Can I use a 12V DC power supply to charge Mavic air batteries?

[Deleted member 94047]

Hello all,

I know this has been asked before in one form or another but I guess it needs to be asked once more; so here goes. I have a 84.4Wh portable power bank I use for powering a small telescope. It can output a consistent 12V DC @3000mA. And I can get the below charging cable from amazon for cheap to plug the MA battery in to said power bank directly. My question is:
(1) Will this even work - considering the original MA battery charger outputs 13.2V @ 3.79 A
(2) If it does work - how many batteries can I possibly charge with this? My simple math would tell me about 3 but I don't trust my math skills.
(3) And this is the part I am worried about - does this have the potential to damage either of the batteries involved?

I should add that I already have three batteries for the MA and that certainly helps. But if this setup can give me juice for charging them on the go I will be one happy flyer. Any insights will be greatly appreciated. And thank you for making this place so resourceful, this forum is like a flight school.

 

[Deleted member 94047]

I ordered the DC charging adapter but it will take 20 days to get here from China. I will see if it works and hopefully I will not end up with two fried batteries.

Edit: the power bank uses the same port for power in and out. Worst case scenario will be the MA battery will charge the power bank instead of it being the other way.

 

[tuscy]

DJI sell a car charger that takes 12v from a car cigar lighter socket via a "black box" and costs around 40GBP. I would suspect that the box contains voltage regulators and other protective circuitry.

What you've found appears to do away with the extra electronics. It will probably work but I'd be wary about using it.

 

[Simmo]

I'm not sure if its the case anymore, but with the M1, charging from the car (12v) never used to work properly unless the car was running (13.8v).

 

[MAvic_South_Oz]

I'm not sure if its the case anymore, but with the M1, charging from the car (12v) never used to work properly unless the car was running (13.8v).

Yep, as with a heap of other recent threads here, I found the easiest way to charge on the go is this (from another thread) . . .

The DJI charger say it needs 13.1v (from memory), so SHOULD be ok when driving with alternator charge . . . however I do a lot of outback touring, fully off grid for over a month sometimes, running fridge / freezer, led lighting etc, and all charging needs for phone / ipads / DJI batteries.

This is just an example of what I bought from a local Australian supplier . . . google 12v to 13.8v step converter in your location, you may get a better price / local service . . .

DC 12V to 13.8V 18A 248W Car Step Up Power Supply Transformer Converter 714998379344 | eBay
Solder and shrink tube on some good 15amp male and female cigarette light plugs, and you're set.

This step converter gives good 13.8v constant, just have to watch battery level in vehicle if not driving (I also have solar panel charging for camps).
I can use the 4 way charger (it only does one at a time anyway), but with 4 batteries I'm usually ok to just do one at a time, changing when stopped at various times through the day.

12v charges a lot faster than the mains charger !!
I find this with other battery charging systems too, like some of my power tool batteries.

 

[Simmo]

Just be wary about the cigarette lighter sockets, they are a crap socket and more often than not, rated to 10 amps.

 

[MAvic_South_Oz]

Here in Australia, the SCA (Supercheap Australia) outlets have a great 15amp plug in M & F, use HD wiring to complete and make as long as needed, but remember voltage drop if going too long, a foot or two is ok.
I use mine on my Arpak 110amp/hr 2nd battery . . . if you only have the main battery, it's probably worth installing a twin 15 amp ciggy socket, fused direct from the battery, again with suitably heavy wiring to take it into the vehicle cabin or wherever.
Just remember, watch vehicle battery volts if charging multiple drone batteries without driving, it could drain a small or weak battery and fail you when trying to start your vehicle engine.

 

[Simmo]

Ahh ok mate! In #5 you just said solder on some good plugs, I took to mean using the existing vehicle socket!

 

[MAvic_South_Oz]

Ahh ok mate! In #5 you just said solder on some good plugs, I took to mean using the existing vehicle socket!

No worries, a 10amp outlet will handle it, that's all that the Arkpak is fused at.
I just installed the HD outlets in various places in my 4WD to service anything I wanted now or in the future.

 

[Deleted member 94047]

Hummm, so I might need something else to get the voltage up from 12 to 13.2V? I am also not sure what happens when two batteries are connected to each other. Which way will the current flow? May be this is not such a great idea after all. That's why I asked, I know next to nothing about batteries and current.

