====== Batteries ======
//Not to be confused with the legal term for hitting someone very hard.//

===== Accumulators =====
In newspeak //rechargeable battery// or just //battery//, this device stores electrical energy in the form of a chemical [[https://en.wikipedia.org/wiki/Voltage|potential difference]].

==== Voltage by accu technology ====

^ Technology ^ V<sub>max</sub>[(maximum voltage cells like this can sustain without being damaged)] ^ V<sub>min</sub>[(minimal voltage where the cell is usable, anything less might damage the cell)] | A<sub>max</sub> (discharging) | A<sub>max</sub> (charging) |
| NiCd | 1,28V | 0,9V-1,1V |  | 250mA-500mA |
| NiMH[([[https://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_battery|Nickel metal hydride]])] | 1,26V-1,45V | 0,9V-1,1V |  | 250mA-500mA |
| Lead acid | 2,1V | 1,4V-1,75V |  |  |
| Li-Mn | 4,05V-4,1V | 2,7V-3,0V | 5A-10A | 1A-1,5A |
| Li-Po |  |  | 10A-15A | 1A-1,5A |

==== charging / discharging ====
Charging and discharging rate is defined as the [[https://batteryuniversity.com/learn/article/what_is_the_c_rate|C-Rate]]. Usually you want to charge at half the rate of the nominal capacity (0.5C or C/2).[(this means that if you want to charge a cell with 1000mAh, you should charge it for two hours at 500mA or less)]

===== common sizes =====

[[https://en.wikipedia.org/wiki/List_of_battery_sizes|Wikipedia: List of battery sizes]]

^ identifier ^ type ^ size ^ usual technology ^ used in |
| AA | round cell | | NiMH |  |  |
| AAA | round cell | | NiMH |  |  |
| 10440 | round cell | Ø10mm x L44mm | Li-Ion | same size as AAA, but different voltage (3.7V vs 1.5V) |
| 18650 | round cell |  | Li-Ion | battery packs, laptop batteries, high-power flashlights, e-cigs |

===== Lithium Ion cells =====
  * [[https://www.youtube.com/watch?v=AvzhmUPOmRc|Opening 18650 cells: Panasonic Sanyo Sony Generic Lithium-ion Battery Teardown]] (Rinoa's Auspicious Travails, 2017)

===== further reading =====
  * [[https://batteryuniversity.com/|Battery University]]