This is an massively improved charger for DJI Mavic Pro.
I have tried many chargers for my Mavic, but they have been really very poor, and not practical for field use. Some are just JUNK.
This forced us to look at something better, but even on the market now, they are usually poor quality chargers. They are basically just a cheap power supply that converts AC to 13.1Vdc. Since they are usually small in size, the total charging amps are reduced to each port added for charging. One charger bought from Ebay in my possession is a 4 port, but when you use all 4, the charging drops to ONLY 2.0 Amps per port. This defeats having 4 ports, as now it takes twice as long to charge. Not a fast charger....
So, we set out to build a charger that would handle proper charging, with proper current AND voltage regulation. We have built one with Buck/Boost converters having one dedicated to each port. The buck/boost used in this charger, are rated up to a max 60 watts each when active cooled.
Each charger that has 2 Buck/Boost converters installed, will be set to deliver 3.4 Amps per charging port for the batteries. While not max, this leaves some headroom and keeps the heat down a bit. This makes a very nice 120watt capable charger. You can feed the input with 5 - 30 Vdc, and it will always supply optimum voltage for DJI batteries at 13.1 Vdc. This is a extremely clean power source and very stable with current AND voltage regulation! Charging from a battery stored at 30 to 40 percent is usually less than 1 hour. In testing, even a battery that needs a little extra balancing, is only slightly over an hour.
One day, a charger bought from Ebay smoked in the field. I had only the BETA 2 port charger left and was forced to use it. It was amazing, and got through a whole day of a larger survey. It kept up almost to the end, and even then it was only about 5 minutes off completing full charges, by rotating the two ports each battery to be charged. The BETA unit was brutally tested this day, and it performed very well! Now, I have started to really appreciate this little guy!!!
Originally I had a 4 port built, but it is not really practical. Fun, but not practical. The supply needed to power the charger was too much, and it was a bit bulky. So, wanting smaller, and better came up with awesome 2 port chargers.
This unit is very flexible on input voltage. This way you can use a CLA in a car, or carry less expensive batteries in a battery bank to charge with. Reduce the cost of having so many extra batteries for the mavic. This unit charges 2 in about an hour, so if you keep rotating batteries on the Mavic, it would always be faster than you can use up your batteries. You will always have one, or two, ready with a full charge. For less than the cost of one DJI battery, you can use this charger, or two, and keep flying all day on only 4 DJI batteries, maybe even 3!
If you had several of these chargers, you can purchase a good quality DC power supply and add these to it for charging many batteries at once. On the bench, we have a 40Amp DC supply with 4 of these 2 port chargers. 8 Batteries can be charged in one hour!
There are a few options you can do with this charger. One option tested already is to use a good AC/DC power supply from Amazon. We tested a 40Amp supply that was only $33.00. Then we ran it off a tiny inverter generator feeding the supply, and then our chargers, and it worked very well. Another option is a battery bank that we built from 8 x 5200mah 3 cell multistar batteries. Since these batteries used to be used on drones, they were circulated out after two years, but they are still good for projects like this. So, now when a large survey is needed, the battery bank works very well and supplies up to 10 mavic battery charges. Then if more is needed, the generator is fired up. Using two fast chargers, a whole day is pretty easy to keep going with this setup.
Since this charger is DC input, you have many choices of how to power the charger. You can even use an adapter with clips, and clip directly to any car battery, use almost any RC battery pack, or make your own supplies. You have many choices as the voltage input can be 10 - 30 Vdc. Just make sure what ever you feed the charger with, can handle 10 Amps supply for each 2 port charger!
One benefit I was after when building this unit, is NOT to leave my batteries charged before a survey, but to only charge right before flight. This reduces wear on the batteries, and insures maximum charge only at time of flight. This charger fits that demand perfectly.
Charging faster than one hour for a depleted battery is difficult, the Mavic batteries have thier own smart regulation, and two things limit getting any faster charging. One is the battery will only accept 3.5 Amps max charge, and the second variable is that the balancing the battery does, takes up the last bit of charging and adds time. This charger is the MAX a Mavic battery is able to charge. There is no better.......
This working model is proof on concept, but now its time to share this awesome idea with people who can use it. There is only a few things that should be done before production. The main issue would be to have a case and caps professionally done with injection moulds. The beta unit is 3D printed, and while it works very well, we are after a more finalized product.
One thing to mention, I have always hated small fans, that quit working in less than a year. So, these chargers will have a quality ball bearing fan installed by default. This adds to the production costs, but it should increase reliability greatly. Lets build a good product!
Help build this charger, lets get this to production. I really want to go full production, and with that, expand into other chargers for better design and upgrades. I use my drones for surveys, and have always wished for something better and have never found it, I think this project is perfect for anyone who wants better options in the field! For the Small contribution, it will save you a ton in the future by reducing your needed quantity of batteries for your Mavic. After this campaign, I plan on advancing with even more innovative charger designs for several different platforms. Mavic Pro 2 will be a variant of this base model as all that needs to be done is the battery ends changed at production. This model will be available soon. Mavic Pro 2 charger is already proto-typed and in use, it is even the same enclosure. Keep an eye out for that Kickstarter. Please, lets get this one going! Help me get this off the ground........Let's get some real good chargers out there!