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Old Jan 26, 2014, 02:19 PM
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Freeing the Phantom 2 / Vision from Proprietary "Smart" Battery

I've been following the discussion in the Phantom 2 owner's thread and felt that this topic deserves a separate place of discussion.

The Phantom 2 / Phantom 2 Vision is required to use DJI's special "smart" battery and is designed to not start with any other battery. This is not good.

Why do this?
While the "smart" battery has a high energy/weight ratio, it is a dangerous proposition to have a sole source for a critical consumable (imagine your truck can only run on GM gasoline...). What if DJI shuts down? What if they decide to cease support for the Phantom 2 a few years down the road because something else better/more profitable come along (remember how Microsoft ended support for their "plays for sure" DRM music)? The recent Colins fiasco that threaten to disrupt supply of DJI parts further highlights the vulnerability of this situation.

Many of our community is unhappy about this and wish that we can choose to use the special "smart" battery. However, it should be at our option and not be forced to only use it to the exclusion of everything else.

So here's what we know so far...
P2/P2V Battery has charger logic inside The P2 battery is like a battery and charger in one. There is logic to measure capacity and to regulate the charging, as well as validation code that will authenticate it with the craft.
P2/P2V's NAZA is different - It is similar to a NAZA V2 but not quite in some way. We know this because the iOSD mini firmware that would work in NAZA V2 would not work in P2 until a firmware upgrade. Also, it doesn't support PPM mode (no UHF system for us...) and at least for now, cannot work with the BTU and ground station link.
Battery validation occurs on P2/P2V - DJI has put special effort in to make sure that the craft will not function unless their battery is detected. Early P2V will literally drop out of the sky if battery validation fails in mid flight, an update fixed this and will only prevent start-up.
Standard LiPo chemistry Despite the fact that the P2 battery have a good energy/weight ratio, it is unlikely that there is anything magical or breakthrough in the battery chemistry. DJI is not a chemical research firm whatever they use for the actual energy storage LiPo part will likely be available in other sources

Hypothesis and things to try
The P2 NAZA is special No one ever said that the P2/P2V uses NAZA V2. We cannot assume so just because it has a yellow sticker. It is possible that the P2/Vision NAZA is special and hard coded to use a particular firmware that listen to a battery validation sequence from the CAN Bus periodically. If the signal isn't there, then it refuses to start the motors or otherwise refuse to fly. If that is the case, then one can perhaps replace the P2 FC with a regular NAZA V2 and see if it works.
The P2 Board is special There may be logic on the board that listens of the battery validation signal and then sends a special "start/stop" command to the NAZA or even cut off voltage. The voltage cut off seems unlikely as the current P2/P2V flies even if battery validation fails in mid-flight. The start/stop command can only be used together with a special NAZA (with corresponding firmware) as regular NAZA don't have this kind of checks built in.

Again, I believe DJI makes great product and would very much want to seem them succeed and profit. There "smart" battery is actually quite good and I would love P2 owners (and everyone else) to be able to use it as an option. However, I believe we deserve a way to protect our investment and not have it held hostage to a proprietary consumable component.

Update Jan 30 2014
Swap the FC - Tiagobaracho have confirmed that the authentication is in the Phantom 2 / Vision FC.
The "Naza" that come with the Phantom 2/Vision is a special rigged version of the NAZA V2 and will not start unless the DJI smart battery is detected. It also have some other quarks that prevents it from being used with a PPM radio or ground station. Tiagobaracho have successfully swapped out the Phantom 2 FC with a regular NAZA with full functionality, including the ability to use any battery (even the DJI smart battery).

http://www.rcgroups.com/forums/showt...48910&page=269

This is a solution, but an expensive one, as it requires one to buy a standalone NAZA V2. We'll continue to look for solutions to see what we can do without spending another $300+

Update Feb 13 2014
Swap the LiPo cells - Hexa have found that DJI uses the BM3328 encrypted battery fual gauge chip to power the board found on the smart battery. This chip handles capacity measurement, cell balancing, communication and authentication with the main controller (the special P2 Naza). While we do not have the data sheet on the Bm3328, it is likely to work like this TI chip http://www.ti.com/lit/an/slva413a/slva413a.pdf#page17

The encryption, if used, would make it difficult for another manufacture to create compatible batteries as they won't have access to the key. However, it doesn't prevent one from using the same chip and attaching other LiPo cells to it. Tiagobaracho have found that he can open up the battery, remove the original cells and solder a battery and balance connector on. This way, he can attach another cell and it would work as the original authentication chip is still talking to the FC.

