Get more from your Mavic
The largest Mavic community in the world
Join Us Now

Hello and some projects...

plexus

Well-Known Member
Joined
Jun 9, 2018
Messages
46
Reactions
11
Age
55
I've been flying little RC helis for about 10 years. Not that fancy 3D stuff - just even trying to fly nose-in is a real challenge for me with them. I like to fly them in a relaxing way. I stopped flying a couple years ago because I was getting tired of doing repairs from even minor crashes. Not my thing. I just want to fly in a relaxed way. I also do photography and music. I did get an AR.Drone in 2010 which was so-so. Also the mQx RC which is fun and more like I was looking for. I held off with DJI because I felt the technology could be taken further. Glad I waited... I just got an MA. It arrived last week. More fly.

A couple projects I am working on that I thought I'd mention. First, the ability to charge batts from USB... and, water recovery floatation. I go on week long back country camping trips and I want to use the MA to do photography and video. The ability to charge off USB packs and recover the MA in the event of water crash is desirable (I have Refresh).

Bad news on the USB: I bought the car charger and my scheme was to use a USB-12V converter to drive the charger. It does power it however, and I knew this was a risk, USB doesn't provide enough power for the charger to engage. I belive the car charger monitors the available current and shut down if it's not enough for wha tthe battery is drawing. USB is [email protected] max = 10.5W. The charger specs are something like [email protected] or about 50W. I also have a generic 5V to 12V converter I use to power other things off batt packs, but it also causes the charger to shut down. With a battery with around 50% charge, I think it will work. I need to experiement more, but I did notice it was charging a battery that was down to 3 LEDs. So perhaps it will top off a battery? I just have to figure out what the limit is. So this might be a solution if you don't drain the battery all the way. I'd say if it can top off a battery 50% that might be worth doing! More to come...

Floatation: I have a solution. It's DIY. I did not like the options presented when I googled: the GoGetter or whatever it's called has a 100' line attached - however I don't know how deep the lakes are I am camping/flying on. so those won't work and are also quite expensive. The flotations ones are also unreliable at depth. I also don't like the styrofoam options I've seen. My solution uses 4 2.5" styrofoam spheres with cutouts for the prop arms. I will then use double-sided velcro to attach them. I have verified that the 4 spheres will hold up 500g. The MA is 440g with battery. I glued the spheres together and tied a 500g weight to the bottom of the bundle. it floated. I have them painted yellow and am waiting for the double-sided velcro. once I have it and can verify it doesn't affect flight performance I will report back with picutres.
 

Bunny Too

Well-Known Member
Premium Pilot
Joined
Feb 7, 2017
Messages
5,278
Reactions
2,204
I've been flying little RC helis for about 10 years. Not that fancy 3D stuff - just even trying to fly nose-in is a real challenge for me with them. I like to fly them in a relaxing way. I stopped flying a couple years ago because I was getting tired of doing repairs from even minor crashes. Not my thing. I just want to fly in a relaxed way. I also do photography and music. I did get an AR.Drone in 2010 which was so-so. Also the mQx RC which is fun and more like I was looking for. I held off with DJI because I felt the technology could be taken further. Glad I waited... I just got an MA. It arrived last week. More fly.

A couple projects I am working on that I thought I'd mention. First, the ability to charge batts from USB... and, water recovery floatation. I go on week long back country camping trips and I want to use the MA to do photography and video. The ability to charge off USB packs and recover the MA in the event of water crash is desirable (I have Refresh).

Bad news on the USB: I bought the car charger and my scheme was to use a USB-12V converter to drive the charger. It does power it however, and I knew this was a risk, USB doesn't provide enough power for the charger to engage. I belive the car charger monitors the available current and shut down if it's not enough for wha tthe battery is drawing. USB is [email protected] max = 10.5W. The charger specs are something like [email protected] or about 50W. I also have a generic 5V to 12V converter I use to power other things off batt packs, but it also causes the charger to shut down. With a battery with around 50% charge, I think it will work. I need to experiement more, but I did notice it was charging a battery that was down to 3 LEDs. So perhaps it will top off a battery? I just have to figure out what the limit is. So this might be a solution if you don't drain the battery all the way. I'd say if it can top off a battery 50% that might be worth doing! More to come...

