Electronic – How much nickel is in a NiMh battery

You're not really looking for the C rating (maximum discharge current in multiples of nominal capacity), you're looking for the adjusted capacity at your nominated discharge current.

A 1.8Ah lithium battery can theoretically give 1.8A for 1hour, or 3A for 1.8/3h = 36 minutes. HOWEVER the capacity for a battery is traditionally quoted for a 20 hour discharge. That is, a capacity rating of 1.8Ah means the battery delivered 90mA for 20 hours in testing.

The relationship between continuous current and time-to-full-discharge is NOT linear. You have discovered that when discharged at 3A, your 1.8Ah battery is delivering much less capacity (only about a quarter!) than a linear interpolation of the amp-hour rating would suggest. This is not unusual.

The better batteries will give rated capacity at several discharge time samples, or even a graph of current vs capacity. A battery intended for remote control uses will probably give better performance, as quick discharge is the intended application of these batteries.

(I use a 1500mAh 3-cell (11.1v) 25C lithium pack to power a 3A LED bike light, and I get around an hour, which is close to rated capacity given a reasonably efficient buck regulator).

How do you determine how many cells are in a Lithium battery?
My assumption is for customer travel and the present limits are;

• MAX Lithium per cell 20Wh
• MAX Lithium per battery 100Wh

The battery in question.

LP635940 Lithium Polymer Battery
3.7V @ 1.8Ah typ. capacity at 0.2C rate
= 6.66 Wh which is less than MAX per cell limit.

How many cells in package? Only 1.
Not because of capacity but because of construction method.

What are cells?
- discrete (separate) manufactured items.

How many items here?
1

How is it made?
Many recurring thin layers of {conductor mesh , electrolyte, insulator}.