Furthermore, it is shown that the smart board would learn the full mark of the new transplanted LiPo cells and reset the battery % indicator to 100% if it is charged through the smart board. It is unclear whether it would also learn the empty mark during full discharge but is likely. This means one can attach any reasonable 3S LiPo and re-calibrate through a full charge/discharge. The remaining challenge is how the battery life counter works...
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Old Jan 26, 2014, 03:44 PM
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Subbed. My thought is that the P2 battery IS magical (higher mah/g energy density than standard lipos) and that the invalid battery protection logic is on the NAZA (but may be spoofed via mod to the mainboard).
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Old Jan 26, 2014, 04:02 PM
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Quote:
Originally Posted by ElGuano View Post
Subbed. My thought is that the P2 battery IS magical (higher mah/g energy density than standard lipos) and that the invalid battery protection logic is on the NAZA (but may be spoofed via mod to the mainboard).
I do agree that the P2 battery is "special" in a good way in terms of it's energy density, which is why I am not opposed to the fact that it exist (Good job for creating it DJI), and I am even OK to pay the price premium a least for now until comparable batteries become common place. However, it is frustrating that our machine (along with our money, time and sweat poured in to it) is critically dependent on a consumable part that is sole sourced.

I too suspect the NAZA and/or it's firmware is special. Though there is perhaps another level of protection in the main board that prevents a direct NAZA swap. Unfortunately, I am fairly new to this bobby and do not have another NAZA to try. It would be very insightful if someone can try to swap a regular NAZA V2 into a Phantom 2 and see what happens.
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Old Jan 26, 2014, 04:09 PM
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I tried a naza v2 in the Pantom 2. it powers up but radio was messed up and the USB did not work. may have to use the OEM naza v2 usb.

I may tinkle with it later, but god am getting old, fed up of diying, just want to fly me copters with out restrictions.
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Old Jan 26, 2014, 04:22 PM
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Quote:
Originally Posted by hexa View Post
I tried a naza v2 in the Pantom 2. it powers up but radio was messed up and the USB did not work. may have to use the OEM naza v2 usb.

I may tinkle with it later, but god am getting old, fed up of diying, just want to fly me copters with out restrictions.
That makes a lot of sense. The LED circuitry on the Phantom 2 Naza is split to the ESCs (front and back ESCs have different bootup patterns) and that's controlled by the USB so it makes sense the mainboard-integrated LED/USB would make sense of the Naza-M V2's output and vice versa. If that's really the only incompatibility, using an old Naza-M would be a non-ideal but possible way to use 3p batteries.
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Old Jan 26, 2014, 04:27 PM
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Quote:
Originally Posted by hexa View Post
I tried a naza v2 in the Pantom 2. it powers up but radio was messed up and the USB did not work. may have to use the OEM naza v2 usb.

I may tinkle with it later, but god am getting old, fed up of diying, just want to fly me copters with out restrictions.
Can you give us some more detail? How is the radio messed up?
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Old Jan 26, 2014, 04:40 PM
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From memory, I could use the radio to arm it normally with both sticks to the left, but the radio would not dis arm it. and the motors were acting weird, with some loud wining, I powered it off. re power on then try to connect to Pc both the phantom and naza assistant software would not connect. I then gave up. Ill investigate some more
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Old Jan 26, 2014, 04:49 PM
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a jailbroken phantom vision!
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Old Jan 26, 2014, 06:08 PM
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Ok seems I did not install the Naza drivers correctly I did that test on a virgin PC, thats why the naza assistant did not connect to the naza-m and the radio settings was off thats why It did not dis arm.

