16S Lithium Ion Battery with 2x 8S Charger - possible?

Hi Everyone,
for a new project (diy e-winch for paragliding) I am building a 16S10P Battery with 21700 cells.

Since chargers for 16S Batteries are hard to get or expensive,
I am thinking of charging the battery with 2x 8S chargers, like this one:

This is how I think it should be possible:

Am I right, or do I have a serious error in my thinking?

Any feedback would be most welcome.

Oh, and if anyone is interested in the DIY Open Source electrical paragliding winch, let me know, I am happy to post details here.


Hi, I myself use rechargeable batteries that consist of a block with 14 S and then charge 7 cells each with 2 separate charging cables and devices through additional charging cables. If you want to do it with a dual charger that has 2 charging outputs, it is not possible because the block is built as a 14 S and has a ground connection. but if you want to use a dual charger because it is practical, it is possible to simply use 2 modules, for example. to build 8 S and charge with a device that has 2 outputs. the serial connection is then made on the device (the winch) that has to be connected and creates a serial connection internally. at eppg and e foil i have been using 15 S systems for a long time, which always consist of 3 pieces of 5 S modules each. By the way, a good example is Makita with the tool as a comparison. 36 volt devices have always been used in this way. Charge 2 18 V modules independently of each other and then connect them to 36 V on the device. I think an e-winch is good if you have the terrain for it. there have been a lot of great developments here in recent years.

your drawing is correct and if the chargers don’t have a connection, it works. i.e. no single common AC power supply may be used if 2 DC chargers are used.

Hey Bratwurst,
many thanks for your reply.
My goal is to build one battery (16s) as it requires only two bus bars, one connection and one (wooden) case to be transported.

I will hence use two separate chargers!

By the way, I am building this project from a fellow austrian :slight_smile:

His approach of using a readily available wifi board (esp32 / paxcounter) with button presses instead of a wobbly lever is awesome.

His github repository is here: GitHub - robertzach/ewinch_remote_controller: transmitter and receiver code for remote controlling a paragliding winch

unfortunately Robert has some information missing in regards to parts that he used, I tried to put it together in a fork of his repository, I also updated some of his remote code:

the cool part is that he is also using an open source ESC, the “VESC” project.


yes, you have to make it as simple as possible for use and transport. so an entire battery is ideal for you. it’s different with my big ones here, 3 modules, each weighing 11 kilograms, are easier to handle than a block with 33 kilograms. yes, in austria there are now more e winds than eppg. i know some. I would also like to do it, but we don’t have any large fields that could be used over the summer. because of a few weeks it doesn’t really make sense for me. But I think that it will become a trend because you don’t disturb anyone with it, so you can do it very inconspicuously, even if you operate it in a “grey area”.

i am currently building an ultra-lightweight electric catamaran. for 3-4 people. and to tow hydrofoilborads with rope. What I will definitely try is to tow a simple singleskin paraglider directly into the 5-10 km/h wind a few hundred meters . the motor power is certainly enough… is also operated with 15 S batteries. I just have to adjust the performance data plate so that it stays legal… on the lake.