Freefly Battery Interface

Freefly Superlight batteries use the Pixhawk Battery Interface, an open standard the we helped create! Freefly SL Series Interface Standard is linked here and should be used by anyone who wants to integrate the SL batteries into your own hardware solution.

For mechanical integration, here are the CAD files: SL8 and SL4

If you have any questions on this specification, please let us know.

Configuration

Safety and Warnings

1. Read the safety instruction and warning before using or charging this lithium ion battery. Improper use may result in severe personal injury or fire.

2. DO NOT disassemble, puncture, shock, crash, short, or put the battery into a fire.

3. Only use an approved Freefly charger. An unqualified charger may cause a fire. DO NOT charge the battery above 4.2 volts per cell. DO NOT exceed 2C charge rate.

4. Store and charge the battery in a fireproof container in a cool or shaded area and in a safe place that children and pets cannot access. DO NOT leave the battery in a vehicle. DO NOT expose the battery to direct sunlight for extended periods of time or place in direct contact with liquids.

5. DO NOT discharge battery with current exceeding the max discharge current. It will cause the battery to overheat and may result in battery deterioration, swelling, bursting, or fire. Always discharge in a fireproof location.

6. STOP USING OR CHARGING the battery immediately if it swells, leaks, or its temperature exceeds 140F (60C) or anything else abnormal occurs.

7. In purchasing this product, the buyer/user agrees to bear all responsibilities of these risks and not hold Freefly Systems, its owners and employees, its distributors, and/or its retailers responsible for any accidents, injury to persons and property damage. If you do not agree to these conditions, please return the battery to the place of purchase.

Limitations of Liability

IN NO EVENT SHALL FREEFLY BE LIABLE TO BUYER FOR ANY INDIRECT, CONSEQUENTIAL, PUNITIVE, INCIDENTAL, OR SPECIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF SUPERLIGHT BATTERIES OR FROM LOSS OF USE, DATA OR PROFITS (HOWEVER CAUSED AND UNDER ANY THEORY OF LIABILITY), EVEN IF FREEFLY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. IN NO EVENT SHALL FREEFLY’S LIABILITY FOR A PRODUCT (WHETHER ASSERTED AS A TORT CLAIM, A CONTRACT CLAIM OR OTHERWISE) EXCEED THE AMOUNTS PAID TO FREEFLY FOR SUCH PRODUCT. NOTWITHSTANDING ANYTHING HEREIN, IN NO EVENT SHALL FREEFLY’S LIABILITY FOR ALL CLAIMS ARISING OUT OF OR RELATING TO THIS AGREEMENT EXCEED THE AMOUNTS PAID BY BUYER TO FREEFLY FOR PRODUCT IN THE LAST TWELVE (12) MONTHS. IN NO EVENT WILL FREEFLY BE LIABLE FOR COSTS OF PROCUREMENT OR SUBSTITUTE GOODS BY BUYER. THE LIMITATIONS SET FORTH HEREIN SHALL APPLY TO ALL LIABILITIES THAT MAY ARISE OUT OF THIRD-PARTY CLAIMS AGAINST BUYER. THESE LIMITATIONS SHALL APPLY NOTWITHSTANDING ANY FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.

Freefly shall not be liable for damages or injuries incurred directly or indirectly from the use of SuperLight Batteries including, but not limited to, the following situations:

• Failure of the operator to follow proper instructions and safety warnings found at www.freeflysystems.com.

• Failure of the operator to understand and operate SuperLight Batteries within the operating limitations described in this manual.

• Failure of the operator to follow safety warnings while using SuperLight Batteries.

• Failure of the operator to follow and comply with local rules and regulations.

• Failure of the operator to follow and comply with the local battery transportation law.

• Failure of the operator to inspect SuperLight Batteries prior to operation.

• Failure of the operator to properly maintain SuperLight through an authorized Freefly Service Center with genuine parts.

