The 4th battery

[eBird]

I recently bought a 4th battery and have found great use for it - but not for flying.
Four batteries may seem like overkill, since on any given outing I've found that it's unlikely the transmitter and/or phone will last much more than 3 batteries, but having a 4th is great for "tuning" purposes.
With 2 or 3 batteries, I never wanted to spend much time tweaking camera or other settings as I swap out filters, or setting up an intelligent flight mode, or making a dry run before filming because it uses up precious battery time and I'd rather use the battery to fly. I use the 4th battery exclusively to do this work, and it will last all day for the multiple 5 minute "setting sessions" you might have in various locales during a day of hiking/flying etc.
The 4th battery can also be used to give your phone or transmitter a little boost if needed using the USB charging adapter, comes in handy.
Just my $0.02

 

[joejaxvic123]

Or you could just sell it to me, I've only got two....

 

[Mr. Salty]

Four batteries may seem like overkill, since on any given outing I've found that it's unlikely the transmitter and/or phone will last much more than 3 batteries

I have three batteries and have spent a day flying with them, cycling through each twice (recharging them with a car charger). I had plenty of charge left in my iPad and the controller. There may be a problem with your controller battery.

 

[buttons276]

Wow I have 3 batteries and I can go through all three atleast twice. (6 flights) and my controller is still at like half power. I must have got lucky on the controller because it seems to last forever