Li-Ion battery pack without bms!?

ESK8 Electronics
41

The charge port is connected directly to the pack POS & NEG. Im measuring the balance leads individually.

42

Well thatā€™s just cool as hell :). Have you done a write up on it?

43

Nice, there no is load them, I guess itā€™s the cells recovering after current in or out

44

Really neat brotha. :lying_face: Mind spilling how you did the software? :yum:

45

@mmaner Nah -On my board I have a normal charge socket that connects directly to battery +ve and -ve .

No BMS in board enclosure at all ( one less thing to break down and I donā€™t need BMS to fail braking down-hill)

My battery has all 11 balance leads bought out to a weatherproof socket ( using 0.75 sq. mm high temp silicon wire) for the external BMS. I put 5A wire fuses in these leads to protect battery ( and prevent a fire) should there be a fault.

So I can charge without BMS directly into normal charge socket on the board ( which I do 99% of the time)

or I can plug in BMS box to monitor only cell voltages during charging through board charging socket

or I can balance charge through BMS box using the 11 balance wires ( which I havenā€™t done for a month or so.

Ultimate flexibility !

3 Likes
46

BMS from AliExpress - with PC uart connection

Even comes with a Bluetooth module for android phone cell voltage monitoring and configuration capacity

https://www.aliexpress.com/item/13S-60A-active-bms-2017-new-Li-ion-smart-bms-pcm-with-android-Bluetooth-app-UART/32821764284.html?spm=2114.search0104.3.89.30717e9as0sSvw&ws_ab_test=searchweb0_0,searchweb201602_2_10152_10065_10151_10344_10068_10130_10342_10547_10343_10340_10548_10341_10084_10083_10618_10307_10131_10132_10133_5711211_10313_10059_10534_100031_10103_10627_10626_10624_10623_10622_10621_5722412_10620_5711312,searchweb201603_25,ppcSwitch_5&algo_expid=d1e41397-3fd7-45fc-8cad-7dd843697eb0-13&algo_pvid=d1e41397-3fd7-45fc-8cad-7dd843697eb0&transAbTest=ae803_3&priceBeautifyAB=0

3 Likes
47

Personally I would include a BMS in all my packs that I build, that way they can easily be charged just with a charging brick, however, I generally only use a low rated amp output current BMS, and bypass it for discharge, only using it to charge and balance the cellsā€¦

I find this very effective if your ESC handles cutoff voltages such as a VESC derivative.

4 Likes
48

Thats quite cool bms and ā€œcharge monitoringā€ box u have made. U should definetely make a sepereate post or tell more info about it.

Looks like u can also configure a few settings or the bluetooth is just for monitoring?

On a side note - to the guy who said his lipos drift in voltage - that is quite true, thats also why li ion tends to be more popular choice, i think, if really high current is not needed, li ion cylindrical cells drift a lot less or almost not at all, if they are from same batch and balanced properly in first place

1 Like