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I am currently designign a 4S2P Li-Ion battery pack. The cells I use are unprotected, so I want to use one of those BMS/Protection/Balance boards like this:

https://www.ebay.de/itm/4S-40A-16-8V-40A-18650-Li-ion-Battery-Batterie-BMS-Protection-Board-mit-Balance/264137388088?hash=item3d7fd0b038:g:EcMAAOSw5e5cd1Qe

I want to include the charging in my project and all these boards talk about being "charging boards" and specifying a "charging voltage".

Do I assume correctly, that those boards do not implement proper CC/CV charging procedures?

If I want balanced charging, and my protection board provides balancing, would I be able to charge the pack by using a CC/CV circuit to apply a charging voltage to the entire pack?

I'm also thinking about not using balancing, since I have new identical cells.

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closed as off-topic by Nick Alexeev Apr 5 at 18:38

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  • \$\begingroup\$ Please post this question to the eBay seller. EE.SE isn't his volunteer application support. \$\endgroup\$ – Nick Alexeev Apr 5 at 18:38
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It doesn't look like it has a CC/CV only balancing, hook the charger up to the CF-4S30A board

Here is a video that shows how it works:

enter image description here Source: https://www.mikrocontroller.net/attachment/379678/610606910_1_1000x700_kontroler-bms-3s-4s-25-30a-zaryada-razryada-zaschity-balansir-dlya-li-ion-vinnitsa_rev003.jpg

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  • \$\begingroup\$ I see. Would external CC/CV circuit work together with the balancing circuit connected? I've read, that some chargers periodically switch between charging and balancing \$\endgroup\$ – Hendrik410 Apr 5 at 18:36
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LiIon cell charge voltage is not fixed. First, because variations in battery chemistry lead to differences in the proper charge termination, and second, because you can make a choice to charge the cells to a slightly lower voltage and get more charge cycles in return for lower capacity, or you can choose to charge the cells to a slightly higher voltage and get the opposite trade.

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