Dual Battery Mod

Still breaking in batteries but flew out 4.71mi. I know not nothing near record but was just wanting to push the bird farther after 9 flights on new mod. FPVLR v2 Boosted and G6 1800s run nice. Next to compare the 2400s. On this flight was flying into the wind with 20-24mph max speed. Return was going 40-49mph. Very impressed. View attachment 44544
What aircraft firmware are you running? 1.1.9? I thought later and more recent firmware versions throttled the downwind speed to a max of 35mph, much to everyone's disappointment, because if you have pay the wind penalty upwind, you ought to get paid back equally downwind!
 
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You don't want the two helper batteries to be HV, or if they are HV, you don't want to charge them all the way to full capacity. This is important. They need to stay just a little behind the primary battery. That is why they are usually set up as non-HV slaves in parallel with the HV smart battery. If you were to hook up full charged, HV helper batteries to the smart battery, the smart battery would believe it was being charged and stop outputting. Nope, you don't want this at altitude..... Just keep the helper batteries non-HV, and you will be OK.
Interesting, as the only reason for using the HV batteries in the first place, requiring an additional $120 HV capable charger, was their higher voltage for their weight, giving maximum flight time. Perhaps the compromise of doing so is the HV battery puffing, but if you already set a record that way, who cares! I bought two 2300 HV Venoms, and the HV charger, but have yet to try them. Your post gives me pause for reconsideration.

Up until now, I have been successfully using the more expensive MaxAmp 2800's at 245g each, with no issues, after some 60 flights averaging 28-29 minutes down to 10% remaining battery. The extra weight so far has not been an issue, but going lighter might extend the flight time to 30+ minutes, if the sweet spot is 208g each on the externals, if the HV 2300 at 4.35V per cell compensates for the 500 mAh loss per cell over the 2800's, but not if they have to be used at only 4.2V per cell. Hmmm.
 
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I think it works out to about the same with the shipping factored in at hobbyking vs fpvcustoms? FPV custom charge $29.95 shipped. Hobbyking charges $14 for shipping plus $15 for the tray I think.
There is a $6 international first class mail option for shipping from Hobbyking, saving $10, if you don't need them in 3 days. Either way, they work great, but may need a couple of pilot holes drilled to fit the P3, which Paul includes at FPVCustoms, as they were originally designed to fit the strut screw holes of the P2, which are slighty different in location. The new holes are really only used for alignment, but you still need them.
 
What aircraft firmware are you running? 1.1.9? I thought later and more recent firmware versions throttled the downwind speed to a max of 35mph, much to everyone's disappointment, because if you have pay the wind penalty upwind, you ought to get paid back equally downwind!

Yeah I got lucky on the P3A I bought last week. Had new motors and 1.3.2 fw. So downgraded that puppy. There is actually a point where going too fast is inefficient. I am planning to study that. Think of it this way: The angle of the P3 has to tilt more to go faster. With that tilt comes the added force against the surface area that is mashing into the air. I didn't care about going too fast on that run because I knew I had plenty left in the tank. But for extreme distance, this is crucial. I read a scientific article that says optimal speed of the P3 is 30mph (considering no wind). That was on a stock bird though, no extra weight and extra surface area to contend with.
 
There is a $6 international first class mail option for shipping from Hobbyking, saving $10, if you don't need them in 3 days. Either way, they work great, but may need a couple of pilot holes drilled to fit the P3, which Paul includes at FPVCustoms, as they were originally designed to fit the strut screw holes of the P2, which are slighty different in location. The new holes are really only used for alignment, but you still need them.


Ahh good to know. I wound up getting a set through FPV Customs so it should be here this coming week. Now I just need to decide on batteries and where to get them. If you guys have any suggestions let me know lol. Need a charger too.
 
Yeah I got lucky on the P3A I bought last week. Had new motors and 1.3.2 fw. So downgraded that puppy. There is actually a point where going too fast is inefficient. I am planning to study that. Think of it this way: The angle of the P3 has to tilt more to go faster. With that tilt comes the added force against the surface area that is mashing into the air. I didn't care about going too fast on that run because I knew I had plenty left in the tank. But for extreme distance, this is crucial. I read a scientific article that says optimal speed of the P3 is 30mph (considering no wind). That was on a stock bird though, no extra weight and extra surface area to contend with.
I picked up a lightly used original motor P3P which still has 1.1.9+ on it, so I'll soon be able to experiment. I know that Unknown Caller found that P-GPS was more efficient than ATTI for his P3P record distances, perhaps for the same reason. Assuming the optimal speed is 30mph, I wonder why DJI uses only 23mph (or something really close to that--can't find the actual number right now) for RTH speed, where efficiency would be critical.
 
I picked up a lightly used original motor P3P which still has 1.1.9+ on it, so I'll soon be able to experiment. I know that Unknown Caller found that P-GPS was more efficient than ATTI for his P3P record distances, perhaps for the same reason. Assuming the optimal speed is 30mph, I wonder why DJI uses only 23mph (or something really close to that--can't find the actual number right now) for RTH speed, where efficiency would be critical.

Yup, and in the case of winds... Being restricted could mean that your RTH will be a failure. That's why it's always important to fly into wind on the way out.

Also there were tests done that show the new motors yield about 2-3mins more vs old motors. These tests were done by hovering which requires a lot of power.
 
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Looks like FPV Customs is reselling the Hobby King battery trays:

EXTERNAL BATTERY BRACKET....INCLUDES 2-3 DAYS SHIPPING

DJI Phantom Carbon Battery Extension Board

Almost double the price but then you won't have to wait for international shipping from HK as I don't see a USA option from them yet.


And paul will predrill the holes in the right place. Since theyre orinally drill for p2 legs. I'm all for savin $ but if a couple bucks is no prob for ya, u cant find a more helpful guy for service
 
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Yup, and in the case of winds... Being restricted could mean that your RTH will be a failure. That's why it's always important to fly into wind on the way out.

Also there were tests done that show the new motors yield about 2-3mins more vs old motors. These tests were done by hovering which requires a lot of power.
I can confirm the extra flight time with new motors. I just dont like the independent 18% reduction in video power output from the aircraft which accompanies it, further reduced to a 30% reduction over the original 323 on the most recent version.
 
I guess it depends on what your ultimate goal is and intended use. For me, I need the new motors for maximum efficiency. I still have my original P3P with old motors which I intend to use for flying FPV.
 
So essentially would having a broken down p3 battery as the slave cause issues !? Since it's supposed to be "HV" ?


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No, not necessarily. I use HV's myself when I am pushing the envelope. You really need to be aware of where your batteries are when doing this. If you forget, or have a mental lapse, this phenomenon will pop up. Even then it is no big deal, you can just blame it on DGI anyway :)... It generally happens when you have a smart battery that may have started an auto discharge and might not be full like you thought it was. And it usually is harmless because it generally happens on the ground. But it will be a mystery unless you know about this.

I think all the aftermarket guys set folks up with standard batteries. I wish they would talk about this more so people would know why. There is absolutely nothing wrong with using the HV's. You just have to take more care that you have, for sure fully charged your smart battery, and you don't need to take the HV all the way up, just most of the way. If it turns out the slave batteries are higher than the smart battery, the copter won't launch. You can either try to let them try to charge the smart battery, something I have never done, or take them down on a smart charger. But whatever you do, always vent at DJI, they deserve it....

OK I have a good illustration of whats under the cap of a P3 smart battery. I'll 'tach here... And I may be testing my idea tonight in my ten foot basement.....
Under the P3 Cap.jpg


[EDITED 2-23-16] I had the location of the ground wire for the balance connector wrong on my original posting of this picture. Be sure to update, if you need to!
 
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No, not necessarily. I use HV's myself when I am pushing the envelope. You really need to be aware of where your batteries are when doing this. If you forget, or have a mental lapse, this phenomenon will pop up. Even then it is no big deal, you can just blame it on DGI anyway :)... It generally happens when you have a smart battery that may have started an auto discharge and might not be full like you thought it was. And it usually is harmless because it generally happens on the ground. But it will be a mystery unless you know about this.

I think all the aftermarket guys set folks up with standard batteries. I wish they would talk about this more so people would know why. There is absolutely nothing wrong with using the HV's. You just have to take more care that you have, for sure fully charged your smart battery, and you don't need to take the HV all the way up, just most of the way. If it turns out the slave batteries are higher than the smart battery, the copter won't launch. You can either try to let them try to charge the smart battery, something I have never done, or take them down on a smart charger. But whatever you do, always vent at DJI, they deserve it....

OK I have a good illustration of whats under the cap of a P3 smart battery. I'll tach here... And I may be testing my idea tonight in my ten foot basement.....View attachment 44585

So if I wanted to do what FPV horizon does in the uk with the v3 mod.

I would run the balance leads to the 2 slave packs in series ... And run the power in series to the Un switched tinned ports?

Effectively tricking the smart cap into thinking each of its 4 cells were actually double the size ?

Edit: I should point out, I'm not trying to rip off horizon, they don't deliver to Canada , and I want to experiment myself.

And doing this would allow the battery & slave to be charged as one battery , which seems like a safer alternative to some ideas out there.

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Nice illustration. So do the battery mods have the leads soldered to the unswitched pads or just to the back of the DJI battery connector? This would explain why the drone powers up if you connect the extra batteries even with the P3 main battery off.
 
I guess it depends on what your ultimate goal is and intended use. For me, I need the new motors for maximum efficiency. I still have my original P3P with old motors which I intend to use for flying FPV.
Same here. My original old motor P3P caught the airborne battery virus and committed harakiri! :eek: The new motor Best Buy replacement has severely reduced video stabilty, much to my consternation, so I found an original motor bird with 18% more video power output on the bird, to complete my fleet!:cool:
 
<offtopic>

IF using wifi-amps on VIDEO side, please read. It's important to know this to achieve long distance flights with your battery mods. There is a catch with 32ch mod that most of us doesn't fully understand and are getting shitty distances compared to some others.

Sunhans and similar wifi-boosters works on 2.4G-2.5G range and helps a lot when you stay between the range or close.

DJI Channel 1 - 12 = 2.286G - 2.396G (out of range)
DJI Channel 13 - 22 = 2.406G - 2496G (this is where the booster actually works best, you can go few channels lower or higher, after that it does NOT work with full potential)
DJI Channel 23 - 32 = 2.506G - 2.596G (out of range)

If you dont have video-side amps (airside, rc-side, or both) forget everything you just read.

</offtopic>
I had great hopes this evening using Channel 21 instead of Channel 30 with my Sunhans amped FPVLR v2 mod on my RC. Unfortunately, the video signal stability at long range was not improved, and was, in fact, the worst yet, even though Channel 21 is just as quiet as Channel 30. What else might I be missing? Transmitter mod is not the issue. It worked perfectly with my original 323 old motor bird out to 5 miles. Now, anything beyond 3 miles is unstable on the replacement 323A bird with new motors.
 
I had great hopes this evening using Channel 21 instead of Channel 30 with my Sunhans amped FPVLR v2 mod on my RC. Unfortunately, the video signal stability at long range was not improved, and was, in fact, the worst yet, even though Channel 21 is just as quiet as Channel 30. What else might I be missing? Transmitter mod is not the issue. It worked perfectly with my original 323 old motor bird out to 5 miles. Now, anything beyond 3 miles is unstable on the replacement 323A bird with new motors.

I had crappy range today too. I think it may be environmental factors. I'm still not even pushing it out to the limits yet due to battery break-in but I was losing video at 3.8 mi. Tried changing channels to no avail. Yesterday I flew 4.7mi with full signal with channel on auto.
 
I had crappy range today too. I think it may be environmental factors. I'm still not even pushing it out to the limits yet due to battery break-in but I was losing video at 3.8 mi. Tried changing channels to no avail. Yesterday I flew 4.7mi with full signal with channel on auto.

Are you guys using the pinwheel 2.4 antennas or dipoles antennas with the side air
amp mod?

Kevin
 
Are you guys using the pinwheel 2.4 antennas or dipoles antennas with the side air
amp mod?

Kevin
No airside mod on mine. Just the Sunhans "hearing aid" on the transmitter. Used to get 5 miles on video in the exact same area with the same transmitter with my old motor bird. No more...:( RC control is fine. Just no FPV!
 
No airside mod on mine. Just the Sunhans "hearing aid" on the transmitter. Used to get 5 miles on video in the exact same area with the same transmitter with my old motor bird. No more...:( RC control is fine. Just no FPV!

Yes, that is what's being posted here, the new motors and new firmware you are
losing 18% of signal!!!!...........that sucks!

Kevin
 
I'm chalking it up to environmental for me... I just did 4.7mi at 150ft alt no problem yesterday while breaking the battery in. Haven't touched a thing but it was a bit hazy/humid today.
 

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