LiGo Batteries (New!)
Grin's modular LiGo battery was born in response to the massive transportation restrictions placed on large lithium ebike packs. Properly certified batteries under 100 watt-hours are largely exempted from the dangerous goods shipping restrictions and are even allowed aboard passenger aircraft with your carry-on luggage. Why not use this as the building block that can be easily re-assembled into a large battery?
After much design consideration we decided to implement this as a flat 10s x1p 18650 cell layout, with every battery having its own independent BMS circuit and each pack being potted to protect against the elements.
In early 2014 we had a number of 10sx1p batteries made up with an overseas pack assembler running a basic BMS circuit and covered in shrinkwrap, using what were at the time state of the art 25R Samsung cells (for 92 Wh total). That proved the concept and let us validate the process of travelling on numerous international flights with our small battery modules, which were then stacked together on landing into a usable capacity ebike pack.
These little batteries proved useful not just on ebikes but also countless other projects too, from electric skateboards and unicycles that we took to events to portable power for camping trips and even LED boat lighting. However, we also hit many limitations with the imported units, ranging from environmental damage to randomly erratic BMS circuits to cell balancing issues. It became clear that we needed to take both the design and manufacturing in-house, and in 2016 this project picked up in earnest.
Our completed LiGo battery packs have more functions than you likely thought possible in a battery pack.
- Rugged fiberglass encased modules can withstand 5m drop
- Flat 20mm profile fits under skateboard decks, in small pockets etc.
- Design allow easy stacking edgewise and lengthwise
- Can readily stack in parallel for required capacity
- Can be series stacked for 72V without issue
- Integrated momentary push button for on/off and other functions
- (pending) Wireless ANT+ communication between modules, so they can be paired to behave like a single large battery
- Ultra low quiescent current drain (<2uA in ship mode)
- Bluetooth access to see pack usage history, set parameters, diagnostics
- Five embedded RGB LED's for SOC indication, wireless pairing, etc.
- No spark when plugged into capacitive loads
- Cell balancing at all voltages, not just full charge
- Over-charge and over-discharge current protection, short circuit protection
How They Work
Each battery has two pairs of + and - leads on them, which are terminated in Anderson Powerpoles. That allows you to easily plug a number of packs together in parallel, and when you are done you have two Anderson connectors left over. Typically one goes into the controller and the other could run lights or act as a charging port.
To turn the battery on, press and hold the button until the first LED goes green, then on releasing the button you will see the green LEDs light up all the way and show the batteries current charge level. The top LED will then show a green heartbeat pulse letting you know that the battery pack is on.
To turn the battery off, press and hold the button again until the first LED goes red. Then on releasing the button, an animation of red LEDs will scroll down telling you that the pack has turned off.
In order to turn on the bluetooth for connecting to a computer or phone to check battery usage history, adjust BMS settings, and upgrade the LiGo firmware, press and hold the button until the first LED turns blue (approx 3 sec). On releasing the button, you will see the blue LEDs wave out from the center indicating that the device is broadcasting and is discoverable. It will exit bluetooth mode after 2 minutes of no connection, or in response to a button press.
|Nominal Voltage||36.0 V|
|Nominal Pack Capacity||2.72 Ah|
|Nominal Pack Energy||98 Wh|
|Dimensions||201 x 74 x21 mm|
|Weight||610 g (1.3lb)|
|Cell Type||10s x 1p LG-MG1|
|Pack Resistance||350 mOhm|
|Discharge Current||10A continuous, 15A max*|
|Quiescent Current||400uA Operating, <2uA Sleep|
|BMS Cutout Topology||Common Charge/Disch Port|
*Final specification firmware will allow 15A burst discharge current, current release is 10A continuous.
Availability and Pilot Sales Program
At the moment, we are shipping LiGo batteries to qualified early adopter customers during our pilot release, and are especially looking for people who need to take advantage of their transportability where other battery options will not work. They are listed on our store page, with a limit of 2 batteries per shipment to keep in compliance with the April 2016 update to the dangerous goods shipping regulations, which reduced from 20 to 2 the number of 20-100Wh batteries that could be included in a box and still be exempt from full dangerous goods classiication.