Mavic Pro Battery Mod

[chazz]

Wow, 3.89V per cell after flying 52k. That's crazy.View attachment 26326

Yeah I think that's a little too much. Did you happen to check what your DJI battery voltage was in the app without the externals plugged in? I'm guessing pretty low compared to that.

 

[CyberNate]

Yeah I think that's a little too much. Did you happen to check what your DJI battery voltage was in the app without the externals plugged in? I'm guessing pretty low compared to that.

3.87V. That's not too bad. .2V difference.

 

[chazz]

Yeah that aint!

 

[Nofate]

Big thanks to Phxbird and others for bringing these Protek packs to our attention. Ive only had my Mavic for a few weeks but got the need for distance bug right away and was experimenting with a maxamps 1600 lihv pack (added 5-6min of flight time) when I saw Phxbird57 post. I was too impatient to wait for shipping on the 3 cell packs so I found some two cell packs at a local hobby shop, broke those apart and made my own 3 cell pack out of it. (No easy task, don't recommend it).

Just got done with the first test flight, added about 15 solid minutes over what I normally get (34min flight time, would be 36 but landed after a few min because I forgot the gimbal cover in my excitement) . With 68,000 ft with a mix of hovering and sport mode. Kept it around 30 miles an hour and sport mode so I didn't kill the battery too quick. I'll upload the video later. So far very impressed with these packs.

I'm not much for wanting to modify my mavic so I hacked the battery pack itself to put this in, wired in parallel with the original cells I just connecting the main power leads and balance leads. I slapped in. .005mohm current sensing resistor on top of the original current sensing resistors which should have tricked the mavic intelligent system to think that it was still the original capacity. But apparently I overheated the resistor (I removed it from a race quads pdb) or am off on my math because it worked a little too well. When I landed at 3.5 volts per cell the system still thought I had 68% left in the tank lol. I have a whole selection of current sensing resistors is coming in and we'll play around with the values. I plan on adding some quick connect connectors so I can play with the different resistance values to find The correct value. The benefit to doing this way as you don't have to ever worry about syncing up external packs or anything of that nature as it is seen as one giant battery pack and you can charge it as normal. Taking apart the original mavic battery pack is no easy feat as they are glued together now however I'm working on a video now to show how you can easily add it in by making a few access points.

 

[Phxbird57]

Big thanks to Phxbird and others for bringing these Protek packs to our attention. Ive only had my Mavic for a few weeks but got the need for distance bug right away and was experimenting with a maxamps 1600 lihv pack (added 5-6min of flight time) when I saw Phxbird57 post. I was too impatient to wait for shipping on the 3 cell packs so I found some two cell packs at a local hobby shop, broke those apart and made my own 3 cell pack out of it. (No easy task, don't recommend it).

Just got done with the first test flight, added about 15 solid minutes over what I normally get (34min flight time, would be 36 but landed after a few min because I forgot the gimbal cover in my excitement) . With 68,000 ft with a mix of hovering and sport mode. Kept it around 30 miles an hour and sport mode so I didn't kill the battery too quick. I'll upload the video later. So far very impressed with these packs.

I'm not much for wanting to modify my mavic so I hacked the battery pack itself to put this in, wired in parallel with the original cells I just connecting the main power leads and balance leads. I slapped in. .005mohm current sensing resistor on top of the original current sensing resistors which should have tricked the mavic intelligent system to think that it was still the original capacity. But apparently I overheated the resistor (I removed it from a race quads pdb) or am off on my math because it worked a little too well. When I landed at 3.5 volts per cell the system still thought I had 68% left in the tank lol. I have a whole selection of current sensing resistors is coming in and we'll play around with the values. I plan on adding some quick connect connectors so I can play with the different resistance values to find The correct value. The benefit to doing this way as you don't have to ever worry about syncing up external packs or anything of that nature as it is seen as one giant battery pack and you can charge it as normal. Taking apart the original mavic battery pack is no easy feat as they are glued together now however I'm working on a video now to show how you can easily add it in by making a few access points.

Nofate would be interested in seeing video of how you did the mod on the stock battery. If we can pack the stock area with a HV battery OH Baby..
Also I'll take the credit for posting the data & video BUT credit needs to go to Mubytrid for directing me to the Protek. batteries .

