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Has anyone ever seen something like a TENS shirt or shorts that has the pads built-in?
I reverse engineered some existing device, there are TONS of safety measures.
At least: current limiting resistor, transformer, voltage/current feedback, GND isolation, MCU protection.
After replicate all of these, I still not brave enough to try it myself, I just find it too dangerous.
PS: TENS device is fun. article seems like a bait.
> down to ~3.0V (discharged). That is NOT how one uses lithium batteries one foe snot want to go boom. Consider 3.6V as empty. Discharging them down to 3.0 can cause them to go boom when recharged...
3.6V is considered the nominal voltage, certainly not the low end cut off. 3.0V is considered basically the highest voltage. Most chemistries suggest even lower, 2.8, or even 2.5 in some situations assuming you can control the cutoff carefully. Perfectly safe to do so. You only start to have issues when you’re south of 2.5 without a load. Most advanced battery usages let the cells drop even below that during heavy lo…
This is not right (3.6v certainly is and can be cut off depending on device and battery).
One thing you are not considering is discharge after the cut off. Fuel gauge, protection circuitry, the cut off circuitry and battery itself has some discharge.
So you don’t want to have the cut off being too low because then the battery is permanently dead after not using it for X period of time.
You want to leave some margin there.
Depending on product, battery chemistry and design I have seen cut-off at 3.0-3.6v.
Earlier quoted context omitted.
3.6V is considered the nominal voltage, certainly not the low end cut off. 3.0V is considered basically the highest voltage. Most chemistries suggest even lower, 2.8, or even 2.5 in some situations assuming you can control the cutoff carefully. Perfectly safe to do so. You only start to have issues when you’re south of 2.5 without a load. Most advanced battery usages let the cells drop even below that during heavy lo…
>3.6V is considered the nominal voltage, certainly not the low end cut off. This is not right (3.6v certainly is and can be cut off depending on device and battery). One thing you are not considering is discharge after the cut off. Fuel gauge, protection circuitry, the cut off circuitry and battery itself has some discharge. So you don’t want to have the cut off being too low because then the battery is permanently d…
The margin is already there at 3.0V. You can still recharge batteries discharged below 3.0V. It just becomes dicey below ~2.5V.
Tangentially related homebrew effort by Basically Homeless to built an aimbot using similar tech. https://youtube.com/watch?v=9alJwQG-Wbk
Earlier quoted context omitted.
>3.6V is considered the nominal voltage, certainly not the low end cut off. This is not right (3.6v certainly is and can be cut off depending on device and battery). One thing you are not considering is discharge after the cut off. Fuel gauge, protection circuitry, the cut off circuitry and battery itself has some discharge. So you don’t want to have the cut off being too low because then the battery is permanently d…
Anyone setting cut-off at 3.6V either is using it in some insanely industrial, ludicrous application where you need to handle cases like multiple years in storage... or doesn't know how to properly design their protection circuitry. The margin is already there at 3.0V. You can still recharge batteries discharged below 3.0V. It just becomes dicey below ~2.5V.
It really depends on application, battery size and leakage. In consumer world of electronics for example there’s an often requirement to make sure device turns on after being on a shelf for 1/2 - 2 years.
Then when you do the math it ends up needing to set the limit to 3-3.6v.
>The margin is already there at 3.0V. You can still recharge batteries discharged below 3.0V. It just becomes dicey below ~2.5V.
The margin isn’t big enough for some products. Furthermore some of the more leading edge batteries (in terms of energy density) have higher leakage which requires having more margin.