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Not being that cleaver so someone else will have to chime in to correct me.
Is this route possible
1/ This battery which is 14ah 4 x the capacity of the original Mavic battery.
14.0Ah 14.8v 320W Endurance Brick Version
2/ Its 14.4V but a simple voltage regulator down to 12v could be used which you can get really tiny.
3/ Because its 14ah, 4 x the Mavic battery capacity, surely the voltage drop off wont happen until it gets say down to 25% of the capacity (3.5ah = mavic fully charged capacity)
4/ By then you would of had 11mah out of it (three times the mavic capacity when full charged)
5/ I know you'll get a bit of wasted energy through heat for the voltage regulator but i looked and its not loads of loss its very minimal in modern voltage regulators.
5/ So say for arguments sake you get 11ah before the titans get down to a voltage that annoys the mavic, but by then you might of had 45mins or more of flight.
6/ So do away with the Mavic battery and replace with 14ah Titan and solder this to the Mavic Battery board.....which will be the red+black for power and the balance leads.
7/ The Titan battery will then run down and when it gets to the critical voltage for Mavic you land having had extended flight times......you will just have to keep an eye on voltage levels in DJI go4 app.
8/ Don't get me wrong I'll fly with mostly with standard batteries but there those times when you could do with 40 minutes or more.
Does any of this makes sense/
Yes and no, but I think I'm following you.
Your correct on the extra run time even if you don't use all the capacity the titan has to offer. What you would have to change is how the mavic board interprets what the low voltage is and full charged voltage is. Beciase what it sees will determines the battery cut OFF to prevent the LiPo cells from catching fire or puffing up.
So wiring it to the DJI battery pack boards could be bad, the DJI board for one might handle the full voltage charge of the titan pack. DJI LiPo cells are full charge at 4.35 per cell, time 3 is 13.05V total. The titan pack has 4 cells that full charge is 4.2V each, total voltage of amchatged pack is 16.8V.
Ok, I'm saying this and also guessing the titan lack is all wired in series for the cells.
If the titan pack is a 4S2P (2 cells paralleled, those 2 paralleled in series for more current drain ability) then the max voltage is 8.4V and the mavic battery board would concider 9 volts a drained battery and therefore already cut off the pack not allowing it to run.
Come to think of it, this is probably exactly why the other guy is using a nano to report the voltage back different by intercepting the communication protocol between the Mavic battery board and the main unit.
Now even if he succeeds and working out the firmware to report a percentage of the pack correctly, the communication protocol can always be changed and or encrypted. Since the one hack on the inspire 1 with GPS is doing the same it would not surprise me if DJI encrypted the protocol cominication in a near firmware update.
Let's assume he makes his nano firmware final and gives it out for free, or worse sells it as a product for $50 and he encrypts and locks the firmware on the nano atmel chip so no one can steal his work.
Everyone buys his mod, and a titan pack, then DJI encrypts the protocol because everyone knows they are not happy about these new developments that others have done with their firmware. Encryption is a sure way of stopping it, they have the processing power on the mavic to do this, they probably didn't do it because they wanted to give us the most flypight time and encryption will increase the processor use and drain more battery. Unless they add a new encryption decoding chip specifically for that task, but now we're at
mavic 2.0 for changing the main board and they will use an secure arm processor that has a section already encryption done more energy efficiently.
Back to my point, they change the firmware, change the protocol, or encrypt it to stop all this hacking. Specifically for the NFZ inspire 1 stuff. Now your titan pack and money spent on the mod doesn't work. Money waisted, I can help you tear down the pack then and show you how to use the batteries for LED flashlights and what charger to get for them. Or make a USB portable battery bank from them so the titan cells won't be a complete waist.
But this is the main risk in dealing with any mod that is hardware/software related. It can always be fixed by the vendor. From working digital security for 15 years it's always a cat and mouse game, but that's job is with much more risk protecting your credit cards, money, and ID. Still the same cat and mouse chase. One finds a vulnerability, they call it a jailbreak and add features but it's really from a vulnerable hack that others can use maliciously. Vendors fix it, or security experts find the vuln and report it secretly to the vendors and hope vendors fix it before the bad guys find it.
They can make DJI go refuse you to fly until you update the mavic to the Latest firmware for the safety of the public. It's nothing against the battery mod, it's all about the other mods. Just bad timing that both topics came up at the same time and one will affect the other. :-(
I hope some of this makes sense,
Scott