Opus BT-C3100 v2.2 - Reviving 0 Volt Cells

wimpie007

wimpie007

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Does anyone else have issues when reviving 0 volt cells that after trickle charging them with another cell and a resistor, you seem unable to use the Opus to get past 2.4 Volts?
I didn't even know that there were batteries that had 2.4 Volt nominal, but it seems there are some Ni-Mh ones.

Anyhow: the Opus seems to think that 2.4 is the maximum, so it drops the amps when reaching this value and then goes to "Full".
Because the charger stops, the cells drop back down to 1.8 or so.
At these voltages, I can't put them in a TP4056 because that doesn't charge well at below 2,8 Volts or so...
 
@Daromer, what are your experiences with charging those 0 volt cells after you've bumped them initially?
The better ones I have gain voltage quickly, but I have a few hundred Samsung 22P's that always fall back to zero.
 
Stefan you charge with mA /A not mAh/Ah.
0 volt cells or close to 0 perhaps 10% will work. Above 1V is higher chance but depends on what types.

You should always bump to above 2.5V otherwise you will get charge-issues. If it takes long time do it in stages. Slow up to 2V and then faster above.
 
Low voltage cells i do revive with tp4056. Succesd rate is way higher that way in comparison to reviving with different testers like liitokala or opus...

Once fully loaded they go into the testers
 
daromer said:
Stefan you charge with mA /A not mAh/Ah.
0 volt cells or close to 0 perhaps 10% will work. Above 1V is higher chance but depends on what types.

You should always bump to above 2.5V otherwise you will get charge-issues. If it takes long time do it in stages. Slow up to 2V and then faster above.
Click to expand...

sorry, you are right, had arough day at the office, mixed it up.


of course: I meant 500mA standard cellphone charger, giving about 70mA per cell. the device i mentionned does not seem to care about 0V. (not in 0V like popped CID, more like below 1v)

if you see something like 20% charged, you could put in the regular charger, but i tend to leave them to full. checking for heaters of course.

best regards.

Stefaan
 
Based on what I see here (and after checking the specifications on the TP4056) it should be possible to 'throw' the 18650's into a TP4056 charger after getting them a little bump.
I'd say 0 -> 1V is a good start. I'm having problems getting cells past the 1 to 2,4 Volt zone myself.

Going by the advises above, I'm (first of all) trying to be more patient about "revived" cells. Secondly, using a highly charged 18650 as a 'source' whenever I can.
Thirdly, maybe I should research adding another set of circuits that "bump" 1V cells to 3V without the logic that the Opus C3100 uses.
In real life, that would mean using a resistor in the 20 Ohm range to get a 200 mA charge into the cells.
(I'm now using a 67 Ohm to get 62 mA of trickle charge for 0 - ??? Volts)

P.S.: also judging by these comments I just threw out about 100 cells because they wouldn't take a charge, but basically it was me being not patient enough for the TP4056 trickle charge to do it's work...
 
If it doesnt go above lets say 1V in reasonable time the cell is most likely self-discharging = bin anyways.

It takes time to charge them up that slowly. If we talk about 60mA into a possible 2000mA cell it takes atleast 10 hours to reach above 3Volt! BUT as said in my world if they doesnt bump up fast enough i bin them. Its not worth the time and most 0 volt or o.1v cells are dead from start :(
 
As said, i have best success with tp4056.
Even my liitokalas dont show any voltage at very beginning but behind they start charging and after some minutes the charger shows a voltage and tries to test cells...

My opuses are not so supportive :)
 
To all dealing with the cell reviving, i strongly recommend to by a cheap laboratory power supply. This comes at something like 40 $, and gives a supply with adjustable Voltage and current limiting, giving an adjustable CV.
/Update/
Just look as example:
https://www.aliexpress.com/item/KD3...ory-Power-Supply-DC-Jack-set/32856663393.html

30 Volts 5 Amps all adjustable!
/End Update/

To answer the first question, i have seen cells being stuck on any voltage, up to 4.0 volt.
One cell rose to 1.6 V and then decreased then again - under loading current.
Some showed up as severe self dischargers, some looked perfect.

In the end, it looks advantageous to go slow for the first load, then recheck.
 
Some more update:
I would NOT try to revive 0 volts cells by feeding them from another better cell. This is definitely uncertain regarding current, in most cases just not the trickle Charge you want, but high load current.
 
of course you should not. Add an resistor in series with the other cell and you have your current limiter
 
mike said:
Cherry67 said:
I would NOT try to revive 0 volts cells
Click to expand...

I would stop reading here :)
Click to expand...

When i think about that, you might be totally right.

My previous last batch had quite a lot 0 V cells, about 2/3rds of them looked like revivable. But, as i look now, i have quite many SDsuspicious around here, still in test.

Unluckily i didnt have a strong noting system on the cells to recognize the incoming voltage. (I will have in future, for sure).
But i guess many of the revived end as SD, or low cap, or both.

On the other hand, i just have a bikepack here, 10s6p, which startet at 11 V total, evenly distributed. i carefully brought them up to 36 V, let them rest 2 days, and half of it hast just passed capacity test, at 3Ah per cell, all equally in voltage. They have still to pass SD Test.

I read somewhere here that the lowest revivable limit should be about 1V, and this confirms (at moment) that someweher between 0V and 1 V a watershed seems to exist.
 
mike said:
Cherry67 said:
I would NOT try to revive 0 volts cells
Click to expand...

I would stop reading here :)
Click to expand...

Some cells revive better than others. There are several factors that play. How the cell got to 0v in the first place, how the cell is revived, and the chemistry of the cell (some brands revive better than others)

I find that if a cell is less than 0.1v there is very little chance. Although when time permits I try to revive anything that will take a charge.

As for the method for revival, slow is the key. I charge at about 50ma until 2v. Then 200ma until charged. The process can take days. I then leave the cell to rest and check for self discharge. Using an RC charger NiMh program is ideal (a bench power supply would be better, but I don't have one). Sometimes I have to parallel a discharged NiMh battery to get the charger to start the process.

Unless you have inclination it's probably not worth the effort. Success rate is often very low. However some batteries come back just fine. I can't remember modal numbers but green sony and pink samsung cells have given some great results. I have no idea how these cells will perform in the long run.
 
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