Mavic Pro Battery Mod

[lolo780]

What's the total flying weight?

 

[Phxbird57]

A picture for motivation.
View attachment 27977

nice setup. that is where I put my batteries at just flipped so to run the leads to the top.

 

[beanbubba]

What's the total flying weight?

I unfortunately lost my last frankenbird and almost finished mod'ing a replacement. At the moment I am at 1256 grams AUW (includes 17g amp).

Lolo, what was your takeoff weight on your record run?

 

[lolo780]

I unfortunately lost my last frankenbird and almost finished mod'ing a replacement. At the moment I am at 1256 grams AUW (includes 17g amp).

Lolo, what was your takeoff weight on your record run?

1106g, DJI batt plus 2x Thunderpower 4500s, fixed cam.

 

[Mechcondrid]

if anyone by chance has a dead or dying mavic battery might i get them to send it to me? i have an idea to make an extended hump back battery with a 3d printed cover to replace the stock batt cover on the pack.
i may be able to get proper readout from the pack to the drone and app of Mah count depending on if i can dump the eeproms of the mavic batt and write them back with modified values via an ISP.

also may toy with an onboard voltage regulation to use LIHV cells at full charge without throwing the battery error, also depends on how it senses this (thinking via the balance lines on the connector so i can then separate the voltage sensing from the actual power supply line to the ESCs)

 

[beanbubba]

if anyone by chance has a dead or dying mavic battery might i get them to send it to me? i have an idea to make an extended hump back battery with a 3d printed cover to replace the stock batt cover on the pack.
i may be able to get proper readout from the pack to the drone and app of Mah count depending on if i can dump the eeproms of the mavic batt and write them back with modified values via an ISP.

also may toy with an onboard voltage regulation to use LIHV cells at full charge without throwing the battery error, also depends on how it senses this (thinking via the balance lines on the connector so i can then separate the voltage sensing from the actual power supply line to the ESCs)

You my friend should productize this and make a nice side business if you can figure this out. Every other person on this thread would buy one without question.

 

[lolo780]

You my friend should productize this and make a nice side business if you can figure this out. Every other person on this thread would buy one without question.

4s support would be fantastic as well.

 

[Mechcondrid]

4s support would be fantastic as well.

that wouldn't likely be to much use; i could but then thatd go into regulating the voltage back down to 12v and then you'd need a regulation circuit that can both dissipate the added heat from dropping the voltage as well as handle the amperage output the drone needs; which means i'd have to put a heatsink of some kind on the PCB

You my friend should productize this and make a nice side business if you can figure this out. Every other person on this thread would buy one without question.

honestly if the mavic battery is anything at all like a laptop battery it has a non-volitile memory chip like an eeprom that simply stores a static number which identifies the serial number, max Mah and maybe some other info.
eeprom chips are generally not burn-once chips and so are rewritable so i could make a custom lipo pack inside of the shell and rewrite the chip to read out the new mah rating
technically stock chargers should also work albeit take significantly longer due to increased capacity since the stock connector is still being used and the same pins being populated still

 

[lolo780]

that wouldn't likely be to much use; i could but then thatd go into regulating the voltage back down to 12v and then you'd need a regulation circuit that can both dissipate the added heat from dropping the voltage as well as handle the amperage output the drone needs; which means i'd have to put a heatsink of some kind on the PCB



honestly if the mavic battery is anything at all like a laptop battery it has a non-volitile memory chip like an eeprom that simply stores a static number which identifies the serial number, max Mah and maybe some other info.
eeprom chips are generally not burn-once chips and so are rewritable so i could make a custom lipo pack inside of the shell and rewrite the chip to read out the new mah rating
technically stock chargers should also work albeit take significantly longer due to increased capacity since the stock connector is still being used and the same pins being populated still

No need to regulate anything. I'm running on 4s already and the whole point is higher motor voltage. The battery board reads the total voltage just fine.

 

[beanbubba]

that wouldn't likely be to much use; i could but then thatd go into regulating the voltage back down to 12v and then you'd need a regulation circuit that can both dissipate the added heat from dropping the voltage as well as handle the amperage output the drone needs; which means i'd have to put a heatsink of some kind on the PCB



honestly if the mavic battery is anything at all like a laptop battery it has a non-volitile memory chip like an eeprom that simply stores a static number which identifies the serial number, max Mah and maybe some other info.
eeprom chips are generally not burn-once chips and so are rewritable so i could make a custom lipo pack inside of the shell and rewrite the chip to read out the new mah rating
technically stock chargers should also work albeit take significantly longer due to increased capacity since the stock connector is still being used and the same pins being populated still

I really would like a fresh set of eyes looking at this. Let us know if you have ideas where to take this mod.

