Thank you for purchasing your very own Fractal Engineering
Whoop Juice Transfer Station, the first 1S balance charging board with selectable cell count!

While I’m very sure you’re most excited to plug in everything and charge all the things, there are a few rules I want you to know so that you may do it safely; for your lipos, your own and your
house’s sake.

  1. This is a balance board, not a parallel board.

This means all cells are in series, therefore no need to multiply the amount of cells by the charging current. If you’re charging 300mAh lipos, set your charger to 0.3A for 1C or 0.6A for 2C. NOT 1.8A!

  1. Only use 1 jumper in the position you want to use

The header has 6 columns and 2 rows. It allows you to close the circuit after the last lipo you plug in. Example: if you want to charge only 4 lipos, place the jumper on the 4th column.
Very simple. Please do not ingest the jumper or plug it horizontally. This kills the jumper.

  1. Only charge together lipos of same capacity

This is really my only recommendation to keep it super safe; that being said you can charge together lipos at any voltage and in any condition (I mean internal resistance ofc, don’t charge a puffed and chewed up old stick in there)

  1. Plug in your lipos first, then the jumper, then the board

When all lipos are in place you will have actual 6S voltage out the XT60 and through the circuit. I recommend plugging the XT60 last to avoid arc damaging your PH2/BT2 or the jumper.

  1. Never leave the board unattended while charging or discharging

That one should be obvious, but really these tiny lipo sticks can still do a lot of damage on a crowded desk; I like to keep my charger in sight at all times. Except when it’s unplugged; then you may relax.

  1. Do not charge over 1.5amps

That means you can still charge up to 750mAh lipos at 2C or 1500mAh lipos at 1C; should be plenty.
While the traces are rated for a little more than that, the jumper is not; it is rated for 2A. I set it to 1.5A after accounting for oxidation and wear.

All boards are checked before packing. I am not responsible for any overcurrent/short damage.
Likewise, if you ordered a PH2 only board, although I left provisions for soldering in your own BT2 or other custom connector, you may do so at your own risk

  1. Do not eat

Just don’t.

That should keep you safe from just about anything harmful this board may do to you;

Thank you and happy charging!

If you have difficulties reading, here’s also a video explaining how this all works live!

Known Issues

  • ISDT P20 Smart Charger: Some conditions may cause an “Abnormal input voltage” message when powered by 24V, try powering with 12V
  • HGLRC HOTA D6, 608AC Charger: Some lipos with high internal resistance may cause a “battery type wrong” message. No solution was found other than using low resistance lipo (Tattu R-Line) or changing charger (Toolkit RC D6 is my personal favorite)