confused between Amp and mAh

[sometrike]

I have some battery packs which are made up of cells marked:

Samsung ICR18650-22P

They are supposed to be 4.4Ah, which I think I understand since there are 14 cells which would be two sets in parallel. Does that sound correct?

When I google Samsung ICR18650-22P, I find sellers advertising the following cells:

Samsung ICR18650-22P-10A 2200mAh Li-ion Batteries

Can someone explain the !0A part? How does it relate to the 2200mAh?

 

[Matador]

I have some battery packs which are made up of cells marked:

Samsung ICR18650-22P

They are supposed to be 4.4Ah, which I think I understand since there are 14 cells which would be two sets in parallel. Does that sound correct?

When I google Samsung ICR18650-22P, I find sellers advertising the following cells:

Samsung ICR18650-22P-10A 2200mAh Li-ion Batteries

Can someone explain the !0A part? How does it relate to the 2200mAh?

Not a singel 18650 format cell can reach 4.4 Ah. Not one. The max is 3.5Ah.
Your cell is 2.2 Ah capacity rated (at 0.2C discharge rate), able to discharge at a rate of 10A max.
10 Amp is current
2.2 Ah is capacity, aka energy content.... equivalent to 2.2A current for one hour.
At 10A (max discharge rate here), you'll discharge this cells in less than 13 minutes. But remember 2.2Ah is when you pull 0.2C (0.44A), so when you pull 10A load, more like 1.6-2.0Ah depending on the cell type (chemistry, electrode, temperature, internal resistance, etc etc). So 10A probably empltying it in 10min or less.

 

[Matador]

Ok I read fast. It's a 2P that's 4.4Ah. So yes cells are 2.2Ah, as you said.

 

[sometrike]

So I want to try to put this in to terms I can understand. The Amps part is like how big of a bucket energy you have. And the mAh is like the size of the spigot at the bottom indicating how much you can get out at wide open.
Correct it in those type terms anyone.

 

[dustNbone]

Backwards. Amperage is a measure of current, amp hours is a measure of energy capacity at a given voltage.

A 2200mAh cell will provide 2.2 amps for one hour before it's depleted, however this cell is only going to give that capacity if drained slowly. 0.2C on a 2.2Ah cell works out to 440mA, if it's being drained faster than this, the capacity will decrease, as more of the energy will be lost to heat. So it's more accurate to say this 2200mAh cell can provide 440mA for 5 hours. Drain it faster than that, and you get less mAh out.

A 10A cell means it can provide 10 amps output without overheating or sagging below an acceptable voltage.

 

[999zip999]

mah is capacity and amp is the size of the hose. Best the have a bad ass cell and under use so it can live for some time. Do you always drive your car with the peddle on the floor ? Not since you were 16.

 

[Matador]

So in other words

The current rating in amperes (10A) is the size of the spigot.
The capacity rating is the size of the Bucket holding the water.

If you force a lot of water through a spigot it will create added resistance and energy will be lost through heat.
Might as well use a big spigot to minimize resistance (A HIGH DRAIN rated cell, like 30 amps)
If the hose you put on the spigot is too small it will add more resistance
If the hose you put on the spigot is too long, it will also add more resistance.

The hose is like electical wires.... Keep them fat and short and you will loose less energy in heat because of resistance. delta P = delta V x I

 

[wesnewell]

The 10A part means that's what each cell is rated for, 10A output. That would mean they are 4.5C discharge rated cells. A 2p pack would be rated for 20A.

 

[amberwolf]

FWIW, a better version of the bucket/spigot metaphor is:

battery capacity Ah = bucket (determines total amount)

battery current capability (C-rate) A = opening in bucket that goes to spigot (determines maximum rate power should be drawn)

controller (current limit) A = spigot (determines maximum rate power *will* be drawn)

 

[Matador]

FWIW, a better version of the bucket/spigot metaphor is:

battery capacity Ah = bucket (determines total amount)

battery current capability (C-rate) A = opening in bucket that goes to spigot (determines maximum rate power should be drawn)

controller (current limit) A = spigot (determines maximum rate power *will* be drawn)

Nice one ! True that s spigot is more like the controller part a you can adjust the flow (aka, current)!