Question for the wise.
I know storage should be between 30-50% for good battery health and longevity. Say you charge to 100% and the weather craps out. Apart from sitting there and ground running it down, or going the inverter route that I’ve read about to discharge. Realistically, how long can you let it sit at 100% for before worrying about battery damage? 1 day? A week?
Thanks.
I have an electric car and since it uses similar pouch cells to the new V2.5 battery, I usually charge it in a similar manner, the car mfg recommend 20-80% normal operating range so I charge the battery and leave at 80% but then when conditions are pretty certain, I charge to 100% just before flying. On my car, if I’m planning a long trip, I charge to 100% prior to departure, otherwise 80% is my typical full charge. Charging to 100% and then not flying is not damaging the battery, but leaving at 100% for long period of time will reduce overall life, that is if you expect it last over 5 years. If you can’t fly, just drop to 80% unless you plan to fly tomorrow. It is difficult to judge how much life is reduced by leaving at 100% for a day or two, but I’m sure it’s not significant if it rarely occurs.
the V2.5 battery doesn’t use pouch cells, but 18650 cells, I guess?
Storing at 50% is considered to be optimal for those battery chemistries, while 80% is tolerable…
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) |
| 60°C | 75% (after 1 year) | 60% (after 3 months) |
Yes, the V2.5 packs use pouch cells.
are you 100% sure about this? Where can I see a reference to this?
Older packs use 2170 cells. The newer packs are a pouch cell form factor.
wow… didn’t know that. Aren’t they - at least mechanically - less safe? Less physical protection, no venting system just in case?
Typically, when soft pouches are used, the chemistry can be exactly the same as other formats. The big difference with drone batteries is that there’s usually no hard case protecting the soft pack; it’s exposed directly to the outside environment.
That’s why they tend to be less safe and more prone to getting dinged, punctured, or damaged in a crash. However, when a protective case is placed around the pouch, there’s really no inherent mechanical safety disadvantage compared to other cell types. In fact, pouch cells can actually be easier to vent than cylindrical cells because they can release pressure with very little resistance.
This is a big reason why most automakers today have shifted toward prismatic or pouch-cell designs instead of cylindrical cells they tend to offer better energy density and volumetric efficiency.
So it’s more about how the pack is designed than the form factor of the cell.