DJI Mavic Air Charging From Battery Packs and Solar Charging

18W Solar Panel

DJI Mavic Air Solar Charging

Introduction

I love my Mavic Air, but have to admit that at 20 mins flight time per battery (in perfect conditions), battery life is not one of its strong points! I have the fly-more package with the three batteries, but still run out of juice – although as my drone skills improve, my decent-footage to battery ratio is getting better!

Many of my trips where I wish to use my Air are multi-day backpacking, cycling and, more recently pack-rafting trips, buying additional batteries at £70 each is one solution to battery life issues, but for longer trips, this just delays the inevitable! Whats really needed is a portable recharging solution, and that’s what this blog is about.

I’ve done the research and reckon I have come up with a decent, renewable, cost effective solution for multi-day trips – see the end of this blog for the buying list.

Disclaimer: as with everything cheap that comes from China, do not use without keeping an eye or rather nose on it!

The idea is simple, while walking, paddling, cycle touring, the solar panel (18V, 18Watt) charges the XT Power battery pack (3.7V, 20AH == 75Watt/Hours). During this time, you just use your drone with the three batteries that came with it. Once you pitch up, or the sun goes down, you use the battery pack to recharge the drone batteries – and repeat…

The XT Power Battery Pack has 2x USB outputs and 1x 12/16/19/20/24V output. It will provide a maximum of 65Watts. The Battery pack can be charged via USB (2A), or by 12-20V DC (at up to 3A). Obviously the latter is far far faster than the former, providing 30W rather than the 10W you’ll see via USB. The mains charger is not supplied, but see the buying list below!

To transfer the power from the battery pack to your drone batteries, you use a 12V auto charger. DJI’s own car charger won’t work very well as it is incredibly fussy about input voltages (refusing to work at 12V for instance). Fortunately, aftermarket 12V chargers, both single and dual are cheaply available. See my previous blog.

In use, the single charger will draw a maximum of 60W from the battery pack, fast charging the Mavic Air battery close to its upper 60W limit. If you wish to be kinder to your batteries, then the dual charger also draws 60W but puts around 30W into the Mavic batteries taking twice the time to charge them.

Usefully, the XT Power pack will show wattage-in and wattage-out on its built in LCD display. It’s also possible to charge 5V devices via USB while the solar panel is connected. Where there is a load during charging, only the load wattage, not the charging wattage is shown. It also has a ‘remaining capacity’ display in percent offing a guide to what’s left in the battery pack.

While charging a Mavic Air battery, nothing else (eg phone, Mavic Air remote) should be connected. These may be charged together from the USB ports once you are done charging your Mavic batteries.

In Use

‘Dead’ Mavic Air batteries are never totally ‘dead’, and the Watt/Hours required to recharge, (even taking efficiency losses into account) is significantly lower that the 27.43Watt/Hour rating quoted on the battery. In use, I found that a fully charged 75Watt/Hour XT Power Pack was able to charge 2.5 Mavic Air batteries (one was part charged already), as well as to top up my phone from 50-100% and to charge the Mavic remote from 2 LED’s to ‘full’. After this, the XT Power pack was indicating 5% remaining.

Recharging the battery pack from the 18W panel is guaranteed to be slow, but I was still able to get it from 5% to 100% after 8 hours of decent sunshine in Scotland. Under a blue sky with the panel aimed directly at the sun (and adjusted as our planet moved), I was seeing 15W from the panel. Laid flat in the same conditions, I saw 11W. For those of you closer to the equator, the flat vs aimed difference will be lower, and conversely, for those further away, worse! That said, the further away you are from the equator, the more summer-daylight you get! Under the more common grey skies we get here in Scotland, I was seeing 6W aimed and around 3W flat – to charge the XT Power Pack in the same day, sunshine (or 2 panels wired in parallel) would definitely be required.  (all wattages as indicated by the display on the XT Power battery).

Connecting It All Up

Aside from the Battery Pack, Panel and Car charger, you might need some soldering skills, heatshrink etc to tie it all together. There are a variety of options depending on how compact you want the solution to be, your ability and how much time you have. For me personally, I re-boxed the Mavic 12V charger, and bought some DC power cables to facilitate easy stowage. Others may opt to simply cut the cable supplied with the XT Power Pack in half, attaching one end to the panel and the other to the Mavic charger. However you do it, make sure that you leave the solar cable long enough to be able to keep the XT Powerpack inside the tent/bothy with the solar panel outside.

Please note that the obvious alternative of connecting the solar panel directly to the Mavic Charger won’t work. The voltage from the panel is too high for the charger (charger LED flashes rapidly). You could lower this via a cheap linear regulator, diode or a different panel, but bear in mind that the DJI battery is ‘clever’, and expects a constant source of power of the type that a solar panel can’t provide. Get the XT Power pack and use that as an in-between power-store!

Buying List

Mandatory Parts

Optional Parts

  1. No soldering required – 5.5mm Jack To Car Cigar Lighter Socket (Mavic charger plugs right into this, as does solar panel)
  2. No soldering required – Connector for Solar Panel (Chop off existing DC car connector, replace with this)
  3. Twin Pack DC Power Socket (chop off the plugs and wire sockets to Panel and (re-boxed) Mavic charger
  4. DC Power cable for soldering to panel/re-boxed charger (instead of 3 above)
  5. 19V Mains charger to fast-charge the XT Power Battery Pack (3x speed vs USB charge)

For a simple no-solder solution, by the mandatory parts together with (1), for something less faffy, include (2) as well. If re-boxing the Mavic charger, buy (3) or simply cut the supplied cable in two, soldering one end to the panel and the other to the Mavic charger. If you don’t wish to destroy the supplied XP Power Cable, buy another one (4)

Disclaimer: as with everything cheap that comes from China, do not use without keeping an eye or rather nose on it!

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