Added 2nd 5200mah battery in parallel, gained a whopping 3.5 minutes

[pat-love]

I am very anxious to get better batteries for longer fligh time !! I really think if 3dr could build 8000mah intelligent battery, it would give us a descent flight time !! That battery could be just a bit thicker and maybe a few grams more and would not affect too much performance... Even if it dos slowdown the drone a bit, who really cares when we are doing videos ?

 

[Andrew Schmidt]

I know this is an old thread, but just in case anyone is interested, I am building a DJI inspire clone with solo internals.... my thinking is that I may be able to increase flight time by doing what you did here... but with the larger motors and props, maybe I will have better results as the motors wont be trying nearly as hard to hold up the weight of two lipos.12x4 props on 630kv motors double the performance of the plastic 9 inch props on 880kv motors.

 

[CanadianSolo]

I had the old DJI Phantom 1.0 not even 1.1 and I added 2nd battery. Same result. Adding 2 batteries on these little drones is just not worth it with factory motors and props. I found it to fly pretty sluggish too.

 

[rassalas]

Still interested in results even to hear how the transmogrified solo does with just one battery.

 

[Andrew Schmidt]

Ill let you guys know how my franken solo turns out!

 

[Sid nguyen]

well at least with all these test if i decide to go fishing with my drone i know how much flight time i would have carrying that squid or fish to the drop off point

 

[DavidPhillips]

In this post, I will detail the results of adding a second 5200mah LiPo battery in parallel with the standard Solo 5200mah battery. This effectively doubled the fuel capacity, but also increased the weight by 430 grams. The battery is a Hobby King multistart 5200mah 10C battery, so basically the lightest weight battery you can get.

Standard single solo battery flight times:
10% RTH kicks in at 16 minutes
6% (13.6 volts) manual landing at 17.5 minutes.

With second 5200mah battery strapped to the belly:
10% RTH kicked in at 19.5 minutes
6% (13.6 volts) manual landing at 21 minutes

The net gain was only 3.5 minutes, for a useful mission time of 19 minutes. I was expecting more like 23-25 minutes based on some rough math and ecalc data. So these results are disappointing to me. I would imagine larger props might add a minute. But regardless, nothing remotely close to being worthwhile. This motor and prop combination just can't efficiently lift that kind of weight. In my opinion, this is not worth the effort and complexity. I probably will not continue to use this.

** This could also be why 3DR is not bothering with a higher capacity battery ** You have to figure a larger battery from 3DR would be even less capacity than what I just tested. Maybe 8000mah or so? Certainly not double the capacity, as it would never fit. Meaning the increased flight time would probably be less or the same as what I got. There is very little to be gained by selling an enhanced battery that only gets you 2-3 minutes. I wouldn't pay extra for that.

However, what I will do is use this XT60 connection as a GPU. I can power the solo off a power supply on the table now rather than wasting batteries.


Power wires soldered to the main power connector inside the solo.

XT60 hanging out the back for the LiPo battery to plug into.

Bonus points if you can guess why this position didn't work. It took me a few minutes to realize that I'm an idiot.

Battery strapped to the belly, where it can actually function

Without the solo battery, the solo has no power information at all. It's being powered only by the auxiliary LiPo. So without the Solo smart battery, it reports 0 volts, and -1 amps due to the logic failure.

Too much weight for the Solo.

Add weights to the Solo but fly with the one battery. Find the balance where the ratio of added weight to flight time is the best. The flight time will begin to drop much more at a certain weight. Now that you know what the most economic weight is you need to find a 4S battery with that weight.

 

[Andrew Schmidt]

I just printed a dual solo battery mount for my 3d printed inspire! I haven't flown yet, because the project has a bit of work to do before its complete, but the bench test snows that with two equally charged solo smart batteries spliced into the same power header, and same SM bus header, solo has no clue there is a second battery. My hypothesis is that it will make it's calculations based on the overload of SM-bus info (both batteries being repetitively queried) and therefore just think the battery is performing as normal, when in fact, there are two.

I'm no expert in the sm-bus architecture, but I believe it works on a simple get-request architecture and when requesting information, the battery to respond first will be the data it uses. If the two are responding simultaneously , this should result in the solo main board inadvertently running smart battery logic on the cumulative of both sm bus responses....... very similar to if you dump two watering cans into a 5 gallon bucket. Say one is slightly lower than the other, solo will take that information into account, and then when the better performing battery responds, it will think the performance improved a little and go back up.

I have bench tested this, and it seems to work, but I wont know for sure until I get this bad boy up in the air. The goal is a clone of the Inspire 2. dual batteries and all, even though they arent 6s.

Wish me luck guys!

 

[utkudemir]

cant see photos