Question about Lithium cells

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Rossrosh

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Which adapter are you referring to? It would help to better answer the next question.

If the adapter on the "output" side is always 5V, then there's no problem at all as long as the charging circuit can handle the current/voltage, which most should be able to handle. Even a TP4056 works at 5V @ 1A, and 3 in parallel could do 3A.

It's a belkin adapter, with one particular USB port able to deliver the total rated 50W given that no other port is used.
To get the 50W delivery from the adapter, I'd have to use a power delivery decoy module to trigger the 50W.

Didn't know 3 tp4056 would allow the current to increase. Thought the module is designed to "limit" the current at 1A.

Even then I'd have to parallel 7 of those units to get about 7A.
That would mean each cell would be then charged at 2.33A. Any other ways to get to 7-7.5A?

For my understanding/ learning, could you educate me on the part I mentioned above, about "balance scale" of current and voltage with using a converter
 

Korishan

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Didn't know 3 tp4056 would allow the current to increase. Thought the module is designed to "limit" the current at 1A.
It is, limit 1A per module. If you had 3 connected in parallel, then that'd be 3A.

You could also go with a TP5100, which can do 2A, I think

That would mean each cell would be then charged at 2.33A. Any other ways to get to 7-7.5A?
I don't recall what cells you have. 2.33A seems a bit high, to be honest. If these are cells pulled from a laptop or similar device, then that is way too high. Those are usually rated around 0.5C, or about 1A max.

For my understanding/ learning, could you educate me on the part I mentioned above, about "balance scale" of current and voltage with using a converter
I don't know what you are referring to here.
 

italianuser

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I'll describe, I'm sure you fellas can guess what it is. It's in the shape of a cylinder narrowing towards the end, with a motor above the wide part, that vibrates 😂
Ehm... a vibrating jet? Sorry, I interrupted some serious stuff... 😅

1627466987914.png
 

Rossrosh

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It is, limit 1A per module. If you had 3 connected in parallel, then that'd be 3A.
Oh dang, you said parallel... I was thinking in series. Brain freeze.

You could also go with a TP5100, which can do 2A, I think
Yup TP5100 can provide up to 2A. So 4 of those puppies in parallel would give 8A. For 3S, that's 2.6A per cell ... right at the max rated charging current for these cells.

If I parallel connect the 4 x TP5100 from the same adapter+PD trigger module, and the 3 sells are series ... Wouldn't it share the same ground ... Causing a short circuit? Back to about isolation.

I don't recall what cells you have. 2.33A seems a bit high, to be honest. If these are cells pulled from a laptop or similar device, then that is way too high. Those are usually rated around 0.5C, or about 1A max.
It is out of a laptop, cells are the Samsung ICR18650-26C. Specs page says max charge current 2.6A

I don't know what you are referring to here.
What I mean is in a scenario without using the TP4056 or TP5100 charging modules, instead I use a step up converter to charge the 3 cells in series. If the adapter can provide the required 33 Watts to charge the 3S (@ 4.2Vx3cellsx2.6A = 33W).
And the convertor gets a 5V input, and It steps up to 12.6V ... Would the convertor then draw a current of 6.6A to output a charging power of 33W (33W÷5V=6.6A)?
Is my analysis/understanding of how the step up converter would work correct (of course not taking into consideration of convertor efficiency)?
 

Wolf

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Or you could throw all that math out and just get a good Power Supply like this....
0-10V 0-10A CC CV HP Agilent Keysight 6282A Just dial it in and charge away.
If shipping wouldn't be so brutal I'd sell you mine reasonable. It can be changed from 115V to 230V according to the manual.
But you should be able to find one on ebay. These are tough old PSs and worth having. I know they aren't automatic and require you to actually pay attention.................. what is this world coming to Alexa? Please dim the lights and check on the charger.
Wolf
1627473133067.png
 

Rossrosh

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Or you could throw all that math out and just get a good Power Supply like this....
0-10V 0-10A CC CV HP Agilent Keysight 6282A Just dial it in and charge away.
If shipping wouldn't be so brutal I'd sell you mine reasonable. It can be changed from 115V to 230V according to the manual.
But you should be able to find one on ebay. These are tough old PSs and worth having. I know they aren't automatic and require you to actually pay attention.................. what is this world coming to Alexa? Please dim the lights and check on the charger.
Wolf
View attachment 25724
🤣 Then it beats the overall purpose of the mod.
Portability + universal charging.

I do have an old PS, that was being replaced at a highschool.

None the less good suggestion 😂
 

Korishan

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And the convertor gets a 5V input, and It steps up to 12.6V ... Would the convertor then draw a current of 6.6A to output a charging power of 33W (33W÷5V=6.6A)?
Is my analysis/understanding of how the step up converter would work correct (of course not taking into consideration of convertor efficiency)?
Yeah, if the output is 33W, that means the input is somewhere around that too, probably closer to 40W ( 33 + 20% = 39.6W). 80% of 40W is about 33W.
So yes, the boost converter will pull 40W @ 5V which would mean it would draw up towards 8A. It would be better to use a USB-C PD adapter that way it could negotiate up to 20V. That would be 2A then.
 