• Use of SuperLight Batteries in a physically or mentally impaired capacity.

• Use of SuperLight Batteries in unsafe conditions, including but not limited to, bad or severe weather, such as rain, wind, snow, lightning, dust storms, etc., or in areas of magnetic or radio interference, such as power stations, broadcasting and cell phone towers, government prohibited airspace, etc.

• Improper operation, misjudgment or risky behavior while using SuperLight Batteries.

SL8 Firmware v2.1

• Summary: SL8 bugfixes and improvements

• Release Date: August 2024

How to Update

• Open this website on a computer and follow instructions -> freeflysystems.com/sl8_v2-1

Release Notes

• Improved State of Charge (SOC) Estimation:

  • This is an important feature that addresses a critical weakness of the old firmware, where a battery could suddenly report 0% in flight, triggering critical fail safes on Astro.

  • Coulomb Counting SOC Estimation: If a fuel gauge error is detected, the system will now switch to Coulomb counting for SOC estimation. This ensures more accurate battery monitoring in case of fuel gauge issues.

• Expanded Operating Temperature Range: The operating temperature requirement has been reduced from 10°C to 0°C, allowing the battery to function in colder environments. This feature requires the new State of Charge (SOC) estimation method.

• Active Cell Balancing: A new feature has been added to perform active cell balancing during the battery’s transition to standby mode. Previously, cell balancing only occurred while the pack was charging. Now, if the cells in a pack are out of balance (exceeding a 10mV threshold) when the pack attempts to enter standby mode, the system will instead turn off the display and shift into a low-power run mode. In this mode, the battery continues to balance the cells until they are within the acceptable threshold or for a maximum of 10 days. Once the cells are balanced or the time limit is reached, the battery will then enter true standby mode. This extended balancing process ensures more consistent performance and longer battery life.

• Enhanced Security: A new lock-out feature has been added to enhance security. This ensures that unauthorized access to the command line interface (CLI) is restricted.

• USB and Standby Mode Improvements: A timer has been added to delay entry into standby mode for 10 seconds after the USB cable is unplugged, allowing users to switch the cable to another device without the battery powering down.

• Alarm System Update: The alarm buzzer will now activate immediately upon detecting a fault, addressing the previous delay caused by timer setup issues.

Health and Lifecycle

SuperLight Batteries display a Health percentage value, called State of Health (SoH).

State of Health is expressed as a percentage of the ratio of predicted Full Charge Capacity (calculated at 25°C) over the Design Capacity (nominal capacity of a new pack).

Best practices

To get the most out of your SuperLight packs there are a few things that you can do to improve performance and longevity.

Temperature

Li-ion batteries operate best around room temperature. This means you will get more flight time out of the pack, and less capacity loss over the life of the pack. When able to, we recommend charging your packs after they have cooled from flight, at room temperature for the best longevity.

Storage

To store your batteries for long periods of time (months or years) we recommend charging them up to around 50% SoC.

Lifecycle

SuperLight batteries typically have a lifetime significantly longer than 500 cycles. We have tested them to over 1000 cycles with greater than 80% capacity remaining.

Over time the batteries will lose some capacity, however, they can continue to be used as long as desired with lower capacity.

Superlight batteries should be disposed of in accordance with local regulations on battery and electronic waste.

Hard Reset

In the event that the firmware locks up or an unforeseen issue occurs, there is a method that allows resetting the battery controller. Note, you should not use this in normal operation - it should never be required. That said, if it is unresponsive, you can try this method to reset the battery. Push and hold until the display goes blank, then release the button (approx 15 seconds). The battery will restart.

Firmware Update

Checking The Battery Firmware

Tap the button on the SL battery while it is powered off to check the current firmware version.

Fault Codes

The Health screen will show fault codes. If there are multiple fault codes the fault screen will scroll through displaying them.

Some faults are latching, and require that a user ejects them from the system re mounts them to try again if the issue has been resolved.

