Question for Batt Gurus!

[Amajn]

Ok i have tenergy 3v rcr123a 900mah batts little blue ones earlier when vaping the chuck i noticed vapor was gone so i took out batts according to tenergy website they have volt discharge protection/pcb it will cut the current at 2.5 volts


So i grabbed my digital multimeter to check volts to see what they are at and the first batt reads at 3.36 volts second checks in at 3.10 under load its 5.54 so im perplexed as to why they stopped going and are acting like they need to be recharged


So i checked my fresh batts same kind blue tenergys im getting 3.88 on both then i checked the under load its 6.82

which is wierd because of the supposed overload protection/discharge kick in

unless its my multimeter but when i check other batts they seem fine so maybe its my batts??

 

[Rocketman]

You have an imbalance.
The 3.0 cells have a "magic chip" in them. They are really 3.6 volts cells that might get charged to a max of 3.8 or so. As soon as a load is put on them the "magic chip" cut each cell to 3.0 to 3.2 volts (so they won't fry something that was designed for the NON-rechargeable 3.0 volt cell). The 5.54 under load, and the imbalance of the cells indicates one is really close to the 2.5 volts. Maybe a couple of fast vapes and the weak one hits the cutoff. Something like 2.64 and 2.90 would give you 5.54.

The two fresh charged ones at 3.88 is pretty high, and if really under atty load, the loaded voltage of 3.41 each is a little high.

Is this OK, hell if I know.

Cell balance is IMPORTANT, Loaded voltage is an indication of charge status and battery condition as well as unloaded full charge voltage for this type of cell.
Maybe one of those battery Gurus can comment.
Rocket

 

[Amajn]

Ok that makes sense but why when testing each cell alone are they both above 3volts is it because that is before the chip actually kicks in to the correct voltage when underload?

If so then how can you truly tell the voltage without using them? is this common? on the tenergy site it says they should max at 3.6 possibly 3.7 i would guess then when you use it underload it would correct to 3.2 3.3
giving you some where around 6.4 6.5 right?

and you could vape until it hit 2.5 on each cell or 5volts

what is fustrating to me is not knowing the actual volts until under load

 

[Rocketman]

Should only take a small load to trick the "magic chip" draw 100ma or so, I don't know the minimum current to trip it. Maybe a small 10 to 30 ohm resistor across voltmeter leads would trip the chip and give a "partial load" voltage.

R

 

[noo]

The battery with the weaker charge is sinking current from the one with the higher charge. This is common in circuits where multiple batteries are connected without isolation.

When not under load, this does not occur, or is negligible, and the batteries can individually supply more power. When placed into the circuit under a load, the battery with the higher charge cannot supply the full amount of power to the load because of the presence of the weaker batter, which is why you are seeing a lower than expected voltage drop across your load. If you measure the potential at each node in the circuit over time, you will find that the battery with a lower charge actually behaves as a reactive load in a very slowly oscillating circuit. What is probably happening is that as the weak battery continues to discharge, it is sinking more and more current from other battery, which is also being drained by the load. You are probably hitting a feedback wall at which the stronger battery can no longer cope with the presence of the weaker battery, even though each battery seems like it would be fine on its own.

The solution is to isolate your batteries! Invert the voltage of one battery and place a regulator before each one. Your "ground" in the circuit is actually now at a -3.7v potential, but the regulators will prevent feedback from occurring, and mismatched batteries will just produce a lower overall terminal voltage.

 

[5cardstud]

You have an imbalance.
The 3.0 cells have a "magic chip" in them. They are really 3.6 volts cells that might get charged to a max of 3.8 or so. As soon as a load is put on them the "magic chip" cut each cell to 3.0 to 3.2 volts (so they won't fry something that was designed for the NON-rechargeable 3.0 volt cell). The 5.54 under load, and the imbalance of the cells indicates one is really close to the 2.5 volts. Maybe a couple of fast vapes and the weak one hits the cutoff. Something like 2.64 and 2.90 would give you 5.54.

The two fresh charged ones at 3.88 is pretty high, and if really under atty load, the loaded voltage of 3.41 each is a little high.

Is this OK, hell if I know.

Cell balance is IMPORTANT, Loaded voltage is an indication of charge status and battery condition as well as unloaded full charge voltage for this type of cell.
Maybe one of those battery Gurus can comment.
Rocket

Thats why. My batteries read charged but they wont vape. After I charge for awhile then they work. It's so weird cause the charger even says they're charged but after being in for a charge they work. They must be imbalanced