Jeg antar at det er mye værre misshandling å lagre batteriet med 94% enn med 6% SOH. Å lade Leaf over 4V anser jeg som misshandling.
Det sies at det som sliter lithium-celler er høye oppladinger og djupe utladinger, og at det værste er høy spenning i kombinasjon med høy temp.
Jeg synes det er vanskelig å finne optimal lagringsspenning, når jeg søker på nettet, og det finnes ulike typer li ion. Noen anbefaler 3,5V, andre 3,75V og noen anbefaler under 3V.
Problemet med billig forbrukerelektronikk i motsetning til biler, er at man ikke har beskyttelse mot djupe utladinger, og kommer man under 2,5V er det ikke sikkert man klarer å lade opp igjen, og går du fra ei utlada celle som blir liggende i skuffen i årevis med noe selvutlading, så kan du få et problem, og noen anbefaler 40% lading for å unngå det. For en bil i daglig bruk, så kan det tenkes at det ideelle er å ligge godt under 40%.
Her er visse løse påstander om ymse typer celler:
Table 3: Estimated recoverable capacity when storing Li-ion for one year at various temperatures. Elevated temperature hastens permanent capacity loss. Not all Li-ion systems behave the same.
Temperature | 40% charge | 100% charge |
0°C | 98% (after 1 year) | 94% (after 1 year) |
25°C | 96% (after 1 year) | 80% (after 1 year) |
40°C | 85% (after 1 year) | 65% (after 1 year) |
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries18650 batteries must be stored in a charged state; 40% is ideal. This will ensure that the battery will not drop below 2.50V/cell with self-discharge and go dormant. Discard them if the voltage goes below 2.00V/cell for more than seven days.
If you are intending long term 18650 storage, a storage charge closer to 50% of usable capacity (~3.7V) rather than 100% (4.2V) will prevent faster battery degradation.
Moli Energy Lithium Ion Battery Storage:
Storage temperature range is -20 to 60° C. Recommended storage voltage range is 4.1 to 2.0 volts per cell. For prolonged storage periods, store discharged [i.e. 2.0 to 3.0 volts per cell] and at -20° to 25° C.
Panasonic Lithium Ion Battery Storage:
The batteries should be stored at room temperature, charged to about 30 to 50% of capacity. We recommend that the batteries be charged about once per year to prevent overdischarge.
PowerStream Note: Test data confirms that storage of lithium-ion batteries is best if the cell is partially discharged. In one test by Cadex Electronics ( http://www.buchmann.ca ) after 1 year storage at 25°C the non-recoverable capacity remaining is 96% when stored at 40% initial charge level, but only 80% if stored with 100% initial charge level. This effect is reduced at lower temperature and is a non-issue at 0°C. At higher temperatures the effect is much worse. Cadex's recommendations are to store below 15° C at 40% of full charge (3.5 volts per cell). Our experience is that with cells stored at room temperature for 3 years that the non-recoverable capacity did not decrease, so this is probably manufacturer dependent.