 

[MAvic_South_Oz]

Hummm, so I might need something else to get the voltage up from 12 to 13.2V? I am also not sure what happens when two batteries are connected to each other. Which way will the current flow? May be this is not such a great idea after all. That's why I asked, I know next to nothing about batteries and current.

Yes mate, it's usually ok with vehicle running, as the alternator amps should push battery up to high 13v . . . if not running, once the power drops to lower than 13.1v (which is pretty fast, maybe 10 - 15 mins ?), then it can be erratic, and it keeps cutting in and out.

(BTW, this is for the Mavic Pro 12v charger, but pretty sure other more recent Mavics will be similar . . . check your charger specs on the plate attached to it, or the manual.)

See post 5, I put a link to the step converter that works a treat for me, off ebay Aust, not the seller I bought from, and you could search your local ebay, I'm sure you will find someone selling the same unit.
Just ensure it's 12v - 13.8v as there are other voltage models, including step down converters.

 

[Simmo]

I am also not sure what happens when two batteries are connected to each other. Which way will the current flow? May be this is not such a great idea after all. That's why I asked, I know next to nothing about batteries and current.

Two batteries in parallel will give you more Current, whereas two in series will give you more voltage.

 

[MAvic_South_Oz]

Two batteries in parallel will give you more Current, whereas two in series will give you more voltage.

Yes, in general off road setups for 2nd batteries are through an isolator (or DC-DC charger), and in parallel.
You can run any accessory of a 24v system though by taking power from either 12v battery, if it's in the usual 2 x 12v series setup.

So when we run 2nd batteries there is no extra amps available (apart form the 2nd battery part), and usually we'll run AGM (or lithium) for 2nd batteries, more reliable for the purpose, they are made to do deeper discharges for accessories like fridges.

 

[tuscy]

Interesting stuff. We also run an auxiliary battery plus solar panels when camping "off grid" (mainly for the fridge to keep the beers cool!). I think the solar panel produces 13V+ to charge the AGM leisure batteries so hopefully when the sun is shining it should be possible to charge the mavic batteries without needing to start the engine.

Regarding the comment about the Mavic battery charging the charger the battery would need to be switched on to produce any output and almost certainly the output is from different pins. Plus it's likely that the DJI 12V charger will have diodes to prevent this scenario.

 

[Simmo]

Sorry Tuscy, I'm in Cairns, in FNQ and we use Solar a lot here......
I just noticed that you are in Hampshire....
What do you use solar panels for??? Shelter from the rain/snow??

 

[tuscy]

Ha ha! Yes indeed! We usually travel to France to find the sun but amazingly we've been able to use it in the UK too... in between snow showers!

 

[Deleted member 94047]

So, to answer my original question - Yes, I can! Yes, but I probably shouldn't!

The little cable made it here from China sooner than expected and I plugged one end in to the power tank and the other in to the MA battery; I turned the power tank on - half dreading what might happen. For a few seconds, nothing happened and I was about to pull the plug out when the little lights on the battery started blinking away. This was a battery that has been charged to 60% already, so I wanted to do a proper test. Went out to the backyard and drained the battery to 20% by hovering. Now it is connected and blinking away. Will see how long it will take to get it to full and how much power will be left over in the power tank after wards. All in all, I am delighted to have found a charging solution for when I am away from civilization

Won't charge if MA battery is below 40%, and will take an hour to charge to 90%. Having reconsidered my needs and the safety and longevity of both batteries involved, I decided to go the Smatree way. Ordered this Smatree Akku Ladestation für DJI Mavic Air Akku: Amazon.de: Kamera after I read some reviews. Pricey but looks like it is exactly what I need.

 

[Manty]

just purchased one. Due to massive NFZ I have to travel to fly. It charged a battery in the field yesterday in 40 minute. Will try 3 charging next time out.

 

[Deleted member 94047]

I have used it a couple of times too, charged all three batteries from around 25-30% to full in about 40 minutes. So far I have gotten 6 batteries worth of recharging from the initial charge. I am very happy with it.

 

[Manty]

Brilliant. Saves buying more batteries for a day out.