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ColdWarPatriot

FT-60E/R 18650 battery pack w/ BMS

by ColdWarPatriot Feb 8, 2019
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Whats the secret to making the BMS work?? I bought two of them, wired up one, no output voltage, tried the second one, no output voltage, asked the seller he sent me two more, tried both of them, no output voltage. I can measure 8.4v on the B+ and B- terminals, and the voltage of the one battery 4.2v at the BM terminal, P+ shows 8.4v to the negative battery terminal, but the negative radio terminal is not connected and there is zero volts at the radio terminals. There must be something simple i am missing here, how to enable the BMS, turn it on, something?

I had trouble with this as well. Are you charging your cells up outside the pack? The BMS output is turned on by a charge voltage across the P+ and P-. (P+ and P- are combined charge/discharge) So the only way to turn it on that I have found is to charge the cells while inside the pack, or charge the cells then only momentarily apply an 8.4v charge voltage to the P+ and P- terminals. I also designed a charging dock for this pack to try to eliminate this problem.

https://www.thingiverse.com/thing:3424025

You may also be able to work around this by placing your original battery pack into the radio, turning it on then off, then quickly swapping over to the new li-ion battery pack. I think the radio may have a capacitor or something in there that stays charged for a short time and is effective in "tricking" the BMS to turn on because the voltage remaining in the radio is just enough to turn on the BMS. This was how i found out the BMS is turned on by a charge voltage across P+ and P-.

FT-60R 18650 Battery Pack Desktop Charger

AHHH!! Bingo! I applied 8.4v for about two seconds with my variable bench supply and sure enough now its working. Well thats really odd that the seller didn't mention that, or at least give me that tidbit of info when i told him the first two weren't working. Would have saved everyone some hassle.

I plan on making the charger for it, though i am going to whip up my own version that holds two packs as i have a dual lithium pack charger that would be perfect for charging two at once and i have some spring loaded contact pins to put in the base for the battery to make contact with. I did a little reshaping of your design to round off the battery case a little more without the double step and sharp angles, still needs some more work but i will eventually get to what i want. I also have about a half a dozen dead NiMH packs that i am going to take the radio contacts out of and modify that part as well, the nickel strip i have for my battery tab welder was close but a bit to thick and too wide but i cut some down to get the first one working. We have two FT-60's here so it would be nice to have at least two packs each.

Glad to hear you got it working!

Fantastic!! Another one of my NiMH packs died and i have a bunch of 18650 batteries to use with these. I found those BMS modules, the exact same one, on eBay for about a buck each, $4 for two of them from a US seller or 99 cents each from a Chinese seller. Should make for some cheap battery packs. Ordered some parts can't wait to build a couple of these!