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Luna hardcase batteries basic FAQ

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  • Luna hardcase batteries basic FAQ


    When talking about installation of a hardcase pack what we are really focusing on is the cradle. We want it securely mounted and we want a good connection between the wires going from the cradle to the controller (or directly to the motor in the case of kits with integrated controllers like BBSHD and Magic pie)

    Sizing batteries for your frame

    First off think about how you want to mount this pack. Will it fit in your triangle, should you mount it upside down within the triangle, on a rear rack, or even on the underside of the downtube. Next look at the current position of the water bottle bosses (the holes for mounting a water bottle on your bike). Is this suitable? If not you can drill holes into the cradle to make it work, taking care to avoid any wires when doing so. You can also put new holes onto your bike if need be, either with rivnuts or simply letting your local bike shop do that for you.

    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. A hardcase battery also needs a bit of extra clearance for getting it in and out of the cradle, roughly 0.5-1" depending on the pack. Shark, Dolphin and Killer Whale require 1". Jumbo Shark requires 0.5".
    Shark unmounted from cradle then fully mounted into cradle:

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    If you buy the pack and it does not fit, Luna can take a battery back if it is completely unused, 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. Please note that due to hazmat regulations it may not necessarily be easy to send it back, and this is your responsibility to do so if needed.


    Next is to connect the wiring to your controller. You can either put matching connectors on cradle/controller, or you can hardwire them together. Hardwiring them would take slightly less time but it would mean you would not be able to disconnect the cradle at that point ever. On the other hand it is one less point of failure if you do not have a connector there. Either way the methods are the same, 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. We do not recommend soldering since it is the most difficult, the easiest (and cheapest) being solder sleeves, the next easiest is crimping.

    By default the hardcase battery cradles come with no connector.* So let's say you want to put an XT90-S with pigtails onto the bare wires of your cradle, and you already have a crimper.

    You can use these crimps to match the XT-90S large 12 gauge wire to the hardcase cradle battery wire that is a bit thinner (about 14 gauge). 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 crimps, because these are the same size wire. For crimping BBS02 wires to a shark pack cradle after cutting off the original connectors on both sides, you can use these 14-16 gauge heatshrink crimps. 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.

    Notes: BBS02 kits may have bullet connectors by default on the power cables from the motor. When using butt splices you need bare wires on both the cradle and the motor, so make sure to cut off the bullet connectors so you have bare wires. If buying a bottle battery the wires are often in the cradle:
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    *The exception to this is BBSHD with shark packs, which is plug and play


    The features of a hardcase pack varies depending on which one you get but all share some similarities. Often this includes a keyed lock which locks it on to the cradle, a button you can push which gives a vague indication of battery charge, a charge port that uses a barrel or XLR connector, and recessed contacts on the bottom which connect with the cradle to form the connection. Additionally on some of the newer designs you may find a USB port or even a small switch on the bottom which can turn the pack itself off. WARNING: To avoid power surges do not leave a device plugged into USB while plugging and unplugging from charger/cradle as this may damage your device. While these features can be nice, please keep in mind that nonessential extras are a freebie and cannot be supported by Luna Support to the extent that the battery itself can. (if for example the USB module gets damaged this module is not repairable because no replacement module is available) You can test voltage on usb port with this guide.

    For best performance be sure to click this link on charging new packs!


    Since the pack is rather heavy it is recommended that you reinforce the pack in a variety of ways.
    There are many points on the cradle where you could potentially put new holes to run zipties around the downtube to increase rigidity, this is a good idea especially for the heavier packs.

    You could also use hot glue on the downtube (on both sides)to get a better platform to secure the cradle and battery, this will reduce the amount of side to side movement.

    Additionally on many packs (Shark) you will see that the pack itself is held to the cradle with a series of small plastic tabs. These tabs are exposed to a lot of stress over time. You may consider putting a light coat of epoxy over them to reinforce here. A great addition when riding is to use heavy duty velcro straps and wrap around both battery pack and downtube, effectively strapping the pack tight in place. This can be a good idea if your primary use is over rough terrain.
    Another approach is to make your mount through the metal on the cradle for a more rigid mounting:
    How long should i leave the pack plugged in?
    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?
    If your battery or charger has a voltage display on it then you can tell that is fully charged based on the voltage readout, there are also voltage displays and simple voltmeters. You can also test the voltage with a multimeter directly from the discharge connector. See below for a rough estimate of how voltage equates to charge percentage, keep in mind these are estimates and not guaranteed, it may vary depending on age of battery and how it has been treated.

    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 t him he highest voltage that the battery would reach when fully charged. See the chart above for your particular battery and look at the 100% voltage level, that is about the voltage it should be charging at.
    How to handle XT60 charger adapters?

