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Battery Capacity Math Question
#11
While I get your comment, and its a good point....
I'm talking "power capacity" by using 16wh vs 32wh as the metric of capacity in my comment.   Here's a quote from https://learn.adafruit.com/all-about-bat...capability -  "Power capacity is how much energy is stored in the battery. This power is often expressed in Watt-hours (the symbol [b]Wh[/b])."   

While the previous poster said "capacity" (without clarification) I think DIY'ers will often mean "how long can I run something" when they say capacity.   In the sense of "how long will my battery run something" - adding cells in series will increase (power) capacity.  Smile
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#12
(09-08-2020, 06:10 PM)OffGridInTheCity Wrote: I'm talking "power capacity" by using 16wh vs 32wh as the metric of capacity in my comment.   Here's a quote from https://learn.adafruit.com/all-about-bat...capability -  "Power capacity is how much energy is stored in the battery. This power is often expressed in Watt-hours (the symbol Wh)."   

No, as I explained above, you are talking about battery "energy" (or "energy capacity") (Wh), not "power capacity" (W). Of course it comes as no surprise that there are some (hobby) pages on the web where authors misuse standard terminology (whether by oversight or inexperience).

Below is an example of the standard terminology, from an nrel.gov FAQ on Grid-Scale Battery Storage.

nrel.gov Wrote:What are the key characteristics of battery storage systems?

Rated power capacity is the total possible instantaneous discharge capability (in kilowatts [kW] or megawatts [MW]) of the BESS, or the maximum rate of discharge that the BESS can achieve, starting from a fully charged state.

Energy capacity is the maximum amount of stored energy (in kilowatt-hours [kWh] or megawatt-hours [MWh])

and excerpted from a page on eia = U.S. Energy Information Administration (my emphasis).

eia Wrote:In 2010, 7 battery storage systems accounted for only 59 megawatts (MW) of power capacity, the maximum amount of power output a battery can provide in any instant, in the United States [...] These observations consider both power capacity and energy capacity, the total amount of energy that can be stored by a battery system [...] At the end of 2018, 869 megawatts (MW) of power capacity, representing 1,236 megawatthours (MWh) of energy capacity, of large-scale battery storage was in operation in the United States

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