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Two TP4056 Questions
#21
If I were to charge a lot of cells to a voltage other than 4.2V I would take a powerful CCCV power supply, like a DPS5020 if this should be done on a budget, and wire up a 40P cell holder. Set it to whatever voltage you like, set the current to 20A, and charge until current drops to 2A. Obviously if you have an even more powerful power supply then you can scale that up as far as you like.
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#22
I have used my adjustable power supply to charge up to 10 in series at 6 amps set to 4.2v. And mine does cc\cv which means it will charge at full current till the cells reach 4.2 then go into current limiting mode to keep the voltage at 4.2. Once the current is basically zero I stop the power supply and the cells are charged
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******Hi My name is Jason and I have SOCD (Solar Obsessive Compulsive Disorder)*******
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Waiting on 2000 Cells of unused Sony vt4 (2000mah 30A) ~ 15kWh      hehehehehe  More Power
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#23
Wink 
(10-11-2017, 10:39 PM)watts-on Wrote:
(10-11-2017, 05:39 PM)Eric Koshinsky Wrote: Question 1: Is there any way to easily use these to charge up to storage state (3.7v) and stop?  I don't really want to add an arduino or anything...just a simple solution if possible.

I stop mine charging at 4V using a schottky diode, with a 0.2V forward voltage in series with the battery. I also added a switch across the diode so I can easily choose 4V for storage or 4.2V for testing.
It seems to confuse the TP4056 slightly in that both the red and green leds light up sometimes when it hits 4V, but other that that it works great.
I guess a diode with a FV of 0.5V may work to get you 3.7V, but I haven't tried it.

This is my rig:
The two cells on the left are charging to 4V as they are tested and the other two are switched for charging to 4.2 ready to go into the Opus.


I didn't need to use those huge diodes (40L15CW), but I had free access to some, so they were the right ones. Big Grin
Hello,
I have a few 18650 batteries that I tested already, discharge them to 3v during their testing, using ZB2L3 tester capacity 18650. So now I want to store them for future project:
1. is 4.0v a good voltage for storage?? I looked on google and could not find anything about voltage, I mean at what voltage should they be when we store 18650 batteries. Now they are empty to 3v, what about charge them back fully and store them when they are at there 4,2v ??
2. about the schottky diode, can you give us the reference please, in case, I want do like you charged them to 4,0v
I am asking, because I looked and found some store for those diodes, but they dont say anything about forward voltage. I have a bunch of 1N4007 diode, can I use those type??
3. I realised a small hack with an epilator supposed to work an 2 AAA bats, so 3-3.2v. I got an TP4056 + Lipo Battery, and it is working fine for about a year. lately, I realised that the battery is 3,7V & 150mA, maybe I will kill the batterie using TP4056, cause its supposed to charge to 4.2V.  so I am thinking to reduce the charging of the TP4056 (confuse it, that the bat is 4,2V, while it is really 3,7v) using some diode as you did. and at the same time, reduce its charging current by charging the resistor on TP4056 (as shown in its datasheet)
Sorry for all those questions, I am a simple hobbyist, trying to dont burn his devices.
Thanx very much for any support  Wink
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#24
(11-09-2019, 09:14 AM)ZipZwan Wrote: 1. is 4.0v a good voltage for storage?? I looked on google and could not find anything about voltage, I mean at what voltage should they be when we store 18650 batteries. Now they are empty to 3v, what about charge them back fully and store them when they are at there 4,2v ??

I'm no expert, but for long term storage, unless specified in the manufacturer's data sheet (which it usually isn't) I think it is probably best at it's nominal voltage, which depending on chemistry is around 3.7V.  But if storing prior to doing a self discharge test, you need to be up near fully charged to be able to see any drop after a few weeks.

(11-09-2019, 09:14 AM)ZipZwan Wrote: 2. about the schottky diode, can you give us the reference please, in case, I want do like you charged them to 4,0v
I am asking, because I looked and found some store for those diodes, but they dont say anything about forward voltage. I have a bunch of 1N4007 diode, can I use those type??

This datasheet for the 40L15CW shows the forward voltage (symbol VF) as 0.25V. Whereas this random 1N4007 is 1.1V.

(11-09-2019, 09:14 AM)ZipZwan Wrote: 3. I realised a small hack with an epilator supposed to work an 2 AAA bats, so 3-3.2v. I got an TP4056 + Lipo Battery, and it is working fine for about a year. lately, I realised that the battery is 3,7V & 15mA, maybe I will kill the batterie using TP4056, cause its supposed to charge to 4.2V.  so I am thinking to reduce the charging of the TP4056 (confuse it, that the bat is 4,2V, while it is really 3,7v) using some diode as you did. and at the same time, reduce its charging current by charging the resistor on TP4056 (as shown in its datasheet)
Sorry for all those questions, I am a simple hobbyist, trying to dont burn his devices.

If the cell has 3.7V written on it, that will be it's nominal voltage not it's fully charged voltage.
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#25
I thought normal diodes were .6v? That would be perfect for storage!
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#26

40a 5v psu, they dont make them anymore like this...
voltage will drop when drawn 55a at 5v.



Total need for this board at max 32A.




Runs easy on 25a at 5v
This board is fed by a other psu, 14v 12a

Might give you an idea to run production. 90 cells a day when we have a working day, 120 cells when we had a day off.
My rule: always have one Amp to spare considering building your board. if you have a 10a 5v psu then 9 tp/tc would be the max.
However if you have a higher voltage psu, you can use buck converters, be careful to buy the right one for the job.
My max buck converter does just 10.75 amp at 5v
Also in my experiment endeavors, most computer psu are not good, check for flickering in the led from your tp/tc boards.
Replace or add the capacitors if needed!
My two cents

Sorry:
first board is to charge 30 cells at one time, put them aside for four weeks then discharge them
Both 1a charge and 1a discharge.

Second board is for testing a whole pack, to see if i divided the cells equally enough among the packs
Selling everything at marketplace.
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#27
(11-11-2019, 04:24 PM)100kwh-hunter Wrote: ...
Also in my experiment endeavors, most computer psu are not good, check for flickering in the led from your tp/tc boards.
Replace or add the capacitors if needed!
...


Some older PSUs require a load on the 12v line to produce a stable 5v out.
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