How are these 18650s arranged?

There's a battery pack that has 6 x18650 with the following specs:

Power Source: Li-ion Battery Pack - 6 x 18650 - 10.8V, 6800mAh, 73.4W
Voltage of full charge and cut-off discharge is 12.6V and 7.5V

Voltage is probably 3.6V, so 3 x 18650 in series = 10.8V. How would the rest of this config play out (series & parallel and mah) to achieve the stated power source specs?

3S2P

3 batteries in series 3*4.2V = 12.6V
2 batteries parallel 2*3,400mAh = 6,800mAh

So basically 2 strings of 3 batteries.

2P3S :^P

Thanks!

I'm assuming all 6 have 3400mAh capacity. I was trying figure out the voltage rating on the batteries. Anyway to figure it out from the the available info?

edit:
10.8v * 6.8Ah = 73.4W
12.6v max charge = 4.2v * 3
7.5v min cut-off = 2.5v * 3

Is that what you were asking?
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All 6 will have 3400mAh capacity (within manufacturing tolerances), unless this is an absolutely awful battery pack built out of leftover cells or something. It would be very bad to build battery banks with different capacities, the lower capacity batteries would be stressed more (higher depth of discharge) therefore have shorter lifespans and degrade quicker, and the higher capacity cells would be “wasted” in that they would have unused excess capacity because the smallest capacity battery will be the “limiting factor” in the pack

Li-Ion are sometimes rated at 3.6v nominal although 3.7v nominal is more common, and almost always 4.2v maximum. The 3.6v vs 3.7v nominal isn’t highly meaningful, IMO. As Henk4U2 said, because the pack was described as “10.8v”, it appears this manufacturer prefers to call their cells 3.6v nominal (3.6*3=10.8) instead of 3.7v - no big deal, and no difference IMO. The reason it maybe sounds weird is that we are accustomed to the marketing department overriding this, and calling the pack “12.6v” instead, because they know customers think “more is better”, so they rate the pack based on 4.2v maximum voltage instead of 3.6v nominal voltage (4.2v*3=12.6v). That’s why you can potentially even see the same pack described with two different voltages and both are correct.

In recent years, (in a slight reversal of the “more is better” theme) I’ve noticed manufacturers seems to have settled into the “nice round numbers” scheme, where packs are just “12v” or “18v”. For example in the battery tool world in the early days of Li-Ion, there used to be 12.6v, or 19.6v, or 21v, or whatever as manufacturers tried to market their tools as “better” based on voltage. The seemingly random numbers seemed to be a holdover from the Ni-Cd days when each cell was 1.2v and you really could have tools that were legitimately 7.4, 9.6, 10.8, 12, 13.2, 14.4, 15.6, 16.8, 18, 19.2, etc. volts. Now they seem to have all settled into the 12v vs 18v convention for the most part.

Thanks, sac, henk and jerommel!

frequently series packs list mah incorrectly

say the cells are 3000 mah
there are 2 in series

they will call that 7.4V, 6000 mah
but it is really 7.4V, 3000 mah

just something to watch out for
amazon has tons of listings like this

most commonly it is a 2S2P
if the cells are 3000 mah, they will call that 7.4V, 12000 mah
which is actually 6000 mah

I'm back again.

I see 2P3S, but that's only 5 batteries while this pack has 6. What happened to the 6th battery? :-D

that means 2 parallel strings of 3 cells each

wle

2x3=6.

battery-battery-battery=1 series

battery-battery-battery=2nd series

Put those series in parallel= 6 batteries in pack.

edit: while it looked good on the preview screen, some formatting arose after submitting.

Ah. Thanks!

I was thinking 2 batteries in Parallel and 3 batteries in Series:D

Super clear. Thanks!