Carsten,
How is the amp hours of a cell not an indication of the energy
stored in the cell?
The cell was already identified as being 3V, as was quoted in my
reply.
I stand by my statement.
-Chuck Harris (¦Å¦Æ¦Ç¦È¦Ë¦Ì¦Í¦Î 'tis trivial, but why bother?)
Carsten Bormann wrote:
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On Aug 29, 2019, at 13:17, somebody I¡¯m not personally addressing here wrote:
The 2.5A is more probably 2.5ah, or 2500mah, which is
an indication of how much energy is stored in the cell.
The ¡°3V2.5A¡± is likely 2.5 Ah, or 2500 mAh, which is an indication of how much charge is stored in the cell (1 Ah = 3600 C). Multiply by the nominal voltage to get an energy, so a 2.5 Ah battery at nominal 3 V is likely to deliver 7.5 Wh or 27 kJ (the energy a human gets from about 1.6 g of sugar).
But for SRAM keep-alive batteries, the charge is actually more interesting, e.g., a 2500 mAh battery is going to deliver an SRAM standby current of 1.5 ?A (microampere) for a 6116 SRAM for about 190 years (of course, battery self-discharge is likely higher than this). Unfortunately, SRAM data sheets often have ¡°typical¡± standby currents (for the IDT 6116 I¡¯m looking at, the max value is a whopping 30 ?A, which makes this battery last 9.5 years ¡ª now you see where that ballpark figure of ¡°10 years¡± is coming from, even if this is at 70 ¡ãC).
(Sorry about the nitpicking, but I just spent a day or so fixing some IoT stuff that claimed it measures energy in W/h. If you are still at an age where you love learning, try practicing to type difficult characters such as ?, ¦¸, ¡ãC, and capital letters ¡ª case does matter in unit names. Oh, and it¡¯s really been Hz, not cycles, for a while already. Since 1960. :-)
Gr¨¹?e, Carsten
PS.: If you want to experience the full wrath of German Engineers about correct usage of units, try