 

[angusc]

@Nofate,

I would be interested in how you connected the balance leads of the second DJI battery pack cells to the primary battery. I cut open one pack and piggybacked it in top of the main battery and soldered the main woes in parallel. I then linked jumper wires from the individual main battery cells to the piggy back cells to try and get one large battery mah readings during the flight but doesn't seem to quite work that way.

I just ordered two new replacement batteries from DJI and need to cut up another one as I think I fried the controller board on the main battery that I was using for the piggy back one to join.

My objective is to find a simple and almost none intrusive (AC) way to run with more than one standard DJI battery. So like you just drilling/cutting access holes in to a battery and soldering in the jumper battery on to it.

Please can you share your video link once you have posted it.

 

[Nofate]

Nofate would be interested in seeing video of how you did the mod on the stock battery. If we can pack the stock area with a HV battery OH Baby..
Also I'll take the credit for posting the data & video BUT credit needs to go to Mubytrid for directing me to the Protek. batteries .

Oh ok cool, big thanks to Mubytrid too, these packs really are a game changer. I'm going to build some 4s and 5s packs for my racing quads. Will be nice to get 8 to 10min flight times instead of 4! I'll be doing the video and pics of the mods in the next day or two, picking up a new pack tonight to be the next one I mod, will post details soon.

 

[Nofate]

@Nofate,

I would be interested in how you connected the balance leads of the second DJI battery pack cells to the primary battery. I cut open one pack and piggybacked it in top of the main battery and soldered the main woes in parallel. I then linked jumper wires from the individual main battery cells to the piggy back cells to try and get one large battery mah readings during the flight but doesn't seem to quite work that way.

I just ordered two new replacement batteries from DJI and need to cut up another one as I think I fried the controller board on the main battery that I was using for the piggy back one to join.

My objective is to find a simple and almost none intrusive (AC) way to run with more than one standard DJI battery. So like you just drilling/cutting access holes in to a battery and soldering in the jumper battery on to it.

Please can you share your video link once you have posted it.

Ya you have to mod th current resistor too, otherwise once it's hits 3400ma or so, it will force you to land as it thinks it's at 10%. We have to trick the system to think that it's the same size battery by lowering the resistance of the circuit with another current sensing resistor. If you look at one of my pics, you can see the access port I cut to get to them easily. I will find the correct values shortly. I must have ruined the resistor I added too it (I removed it from a race quads power distribution board and had to hear the hell out of it to remove it) as it basically acted as a shunt and after flying for 35min, it said I only used 1800ma and the pack was at 58%. Whoops. I was watching the voltage though and landed at 3.5 on the nose. I have a selection of new resistors coming in and will find the correct value and post it up along with how to cut the access ports without having to take apart the battery in the next few days,

 

[Nofate]

Forgot to mention, if you don't already have one, go out and grab a soldering iron with digital temp control such at the hakko fx888d. Pick up a fine point tip and set the temp to 520F. This will melt the plastic on the mavic battery case like a hot knife through butter. No mess and no smoke. Drilling and Dremel is just not safe here, one slip up and you will destroy the pack when cutting he access ports. The soldering iron method allows smooth and controlled removal of the plastic.

 

[Phxbird57]

got back out today for a 3 test flight. still breaking in the batteries so no long flights yet. Today I had one heck of a time getting to batteries to work together. I would start with the main battery and then plug in the 2 Protek's and the main battery would look like it's charging. It did not matter if I pluged in the 2 fast or slow or one and wait and then plug the second one in. I wasted 30 minutes and 10% battery.. I ended up taking off with the main battery strobing like it's charging( what it will do is strobe for a minute or so and then turn off. you get a red led from the back light. ) The light turned red I was out about 50 ft and brought it back landed and then with out unplugging the external batteries I started the main battery back up and it worked. I flow it out to 25k ( started with 92%) turned at 74% and landed with 44%. I am hoping there is a faster way to get it up in the air.
Airdata UAV - Flight Data Analysis for Drones

 

[dirtybum]

Forgot to mention, if you don't already have one, go out and grab a soldering iron with digital temp control such at the hakko fx888d. Pick up a fine point tip and set the temp to 520F. This will melt the plastic on the mavic battery case like a hot knife through butter. No mess and no smoke. Drilling and Dremel is just not safe here, one slip up and you will destroy the pack when cutting he access ports. The soldering iron method allows smooth and controlled removal of the plastic.

