Battery current listed in coulombs?

[Altair_the_Vexed]

I'm doing a project for a client and the spec sheet battery they want to use lists the various charging and discharging currents in coulombs! Coulombs are the unit of charge, not current. Current is measured in C/s (coulombs per second) - more commonly known as amperes ("amps", symbol A).

So why would they list current as coulombs?

At least, it looks like that's what they mean - here's an example:

• Standard Charge Current = 0.2C₅

What's that sub-script 5 about? Is that supposed to be "C/s"?

Any idea what is going on? Am I missing some simple fact? Or do I just need to tell the client to get an new battery supplier who actually knows what they're doing?

[factotum]

I think C refers to "Charge Rate", and it's essentially a multiple of the battery capacity? So, if you have a 1Ah battery, a charge rate of 0.2C would be 0.2A (0.2x the current that will discharge the battery in one hour). I would probably confirm that with the battery manufacturer rather than taking my word for it, though.

[GeorgePresson]

"C" is the rated capacity of the battery in amp-hours. The subscript "5" usually means the time period used by the manufacturer to calculate C. C is usually measured with discharge over a 20 hour period (C20) but this uses a 5 hour test, so read C5 as "C over a 5 hour discharge time".
In that missing is A i.e., Standard Charge Current = 0.2C5A...