useful it can be tricky. See this link for info.
    What is the small white plug that is sometimes on the battery
    This is a plug for a voltmeter display. We don't always have the display in stock so it may not be included, when we do have it we include it.
    Tips and tricks
    Do NOT throw away the box and packing the battery came in, the one with the hazmat warnings. At least for the first month or two.

    When the xt60 charging connector is not in use it is advisable to keep it covered in a piece of electrical tape to prevent it accidentally shorting out on something.
    For best performance be sure to check out our post on charging new packs!


    What do I do if the battery is dead, multimeter shows no voltage at discharge connector?

    Often if this happens it is due to the anti-spark feature built into the BMS. Say you did not properly make a connection somewhere and the wires sparked, the BMS would shut itself down to prevent damage to the system. If this happens the first thing you always want to do is to try resetting the BMS by using your charger to try charging through the battery's discharge connector for a few seconds, maybe a minute. You just run a jumper (basically regular wires) from the connector on the charger to the discharge connector on the battery, making sure you go postive>positive and negative>negative. At Luna we call this jumpstarting it. You should not have to do this very long, just a minute should be fine.
    Sparking when plugging in the charger?

    Make sure you are plugging charger into the wall outlet (so the charger is powered up) before plugging charger into the battery. Otherwise it may cause an inrush of current from battery to capacitors in the charger unless capacitors are already charged up from the charger being plugged in.

    further troubleshooting:
    Troubleshooting your battery and charger

    how to test a bms:​

    how to replace a bms if need be:

    How to replace BMS on a battery

    other link to BMS swap:

    How to swap BMS on a frame pack lickity split

    How to open a softpack
    Last edited by Sebz; 4 weeks ago.