DJI FPV modding

Kilrah · Jun 18, 2021

Several problems with that, firstly if you had a full battery, discharged it and then connected full cells the BMS would think the battery is still empty and give bogus readings. It's meant to be constantly connected to the cells and monitor /accumulate any charge that goes in or out.

Secondly if you just disconnect the cells from the BMS board it'll see something's seriously wrong with the battery, go into "permanent failure" state and not turn on again. On older ones you could swap the cells but you had to be careful to disconnect/reconnect the main wires and cells one by one in a particular order not to trip it so it's not practical to do every flight, and I'm not sure it's possible anymore.

anethema · Jun 18, 2021

Kilrah said:
Several problems with that, firstly if you had a full battery, discharged it and then connected full cells the BMS would think the battery is still empty and give bogus readings. It's meant to be constantly connected to the cells and monitor /accumulate any charge that goes in or out.

Secondly if you just disconnect the cells from the BMS board it'll see something's seriously wrong with the battery, go into "permanent failure" state and not turn on again. On older ones you could swap the cells but you had to be careful to disconnect/reconnect the main wires and cells one by one in a particular order not to trip it so it's not practical to do every flight, and I'm not sure it's possible anymore.

Do you know this or are you assuming ? I should open one up, disconnect then reconnect the cells. Be curious to see if it gives a fault condition.

Kilrah · Jun 18, 2021

No it's well known, people have been doing battery modding on DJI stuff for quite a while. It won't give a fault condition, the battery will just not power on again.

anethema · Jun 18, 2021

Kilrah said:
No it's well known, people have been doing battery modding on DJI stuff for quite a while. It won't give a fault condition, the battery will just not power on again.

So if you disconnect and reconnect the cells the battery is perma bricked?

Kilrah · Jun 18, 2021

Yup, this is not reversible unless you have access to programming tools, software and keys for the specific BMS chip used in that battery (DJI have used different ones over the years).
On the old batteries you could avoid it by disconnecting/connecting the cells one at a time in order but I don't know if that still works. If it saw a middle cell disappear it bricked.

GooseFPV · Jun 19, 2021

anethema said:
Been thinking of playing with modding the drone. One of the main interesting things would be transplanting the guts into a normal carbon fiber frame.
The main question I had was in most quads the IMU gear is mounted on the flight controller board but on this drone it’s in the front soft mounted on 4 bungies at an angle to the level direction.

I imagine if I could cool everything I could mount the other boards flat or in a stack, but the IMU would probably need to get a printed part to mount it at the same angle no? Anyone have a guess? Gonna order a frame and try it out anyways be interesting to see!

Hi Anethema, great project! FYI in the ‘DJI FPV drone’ group on Facebook, ‘Moppel Mat’ is making some progress swapping in a different carbon frame (screen grab attached) so he might be able to help. Full disclosure, I’m trying to collect all the successful mods and hacks together on a single page (DJI FPV Drone Mods & Hacks) so watching your efforts with interest!

anethema · Jun 19, 2021

GooseFPV said:
Hi Anethema, great project! FYI in the ‘DJI FPV drone’ group on Facebook, ‘Moppel Mat’ is making some progress swapping in a different carbon frame (screen grab attached) so he might be able to help. Full disclosure, I’m trying to collect all the successful mods and hacks together on a single page (DJI FPV Drone Mods & Hacks) so watching your efforts with interest!

Thanks I’ll check that out !

Noobnoobnoob · Jun 21, 2021

Many have tried to make late model DJI aircraft run on "normal" lipos. The early DJI Phantoms I believe were able to be retrofit but newer ones are almost impossible to run - and I use almost because it has been done on Inspire 1 with incredible difficulty and some hacking to screw with the codes- It is very tough to do and might not even be worth it. One of the things that sets the DJI FPV appart from traditional quads is the intelligent functions like low battery rth etc, once you get rid of these functions the craft seems pretty irrelevant. I think too that the components are too bulky for a traditional frame, balancing the animal will be tough and making sure the components cool properly will also be a challenge, even with forced cooling this beast gets hot. It'll be a major challenge that will only be worth it to the one that succeeds.

anethema · Jun 21, 2021

Noobnoobnoob said:
Many have tried to make late model DJI aircraft run on "normal" lipos. The early DJI Phantoms I believe were able to be retrofit but newer ones are almost impossible to run - and I use almost because it has been done on Inspire 1 with incredible difficulty and some hacking to screw with the codes- It is very tough to do and might not even be worth it. One of the things that sets the DJI FPV appart from traditional quads is the intelligent functions like low battery rth etc, once you get rid of these functions the craft seems pretty irrelevant. I think too that the components are too bulky for a traditional frame, balancing the animal will be tough and making sure the components cool properly will also be a challenge, even with forced cooling this beast gets hot. It'll be a major challenge that will only be worth it to the one that succeeds.

Ya it’s really just for fun.

Romulus Archibald · Jun 21, 2021

Monitoring this thread with great interest.

cootertwo · Jun 21, 2021

Yup, me too, watching..... Also, to add, this battery thing is very similar, if not exact, to the 3DR Solo batteries. There have been some successful lipo transplants there.