Serial charging of LiPo batteries is a common practice for charging multiple 1S LiPo batteries for tiny whoops. When charging in series, multiple LiPo are connected end-to-end so that the voltage of each battery adds up, resulting in a higher overall voltage pack.
New to FPV? You can learn about LiPo batteries in this tutorial.
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What’s Serial Charging?
Just like “parallel charging“, serial charging is a fast way of charging multiple LiPo batteries. But instead of connecting them in parallel (each cell that’s connected increases the total capacity), the batteries are connected in series (each battery added increases the voltage).
With serial charging, you connect the positive of each pack to the negative of the next, stringing them all together (in a series). It’s basically like building a multiple-cell battery. By connecting four 1S batteries in series, you have a 4S battery, and with two 1S batteries, you have a 2S battery.
What are the Benefits of Serial Charging?
You don’t need to worry about the voltage of each battery before connecting unlike parallel charging, you just need to make sure the batteries are of similar capacity for safety.
You can use almost any LiPo charger that you are likely to already have, and you don’t have to purchase a separate 1S charger. However, you will probably need to buy or make a 1S serial charging board but it’s usually cheaper.
Most 1S chargers on the market lack the ability to put batteries into storage charge. With serial charging, you can easily get all of your batteries back to 3.85V just like a normal multi-cell LiPo.
If you want to discharge a bunch of fully charged 1S LiPo quickly, by connecting them to a serial charge board and discharge them as one single battery is more efficient too.
Downsides of Serial Charging
Most LiPo chargers only go up to 6S, which means you can only charge up to 6 cells at once. It’s hardly a downside though because most 1S chargers only 6 outputs as well.
The advantages of serial charging mainly apply to 1S LiPo however, for 2S and higher cell-count packs it’s still better to parallel charge them in my opinion.
How to Serial Charge LiPo?
You will need a 1S serial charging board, buy one here:
- NewBeeDrone: https://oscarliang.com/product-d3mu
- AliExpress: https://s.click.aliexpress.com/e/_Dnn0omP
- Amazon: http://bit.ly/3VxGI5d
Or you can make a cable, though I think it’s much easier to just buy one: https://intofpv.com/t-make-a-1s-lipo-batteries-charging-cable
I really like the ViFly Whoop 1S Series Charging Board, because it has a cell count selector and you can plug in as many cells as you like (between 1 to 6). It has 3 options for different connector (BT2.0, PH2.0 and GNB27), and is only $15.99.
It’s very important to use a balancing charger that keeps track of individual cell voltages (it requires you to plug in the balance lead for charging), otherwise you’re likely to overcharge some of the cells.
If you already have a charger for 6S LiPo , chances are good that it will do balance charging. However, it’s fairly common for these chargers to not accept 1S packs or provide cables that can connect them. The serial board will allow you to make use of your existing charger, you can charge, discharge, storage charge etc just like a bigger LiPo.