80% more run time than lipo
- Thread starter Howdeedoodee
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The amp meter link didn't work, but I googled it. Are you talking about the dual display squad box? The case isn't much in them, I own one. By it's self some can do 10A, but that won't be enough. It will need the external shunt and they make it look small in the pictures, but they are bigger then they look and have some good weight.
I watched some of his videos when he was designing them, I missed this one. But this goes to the voltage boost in the images I mentioned above since that guy can't change the speed controler mavic cutoff he's boosting the voltage to get the most out of the pack. Tricky part is having the booster designed to be able to handle enough power the mavic needs. It can be done, and designed, but the boost will loose a little power since the efficiency is usually about 96% with a 4% loss. Still would be better then the LiPo. Cooling will be needed also, those chips get hot when pushing high amps.
Now if DJI did change the firmware in the speed controllers to compensate for the lower voltage cutoff it would be better then booting a titan pack and a mod with a boost. They can do this, even the phantom 2 has program pins for firmwareware updates on the ESC's. They just didn't let the public update them. One of the main reasons I sold my mavic, and the firmware updates fixing one thing and breaking three other things.
Scott
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Clinton1
Well-Known Member
Looks like you wear searching the same thing I was, I found this one and on much worse. It was scary to watch the other one being torn apart.
For the main board in the reference of pictures, it does look like the one board was the mavic main battery board.
I found this, you will notice the lack was black. Probably a pre-production run of the pack for testing. But still the same with maybe some firmware changes.
DJI Mavic Battery Disassemble
Scott
I just realized the MH-Electronics PCB probably has a known resistance or maybe a shunt on the other side, or a high end surface moist resistor used as a shunt because the one thing missing I didn't realize was something to monitor the current drain for the over current draw error. The mavic also monitors this as wall, so this also has to be monitored by the nano and reported to the mavic.
But this is just and educated guess.
Scott
Oingo Boingo
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Yep 80% more runtime.... Just makes your kit like like a homebrew project.... Not to mention that the battery statts are fairly much a thumb suck. Not mention that the battery stats are blanked out in your flight logs. So hope u don't crash and want to claim from DJI.... Cause IT VOIDS UR WARRANTY
digdat0
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It’s a pain. You need to separate the sides which have pressure clips and they are glued. I made a vid showing it open. It took me over an hour of careful prying to get there. Other guys weren’t so lucky with s clthe an openining. The key is breaking the glue. I wanted to try some acetone down there, but haven’t tried. Someone wanna donate a battery lol
digdat0
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“I use a arduino board , write a program send the battery voltage info to Mavic. but use the voltage cannot know the remaining power of the battery exactly. You can sniff the packets between the smart battery and Mavic , then use a arduino resend the packets and display what you want to display on DJI go”
And
“you can replace the battery cell of the original battery , read the bq30z55 document at first, my test battery is the "black battery" ( battery for factory test). i do not know if normal battery is also working. but when change the battery cell , the battery can not work very will as the data inside the chip is not current . more work need to do. i have not complete it”
Note, he has a beta mavic battery which is not s lipo but is a LiOn .. look at his pics. He shows it opened.
“you can fly with the "cell mod" battery even if the battery info is not correcT”
“Have already reversed the protocol . but dji can change the protocol on update easily .although it do not change util now”
And
“you can replace the battery cell of the original battery , read the bq30z55 document at first, my test battery is the "black battery" ( battery for factory test). i do not know if normal battery is also working. but when change the battery cell , the battery can not work very will as the data inside the chip is not current . more work need to do. i have not complete it”
Note, he has a beta mavic battery which is not s lipo but is a LiOn .. look at his pics. He shows it opened.
“you can fly with the "cell mod" battery even if the battery info is not correcT”
“Have already reversed the protocol . but dji can change the protocol on update easily .although it do not change util now”
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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/
Attachments
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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/
I asked for a battery in a different thread a long ok g time ago.
I didn't care if it took a bath in a river or anything, just wanted to see the electronics and reverse engineering it a little.
No bites :-(
Carful with acetone, most plastics are ABS based and acetone will melt the plastic, in fact it will act like superglue with two joints of ABS and how I glue parts together for 3D printing. Their is a very high chance the mavic is made with some ABS and it will make it worse.
Scott
Their are comments on the pictures. That would have helped with translator if I knew that, lol.
Thanks. I just did a project that was a 2 18650 cells replacing a LiPo and used one of the pololu step-ups. I was surprised for the size and that is could maintain 1.5A constant, but does get a little hot running it at full. I only needed it to maintain 600mAh current, so half of max rated. Usually a good rule of thumb for keeping electronics cooler is always over spec them.
But now I wonder after looking at pololu' site if he is really stepping up the voltage to the mavic, or stepping down the voltage to the nano that runs on 5V?
I don't see a pololu or any other regulator of that size that would be able to d high amperage like 20 to 30 amps when needed for those temporary times. I should have realized this earlier.
My guess is he's regulating the voltage to the nano, the nano is doing the sensing and reporting back to the mavic as "Man in the middle" style.
So like tapping an RF signal, he is only tapping and sampling the current and voltage at a small % and then reporting it back at the normal levels by multiplying it back up in the code just trying to get the app to report is correclty and so the mavic auto land features and failsafes with the battery still work as designed.
Scott
Yes, I like the Pololu. Some of the best, smallest, and most efficient converters I've ever tested for the size.
His might be another manufacture, I don't see one that size with a variable adjustable pot on it with pololu.
But if it being used for the nano voltage then not a big deal on quality, the nano doesn't draw that much current load.
Pololu - Comparing Products in 2 Categories
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
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