Cleaning

Keep debris and moisture out of connectors.

Safety

Use only Freefly SL8 Fast Chargers.

Make sure someone is nearby while batteries are charging. Do not charge batteries unattended. Place the batteries in a fireproof container for charging and storage.

DO NOT charge the battery above 4.2 volts per cell. DO NOT exceed 1.5C charge rate.

Charging Time

SL8-Air batteries charge from empty in about 90 minutes.

Firmware v1.9 gives a conservative charging time estimate. Actual charging times can be faster than the time shown on the display.

Temperature

The charging temperature range is 0 to 50 C°.

• If a charger is connected while the battery is too hot or cold to charge, the battery will not charge and an error message will be displayed. If the charger remains connected to the battery, charging will begin automatically when the battery cools/warms sufficiently.

• In cold environments: If charging begins while the pack is above 0 C°, the heat of charging can be sufficient to keep the pack warm enough to charge even if the ambient temperature is lower.

• In hot environments: Charging will stop when cells get to 50 C° and restart charging automatically at 45 C°.

Capacity and Voltage

Transport

Airline Travel

Please consult local regulations.

Detail of FAA regulations here:

• https://www.faa.gov/hazmat/packsafe/more_info/?hazmat=7

• https://www.faa.gov/hazmat/packsafe/resources/media/Airline_passengers_and_batteries.pdf

Shipping

We’ve found that FedEx provides the easiest path to ship batteries. Their website has a search tool to find FedEx locations that can accept batteries can be found good shipments, go to https://www.fedex.com/locate > More... > Dangerous Goods Shipping > and Search in your area.

If you’d like to pack the batteries yourself, guidelines can be found in the UPS guide to safely packing batteries. Refer to the Lithium batteries section (SL batteries are classified UN3481). These guidelines are universal across shipping providers.

Battery Management System

Each SuperLight pack has a built-in Battery Management System (BMS) that manages charging and discharging. As a result, the experience of using SuperLight Batteries is similar to using a smartphone or laptop computer battery, rather than a hobby-style lipo pack.

User Interface

Press the button once to check state of charge. Press again to turn on the battery.

Press the button to cycle through top-level screens. Hold for detail, when available (see table below). Press to return to top level.

Standby: When a battery is ejected from a device, it will automatically enter standby. After 30 seconds of inactivity, the battery will revert to standby automatically. To activate standby manually, press and hold the button.

Display Navigation

States

• Standby: This is a low power state where the screen is turned off and the batteryt will consume less than 100uA.

  • Deep sleep: The battery enters a mode called ship mode when it has been discharged to a minimum voltage level (2.7 V). It will consume less than 10uA in this mode, and should allow the cells to last for 3 years or more.

• SoC: This is a quick display screen that shows battery percentage, as well as the firmware version number. Batteries will go back to standby after 5 seconds.

• On

  • ID Sense: In this state the batteries are searching for a smart host, such as Astro

  • Hotswap: In this state the batteries are active and are supplying current to a smart host, such as Astro

  • Enabled: In this state the batteries are active and are supplying current to a passive host, such as Movi Pro SuperLight Battery adapters

• Airmode: When a smart host, such as an Astro, commands batteries to go to Airmode, SuperLight batteries will bypass all protections and provide power without any interruption. If there are any faults during a flight, error messages will be displayed, but the output will not be affected. Once batteries are commanded to leave Airmode, protections reactivate, thus batteries may shut off to protect themselves.

USB Power Output

The USB-C port offers Power Delivery, which means the SuperLight battery will negotiate with a connected device to send power at a voltage best for your device. It will provide up to 60W power. For instance, it will charge your:

• Macbook Pro

• iPhone

• iPad

• Astro Controller

How to use:

• Plug USB C cable to battery and other end to a device you want to charge.

• Turn on the battery to start charging the device.

• You can also press to cycle through screens until you see the USB screen to see more details about the USB charging state.

