Mavic Pro Factory Battery Controller Mod

[beanbubba]

Yeah did you test it the way you originally had it with just the balance lead plugged in and the power leads to the clip? If that worked i think that would be better...

I had the same thing with the phantom battery before i did the jumper thing and even then it was a little glitchy. Working with this thing requires a lot of patience..The way i finally got it to work was i would hold in the power button while plugging in the balance lead without the power lead plugged in to the battery and if it didn't work the first time i would keep pushing the power button in and out like your turning the battery on at the same time plugging in the balance lead. somethings it would take 15 times doing this.. It's really important to plug in the balance lead before the power lead. Also if you get it to work i personally wouldn't run 3 power leads off of it and only do one and run the other two externals the normal way but of course it always good to test different ways.. Do me a favor and if you get pissed off at this thing to the point you feel like smashing it off the ground please don't because id take it off your hands..

Appreciate the moral support

I got so frustrated I have busted open a second battery to trace my steps. It was working flawlessly until (like you said) I plugged in the balance cable first. I will give you techniques a try now and report back.

 

[chazz]

Appreciate the moral support

I got so frustrated I have busted open a second battery to trace my steps. It was working flawlessly until (like you said) I plugged in the balance cable first. I will give you techniques a try now and report back.

So are you saying that plugging in the balance lead first is what messed it up? Because that's total opposite of how the phantom battery was..I had to plug that in first...Sorry if what I'm saying to do messed something up but that's what eventually worked for me...

 

[beanbubba]

So are you saying that plugging in the balance lead first is what messed it up? Because that's total opposite of how the phantom battery was..I had to plug that in first...Sorry if what I'm saying to do messed something up but that's what eventually worked for me...

Typing to fast. What you said! It error out when I didn't plug the balance cable first. I was testing with 2 batteries many times always plugging both balance cables, then both power cables. It specifically error out when I plugged one balance cable, then 2 power cables, then the other balance cable (I am fairly sure this was the sequence of events, but I was trying so many different situations I may have misremembered). I still have't figured out how too clear the error and already made myself another frrankenbattery. If you want to private message me your shipping address, I will send you this error'd unit if you want to have a go at it.

 

[spankdog]

Is it possible that the board has some circuitry to detect a bad battery and disable it? Only reason I ask is because Makita 18v LXT tool batteries have a board inside that does this (prevents charging) and is not re-settable. Once it "detects" a bad battery it is garbage. I know its a completely different battery but just a thought.

 

[beanbubba]

Is it possible that the board has some circuitry to detect a bad battery and disable it? Only reason I ask is because Makita 18v LXT tool batteries have a board inside that does this (prevents charging) and is not re-settable. Once it "detects" a bad battery it is garbage. I know its a completely different battery but just a thought.

Thats what I fear. I hope there is some technician from DJI that knows the magic reset procedure and anonymously posts it here

 

[beanbubba]

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...

 

[beanbubba]

OK, I finally got all my **** together and testing on the bench now. This is a post that you should take the time to digest (especially for all you leaders that have been painfully quiet on this thread for a reason I do not understand).

First, I am taking my time and carefully documenting every single step of this process to make sure I don't brick another battery controller. Until chazz figures out the reset procedure of the controller, best to be careful. Good news is that I have performed around 50 tests tonight and no bricking of controller experienced!

1) Plug battery#1 balance cable to controller, the controller will auto power on immediately.
2) Plug battery#1 power cable to controller, then immediately power off the controller.
3) Plug battery#2 balance cable to controller, the controller will stay powered off.
4) Plug battery#2 power cable to controller, the controller will stay powered off.
5) Plug the frankenbattery controller to your Mavic then power on.
6) When test complete, power off battery controller then remove from the Mavic.
7) Remove all battery power cables.
8) Then remove all balance cables.

I do not know if this is the only procedure that works, but I tested, retested, and retested agian and again. This exact procedure performed in order did NOT brick the controller. So until chazz figures out the controller reset procedure, I would not venture from this method if you attempt this mod.

Using the new frankenbattery, I measured dual LiHv5200's as seen by the bird and external charger to start the test.






I removed the propellers from the bird, put in sport mode, and a rubber band on right stick forward. I let it run an hour and took measurements again.



At this rate it will take several hours to run the batteries all the way down. I will report back the results at that time.

I am way out of my expertise area and need expert analysis on the battery reports. It looks very promising but I am still learning battery telemetry and need help from you guys on deciphering the data output.

Bueller... is this mic on???

 

[beanbubba]

This is taking way too long and it is super late in my timezone. I took one more measurement for now, then tomorrow I will run them down to 0% on the go4 app and keep our fingers crossed for the final verdict.

 

[digdat0]

I’m anxiously reading ... this is a cool idea bean

 

[Japtastic]

Yeah good on you for experimenting. Subscribed.

