Highest battery storage charge?

[Julez]

Hi
I am going to be using various DJI drones for search and rescue in the UK, so speed of response is important. I know that keeping LiPos at full charge shortens their life, but also I need to deploy quickly without waiting forever to get up to full charge. Does anyone have any reliable info ( not speculation!) about just how high a voltage/percentage I can store batteries at ( and how low a temp?) without drastically reducing their capacity.
Any advice most welcome

 

[R Martin]

Hi
I am going to be using various DJI drones for search and rescue in the UK, so speed of response is important. I know that keeping LiPos at full charge shortens their life, but also I need to deploy quickly without waiting forever to get up to full charge. Does anyone have any reliable info ( not speculation!) about just how high a voltage/percentage I can store batteries at ( and how low a temp?) without drastically reducing their capacity.
Any advice most welcome

That depends entirely upon the battery being stored. My 5500mA LIHVs are stored at 23.1V and only charged prior to flight to the full 26.1V. A high capacity charged takes about 45 minutes to get a battery from storage voltage to operational status. That gives you almost enough time for flight planning and regulatory paperwork to get in the air.
Your results will vary based upon the battery you use.

 

[Capt KO]

The problem with flying a battery that has been stored and not recently charged fully, you can never be certain of it's true voltage. Or time remaining. They often drop voltage very quickly without warning. Not the same as flying a battery down then starting another flight. Too dangerous unless life-threatening scenario. Use the 10 day discharge and keep 1 full. Stay safe and thank you for your service.

 

[Capt KO]

PS: store in the refrigerator for longest life.

 

[Andy9]

He said that his flights are going to be for search and rescue purposes.
As such I don't believe that there is time to charge prior the flight.
I would have all the time one batt. charged to full and rotate it between other batteries which would be charged to storage level. This would make an instant response possible and during that somebody can charge other batteries.

 

[ISchonfeld]

I would have all the time one batt. charged to full and rotate it between other batteries which would be charged to storage level.

I have a similar problem as the OP and use a similar method as quoted above. I keep 2 sets of 2 batteries and charge 2 every 10 days. The 2 that get charged alternate. This way each pair of batteries gets at least a little rest below the full charge. Yes, batteries are cycled about 18 times a year (plus flight usage). But I know I'll have 2 batteries ready to go, and when a call comes in I can put 2 on charge while responding, prepping and flying the 2 that are already charged. I'm figuring that it will be a few years before I've exhausted the number charge cycles on these batteries, and by that time the UAS and batteries will be replaced anyway.

One important thing is that batteries are all kept at room temperature, and not kept in a vehicle subject to summer overheating and winter cold. I can't speak to the idea of refrigerating them.

 

[Julez]

Thanks for the advice. I think the 'rotating' strategy sounds the most practical all round.