Dual Battery Mod

[Gimpster]

For anyone else wanting to mount down low....

I did have compass errors as a previous poster did running them side saddle near the legs on my tray. I experimented a bit, and I'm able to push the compass side all the way forward (towards the camera lens side) and counter balance with the other side all the way back. Doing that eliminated my compass issues and I've had 3-4 successful flights light this.

I'm pretty happy with twin 1600's on a weight vs. flight time performance. To be honest, after 24-5 minutes... I'm pretty bored of flying around lol. Not a lot of cool things to look at around here in Des Moines.

Buddy gave me a bunch of 2200's he didn't use anymore, so I will start using those now too.

 

[BeauS]

Horzon has posted the V3 power mod V3.6. It has the 6600 mAh external now.

Phantom 3 Power Mod V3.6

 

[dirtybum]

Horzon has posted the V3 power mod V3.6. It has the 6600 mAh external now.

Phantom 3 Power Mod V3.6

I sent my single multiStar 6.6 to horizon to split. I was using it as a single battery behind the camera just like I do with my 5.2. The 6.6 was giving me the best flight time I've gotten of any battery almost 40 minutes. But it was just to unmanageable after you hit 10%
Trying to keep the throttle up on auto land and make it back a few thousand feet was hard to control the aircraft. Now that they've split the 6.6 I can't get 30 minutes out of it. Same exact battery I was getting 40 minutes out of.

 

[BeauS]

I sent my single multiStar 6.6 to horizon to split. I was using it as a single battery behind the camera just like I do with my 5.2. The 6.6 was giving me the best flight time I've gotten of any battery almost 40 minutes. But it was just to unmanageable after you hit 10%
Trying to keep the throttle up on auto land and make it back a few thousand feet was hard to control the aircraft. Now that they've split the 6.6 I can't get 30 minutes out of it. Same exact battery I was getting 40 minutes out of.

I remember you saying the single battery gets you better performance. Why does the split struggle so much?

 

[Ed209]

I have a meeting tomorrow with the Chief Engineer in the battery division. We've been exchanging emails since last week and I've been providing him with data on the 2x2S vs 4S batteries. I hope to have a definitive reason soon

 

[Phantom751874]

I remember you saying the single battery gets you better performance. Why does the split struggle so much?

I believe the split batteries introduce more internal resistance. 2 2s split batteries think they are 1 bigger 4s battery when they are wired in series. All that external cabling introduces resistance. My Hobby King charger can measure internal battery resistance. Split batteries on average had more than 2x the measured resistance than single 4s batteries. That's my theory anyway.

 

[Ed209]

I believe the split batteries introduce more internal resistance. 2 2s split batteries think they are 1 bigger 4s battery when they are wired in series. All that external cabling introduces resistance. My Hobby King charger can measure internal battery resistance. Split batteries on average had more than 2x the measured resistance than single 4s batteries. That's my theory anyway.

This is what I believe too. Just trying to get some expert testimony/concurrence. And possibly some tips.

 

[dirtybum]

I believe the split batteries introduce more internal resistance. 2 2s split batteries think they are 1 bigger 4s battery when they are wired in series. All that external cabling introduces resistance. My Hobby King charger can measure internal battery resistance. Split batteries on average had more than 2x the measured resistance than single 4s batteries. That's my theory anyway.

This is what I believe too. Just trying to get some expert testimony/concurrence. And possibly some tips.

Resistance IS the answer,phantoms explanation makes sense! It will be interesting to see the battery engineers response Ed!

 

[Ed209]

Resistance IS the answer,phantoms explanation makes sense! It will be interesting to see the battery engineers response Ed!

Yes I know. I'm hoping he may know of a way to get the resistance down a bit perhaps with thinner gauge wiring or a different material. We don't need the max current out of these batteries so rewiring them could be an option if the resistance can be brought down.

 

[dirtybum]

I'd rewire it within thinner wire, if they said that was a solution. Horizon said the thicker wires would cause less resistance, I don't know about that though

 

[dirtybum]

Is this the longest flight time a p3 has gotten??

 

[Ed209]

Is this the longest flight time a p3 has gotten??View attachment 54501View attachment 54502

It might be but it doesn't coun't because you removed the camera

Hahaha j/k! It could be I think.

 

[dirtybum]

It might be but it doesn't coun't because you removed the camera

Hahaha j/k! It could be I think.

I totally agree, it's just for conversations sake, that's why put over here in the dual battery mod section, just for us to throw it around, not to use it as bragging rights[emoji41]

 

[Gimpster]

So I decided to ditch my temporary wooden mount and design a couple side-saddle battery mounts. I was occasionally getting compass issues, so mounting down low is just a no-go. Let me know what you think. I need to make a couple small tweaks in the design to be perfect, but I'm pretty happy with them.

I should work on designing one for when removing the gimbal for record flights like dirtybum too

 

[Mark The Droner]

I dunno. That looks a little scary to me - weight-wise and aerodynamic-wise.

Good luck!

 

[maxwell smart]

Yea but toughs bananas are ready to eat.

 

[Phantom751874]

Trim the boards down they are too wide. Also ditch the braces under the motors they aren't needed don't do much just add weight. I've had 3 P3's about to have a 4th and none of the 3 have cracking issues and 2 of the 3 are are original v1 shells.

I'm not saying it won't happen to yours but if your within warranty no harm done DJi will replace the shell. If your not under warranty then the shell replacement doesn't look too bad.

 

[MVodhanel]

I screwed up on the Multi-Star tests. I didn't see any HV batteries, and I swear I thought I looked hard for them. So, I did my tests on standard 4.2 volt batteries. I split the 5200 and 6600, 4s's into 2s's and tried various different combinations of 2s's in series, or pair of parallel 2s's in series. It is a very flexible setup. Se pics below.

I have a batch of Multi-Star HV's now, so I guess I get to start over. I was getting about a 35 minute flight from a combined 5200 and 6600.

The HV's I have are 40000 (I have others coming in, as well). I have high hopes for getting my quietness back with these....

 

[dirtybum]

I screwed up on the Multi-Star tests. I didn't see any HV batteries, and I swear I thought I looked hard for them. So, I did my tests on standard 4.2 volt batteries. I split the 5200 and 6600, 4s's into 2s's and tried various different combinations of 2s's in series, or pair of parallel 2s's in series. It is a very flexible setup. Se pics below.

I have a batch of Multi-Star HV's now, so I guess I get to start over. I was getting about a 35 minute flight from a combined 5200 and 6600.

The HV's I have are 40000 (I have others coming in, as well). I have high hopes for getting my quietness back with these....

View attachment 54568 View attachment 54569 View attachment 54570 View attachment 54571

You got any extra batteries you need to send my way to "test"let me know

 

[Ed209]

I screwed up on the Multi-Star tests. I didn't see any HV batteries, and I swear I thought I looked hard for them. So, I did my tests on standard 4.2 volt batteries. I split the 5200 and 6600, 4s's into 2s's and tried various different combinations of 2s's in series, or pair of parallel 2s's in series. It is a very flexible setup. Se pics below.

I have a batch of Multi-Star HV's now, so I guess I get to start over. I was getting about a 35 minute flight from a combined 5200 and 6600.

The HV's I have are 40000 (I have others coming in, as well). I have high hopes for getting my quietness back with these....

View attachment 54568 View attachment 54569 View attachment 54570 View attachment 54571

I tested the 4.2v multi 4000 by accident too. Stupid rush ordering mistake. I got 27:16 to 14%.