    This is a standard xt60 barrel adapter. Replacements sold here. Treat it delicately and don't let it hang off the bike. For example keeping the battery on a surface where the cable can also rest.
    Are there things I can do to best care for the battery and prolong its life?
    You can best care for the battery by not running it all the way down to zero, for the best care of it you really want to keep it above 20%. This is where having a large capacity battery is great because you will not be putting it through such a high depth of discharge, thus increasing its cycle life. Another way of caring for the battery is to make sure you use the right type of cell for your application, and if you are using a cell not designed for high amps, try not to pull too much amps from it. So if you are for example using an NCRB pack designed for range, if you want max cycle life maybe don't use it for a high performance application that would be better suited for a cell like GA or 30Q. Ideally you also want to be storing your batteries at about 50% capacity, only charging to 80% of capacity and discharging to 10% of capacity, while taking time to sometimes charge all the way to 100% for 1 or 2 cycles every month in order to keep it balanced since it will only do balance charging when it is at 100%.
    Why does my voltage drop after a full charge?
    All lithium batteries have a little voltage sag from where they are when fully charged. The amount of sag is proportional to the number of cycles and how much its been through (heat, repeated deep discharge, pulling more current than the stated continuous discharge rate, age)
    Store your batteries somewhere dry at room temperature. Storing at freezing cold temps will drain the pack of power. You may need to balance the pack a few times if you have kept it stored for an extended period of time. You can do this by draining the battery a small amount then charging to 100% until charger shuts off, do this a few times.
    Water resistance varies depending on the pack. Waterproofing may be improved on by sealing with liquid tape, silicone, dielectric grease etc around the edges of the housing and other potential points of water entry. See this link for details. The most straightforward thing would be to simply cover your battery with a plastic bag if it is heavily raining, if you have concerns.
    Tips and tricks
    If possible we recommend taking your keys to a local locksmith after you receive your battery and have a set of copied keys made from the original. This will help ensure that if you ever lose the original set of keys you have backups. We do not have replacement keys so doing this before you lose the original set is a good idea. A locksmith can probably make you a new set of keys by looking at the lock but it is probably more expensive and time-consuming for him to do so.

    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

    Other helpful links:


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

    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 discharge connector for a few seconds, maybe a minute. You just run a jumper (basically regular wires) from the charger's connector to the battery's discharge contact, making sure you go postive>positive and negative>negative. At Luna we call this jumpstarting it.
    Jumping your Luna Shark Battery Pack
    This link shows how the basic procedure is done. It is the same regardless of what type of pack you have, and which side is positive an negative is also the same regardless (assuming you have the pack facing the same position)

    The contacts on my bottle battery cradle seem a bit loose, what do? Cradle battery fix

    More troubleshooting:

    Jumbo shark and killer whale pack charging issues:

    Try this first:

    Unplug everything (charger from wall, charger from pack, pack from cradle, and charger adapter if you have one). Give the charger 30 seconds or so before proceeding.
    Select the % you want.
    Plug the AC male connector on the charger in the wall outlet.
    Unplug the battery from the bike, turn off the switch on the battery.
    Plug your charging adaptor to the battery (if you have one) if not just plug the charger in the battery
    Plug the XT-60 front the charger to the XT-60 of the adaptor. (again if you have a charging adaptor)
    Turn the power switch "on" for the charge (important)
    Once done unplug the charger and turn the switch off.

    NOTE: Some killer whale pack needs to be in the "off" position to be able to charge normally, it's due that some have a different BMS.

    If you still have issues:

    While the charger is connected, if the battery's on/off switch is cycled off then back on, the charger will start to charge. Ideally you just plug charger into the wall outlet then plug charger into pack with the pack switched in the ON position but there was a revision to the design so you may need to cycle the switch first. Also, after the battery is finished charging we recommend putting the switch into the off position or it will slowly drain the battery due to being in standby mode.

    How to test charge port on a hardcase battery:
    If your pack is not taking a charge but is discharging fine then most of the time the issue is with the XT60 barrel adapter. You can test by using a different adapter and plugging it into the charge port then testing for voltage with a multimeter by putting your multimeter leads into the xt60 (do not do this directly into the charge port). If you see voltage then the charge port is working and the issue is either your previous adapter or the charger.
    If you do not see voltage when testing with a new adapter open up the battery and bypass the charge port by testing the wires going to the charge port, pushing your multimeter leads through the insulation. If you now see voltage then the charge port is broken. You can fix by either replacing if a replacement charge port exists, or bypassing by crimping an xt60 onto the wires that were going to the charge port. .

    More info on troubleshoot charger
    Last edited by paxtana; 2 weeks ago.