Dual Battery Mod

dirtybum · Mar 29, 2016

hebs said:
My thoughts exactly - this was only a hover test. I expect that the motors will be under more strain when on the move. There is a trade-off between more airtime and excessive wear on the bird.

If I mod it correctly then I'll be able to use a selection of batteries with ease.

I notice that the mod at the start of this thread does not use a balance lead but the horizon mod does - is it really needed for flight?

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The horizon mod is a joke, I can use their split pack with their battery balanced together or their split pack with my own modded battery not tied by balanced leads same results

Silverwingflinx · Mar 29, 2016

Today I flew with the venom fly 2300 mah 208 grams,I took it easy constant flite 28 mins down to 10% auto land.no hovering and I started with about 98% Dji batt with 3 charges.i also had to fly in 20/30km winds.thats not bad!!! Next time I will fly down to 1% see if I can hit 32 mins.

Augusto Jimenez · Mar 29, 2016

hebs said:
Has anyone tried the HobbyKing MultiStar HV lipo's?
MultiStar LiHV High Capacity 4S 6600mAh Multi-Rotor Lipo Pack

Are they any good? Iv been doing some payload/ endurance testing with standard DJI batteries to work out at what point the weight of the battery exceeds the return in terms of flight time. I have some interesting results - happy to share if anybody is interested.

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Yes!!! I want to do the same, as Its much better that the in-drone and external batteries to be the same type, same age. Others can be a LOAD to the original batt and cause its PREMATURE AGING. I am pretty interested on your data and also the way you attached the other(s) batt. (for stability purposes).
Indeed I thank you to sharing those to me!!

Phantom751874 · Mar 29, 2016

Say whaaa?

Silverwingflinx · Mar 29, 2016

Phantom751874 said:
Say whaaa?

Thax now I know I can hit 0% lol.now that's flying!! Do you know more about that antenna mod?

Augusto Jimenez · Mar 29, 2016

hebs said:
Payload vs flight time testing

I've tried to eliminate as many variables as possible so that I can make as accurate comparison as possible.

- all tests were performed indoors over two days (hover test) - no wind and minimal temperate and pressure variations.
- I used 2 different DJI batteries (I only have 2!) to minimise the chances of using a battery with uniquely good or bad characteristics (both started on about 30-40 cycles).
- each test was repeated 3 times in order to gain an average.

During each test the battery %, mah and voltage were recorded at takeoff and upon landing. The flight duration was noted. Most flights took off at 98% and were landed at 15% battery. The hover was at 0.8/0.9m.

I conducted 3 test flights with each of the following payloads:
0g (control), 200g, 400g, 600g, 800g, 1000g and 1200g.

- For each test I calculated the average mah consumed per second (rather than converting into power / watts - amps etc...)

RESULTS

No payload. 3.5 mah per second (210 per min)
200g. 4.2 mah per second (252 per min)
400g. 5.0 mah per second (300 per min)
600g. 5.9 mah per second (354 per min)
800g. 6.9 mah per second (414 per min)
1000g. 8.2 mah per second (492 per min)
1200g. 11.2 mah per second (672 per min)
1400g. Test aborted - discharge overload warning

On average each test consumed 3640mah (about 85% of the battery capacity).

CONCLUSION

There is a steady increase in power consumption as weight is added upto apx 1000g. At 1200g payload the power consumption increases significantly and at 1400g the bird took off but hovered for only 15 seconds before one of the battery cells (as displayed in the DJI Go app) went red and triggered several warnings. The bird was clearly struggling to hover and I aborted the test. I'm not sure what the maximum payload is but I don't want to trash my batteries or set fire to my P3 (or house!).

I have done these tests to work out the theoretical best match for different batteries combinations - I say theoretical because I haven't bought any other batteries just yet and I can only go off what each of the battery manufacturers claim the capacities and weights to be.

