This is my attempt to add simplicity to the short commuter board we are building now.
With v1 board, I had to take the batteries out of the enclosure, connect them separately to a smart balance charger, and put them inside once charged. This is inconvenient to say the least.With the current revision, we are solving this.
What is BMS?
It is short for Battery Management System.
Lithium based batteries (especially LiPo) need to be balanced (have same voltage) in order to perform at their best and not to catch fire. This is why we use specialized chargers and balance ports.
BMS unit allows you to charge your batteries with simple charger and still get nicely balanced cells. It takes care of the balancing for you.
Let's Make It Work
The simplest setup you can have in an esk8 is a 6s battery, consisting of 2x3s LiPo batteries. We all usually start there. Now we just need to wire these to a BMS unit.
These units are cheap, and ebay is a good place to find these. Now let's get to the wiring.
At first it might look weird and incomplete, note the missing wires from the balance ports.
These BMS units are sometimes very picky about double wiring. For example: B+ from the charging port is connected to the main B+, the same goes with B-. We are connecting these only once with the main leads. Also, the main - lead from the first battery is connected to the main + of the second one, so we are omitting the same connection in the balance ports.
Other thing to note, this unit is used only for charging, the P-, P+ port is used only to get voltage in.
Thicker wires will go directly to the ESC, and to the motor. While operating, the currents are high, much higher than this tiny BMS can handle. And all modern speed controllers will monitor the battery status and will shut it down before it gets fully discharged.
Wiring
The wiring of the balance ports can be done with extension cables which will plug directly to the balance leads of the batteries. This will eliminate (or at least reduce) short circuiting.
The batteries can be connected together with thicker wires, choose 12AWG, and the appropriate connector. In my case it was XT60.
Careful soldering of everything and you are done!
Was this helpful? Leave a comment below, I would love to know your take from this.
Enjoy,
Dani