Floatation: I have a solution. It's DIY. I did not like the options presented when I googled: the GoGetter or whatever it's called has a 100' line attached - however I don't know how deep the lakes are I am camping/flying on. so those won't work and are also quite expensive. The flotations ones are also unreliable at depth. I also don't like the styrofoam options I've seen. My solution uses 4 2.5" styrofoam spheres with cutouts for the prop arms. I will then use double-sided velcro to attach them. I have verified that the 4 spheres will hold up 500g. The MA is 440g with battery. I glued the spheres together and tied a 500g weight to the bottom of the bundle. it floated. I have them painted yellow and am waiting for the double-sided velcro. once I have it and can verify it doesn't affect flight performance I will report back with picutres.
Howdy from Wyoming @plexus , welcome to the community, plenty of fine folk and excellent information here.
 

MikeinMA

Member
Joined
May 2, 2018
Messages
11
Reactions
13
Age
57
Welcome. I'm interested in your flotation device idea. I did something similar with Styrofoam balls and hot glued them to some landing gear. My hope is the landing gear will stay attached if the MA hits the water. I went with these as they seem to clip on and have decent depth into the Styrofoam. Keep us posted...
 

plexus

Well-Known Member
Joined
Jun 9, 2018
Messages
46
Reactions
11
Age
55
On the flotation: my plan was to cut tight holes through the spheres in a location that maximizes strength and thread through 5mm wide double sided velcro tro strap them onto the arms. I've made the cut out and they fit tight and snug. with the strap they will be pretty secure. they also act as feet to increase the landed height which can be useful. I would expect they would increase sensitivity to wind. also performance may be affected. In the meantime I spray painted them yellow for better visibility. the paint solvent dissolved some of the surface of the spheres - this had a unexpected benefit of making the outside of the sphere a bit harder. however I will have to verify again with the 500g weight to see if loft was affected.

On the USB charger: I drained the MA batt down to flashing-3rd LED. The USB converter was not enough to keep the battery charging. It would start and then shut everything down. draw was measuring on my Drok USB meter at 1,88A. I then charged it up until flashing-4th LED and same thing. I think this could work if 5 packs and 6 converters were paralleled up. USB is 10W and the charger is rated for [email protected] or 60W - this is why 6 are needed. Now, I'd first want to actually measure the power draw on the 12V input of the car charger to get a more real-life number. With luck its lower and less packs can be used. But whatever the actual draw is, divide by 10 and thats how many USB pack+converters you'd need to parallel up. This is assuming they all behave ok when paralleled and you'd have to take into account some efficiency loss. This isn't something I want to do right now. I ordered 2 extra batts to add to my 3 for a total of 5. at 12 mins per thats 60 mins. I will see if how that goes on a week long trip. surely its a constraint. but it will force efficency. hopefully someone comes out with a solution. it is doable with enough batteries....

HEY! Idea... don't use USB packs. Use LiPo cells. 4 LiPo cells in series is 15V. the charger is rated for 14V in. 15 should be fine as they have to allow for some tolerance because its a car circuit. I'd be comfortable putting 15V into it. easy to test with a bench supply. 4 LiPos in series with as much capacity as you need. Here is a 4S 5000mAH on ebay for $85 CAD shipped HRB 5000mAh 14.8V 4S Lipo Battery 50C 100C Deans For Quadcopter Airplane Drone | eBay That would theoretically recharge 2 MA batteries fron dead to full. Maybe 3. That would be worth it! I may get one of these batteries and simply connect it to the car charger jack on the converter. There's the solution! Theoretically...