TalentCell YS1203000 "State of charge" monitor - take two!

As discussed, I have decided to fork the original “TalentCell YS1203000 “State of charge” monitor” topic into several parts as it was becoming unwieldy.

The original thread can be found here:



Ref:  The original message with approximate values for the state-of-charge indicator lights.

Today, I have officially wrapped this up.

Today, I:

  1. Re-measured the state-of-charge indicator trip points with the more accurate metering on the new bench supply.

  2. Measured the un-modified trip points on batteries 2 and 3.

  3. Made the component changes on the last two batteries.

  4. Measured the now modified trip points on batteries 2 and 3.

(Rather than try to make a table, here’s a picture from my notes.)

You will notice that all the modified trip points are right around 11.5, 11.0, 10.5, and 10.0 volts which should be appropriate for the Li-Ion battery chemistry.

Here is a sectional view of the TalentCell battery state-of-charge indicator.

All tht needs to be done is to replace the three highlighted resistors, (1k&,ohm;) with 510Ω resistors to recalibrate the battery’s meter for Lithium-ion battery cells.

What say ye?

@mitch.kremm @cleoqc
Can you folks communicate this modification to TalentCell for inclusion in subsequent Li-ion battery packs?


Just in case you’re interested:

Here’s what happens when you let the “magic smoke” out of an electrolytic capacitor.

It turns out that electrolytic capacitors have “magic fur” instead of “magic smoke” inside them.

It’s a good thing I have spares!


Is this the behavior goal?

11.5v will go off about 1 hr ~90% capacity left
11v will extinguish at about 3 hrs 65% capacity left
10.5 at 6 hrs 30% capacity left
10.0 at 8 hrs 6% capacity left. (15-30min)
9.5 dies


If you go back to the original thread, (the relevant posting is marked), you will note that you set your drop-dead at 9.75v, and the voltage steps were the ones agreed upon.

Giving the user 15-30 minutes to get out of what he’s doing and shut down seems like enough time.  Though, IMHO, I would design the last LED to go red, warning the user that death is imminent.

1 Like

Or play a submarine dive klaxon


We want to warn 'em, not give 'em a heart attack!

“Battle Stations” is a better sound if you want to scare the poor sod outta his socks.