Battery that is 200V+ (18650 cells)

[werto165]

Has anyone had experience with 200+V battery packs made from 18650 cells?  I need to construct one for a project and I was wondering if anyone has any pointers if so could they DM me? 

 

Thanks. 

[Raudi_]

What cells are you gonna use?

[mariushm]

200v DC is kind of a strange number... could you elaborate on why you would need such a high DC voltage?

 

It may make more sense for safety and other reasons (faster charging, thermals)  to build 24v (~6 in series) or 48v (~12 x 3.7v..4.2v in series) battery packs and use a dc-dc converter to boost to 200v or whatever voltage you'll need (there's ready made inverters and converters used for solar power industry, which can take 24-48v and convert it to higher AC or DC voltage.

 

[Unimportant]

Agree on using a lower voltage and boosting it. The main practical reason would be that a fully charged Li-ion cell is about 4.2V, while the cut-off voltage for a drained cell is around 3V. So, if you were to put 48 cells in series to get about 202V when fully charged, the voltage would drop during use to about 144V before you'd consider the pack to be depleted. If you use 67 cells to stay above 200V even when drained, it would be at 281V when fully charged. Such a large range is impractical to work with in most cases. The boost converter approach would naturally include regulation which provides a steady output voltage.

[Hackentosher]

Ayy I'm going to be working on a 250v 18650 pack pretty soon. I'm worried about balancing, so I think I'll make 10 6s batteries with BMSs, and wire them in series. Just be careful with all of that, wear rubber sole shoes, know what you're touching, and keep your head on a swivel. I also recommend using xt60s for everything and nice silicone wire. Fuse your cells if possible. Also beware that whatever you plug in probably has some big filter caps which will pull a pretty huge inrush current, causing a big spark when you plug it in.