Dual Battery Mod

[Digdat0]

Understand the principle of waiting initially before flying off to make sure main battery does not go into charging mode. But does this ever happen mid-flight and if it did, would the drone continue to fly on the axillary battery or with the FW shut things down because it's not a genuine DJI battery.
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Yes, it could happen in flight. Usually right at the beginning of the flight, but it can happen. The situation is that the aircraft will remain powered on and inflight, but the power will be driven by the externals as the internal battery will go into charge mode. This will remain until the battery is charged, in which case it will simply turn off. The externals will still power the aircraft, but you will lose all video and telemetry (no battery % reading, no voltage, no distance, no speed info). You will stay in the air, but will be flying blind. The DJI battery will not turn itself on.

 

[dan84uk]

Understand the principle of waiting initially before flying off to make sure main battery does not go into charging mode. But does this ever happen mid-flight and if it did, would the drone continue to fly on the axillary battery or with the FW shut things down because it's not a genuine DJI battery.

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No never, its just surface charge, as soon as you place load the batteries with the props the voltage equalizes and as far as the drone is concerned its one battery, just take off and wait 30 secs. When I switch off the main battery with the external connected the my drone will remains switched on. Ive soldered directly to the drone.

I cant think of a scenario that would cause a voltage difference in flight that would put it into charge mode. Well unless the main battery failed, in that case the external battery should actually save you.

The extra battery actually makes the drone safer if anything. Assuming you have soldered post main battery pcb.

If im wrong someone please correct me.

 

[WilliamM]

Yes, it could happen in flight. Usually right at the beginning of the flight, but it can happen. The situation is that the aircraft will remain powered on and inflight, but the power will be driven by the externals as the internal battery will go into charge mode. This will remain until the battery is charged, in which case it will simply turn off. The externals will still power the aircraft, but you will lose all video and telemetry (no battery % reading, no voltage, no distance, no speed info). You will stay in the air, but will be flying blind. The DJI battery will not turn itself on.

So in this situation the FW doesn't shut down the drone, but does shut down the 2.4 GHz signal? And if you were out of VLOS and had no telemetry at all, that would be a issue. But I assume that "Home lock" and RTH (at least via the S2) should still work, correct?

 

[WilliamM]

No never, its just surface charge, as soon as you place load the batteries with the props the voltage equalizes and as far as the drone is concerned its one battery, just take off and wait 30 secs. When I switch off the main battery without the external connected the my drone will remains switched on. Ive soldered directly to the drone.

I cant think of a scenario that would cause a voltage difference in flight that would put it into charge mode. Well unless the main battery failed, in that case the external battery should actually save you.

The extra battery actually makes the drone safer if anything. Assuming you have soldered post main battery pcb.

If im wrong someone please correct me.

I'm going to be using the battery clip thing. Was this a typo? "When I switch off the main battery without the external connected the my drone will remains switched on." Did you mean to say, "with the external connected"?

 

[dan84uk]

I'm going to be using the battery clip thing. Was this a typo? "When I switch off the main battery without the external connected the my drone will remains switched on." Did you mean to say, "with the external connected"?

Corrected lol

 

[Digdat0]

So in this situation the FW doesn't shut down the drone, but does shut down the 2.4 GHz signal? And if you were out of VLOS and had no telemetry at all, that would be a issue. But I assume that "Home lock" and RTH (at least via the S2) should still work, correct?

No, the 2.4ghz signal will still work. You will have full RC control, but in my experience the video will drop and all telemetry (RTH, home spot, etc will also stop working). I do not believe RTH will work, but i haven't tested it (not sure i want to!) I can only see this happening in two very extreme situations 1) You take off quickly after plugging in external and it starts to charge. In this case "battery error" will come up pretty soon (while within VLOS) and you should come right back. 2) You are running externals down to zero %% and the main DJI battery powers down because volts are too low, but still in flight from the external battery power. This happened to me once after a long distance flight and I had to fly it by feel .. i knew that it was aimed at me, but i had no idea how high, or how close. I lost telemetry about 2000 feet out, and was fighting autolanding. I just held the RC sticks where they were and prayed .. finally i saw it come in and landed by visual. If it had gone down, i would have had no idea where it was.

My 2cents is, if you run into the issue where external charges the stcok battery, just let it do it. It will finish and then the battery will power off. Simply turn it back on and you are good to fly.

 

[dan84uk]

My 2cents is, if you run into the issue where external charges the stcok battery, just let it do it. It will finish and then the battery will power off. Simply turn it back on and you are good to fly.

That does make perfect sense, however that wouldn't work for me. Mine kept going into charge mode repeatedly! It was powered off though.

 

[Digdat0]

That does make perfect sense, however that wouldn't work for me. Mine kept going into charge mode repeatedly! It was powered off though.