Rossrosh

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Yeah, if the output is 33W, that means the input is somewhere around that too, probably closer to 40W ( 33 + 20% = 39.6W). 80% of 40W is about 33W.
So yes, the boost converter will pull 40W @ 5V which would mean it would draw up towards 8A. It would be better to use a USB-C PD adapter that way it could negotiate up to 20V. That would be 2A then.
Thanks, this confirms my understanding so far.
Now to put it into to practice... Hope this doesn't blow up!

Got some insight to connecting a few of those tp5100 connected in parallel and whether it would short or not?
 

Korishan

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Got some insight to connecting a few of those tp5100 connected in parallel and whether it would short or not?
Connecting in parallel is a non-issue. Connecting in series can be problematic. Meaning, the TP5100 can do 2s. However, most modules are not designed properly to handle the 2S configuration.
@rev0 has figured out the requirements to make it work in 2S mode without letting the smoking genie out of the chip
 

Rossrosh

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Connecting in parallel is a non-issue. Connecting in series can be problematic. Meaning, the TP5100 can do 2s. However, most modules are not designed properly to handle the 2S configuration.
@rev0 has figured out the requirements to make it work in 2S mode without letting the smoking genie out of the chip
Oh... Thought it would cause a short just as a TP4056 would... If the grounds aren't isolated. Thought I'd be the same with the TP5100
 

Wolf

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For the TP5100 to work in 2s this jumper needs to be shorted.
Wolf

1627500636861.png
 

rev0

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Connecting in parallel is a non-issue. Connecting in series can be problematic. Meaning, the TP5100 can do 2s. However, most modules are not designed properly to handle the 2S configuration.
@rev0 has figured out the requirements to make it work in 2S mode without letting the smoking genie out of the chip
Yeah, the TP5100 will self destruct in 2s mode "stock", you need to add 2 lower value capacitors in parallel with the existing ones for it to work:

1627501250181.png
 

Korishan

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For the TP5100 to work in 2s this jumper needs to be shorted.
I think also to be reliable, the resistor needs to be replaced too. I don't remember for sure, tho.

as typing this, rev0 responded.....

Thought it would cause a short just as a TP4056 would..
This is only if connecting them in series to series cells. If you connect all the Gnd's together, it can cause smoke.

1627501819334.png

Ok, so if we go with this example:
Left - 4s with 4x TP4056's with the Gnd's connected = POOF!
Middle - 2s with 2x TP5100 connected to the cells in 2s configuration with Gnd's connected = OK!
Right - 4s with 2x TP5100 connected with each TP unit connected to its own 2s cells, and with Gnd's connected = POOF!

Thank you for joining my presentation :p I hope that gets across what I was talking about.
 

Rossrosh

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I think also to be reliable, the resistor needs to be replaced too. I don't remember for sure, tho.

as typing this, rev0 responded.....


This is only if connecting them in series to series cells. If you connect all the Gnd's together, it can cause smoke.

View attachment 25730
Ok, so if we go with this example:
Left - 4s with 4x TP4056's with the Gnd's connected = POOF!
Middle - 2s with 2x TP5100 connected to the cells in 2s configuration with Gnd's connected = OK!
Right - 4s with 2x TP5100 connected with each TP unit connected to its own 2s cells, and with Gnd's connected = POOF!

Thank you for joining my presentation :p I hope that gets across what I was talking about.
Haha It most certainly did ... Poof = Not good.

Referring back to one of your previous suggestion of connecting a few TP4056 in parallel to charge 3S cells. Mind telling me if that'd go Poof?

I think this would round up most of the curiosity
 
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koshaymacky

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I had a feeling about that. Also I've been searching for a higher Watt isolator (8 to 10W) for another project, but haven't come across one so far (except for only 5W).


That doesn't sound healthy for the that 1p

Learning something new (guess now I've a couple of spares). I thought if the battery it's charging gets full... the voltage and current will still flow through the BMS, just without it going to the cells anymore.


True. I just started these projects to repurpose cells and parts currently at hand.


Thats true... But not great when the amps are limited below the capable output.


It's for real world, but I'm inquiring/learning before applying.

I'll describe, I'm sure you fellas can guess what it is. It's in the shape of a cylinder narrowing towards the end, with a motor above the wide part, that vibrates 😂
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Regardless of the application, the idea was to use in series to get the preferred power, but also increase capacity even a little bit, given the physical limitations of the device. omegle is far better
Also to charge the batteries fast at the highest rated charging current of the cells

Ehm... a vibrating jet? Sorry, I interrupted some serious stuff... 😅
 
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