Thats a good tip, I keep a couple tips seperate that I use just for cutting and fusing plastic

 

[chazz]

Forgot to mention, if you don't already have one, go out and grab a soldering iron with digital temp control such at the hakko fx888d. Pick up a fine point tip and set the temp to 520F. This will melt the plastic on the mavic battery case like a hot knife through butter. No mess and no smoke. Drilling and Dremel is just not safe here, one slip up and you will destroy the pack when cutting he access ports. The soldering iron method allows smooth and controlled removal of the plastic.

Looking forward to your video...That soldering iron might look like a kids toy but the thing works awesome. I have one and before i got it i dreaded soldering and now I actually look for reasons to..,

 

[CyberNate]

So I've run both the Thunder power dual 4500s and the protek 3600s. Definitely prefer the proteks as they are easier to get the energy out of them. The Thunder power will out last them, but I had to fly in landing mode for 5 minutes to do it, showing 3.3v per cell at the end and 3.7v when checking them later. That's not fun. As I expected, the protek bottom end is not so good, but I still did over 102k feet just flying around in random directions and a decent amount of wind. These proteks on a good day could get close to the mavic limit of 58k. Same goes for TP 4500s, but you'll be fighting auto landing for 2 miles coming home. These are early cycles, so hopefully they both get better.

 

[chazz]

Ya you have to mod th current resistor too, otherwise once it's hits 3400ma or so, it will force you to land as it thinks it's at 10%. We have to trick the system to think that it's the same size battery by lowering the resistance of the circuit with another current sensing resistor. If you look at one of my pics, you can see the access port I cut to get to them easily. I will find the correct values shortly. I must have ruined the resistor I added too it (I removed it from a race quads power distribution board and had to hear the **** out of it to remove it) as it basically acted as a shunt and after flying for 35min, it said I only used 1800ma and the pack was at 58%. Whoops. I was watching the voltage though and landed at 3.5 on the nose. I have a selection of new resistors coming in and will find the correct value and post it up along with how to cut the access ports without having to take apart the battery in the next few days,

I have the same issue with my setup...85% left at 3.49V.. I have a MS8 plugged to the main board on the bird and a ms4 plugged onto the battery board in place of the original cells. I put some jumpers in there to bypass some chit...I was personally thinking to just change the wire gauge of the jumpers to let less go around but i wonder once you figure out the correct resistor will it be the same for me? But Its really not too bad this way as long as you get a feel for where your at with voltage...

 

[CyberNate]

Did 110K ft and 41 minutes yesterday with the proteks just flying around in various directions. I even even had a bit of wind. They are looking pretty good and as stated before might be able to reach the 59K limit, but just barely on the perfect day. The bottom end really tanks at the end. You don't want to rely on the critically low voltage autolanding to fly any distance. It almost dropped out of the sky on me coming in with feed cutting in and out as voltage quickly dropped below 3.3V once I got to 3.5V. The proteks and Thunder Power are the complete opposite of each other in characteristics. Thunder Power run forever at low voltage, while the Protek first 10 percent last very long but bottom end tanks. I guess you could combine 1 ThunderPower and 1 Protek if you wanted to balance the flight. (Lowell's idea).

I have only flown them with Platinum props. I really should try the old props as well. If there is any wind, then you'll want the old props which handle headwind better.

I guess it's was just under 110k, but
Would be more without all the turning.

 

[dirtybum]

So Nate, you was running double 3600's with the platinum props? Where was your strapping them?

 

[CyberNate]

So Nate, you was running double 3600's with the platinum props? Where was your strapping them?

I just dual locked to the sides. Pushed them forward enough to keep them out of rear prop thrust area.

 

[CyberNate]

So Nate, you was running double 3600's with the platinum props? Where was your strapping them?

I do wish they were a little bigger in capacity. I can imagine the one you made will really kick ***.

 

[dirtybum]

I did wish they were a little bigger in capacity. I can imagine the one you made will really kick ***.

It's just a 4S right now but it does kick *** on the phantoms. I have the 4S protek 4200, that would make a really light 3S. The problem is, those batteries are so expensive, it's not like just picking up a handful of multi stars$$

 

[dirtybum]

You could do a protek 3.6 and make a protek 4.2 , run those together for 7800mah @ 475ish g $160

It would be a very compatible competition for the thunder powers where you're getting 7000 MAH for just under 250 g