Li-ion or Li-Po setting in charger

[KrisP]

Hi,

I have the Swallow 2 Advance charger which is apparently the same as some other brand of chargers, anyway when you choose Li-ion in the menu it says 3.6v and when you choose Li-Po it says 3.7v. All my li-ion cells clearly say 3.7v on them, so i'm unsure what setting I should be using. I've been using the Li-ion setting to be on the safe side, but it only charges the cells to 4.1v. The instructions also say that the Li-ion setting will charge to 4.1v and the Li-Po setting will charge to 4.2v.

What are others doing with their charger like this?


Thanks,

Kris.

 

[VidPro]

The instructions also say that the Li-ion setting will charge to 4.1v and the Li-Po setting will charge to 4.2v

and that is the important part, li-po isnt that much different from li-ion, cept a good li-ion cell will fail completly wheras a li-po cell will puff up, when it gasses, be that from overcharge OR from age and other stuff.

you will get many more "cycles" or short cycles from not charging so fully and keeping either of them at 4.1v max.

both of them can potentially be charged to the 4.20 +- .05 MAX . i prefer the 4.25+ myself, BUT they arent going to BE left there for long. my tests of high charge parked showed they die an early death.

potentially you can get away with either, on either type of cell, and on either you would prefer the lower 4.1v for longevity, and higher safety.
li-ion or li-pos could be marked or mis marked for 3.6 or 3.7 it is only the "nominal" voltage, and the max voltage is what is important.
although there were cells way back when that were lower voltage, because of the type of materials in them.

then of course there is li-Fe-po cells which none of them go as high as the 4.1v, you have to have a diode or a cheeze ball chip adapter thing in to charge them so the voltage is even lower.

a lot of help i am
i only use the higher for cells i need the last microbe of capacity for, that i know are working 100% par, and that i charged it because i intend to USE it definatly.
the last little bit of voltage dont give you diddly in capacity, its such a small ammount of total capacity differance.

for BIG fat cells, the specs can be to never go past 4.1V , like C and D sizes. and most "packs" with multicells stop at 4.2v per cell, and No +- they stop at 4.2 and never over.

follow the instructions, if you have canned cells they are li-ion, if they are bagged cells they are li-po.

 

[cy]

using schulze here... prefer 3.6V setting for normal li-ion usage. gives slightly less capacity than 3.7v setting. but you will gain hundreds+ more charge cycles from your cells.

then the times you need do max capacity, select 3.7v setting.

 

[KrisP]

Thanks for the replies

I'd rather longevity than the extra bit of capacity, so i'll leave it on the Li-ion 3.6v(4.1v) setting. I'm using it to charge AW C-cells and protected Trustfire 14500's.

 

[VidPro]

Thanks for the replies

I'd rather longevity than the extra bit of capacity, so i'll leave it on the 3.7v(4.1v) setting. I'm using it to charge AW C-cells and protected Trustfire 14500's.

on the what ? "on the 3.7v(4.1v)"
dont you mean, , , ,ahh you know what you mean :green:

 

[KrisP]

Fixed

 

[SilverFox]

Another consideration has to do with cooler temperatures...

Some Li-Po chargers have an ambient temperature sensor built into the charger. When the ambient temperature drops below around 40 F, I think, it limits the charge to 4.1 volts per cell. There is evidence that shows that if you charge to 4.2 volts in cooler temperatures, you end up with overcharged cells and puffed Li-Po cells.

I believe this is one of the reasons that Saft Li-Ion cells are specified to 4.1 volts.

Tom

 

[MrAl]

Hi there,

Tom, wow that makes me wonder because there starts to be significant
total capacity loss as the voltage is reduced lower than 4.20 volts as i am
sure you already know. For example, a 1.2 percent decrease from 4.200
volts (4.150v) results in a 9 percent loss of Li-ion cell capacity. This leads
me to believe that decreasing even more (to 4.100v) would lead to
maybe 20 percent loss of capacity.

Graphs:

http://www.postimage.org/image.php?v=aV21BGxA

 

[SilverFox]

Hello Al,

Well I didn't quite have the facts straight...

Let me make a correction. The FMA Cellpro 4S has a cold temperature protection algorithm that kicks in at 32 F and limits the charge to 4.0 volts per cell.

I thought earlier models kicked in at 40 F and limited the voltage to 4.1, but I can seem to find any references to that.

Oh well, 4.0 volts is even more of a capacity reduction...

It is interesting to note that they were able to destroy a Li-Po pack in 10 cycles charging it to 4.2 volts at 32 F. It sounds like this problem also shows up when taking room temperature cells into the cold. I guess we should pay attention to this, now that winter is approaching.

Tom

 

[MrAl]

Hi again,

OH yes that is interesting because i was considering charging some
cells outside in the car and with winter the car inside temperature is
easily 32 degree sometimes. Thanks for the info.

 

[DM51]

It is interesting to note that they were able to destroy a Li-Po pack in 10 cycles charging it to 4.2 volts at 32 F. It sounds like this problem also shows up when taking room temperature cells into the cold.

I can understand the point about charging in cold temperatures, but are they saying this applies to USE in cold temperatures too?

To continue the example, if the cell is charged to 4.2V inside at 70°F, then taken outside where it is 32°F, are they saying that using it at that temperature will damage the cell? That doesn't sound right.

 

[SilverFox]

Hello DM51,

It depends on how fast you use the cell...

FMA is claiming that if you start with a cell charged to 4.2 volts at 70 F, and take it outside and let it cool down to 32 F before using it, it will have the same effect as if you charged it to over 4.3 volts at 70 F.

I am not sure if this is exclusively a Li-Po thing, or if it also applies to Li-Ion cells.

Tom

 

[DM51]

That is very interesting. If it proves to be true for Li-Ion cells as well as Li-Po, and I can't think of a reason why there should be much difference, it would be a good argument for limiting the charge to 4.1V in winter-time.

However that would be difficult for people who don't use programmable chargers.

 

[cy]

Tom, thanks for this new info!

 

[zehnmm]

Very interesting information in this thread.

FYI, I am using a Schulze charger to charge my C li-ions. I have been charging on the li-ion setting, which for my charger, is for 3.6V. Given this, I estimate I get from 2700 to 2800 mah of usable capacity (versus the 3300 mah maximum capacity.) For example, my typical runtimes for my ROP Low are 82-85 min. using the C li-ions.

 

[Aircraft800]

Thanks for all of the good info!!

I have been balance charging my AW C Cells to 4.2v with my RC Power 601BC, a total of about 12 cycles. Now I think I'll change my Li-Ion setting to 3.6v so the end charge will be 4.1v to save on battery life/cycles.