I bought a Phantom 4 back in 2017 and used it just for recreational video stuff but haven’t used it for a few years. I would like to use it again this summer to film a Fliteboard moving at sea but when I got it out recently neither of the batteries now work. From a bit of research they’re not easily fixable. I was looking at new batteries and can get non-original ones from BatteryBuy for about £62 inc delivery, but I noticed that I could just buy a new Mini 4K for £269. I know they’re not comparable prices but my experience with non-original batteries is that they start to deteriorate within a year, and I’m guessing technology has moved on since 2017 and there may be advantages to the Mini, and I’m guessing the weight makes it a bit easier (and safer?) to bring back onto the boat.
I’d be very grateful to hear your advice, and specifically your thoughts about the relative stability of the 2 drones as there will almost certainly be some wind out on the water.
Thanks in advance…
An awful lot has changed with regards to drones and airspace regulations.
In particular around the types of registration you must now have in place before flying.
Grab a coffee, it’s bit of a read 
Pingpsikes very good point not withstanding.
Maybe try leaving the batteries on charge for a day or 2. In a safe place ofc.
I know apparently dead macbooks from around that time could be revived this way.
If you do decide to go for a new drone you might try advertising your P4 for sale on here.
There might be a deal to be made.
A point to be aware of; if you’re used to a Phantom, a Mini 4K will be much harder to keep sight of in the air, which the CAA demands, especially below the skyline. Factor in the cost of a Strobon light (with GADC discount, of course)!
There’s a cracking deal on DJI mini 4 pro (DJI store) at the moment, 5 must be imminent!
Six months isn’t really imminent 
DJI have sales all the time 
39% off their power 1000
Thanks - I tried that but sadly they remain lifeless!
Thanks - will do that. I’m back up in Scotland next week and will photograph it all then.
Check eBay - non-genuine (sometimes “genuine” - but I’m even more suspicious if that’s claimed 
) batteries can be bought on there.
Recently bought one for my P2.
I did that too. Just sell the phantom as is and get yourself a 249g dji drone.