New rough test Phanton 2 with Naza-m V2,
The PH2 USB works,
The Naza-m assistant software works, lipo show up as 12.3 3s that seems to work.
DJI gimbal works but the tilt distance is short, seems the white radio is causing that, may have some sort of exp on that channel.

What don’t work are the 2 back leds they flash on when the battery is turned on but they don’t come on after arming.

I think the DJI ultra special battery is a myth meaning the copter won’t power up if it does not read an original DJI battery, not true
I think all is in that battery is a balance circuit if there is one, some sort of power switching chip. and a chip that store the battery ID and charge cycle amount.

If you take out the DJI battery power it up then stick a multimeter probe in the battery power plug, you will read the battery volts.

I also hot wire a standard 3s to the PH2 power input on the PH2 circuit board and the copter power up fine.

I think am seeing some light here, those DJI Goons took put the ppm In P2.
I may just fit this naza-m figure out the none working Led and use my nice PPM radio.
To hell with DJI and their super white radio.

I also tried to pop open a battery but it seems they have done a good job extra super gluing it.


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Old Jan 26, 2014, 06:24 PM
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Yep, we know that the battery itself doesn't have any authentication requirement. If you turn it on, it'll deliver standard 3S power. Some folks have swapped their P1s to P2 lower shells and successfully used P2 batteries to fly.

The question is how the P2-Naza (or mainboard) authenticates the battery and restricts arming the motors. If something like a simple resistor on the mainboard can spoof an authenticated battery, that opens up a lot of possibilities for P2/P2V owners.

A few people have opened up their P2 batteries. The cap snaps off and you can see the individual cells and the two circuit boards that make up the parallel distribution and charge circuitry.
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Old Jan 26, 2014, 06:32 PM
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correction my bad
Quote:
I think the DJI ultra special battery is a myth meaning the copter won’t power up if it does not read an original DJI battery, not true
I think all is in that battery is a balance circuit if there is one, some sort of power switching chip. and a chip that store the battery ID and charge cycle amount.
I ran the first test with with the NAZA-m

Yep the copter will not power up from hot wire 3s, in stock.

It power up fine with the naza m- so it seems the restriction is set in the PH2 FC. and not on the PH2 circuit board.
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Old Jan 26, 2014, 06:35 PM
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Quote:
Originally Posted by ElGuano View Post
Yep, we know that the battery itself doesn't have any authentication requirement. If you turn it on, it'll deliver standard 3S power. Some folks have swapped their P1s to P2 lower shells and successfully used P2 batteries to fly.

The question is how the P2-Naza (or mainboard) authenticates the battery and restricts arming the motors. If something like a simple resistor on the mainboard can spoof an authenticated battery, that opens up a lot of possibilities for P2/P2V owners.

A few people have opened up their P2 batteries. The cap snaps off and you can see the individual cells and the two circuit boards that make up the parallel distribution and charge circuitry.
I think it can be done. just need the right tools to read info the battery is sending.
Am sure some one will hack it soon.
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Old Jan 26, 2014, 06:48 PM
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hexa,
I bought a osciloscope ( i work with eletronics, but not so much with digital signals)...
I will be receiving it around february 5....,.. I can simply attach to the data pins and see whats going on...
If I see a waveform.... we have a problem because no resistor should be able to trick that....
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Old Jan 26, 2014, 06:48 PM
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this thread is all i have been waiting for ! lol
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Old Jan 26, 2014, 06:55 PM
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Freeing the Phantom 2 / Vision from Proprietary "Smart" Battery

Sounds good @ tiagobaracho. I have a lil digital scope some where. I'll have to dig it up.

Can you recall where on here some one has open battery up and the shell swapping. Would like to see the pics.

So much good stuff has missed me when I wasn't around.
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