Recently i bought some new Lipo batteries for my quad, and my battery population grow from 2 to 8. As happy as i was about the increased time i could spend outdoors flying my quad, this meant a very long charge time for all 8 batteries.
I research about parallel charging and found out that no special equipment is required, you can basically extent and split the outputs on the charger. Of course some basic parallel charging principals are watched, follow the instructable to the last step.
Step 1: Lets Get Started
Reused / recycled project box
I plan to charge up to 4 Lipos at the same time, therefore no electric connections should be exposed. I decide to reuse a power adapter box of an old printer. Since the box is only 66*56*29 cm all the split connections will be placed closely to each other.
I had to use a small saw in order to open the box and to remove the electronics
Splitting the Charger outputs
The charger has 2 outputs :
- output charge plug
- balance socket
The output charge and the female XT60 connections were placed out onto a double sided PCB board with a matching size as the inner space of the power adapter box.The holes were very helpful in positioning the XT60 connectors and the holes for the 3mm screws I used to hold the two parts of the power adapter box together.
The balance socket was split with a single sided PCB board, and exposed pins for the battery's balance plug. The positioning of the pins is according to the balance plug output on the charger.
Step 2: Boxing and Casing
I used a male XT60 positioned horizontally on the holed PCB and I cut some spacing for the connectors to be soldered onto both sides of the PCB for a stronger grip. I used some rubber spacers (which were salvaged of an old printer paper rolling rods) to position the PCB with the horizontal XT60 connector to match the already available side opening of the box.
I drilled 4 3mm holes from the inside of the bottom side of the box, according to the holes I expended on the PCB board. In the same way I drilled the holes on the top side of the box. Then I manually cut the square openings for the XT60 female connectors. I cut them using an utility knife. I also cut some of the lip on the to side of the box to create an opening for the pins of the balance split PCB.
Before closing I put inside the balance split PCB (matching the pins layout to the layout on the charger) and hot glued it, to prevent it from moving.
Once every thing is in place, I inserted the 3mm screws and threaded them into the top side of the box.
Step 3: Basic Principles of Lipo Batteries Parallel Charging
Some basic a principles should be noted for Lipo batteries parallel charging :
ONLY USE LIPO/LIFE/LI-ION BATTERIES WITH THE SAME CELL COUNT
- ONLY USE LIPO BATTERIES WITH THE SAME CELL COUNT.
- Preferably use matching capacity (mah) and discharge rate values.
- Charge the batteries when they are with the same charge level. In order level the batteries ti the same level connect them for some time together and measure the cells levels to verify a matching level (depending on the differences).
- Always plug the "main" plugs (XT60) first, wait several minutes and then plug the balance plugs.
- Of course be VERY CAREFUL and MIND to plug the balance plugs correctly. Backwards plugging will cause a short circuit and sparking.
- To determine the charge rate add the batteries capacities together, then set the sum as the charge current.