Mavic Pro Factory Battery Controller Mod

[beanbubba]

That is awesome! Looking forward to the test flight!

Uggg... I bricked this mod. Not sure exactly what happened. But I have 2 more controllers left to try again.

 

[angusc]

This would be a cool product for DJI to produce and support. I am going to hot glue all this into place and hopefully this will be my daily flyer...

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Hi @beanbubba and others here,

I would like to start some stock battery modifications of my own and like many of you this would be my first time trying such modifications. Can you share the wiring schematic when connecting multiple batteries to the Mavic controller board showing how to connect the balance leads from multiple batteries please? Also what is the best way to get accurate battery discharge information on the app when having multiple batteries connected.....is it even possible?

Thank you all for any support that you can offer me.

 

[Fredo]

Hi all, here is my own test result on 2 original Mavic batteries in parallel:
Please comment.

 

[Progenite]

Hi all, here is my own test result on 2 original Mavic batteries in parallel:
Please comment.

Did you then directly put the extra battery in the Mavic? It would be interesting to know what real percentage remained in that battery. it is seen that it recovers 2% in a few seconds after landing. I think it does not take advantage of all the mAh of the 2 batteries.

 

[Fredo]

At the end of the fly, the main battery was at 11% and the second battery at 28% !

 

[beanbubba]

UPDATE: I am personally abandoning any further effort on this mod. I just blew through 4 brand new batteries attempting to streamline and document this mod. There are obviously different battery controller firmwares that behave differently and unpredictably. And after bricking 6 batteries total, I am throwing in the towel. There are ways to make this work, but I can't repeat it reliably and Mavic batteries are way too expensive for the relatively little overall benefit.

Strike three...

 

[dirkclod]

Can't say you didn't try bean .

 

[lolo780]

UPDATE: I am personally abandoning any further effort on this mod. I just blew through 4 brand new batteries attempting to streamline and document this mod. There are obviously different battery controller firmwares that behave differently and unpredictably. And after bricking 6 batteries total, I am throwing in the towel. There are ways to make this work, but I can't repeat it reliably and Mavic batteries are way too expensive for the relatively little overall benefit.

Strike three...

I stopped at one. Temperamental $$$ traps. On the plus side the board by itself seems to work to get the pack voltage OSD. This is a bricked battery that's not even powered up, with a 4s pack connected direct to the ESC board.

You could direct wire the cells and install an xt30 plug plus JST balance lead to recharge like any normal battery.

 

[beanbubba]

Can't say you didn't try bean .

Thx dirkclod Amazon finally gave me the courage to stop the madness. Specifically, I went to order another mavic battery and Amazon said I had exceeded the monthly purchase allowance for this item (no joke). Thank you amazon!!

 

[lolo780]

Thx dirkclod Amazon finally gave me the courage to stop the madness. Specifically, I went to order another mavic battery and Amazon said I had exceeded the monthly purchase allowance for this item (no joke). Thank you amazon!!

Is that your wife's name? [emoji23] [emoji23]

 

[beanbubba]

I stopped at one. Temperamental $$$ traps. On the plus side the board by itself seems to work to get the pack voltage OSD. This is a bricked battery that's not even powered up, with a 4s pack connected direct to the ESC board.

You could direct wire the cells and install an xt30 plug plus JST balance lead to recharge like any normal battery.

Lolo, please elaborate. I think I follow, but not crystal clear from your descriptions.

 

[lolo780]

The bricked stock battery is plugged in the usual spot, not powered up.

4s pack is plugged in to the external battery hardwire and is the only power source. For whatever reason, the battery board still sends the esc board voltage and temp info.

Individual cell voltages are the DJI cells as the external was fully charged.

 

[beanbubba]

The bricked stock battery is plugged in the usual spot, not powered up.

4s pack is plugged in to the external battery hardwire and is the only power source. For whatever reason, the battery board still sends the esc board voltage and temp info.

Individual cell voltages are the DJI cells as the external was fully charged.

Hmmmmm.... I never looked at a powered down controller on the go4 app. If it reports voltage (which is all we care about) and we rerouted the balance wires to your external battery... maybe this mod has some legs left on it

 

[lolo780]

Don't give up yet!

I'm going to extend the thermistor wires to read external pack temp.

There's probably a tidy way to permanently integrate a BMS to the battery board on the aircraft and then use thinner wire to connect the ESC since no current flows.

What would be really cool is being able to use the 3 available analog OSD readings for other purposes.

My first idea would be a shunt on the main power and have the voltage pop up in cell 1 for example. Instantaneous battery current could be read this way.

mAh could also be done with a bit of work by translating mAh to volts with a suitable scaling so full cell voltage = max battery capacity. Count up or down depending on pilot preference.

 

[beanbubba]

Don't give up yet!

I'm going to extend the thermistor wires to read external pack temp.

There's probably a tidy way to permanently integrate a BMS to the battery board on the aircraft and then use thinner wire to connect the ESC since no current flows.

What would be really cool is being able to use the 3 available analog OSD readings for other purposes.

My first idea would be a shunt on the main power and have the voltage pop up in cell 1 for example. Instantaneous battery current could be read this way.

mAh could also be done with a bit of work by translating mAh to volts with a suitable scaling so full cell voltage = max battery capacity. Count up or down depending on pilot preference.

I never reported this because I doubt anyone cared, but in prior testing I extended the temperature unit with 28awg wire out to one of the rotor motors. This was when we had overweight solutions and I was wanting to monitor when the motors started to overheat. Anyway, this never worked and got endless errors about the temp monitor. Probably some resistance issue or other electrical anomaly outside of my area of expertise and I didn't pursue this any further due to other items of more interest.

I would be thrilled if you can figure out a way to take advantage of this sensor in a predictable manner!!

 

[lolo780]

I never reported this because I doubt anyone cared, but in prior testing I extended the temperature unit with 28awg wire out to one of the rotor motors. This was when we had overweight solutions and I was wanting to monitor when the motors started to overheat. Anyway, this never worked and got endless errors about the temp monitor. Probably some resistance issue or other electrical anomaly outside of my area of expertise and I didn't pursue this any further due to other items of more interest.

I would be thrilled if you can figure out a way to take advantage of this sensor in a predictable manner!!

Did the temp sensor report bogus values even with motors off?

 

[beanbubba]

Did the temp sensor report bogus values even with motors off?

Not bogus values, just a general failure message when I extended the pair of wires. I removed the extension and re-soldered back to the original setup and the errors went away. I only spent about an hour on this and never tried again.

 

[beanbubba]

Don't give up yet!

I'm going to extend the thermistor wires to read external pack temp.

There's probably a tidy way to permanently integrate a BMS to the battery board on the aircraft and then use thinner wire to connect the ESC since no current flows.

What would be really cool is being able to use the 3 available analog OSD readings for other purposes.

My first idea would be a shunt on the main power and have the voltage pop up in cell 1 for example. Instantaneous battery current could be read this way.

mAh could also be done with a bit of work by translating mAh to volts with a suitable scaling so full cell voltage = max battery capacity. Count up or down depending on pilot preference.

Do we really need mAh corrected for an external reading? Isn't voltage more than adequate (as our trusted advisor @CyberNate beat into my skull months ago against my will)?

 

[lolo780]

It would be nice to have, and works just like the factory % reading.

 

[CyberNate]

Do we really need mAh corrected for an external reading? Isn't voltage more than adequate (as our trusted advisor @CyberNate beat into my skull months ago against my will)?

Having true mah reading is also important. Batteries vary in voltage curve and are affected by temperature. Anyway voltage can be enough if you know the vintage curve well for the packs you are using in a given a conditions.