• Simply remove the USB cable from the battery and the battery will power off automatically.

Weather and Temperature

Temperature

Specified ambient operating temperature is -20°C to 50°C.

• Note, the battery temperature may be significantly different than the ambient air temperature due to thermal mass of the cells. They take a significant amount of time to change temperature.

• Cells heat during discharge, especially during flight. The amount of heating is heavily dependent upon starting temperature, discharge rate, etc. 30 degrees C of heating during a flight is common.

• Batteries perform optimally around room temperature. If possible, keeping them near room temp before use is encouraged, but not required.

• Cold Operation:

  • Charging: If the battery cell temperature is less than 0°C and charging is attempted, the battery will display a fault ("Under Temp Chg") and not re-allow charge until the temperature is raised above 5°C.

  • Discharging: If the battery cell temperature is less than 10°C and discharging is attempted, the battery will display a fault ("Under Temp Dsg") and not allow discharge until the temperature is raised above 15°C.

• Hot Operation:

  • Charging: If the battery cell temperature exceeds 50°C during charging, the battery will display a fault ("Over Temp Chg") and not re-allow charge until the temperature is lowers below 45°C.

  • Discharging: If the battery cell temperature exceeds 70°C during discharge, a warning will be triggered telling the operator to reduce output and land or halt battery use ASAP. If the battery cell temperature exceeds 80°C during discharge, the battery will display a fault ("Over Temp Dsg") and not re-allow discharge until the temperature is lowers below 60°C.

Weather

SuperLight batteries are water resistant. Not for submerged use. Not for use in salt spray or water.

The connectors cannot be mated while wet. Water must be blown out before mating the connectors.

If you fly in rain, it is important to ensure you dry the pack off before attempting to plug into it's USB-C port or to plug the pack into a charger. Blow out the connectors to ensure you don't trap any water inside.

SuperLight Lithium-ion batteries are designed and manufactured by Freefly. They work with any device that uses the Freefly Open Battery Interface: Astro today, others coming soon.

Every pack has a built-in Battery Management System (BMS) and OLED screen. The BMS manages discharging and charging without balance leads, and applies many protections during charge and discharge to improve safety, diagnostics and performance. They also include a critical flight mode which limits protections in order to prevent false power cutoff while airborne. The OLED screen gives detailed information about pack status, like state of charge, voltage, current, temperature, life time statistics, etc. The USB-C port can charge devices (such as phones, computers such as MacBookPro, etc) that support USB Power Delivery from 5V up to 20V with 60W.

On July 13th, 2024 Freefly released a service bulletin recommending that customers install ESD stickers to mitigate the risk of damage from ESD into the SL8 heatsink. ESD stickers can be ordered for free here.

1. Wipe the heatsink and front surface of the SL8 with the included alcohol wipe

2. Let the alcohol fully dry. This can be sped up by dabbing the alcohol with a lint free cloth.

3. Apply the ESD sticker to the battery as shown.

   1. Remove the backing from the ESD Sticker and discard it.

   2. Align the cutouts in the sticker with the User Button, OLED Screen, and USB Port on the battery and lightly tack it into place.

      1. You may need to lift the USB cover to pass it through the sticker.

      2. If things are not aligned you can gently remove and reapply the sticker for better alignment.

   3. If the sticker aligns well with the UI features, fully adhere that area of the sticker then work downward towards the battery connector applying the remainder of the sticker.

   4. Apply pressure around all of the ESD Sticker's edges to finish the application process.

4. When correctly applied the SL8 Battery should look like the image below.

Freefly SL batteries are covered by Freefly's warranty for 1 year or 500 cycles (whichever happens first).

The warranty covers:

• Manufacturing defects

• Functionality failures

  • Does not charge/discharge

  • Screen does not work

  • Displays permanent Error Code

  • Displays repeated Error Code under normal usage

Warranty is void if any of the following criteria are exceeded:

with any questions or warranty claims.