So the reason it goes into charge mode is because the volts in the external are greater than in the DJI battery. If you just leave it like that to charge, it should fill up and be full and stop. Then, if you turn the battery back on all should be good. I dont have a video of that at the moment, but here's what happens when you turn off the DJI battery with external plugged in. You can see the drone remains powered on, but the battery details are all gone:

Are you topping off your DJI battery to 100%? If not, that will help. Here's a short vid on doing that:

 

[dan84uk]

So the reason it goes into charge mode is because the volts in the external are greater than in the DJI battery. If you just leave it like that to charge, it should fill up and be full and stop. Then, if you turn the battery back on all should be good. I dont have a video of that at the moment, but here's what happens when you turn off the DJI battery with external plugged in. You can see the drone remains powered on, but the battery details are all gone:

Are you topping off your DJI battery to 100%? If not, that will help. Here's a short vid on doing that:

I know and i agree it should work and have seen it work on youtube videos, im just saying for whatever reason mine doesn't on my phantom standard with my setup, Yep i top it off on the DJI charger.

If i connect the external, the main goes into charging mode, then switches of. If i turn it back on again, it goes back into charging mode yet again and again. Im sure it would eventually stop, it made no sense to me either. Turning the props on then connecting the external or just after solves it for me. Might be my old firmware i use.

 

[Lee SK]

LeeSk!! Been a long time since we've seen ya. Come more often! I think the 5.2 multistar is still the best, the multistar 6600 is giving good times as well. I wonder if there are crazy combos which could produce good results.

Please recommend P3 external battery again.... 6600? 8000? 10000?

 

[WilliamM]

Please recommend P3 external battery again.... 6600? 8000? 10000?

I'm new to doing a battery mod, but from my reading the 5200 seems to be the most common. And the 6600 or 8000 as a max, but 10000 that's too much. Personal I went small with a 3400, which I know is on the low end, buts that's all I need.

 

[Digdat0]

Please recommend P3 external battery again.... 6600? 8000? 10000?

My longest (with camera) was with the 6600. Before the new record dirtybum set (with the 10.0), i think he was pushing the 5.2. I think the 5.2 or 6600 Multistar are still the best two for with camera.

 

[chazz]

All this talk about batteries made me split my MS 6600 LiHV...I didn't think i was going to do it again but the last flight with the split 8 was pretty impressive...can't wait to compare the two...Lookin for a MS10000 LiHV if anybody knows where to get one...

 

[dirtybum]

I'm not doubting that the split 8.0 produced a decent number, but I thought we already lasted to rest the fact that splitting a battery reduces the battery is the tension?


Sent from my iPhone using PhantomPilotswow my I-phone really screwed up the words/spelling on this post, it doesn't even make sense [emoji41]

 

[Habanero]

Hi everyone this is my first post in this great forum. Been flying my P3P with old motors for a while and reading this forum. today finally singned up , sorry for not giving my 2 cents before

Dirtybum it's true that splitting the batteries increase internal resistance, that will also lower the c rating but the 10c on a 5200 will yield 52amp so we won't notice that only the total capacity . I suspect they are not magically weld together we just need to find how to conect them with low resistance like they originally are. Has any one try 10awg wire? The thicker the wire the lower R but longer more R. This it's what happens we are making it longer now me need to make it thicker to compensate . How much ? Well that will need some testing . I have a 5200 and a 4000 in order hoping I can split then and keep near the same # that before split...really like the batt on the sides for many reasons. But don't doubt they work great single to.

The thing is that I just got a 5200 lipo for $20 at hobbyking To make 2 packs of 2600 for each side total weight it's 433g /2 about 217g each so.


2600mah/217g/$10 it's a great deal even if you lose a bit and they are now 2300 for $10 and only weigh 217g... be very hard to beat that with two smaller 4s packs ...

Also does any one know if using lipo and not lihv will reduce or eliminate the minor glitch of OEM battery charging because lipo will have lower voltage ? I have both kinds in order to test that to....

Thank you every one lots of great info in this forum ....

 

[Digdat0]

Also does any one know if using lipo and not lihv will reduce or eliminate the minor glitch of OEM battery charging because lipo will have lower voltage ? I have both kinds in order to test that to....

Thank you every one lots of great info in this forum ....

charging issue only happens when i use liHV fully charged,never enounctered it with my regular lipo.

 

[WilliamM]

charging issue only happens when i use liHV fully charged,never enounctered it with my regular lipo.

Now you have me thinking I should have gotten the 14.8v over the 15.2v. I guess you could just pull the plug on the charger at the 4.2v per cell on the LiHv and you'd be safe.

 

[Digdat0]

Now you have me thinking I should have gotten the 14.8v over the 15.2v. I guess you could just pull the plug on the charger at the 4.2v per cell on the LiHv and you'd be safe.

I find that with newer batteries for the phantom, charging issue happens less often. If you top off your batteries to 100%, it shouldn't be an issue. but, if it does, its really not a big deal. Just let it finish, the battery will turn off and turn back on and fly. its only about 10-15 seconds for me if it does happen. I think the lihv benefits outweigh the negative effects of the charging issue.

 

[dirtybum]

When I plug in external then take off within seconds I rarely get the charging/blinking sequence. But I mean seconds! I charge externals to 4.35 for p3 and 4.30 for P4


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[dirtybum]

Please recommend P3 external battery again.... 6600? 8000? 10000?

Depends on your goals Lee.

Taking pictures and joy flying = 5.2 & 4.0
Record distance runs = 6.6 & 8.0

Pushing your luck and possibly dropping your bird outta the sky = 10.0[emoji41]


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