Theoretical hover times using 85% capacity:

1 - 30min 36sec - 1 x MultiStar 16,000 mah battery (remove DJI battery) - 831g @ 7.1 mah/s
2 - 28min 28sec - 2 x MultiStar 5200 mah batteries with DJI battery - 836g @ 7.1 mah/s
3 - 27min 39sec - 3 x standard DJI batteries - 732g @ 6.6 mah/s
4 - 27min 35sec - 2 x MultiStar 6600 mah batteries (remove DJI battery) - 714g @ 6.5 mah/s
5 - 26min 58sec - 2 x MultiStar 6600 mah batteries with DJI battery - 1064g @ 8.9 mah\s
6 - 26min 54sec - 2 x MultiStar 4000 mah batteries with DJI battery - 690g @ 6.3 mah/s
7 - 26min 14sec - 2 x Hyperion 5200 mah batteries with DJI battery - 932g @ 7.7 mah/s
8 - 26min 13sec - 2 x Hyperion 3650 mah batteries with DJI battery - 640g @ 6.1 mah/s
9 - 26min 9sec - 2 x MultiStar 5200 mah batteries (remove DJI battery) - 486g @ 5.4 mah/s
10 - 26min 7sec - 1 x MultiStar 10,000 mah battery (remove DJI battery) - 444g @ 5.2 mah/s

I have assumed 2 ways of mounting batteries:
1 - in parallel with a DJI battery,
2 - as a replacement to a DJI battery - as shown in page 40 of this thread.

Based on these results I am going to buy and test the MultiStar 16,000 mah and 2 X MultiStar 6600mah.

I've only listed LiHV batteries that I can get in the UK but I could add some others to this list to compare if people are interested (need weight and mah). I would be interested to see if the theory is similar to people's experience.

I'll post some photos of the tests.

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Thanks for your information. It is very clear.
Could you test those Multistar's? I think you can not, as these have different voltage than 15.2V right?
Anyway, important data!

Ajginger · Mar 30, 2016

Hi all, I want to use the type of battery in the link below to test extended flight times with it.
I posted earlier about this but didn't get any clear answers. These batteries are massive capacity for weight and many types on the market.

Now that there are a couple of experienced guys on this thread that are doing their own mods I thought I would ask again.

Before answering, Pretend its of utmost importance that we use this type of battery. (Life or death) What would be needed to make it work?

The only problem that I see is that these are 12 volt. Does this matter?

When my dji batteries are fully charged they are around 17 volts, when I land they are around 3 volts so the bird must not need to be at 15.2 to operate?

How important is it to match voltage on the extra batt to the dji battery ?

Portable 20000mAh Car Jump Starter Booster USB Power Bank Battery Charger+line

Ed209 · Mar 30, 2016

Ajginger said:
Hi all, I want to use the type of battery in the link below to test extended flight times with it.
I posted earlier about this but didn't get any clear answers. These batteries are massive capacity for weight and many types on the market.

Now that there are a couple of experienced guys on this thread that are doing their own mods I thought I would ask again.

Before answering, Pretend its of utmost importance that we use this type of battery. (Life or death) What would be needed to make it work?

The only problem that I see is that these are 12 volt. Does this matter?

When my dji batteries are fully charged they are around 17 volts, when I land they are around 3 volts so the bird must not need to be at 15.2 to operate?

How important is it to match voltage on the extra batt to the dji battery ?

Portable 20000mAh Car Jump Starter Booster USB Power Bank Battery Charger+line

Absolutely important. 12v is not enough to sustain anything. Besides any imbalance between the battery packs will cause the strongest pack to start charging the weakest pack. Not good. That batter you linked would not work.

hebs · Mar 30, 2016

Augusto Jimenez said:
?.......
Could you test those Multistar's? I think you can not, as these have different voltage than 15.2V right?
Anyway, important data!

I'm pretty sure that the standard DJI battery is technically LiHV (15.2v). It even says that on the DJI website. I haven't taken one apart but there are several posts in this site that confirm that.

There are also several posts that say normal 4S Lipo (14.8v) batteries have worked in parallel with the DJI battery.

One can but try

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Ajginger · Mar 30, 2016

I just tested my new 4s lipo 14.8 v parallel fpvcustoms mod this afternoon.

21 min, 48211.2 ft.
23 200 ft one way.

Ajginger · Mar 30, 2016

How come 14.8 v works but not 12 volt ?

Ajginger · Mar 30, 2016

What about this then ?
Industrial version of the Portable lithium ion battery pack Battery Power Station weighs only 1 pound with output 5V , 5.5V , 6V , 6.5V , 7.5V , 8.4V , 9V , 10V , 11V , 12V , 13V , 14V , 15V , 16V , 18V , 19V

maxwell smart · Mar 30, 2016

the next long rang antenna.
WiFi Antenna MACH 1 Double Biquad Wireless Booster Long Range GET FREE INTERNET | RF Coaxial Cables, Adapters, Connectors, Antennas, router mod kits, ham radio products, Alfa and cellphone boosters

dirtybum · Mar 30, 2016

Ajginger said:
How come 14.8 v works but not 12 volt ?

Ajginger said:
What about this then ?
Industrial version of the Portable lithium ion battery pack Battery Power Station weighs only 1 pound with output 5V , 5.5V , 6V , 6.5V , 7.5V , 8.4V , 9V , 10V , 11V , 12V , 13V , 14V , 15V , 16V , 18V , 19V

maxwell smart said:
the next long rang antenna.
WiFi Antenna MACH 1 Double Biquad Wireless Booster Long Range GET FREE INTERNET | RF Coaxial Cables, Adapters, Connectors, Antennas, router mod kits, ham radio products, Alfa and cellphone boosters

All i can say is try it and report back!! Thats what the rest of do with this stuff and we have success and failures! And sometimes we find something that works and sometimes we waste money!

KyleMaxxUAV · Mar 30, 2016

So are you guys soldering into the always hot side or the switched side of the battery cap

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KyleMaxxUAV · Mar 30, 2016

And anyone who has the horizon power mod .. Maybe it's just soldered to the wrong one (switched or Unswitched ) ?

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dirtybum · Mar 30, 2016

P3P Canada said:
And anyone who has the horizon power mod .. Maybe it's just soldered to the wrong one (switched or Unswitched ) ?

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I solder all mine to the top posts (switched)on the circuitboard. It's not that there's a problem with the horizon main battery mod, I can use it with my standard lipo set up and get the same results as my own modded battery with my standard lipo set ups ! the problem problem is with their split pack not producing what they claim and there split packs don't burn down evenly with the main battery

Ed209 · Mar 30, 2016

Ajginger said:
What about this then ?
Industrial version of the Portable lithium ion battery pack Battery Power Station weighs only 1 pound with output 5V , 5.5V , 6V , 6.5V , 7.5V , 8.4V , 9V , 10V , 11V , 12V , 13V , 14V , 15V , 16V , 18V , 19V

The problem with all these jump starter type packs is the continuous current. 4 amps is not enough. I can't remember but I believe the total minimum required is something like 12A.

Ed209 · Mar 30, 2016

P3P Canada said:
And anyone who has the horizon power mod .. Maybe it's just soldered to the wrong one (switched or Unswitched ) ?

I took apart the FPV customs mod and they are tapped into the switched power.

dirtybum said:
I solder all mine to the top posts (switched)on the circuitboard. It's not that there's a problem with the horizon main battery mod, I can use it with my standard lipo set up and get the same results as my own modded battery with my standard lipo set ups ! the problem problem is with their split pack not producing what they claim and there split packs don't burn down evenly with the main battery

Same result here. Horizon modded DJI battery and Hyperion 2400s run as expected.

NormanNormal · Mar 30, 2016

Ed209 said:
I took apart the FPV customs mod and they are tapped into the switched power.

Same result here. Horizon modded DJI battery and Hyperion 2400s run as expected.

Forgive me for not finding it in the thread, but what flight times are you seeing with dual Hyperion 2400 packs?