Mod discharging batteries at different rates

[EmbraSewerRat]

So, an Aspire Speeder has been discharging 3 pairs of Samsung 30qs at different rates thus when it comes to popping them on to charge one cell is say 3.00v the other is 3.1V. Seems to behave with our VTC5As.
Cells were bought from that lovely @Ben fogstar

Does this un pair the cells in anyway?
Is this likely to result in less life span for the cells?

Should i be concerned about this?

 

[Michael jackson]

Do you rotate them in your mod? As in switch what side they are in each time

 

[EmbraSewerRat]

Try to mind and do that.
But, it doesnae happen in my Noisy Cricket or ye olde IPV4.

 

[mattyk2010]

My cuboid used to do this and as long as your rotating your battery's they will have the same amount of ware and will be fine [emoji5]

 

[Simon G]

They are in series right?

... they can't be discharging at different rates, it's not possible is it?

 

[jsixtysix]

Even if you buy the cells at the same time there's no guarantee they will be identical. Mooch mentioned recently, that in these circumstances it's most likely the mod is inaccurately reading them. Advice was to swap positions and see if the mod screen shows the same battery with the same problem in it's new place then something might be up with the cell, but a 0.1 difference is nothing serious.

 

[mick brown]

I have the odd mod that does that. With 0.1 difference I wouldn't have thought it's much to be concerned about. That's the way I see it anyway . There's not alot you can do about it really if you like that particular mod.

 

[conanthewarrior]

They are in series right?

... they can't be discharging at different rates, it's not possible is it?

I think it can happen, some of my regulated mods that run in series I have noticed batteries discharge at different rates. I can't honestly remember if this was with new batteries though, or old ones. You can even see this on some mods that display both batteries that run in series one slightly lower than the other.

@EmbraSewerRat , I'm not familiar with the mod, but does it always happen in the same position? Say cell 1 in slot 1 discharging faster? Or is it random? As it is happening with 3 different sets of batteries it doesn't sound like a coincidence.

0.1V isn't a massive amount, but keep an eye on it. If you notice it get any larger, I would look into a few things before continuing to use the mod.

 

[Simon G]

I think it can happen, some of my regulated mods that run in series I have noticed batteries discharge at different rates. I can't honestly remember if this was with new batteries though, or old ones. You can even see this on some mods that display both batteries that run in series one slightly lower than the other.

... agreed, but my understanding is that's because of differences in the cells though not because of the mod.

The query was "an Aspire Speeder has been discharging 3 pairs of Samsung 30qs at different rates" ... I'm suggesting that the speeder isn't discharging them at different rates, however the cells themselves might be discharging at different rates because one is performing slightly better or have they slightly different capacities which would make them look like they were.

 

[Tubbyengineer]

So, an Aspire Speeder has been discharging 3 pairs of Samsung 30qs at different rates thus when it comes to popping them on to charge one cell is say 3.00v the other is 3.1V. Seems to behave with our VTC5As.
Cells were bought from that lovely @Ben fogstar

Does this un pair the cells in anyway?
Is this likely to result in less life span for the cells?

Should i be concerned about this?

There are a lot of variables that affect how cells discharge, including slight differences in the electrolyte, insulator sheets, cathode, internal resistance, contact point resistance, wiring resistance etc. so you will more than likely experience uneven discharge to a certain extent. Pairing batteries is more about having a pair of batteries that are the same make and model with the same number of similar discharge cycles - this helps to ensure that barring unforseen circumstances your cells will degrade at similar rates and will reach end of life at roughly the same time.

This slight difference in discharge doesn't "unpair" the cells and won't really result in much of a difference in lifespan - although rotating the positions of the cells in the mod will help to ensure that any diffrences caused by the mod (contact or wiring resistance) are evened out across both cells...