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First flight in over 6 months - any extra checks/precautions?

cambspilot

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I got a Mavic Mini about a year ago and had some good fun with it over summer last year, but as the weather got colder it got put in a cupboard and forgotten about. I'm now thinking of getting it out again and flying it for the first time in over 6 months. Is there anything I should be aware of that might need extra checks after such a long gap without any use? I'm thinking in particular regarding charging the batteries, but if there's anything else I should be aware of then I'm all ears.

Also, a UK specific question - I've been reading through all the rule changes that came into force at the start of this year. Am I right in saying that as the Mini is under 250g and has a camera, I now need to get an Operator ID (not needed last year), but I still don't need a Flyer ID or A2CofC?
 
As the Mini have had problems with deformed props in the past coming from how the craft have been stored & if the props have been put under pressure ... it can be wise to put on fresh props to avoid any mishaps like uncommanded descents or not being able to reach a heading speed according to spec.

Batteries ... well "put in a cupboard and forgotten about" isn't anything that goes well together with batteries. If they were put away in storage voltage (3,7-3,8V approx. 30-50%) they most probably are OK ... but if full or nearly empty it can be a problem ... either directly as they don't take charge or in the long run when the total life time have been severely shortened. The same goes for the battery in your RC.

Softwares & firmwares aren't crucial to get updated immediately ... if everything worked 6 month ago it should work now also.

I'm leaving over the UK rules to a local member ...
 
@cambspilot you will need an operator ID £9 for a year and to be perfectly honest with you i would advise that you take the flyer ID test and then if your drone does happen to go over the 250 grams with such things as landing gear extenders or the provided prop guards then you are covered it is free and lasts for 5 years and it also demonstrates that you have a basic understanding of the rules and regs go on the CAA website and its all explained
 
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Thanks both for the replies. With regards the battery I share your concern as I now have no idea what state they were left in after I last used them, hence asking if there's anything specific I can do with regards their first re-charge, or perhaps anything to monitor when using them. I'm not too bothered if they now only have, say, only 80% or 90% of their original maximum capacity, but I'd hate to be in a situation mid-flight where they were reporting plenty of charge and then suddenly dropped to zero without warning (I once had an old phone that regularly did that!)

I'm thinking of getting a new battery, and then doing a couple of test flights, one with an old battery and one with the new, where I just hover at head-height until the battery is nearly all used up. The I can see how long the battery lasts in each case, and look at the logs for any glaring differences in behaviour regarding the battery voltage/temperature/anything else.
 
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How'd you get on @cambspilot ?
Like you, mine hibernated for the winter. Batteries were left on a full charge last autumn.
Charged them up, was exactly the same as if I'd flown it yesterday (apart from my skills which were a little rusty!)

Gone through all batteries at least three time in the past week and no faults- still charging to 100% and holding their charge well.
 
So far I've tested a new battery against one of my three old batteries. There was no significant difference between the old and new. I was going to wait until I'd done all three old ones before reporting back, but since you asked, that's what I've done so far. An assortment of seemingly relevant stats from the flight logs (via AirData) are below, read on only if you want excessive detail!

The test was to take off, fly forwards a few metres to get out of the middle of the footpath I was taking off from, leave the drone hovering until the battery reached 10%, and then return to the path and land.

Old batteryNew battery
Flight time25m 40s26m 11s
Initial battery capacity2352 mAh (100%)2367 mAh (99%)
Battery temperature range26.0 - 45.1 C21.0 - 41.5 C
Battery voltage range8.3 - 6.6 V8.2 - 6.8 V
Minor cell voltage deviations (> 0.01V) per minute00.8 (all in the first 40 seconds of flight)
Major cell voltage deviations (> 0.07V)00

I found the temperature range to be the most interesting difference, but I doubt there's that much you can actually read into it. The old battery went straight from a very warm house to the drone's case, in a rucsac, against my back, for a 20 minute walk, before it was flown. But the new battery was exposed to the air for the duration of the old battery's 25 minute flight before it was used.

One other thing I learnt is that standing next to a hovering drone for 25 minutes and doing nothing is a lot more tedious than I thought it would be, which is why I haven't tested the other two batteries in this way yet :)
 
Ha ha, you need to take a good book with you!

Well I think we've proven maybe managing the batteries would be optimal but not necessarily required... Or we've just been lucky!
 
Updated results for all the batteries I own:

Old battery 1Old battery 2Old battery 3New battery
Flight time25m 40s25m 11s25m 05s26m 11s
Initial battery capacity2352 mAh (100%)2175 mAh (98%)2184 mAh (97%)2367 mAh (99%)
Battery temperature range26.0 - 45.1 C19.8 - 38.2 C22.4 - 38.8 C21.0 - 41.5 C
Battery volatage range8.3 - 6.6 V8.2 - 6.6 V8.2 - 6.6 V8.2 - 6.8V
Minor cell voltage deviations per minute00.10.20.8 (all in first 40 seconds of flight)
Major cell voltage deviations0000
% flight time compared to new battery98%96%96%100%
% initial battery capacity compared to new battery99%92%92%100%

So old batteries #2 and #3 don't seem to be in quite as good a state as old battery #1 in terms of the battery capacity, but that only translates into a small percentage reduction in the flight time, not as much as the percentage reduction in capacity.

I also noticed that one of the things AirData shows for each flight is the battery serial number, so I was able to compare the battery capacities I have now with flights last year. It turns out that, through complete chance, I had hardly ever used the battery that I'm now calling battery 1. It looked like for the vast majority of the time I only used two batteries per day of flying, and just alternated between batteries 2 and 3. Perhaps due to the order I put them back into the charger after use, who knows?

Anyway, I can see that the initial capacity of batteries 2 and 3 was gradually falling over the months that I was flying last summer, with both starting in the 2300's and ending in the low 2200's. So for them now to be 2175 and 2184 is probably not that surprising or concerning.

And with that, I think I've reached the point of over-analysis. All the batteries seem fine to me, and don't seem to have suffered badly through lack of care of winter. But every now and then I'll check over their performance in AirData to be sure.
 
I'd just do a hover test in the room for a full battery and just observe it to be sure. Providing you stored it correctly it should be fine coming out of hibernation
 
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