Good question. They are LiPo batteries, after all. Honestly, two years into owning a Movi and working with LiPo's, I've stopped worrying about storage charge. Haven't lost a battery to it yet. I've killed two of them by over-discharging by accident (left Bartech plugged in over night and forgot about it), but never due to storage. I think you'd be safe to bring them down to 50% charge if you're really concerned, especially if you're going to let them sit for a few months. Several of my batteries have sat at full charge for over a month with no problem.
Based on a limited sample, "it happened to me once" -- I would not leave the MoVI Pro batteries installed on the MoVI Pro itself. What happened was that they discharged over a period of several days. The MoVI Pro was not left powered up. I can speculate that there might be a slight leakage current drawn from them when they are installed sufficient to discharge the batteries over time, but that really is baseless speculation. I don't know. But in light of that one incident, I remove them from the MoVI Pro when I know I'm not going to be using it for several days. As Graham says, bringing them down to 50% charge capacity is probably the correct way to proceed for long term storage. The MoVI Pro manual does state: "Do not store fully charged MōVI Pro Battery Packs for long periods of time." (Page 10.) It goes on to say: »» Do not discharge MōVI Pro Battery Packs with current exceeding the 8-10A of continuous discharge current. It will cause the battery to overheat and may result in battery deterioration, swelling, bursting, or fire. »» Always discharge in a fireproof location. The above suggests there is some means for discharging the batteries other than on the MoVI Pro -- or possibly it also means, run the MoVI Pro in a fireproof location if you're using it as the means for discharging the LiPos. For what it's worth, and changing the topic slightly, I also find that the IDX batteries for the MoVI Controller stay charged longer if you physically dismount them from the Controller for storage. Again -- limited sample data, but the MoVI Controller was powered off but the battery barrel connector was plugged in and several days later the battery was discharged. I just don't like going to either unit after several days and discovering the batts are dead! Andy Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Did you discover that the hard way, James? There will also be some internal self-discharge, but that's usually pretty slow. Andy Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
I've wondered if the chargers will slowly drain the batteries if you don't have them plugged in to AC power. The green lights stay on on the charger when the battery is plugged in, whether there's AC power or no.
Hi Graham: Yeah, if there is an LED on that would indicate there is some small (but finite) back-current. I would disconnect the battery completely. Andy Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert