Charging Multiple LiPo Batteries With One Charger

In this tutorial, I’ll be going over everything you need to know in order to charge multiple lipo batteries. by basically using just one part that you don’t already have called a parallel charging board, you’ll be able to charge up to 6 Lipo batteries all at the same time.

How It Works

Here’s a detailed schematic of a harness used to charge two 3s 11.1v lipo in series. In series, the positive of the bottom battery is connected to the negative of the upper battery. Notice how this connection is made twice, through both the power harness and the balance harness. More on this later.

How To Para Charge

First you will need to build or purchase a parallel charge plug or board that the charge leads from each battery will be plugged into. The positive from each plug is hooked to positive and the negative of each plug is hooked to negative (parallel circuit). To keep things in reason, most will only build a plug or board that will support up to 5 or 6 batts maximum.

Things start to become a little congested as you can see with that amount of wiring and batteries, especially if you still want to use a fire safe charge container or bag.

My general rule is it’s better to charge in parallel. With parallel charging, the batteries must have the same number of cells and a similar state of discharge. The same number of cells rule is easy for me because I keep all of my battery pairs permanently connected. For example in my Revo, my 2s batteries are wired together in series all the time. My ESC only has one plug for the batteries. Same thing goes for a pair of my 4s 14.8 lipo battery. They are permanently wired together in parallel. So regardless of the single pack configuration, all of my battery pairs are 4s before they hit an ESC or a charger. Makes life easier.

Here’s an example of two of my 4s lipos “permanently” wired together. The stay connected to this harness all the time. In these pictures, I have a protective cap installed on the balance plug. This keeps that connector clear while I’m driving.

Requirements and recommendations for serial charging

• Serial wiring adapter for the main leads that matches your charger’s output capabilities. Because serial charging effectively creates a larger cell count pack, the capabilities of the charger will limit the number of packs that can be charged in series. For example a 6s capable charger can charge 2x 3s pack in series. Charging 2x 4s packs in series would require an 8s capable charger.
• A wiring adapter for the balance leads is basically required and needs to have the same number of connections as the main leads adapter.
• All the packs you charge in series must be the same capacity. For example you could charge a 3s 2200mAh lipo, a 2s 2200mAh lipo and a 4s 2200 mAh lipo in series together, but you can not charge a 3s 2200mAh lipo in series with a 3s 3200mAh lipo.
• All the packs to be charged in series together need to be very close to the same voltage per cell. If I had to put a number on it I would say within .05V per cell.
• Serial charging is best suited for someone looking to charge flight packs made up of pairs of packs like 2x 3s 2200mAh packs used in a 500 sized heli.

Things You Should Not Do

1. Because the lipo cells are connected to each other throughout multiple batteries, you should never plug in a fully or half charged battery with a battery that’s dead. Basically, the farther apart the voltages are, the hotter the wires will get. So all of the batteries should be hovering around the same voltage.
2. Another important thing to remember, is that you can’t charge two completely different batteries with each other. You can mix lipo packs from different brand names, but the cell count needs to be the same, and the battery capacity needs to be the same.

if i understand this right a 3s 2000mAh 10c 12.4 battery contains inside it 3x 1 cells 2000mAh 10c ~4.15v packs (safe recommended charging voltage). So with those Lipo batterys that are now showing up i could take apart a larger pack like a Gens 500mAh 2s 7.4v 65c – 130c to get 2x 500mAh 65c – 130c ~4.35v (can be safely charged to 4.35v per cell) for a single cell rc model and say run in a hubsan quadcopter as a example provided it fits. This would be a massive improvment over the stock batterys of most single cell quads right? slightly higher volts with high discharge giving way more power at a cost of weight.

That’s it!

Hopefully this short guide gave you some idea what multiple charging is, and how to do it on your own in a safe fashion.