Mavic Pro Factory Battery Controller Mod

 

[Mechcondrid]

No need to regulate anything. I'm running on 4s already and the whole point is higher motor voltage. The battery board reads the total voltage just fine.

coming from an electrical engineering viewpoint i'd be very worried about long term usability on that causing premature failure on the voltage regulators in the ESCs and daughterboards in the drone; all regs have a tolerance (usually anywhere from 15 to 30% over and under the min-max voltages) for over or under volting their power supplies but over volting creates more heat on the silicon package that it then has to dissipate and if your into pc overclocking or custom circuits you'll know it is not a good long term idea to let circuits run significantly hotter than the TDP the package is designed for without an additional cooling method or aid.
it will work yes but it'll mean an early grave for the chip at some point.

 

[beanbubba]

coming from an electrical engineering viewpoint i'd be very worried about long term usability on that causing premature failure on the voltage regulators in the ESCs and daughterboards in the drone; all regs have a tolerance (usually anywhere from 15 to 30% over and under the min-max voltages) for over or under volting their power supplies but over volting creates more heat on the silicon package that it then has to dissipate and if your into pc overclocking or custom circuits you'll know it is not a good long term idea to let circuits run significantly hotter than the TDP the package is designed for without an additional cooling method or aid.
it will work yes but it'll mean an early grave for the chip at some point.

Mechcondrid, please move this line of postings to the mavic battery controller thread. Thanks and I look forward to your input!

Mavic Pro Factory Battery Controller Mod

 

[lolo780]

coming from an electrical engineering viewpoint i'd be very worried about long term usability on that causing premature failure on the voltage regulators in the ESCs and daughterboards in the drone; all regs have a tolerance (usually anywhere from 15 to 30% over and under the min-max voltages) for over or under volting their power supplies but over volting creates more heat on the silicon package that it then has to dissipate and if your into pc overclocking or custom circuits you'll know it is not a good long term idea to let circuits run significantly hotter than the TDP the package is designed for without an additional cooling method or aid.
it will work yes but it'll mean an early grave for the chip at some point.

Temps are cooler than stock as I have extra airflow around the boards. In fact the ESCs on 4s run even cooler moving less current.

The lc1160 power distribution is also used on the Phantom which is 4s from the factory so I'm not worried. So far I've got about an hour of run time on 4s and it's been nothing short of spectacular performance and efficiency.

Oh and the mosfets are 30v rated so no worries there.

 

[Mechcondrid]

Temps are cooler than stock as I have extra airflow around the boards. In fact the ESCs on 4s run even cooler moving less current.

The lc1160 power distribution is also used on the Phantom which is 4s from the factory so I'm not worried. So far I've got about an hour of run time on 4s and it's been nothing short of spectacular performance and efficiency.

Oh and the mosfets are 30v rated so no worries there.

ok good to know then, that simplifies some things design wise

 

[Blade slap]

Temps are cooler than stock as I have extra airflow around the boards. In fact the ESCs on 4s run even cooler moving less current.

The lc1160 power distribution is also used on the Phantom which is 4s from the factory so I'm not worried. So far I've got about an hour of run time on 4s and it's been nothing short of spectacular performance and efficiency.

Oh and the mosfets are 30v rated so no worries there.

Dear lolo very good work and you take the risk . Question : means that you just connect 4s directly to mavic board just setting as no dji battery or you go trough the pcb battery, clearly not connecting the lipo balancer ?

 

[lolo780]

4s straight to the ESC

 

[Blade slap]

4s straight to the ESC

Thanks ...straight like that ? correctly?

 

[lolo780]

Thanks ...straight like that ? correctly?View attachment 28336

I go to the ESC board where the stock wires join the copper pads to minimize wiring losses.

 

[Blade slap]

I go to the ESC board where the stock wires join the copper pads to minimize wiring losses.

Thanks

 

[chazz]

No need to regulate anything. I'm running on 4s already and the whole point is higher motor voltage. The battery board reads the total voltage just fine.

Why doesn't your cell voltage match the total voltage?