 

[beanbubba]

Bird is back running on the bench and at 45% battery... tick tock

 

[Slayerstwin]

Typing to fast. What you said! It error out when I didn't plug the balance cable first. I was testing with 2 batteries many times always plugging both balance cables, then both power cables. It specifically error out when I plugged one balance cable, then 2 power cables, then the other balance cable (I am fairly sure this was the sequence of events, but I was trying so many different situations I may have misremembered). I still have't figured out how too clear the error and already made myself another frrankenbattery. If you want to private message me your shipping address, I will send you this error'd unit if you want to have a go at it.

Did you try holding the button down for 30 to 40 seconds to reset the battery?

 

[beanbubba]

Did you try holding the button down for 30 to 40 seconds to reset the battery?

Man I tried every known combo of button/power sequences for 2 hours straight, no dice. I shipped the unit to chazz and he is going to take a shot at it.

 

[beanbubba]

Well, I watched the battery tick down to 5% (it was averaging about 1% per minute), then it did not go any lower. After 5 minutes I figured I better take a measurement or I will lose this moment.



Here are the readings after powering the bird back on.




I can't say for sure, but it kinda looks like after each flight the readings re-adjust for the factory 4000 LiHv. I really need to do a flight that is uninterrupted as that "appears" to give the wanted results, but I have no idea what I am talking about and learning on the fly. Does anyone with battery telemetry expertise see any patterns here worth mention?

 

[beanbubba]

Alright race fans. I think we might be able to concluded that the voltage readings for this mod are correct 100% of the time (minus the .05 consistent delta from my charger readout and the go4 app). Best part of this mod is no external battery mod is needed and you can actually power on and off the mavic with the power switch.

But the percentage indicator has a mind of its own and will change drastically depending on the situation. My next major test is to do a real flight test on freshly charged batteries and run to 0% and report results (but it is storming here now).

Good day gentlemen!

Does anyone know how low of voltage the mavic will go before shutting down? This had been idling at 0% for 15 minutes and I didn't want to risk going too low and powered it off.

 

[digdat0]

my only reference, while flying under load was critically low is 2.9 was 2.88v for me. It fell out of the sky at 2.5v per cell. thtas low but ya stil have a bit to go

 

[beanbubba]

my only reference, while flying under load was critically low is 2.9 was 2.88v for me. It fell out of the sky at 2.5v per cell. thtas low but ya stil have a bit to go

I had never paid attention to the voltages up until now and relied on the percentage indicator. For the top record range runs, what voltages were they finishing at?

 

[chazz]

The way I got somewhat used to relying on voltage on the phantom was i flew with an official battery with a few externals and took some notes. Well, i had my women takin notes while i was calling off some numbers (she thinks I'm nuts by the way)...For example i would call off like 97% and 4volts and then 85% 3.94V and 63% 3.77 (63% or 3.77 is where i turn around) randomly all the way to maybe 3.15V when i had to fight to keep it flying...I was also calling out some flight times periodical while i was dong this...With the phantom, at least, the volts start dropping fast when you start getting below 3.6V per cell...If you do this and find someone willing to write some numbers down while you call them out, i suggest labeling where you want them to write what on the piece of paper because after i saw what my women had on the paper (well,napkin) I would compare it to deciphering Egyptian hieroglyphs..In her defense she had no idea what the numbers were i was asking her to write...

For the first flight maybe keep it close... Good luck man! I'm anxious to see your results...

 

[CyberNate]

Alright race fans. I think we might be able to concluded that the voltage readings for this mod are correct 100% of the time (minus the .05 consistent delta from my charger readout and the go4 app). Best part of this mod is no external battery mod is needed and you can actually power on and off the mavic with the power switch.

But the percentage indicator has a mind of its own and will change drastically depending on the situation. My next major test is to do a real flight test on freshly charged batteries and run to 0% and report results (but it is storming here now).

Good day gentlemen!

Does anyone know how low of voltage the mavic will go before shutting down? This had been idling at 0% for 15 minutes and I didn't want to risk going too low and powered it off.


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With this mod you have a legitimate way to utilize the Titan batteries. The Titans are good, it's just that they are designed to be run down much further than the lihv. You should run 2 x 7000mah with this mod and run the voltage down to under 3v per cell while under load. That should give some amazing runtime. Having 2 3s2p packs is basically dividing current by 4 across the cells. That should be good enough to keep these 18650ga cells within the recommended operating range during distance flying. Don't add any extra weight. You should get over well over 50 minutes flight time and easily smash the record. Keep the flight slow like around 30mph as these 18650ga cells have a lot of voltage sag with higher current draw.

 

[beanbubba]

With this mod you have a legitimate way to utilize the Titan batteries. The Titans are good, it's just that they are designed to be run down much further than the lihv. You should run 2 x 7000mah with this mod and run the voltage down to under 3v per cell while under load. That should give some amazing runtime. Having 2 3s2p packs is basically dividing current by 4 across the cells. That should be good enough to keep these 18650ga cells within the recommended operating range during distance flying. Don't add any extra weight. You should get over well over 50 minutes flight time and easily smash the record. Keep the flight slow like around 30mph as these 18650ga cells have a lot of voltage sag with higher current draw.

Cybernate's words sound like angels singing!!!