No announcement yet.

Luna softpack batteries basic FAQ

This topic is closed.
This is a sticky topic.
  • Filter
  • Time
  • Show
Clear All
new posts

    Luna softpack batteries basic FAQ

    Luna softpack and fusion battery basics

    It is important to regularly check the discharge contacts to make sure nothing is bent out of shape or covered with debris or caked road salt, to ensure proper flow of power.
    How do i know when it is fully charged?
    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 this page 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.

    When charging the Battery Management System (BMS) monitors the pack so individual cells do not go over 4.2 volt. (High voltage BMS cutoff is 4.25-4.3V)

    A fully charged 52 volt pack is 58.8 Volts.
    A fully charged 48 volt pack is 54.6 Volts
    A fully charged 36 volt pack is 42.0 volts
    A fully charged 60 volt pack is 67.2 volts
    A fully charged 72 volt pack is 84.0 volts

    Maximum charge current
    3 amps or lower for the mini 30Q cube
    3 amps for any 10ah made of PF cells
    5 amps for the 10/12.5ah w/ 25R cell 5 amps for any other soft pack over 12ah
    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.
    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.
    Click image for larger version  Name:	36.png Views:	3 Size:	64.4 KB ID:	46245
    Click image for larger version  Name:	48.png Views:	1 Size:	63.6 KB ID:	46246
    Click image for larger version  Name:	52.png Views:	3 Size:	63.1 KB ID:	46247
    Click image for larger version  Name:	60.png Views:	3 Size:	63.9 KB ID:	46248
    Click image for larger version  Name:	72.png Views:	3 Size:	64.3 KB ID:	46249
    See above for a very rough estimate of how voltage relates to charge. These numbers are not a guarantee of real world performance but intended for educational use only
    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 (plug is only present on some models). We don't always have the display in stock so it may not be included, when we do have it we include it.
    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 a 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 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%. Please see the "essential reading" links above for more details.
    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).
    Other times you may see sag is when pulling a lot of power from the pack, especially when the charge is getting low on the pack. Please see this link for a more thorough explanation of voltage sag.
    Store your batteries somewhere dry at room temperature. Storing at freezing cold temps is fine as long as you heat it up slowly before charging. 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 but no battery is entirely waterproof. 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 sealing the battery with RTV and put it in a bike bag with sealed zippers, if you have concerns. Do not use if water can get in contact with the battery. Also see this link
    Also if you expect very heavy water exposure it is highly recommended at a minimum to use dielectric grease on discharge and charge contacts.
    Do not expose your pack to ocean water or road salt, if you absolutely must do this make sure that the battery is protected and that you are using dielectric grease on the discharge/charge contacts.

    For an in-depth discussion on this topic please check out this link
    Tips and tricks

    CRITICAL: Never ever attempt to charge a frozen Li-Ion battery that is under 32 deg F (or 0 deg Celcius) Below freezing permanent damage will occur if you try to charge your battery pack. If your pack is frozen bring it inside your house and let it sit for a few hours till the battery is over 50F (10C)
    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, advisable to keep it protected to prevent accidentally shorting out on something. (If your battery is a fusion pack it does not deliver power on the pack's charge port except when plugged in, so this would not apply)
    • When charging is complete, unplug charger from both battery AND outlet. Charger needs to be unplugged from outlet to reset it to a new charge cycle.


    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. Dimensions on listing may slightly vary across production runs.



    There are two connectors on the battery, one is for charging the other is the discharge connector. The small one (XT60) is for charging (in the case of fusion packs it uses Rosenberger). The large connector (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. (Note: BBSHD uses Anderson connectors which can be plug and play using our XT90-Anderson adapter) 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 use heat shrink solder sleeves. Tools needed may include heatshrink, soldering gun/solder, crimper, lighter, and butt splices or solder sleeves. (
    Soldering is also an option, we do not recommend soldering since it is the most difficult, the easiest (and cheapest) being solder sleeves, the next easiest is crimping)
    Crimping instructions Further crimping instructions
    Using heatshrink solder sleeves Solder sleeves more info
    Other alternatives Posiloc connectors (mostly for smaller wiring)
    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.
    Click image for larger version  Name:	connectors on bbs02.png Views:	1 Size:	25.6 KB ID:	45960
    See above for an example of default BBS02 bullet connectors you would remove for replacing with XT90 connectors. When using butt splices or solder sleeves you need bare wires on the controller, so make sure to cut off the bullet connectors so you have bare wires (verify which is the power wiring if you are uncertain)

    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. If using a solder sleeve you do not need a step down connector, just carefully heat it until solder melts and connection is secure. It takes a bit more time on larger wire and you may want to practice beforehand on a spare length of wire.

    In a pinch you could also use wire nuts and wrap in electrical tape but this is not a reliable long term solution and not recommended for anything except bench testing. The same is also true of other connectors like WAGO, which are good but not for high current applications.

    Softpacks can be reinforced a variety of ways to enhance impact resistance. Padding and custom enclosures are a very good idea to prevent damage from regular use, taking pack on jumps, dropping the pack, or dropping the bike. Regardless of what steps you take, protecting the battery is your responsibility and should be taken seriously. (note: on fusion packs they are already very well reinforced)

    Custom enclosures can take time and money, here is one way to toughen up the pack easily.


    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.
    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)
    How to charge through discharge (jumpstart)
    How to bypass battery system for troubleshooting by using charger to power the kit
    (if you have a standard charger you need a female barrel to xt60 adapter. if you have a Luna charger just go from the xt60 to the controller)
    How to load test a battery to check if it cuts out.
    More troubleshooting:
    Last edited by Sebz; 10-15-2020, 09:31 AM.