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

[Pedals2Paddles]

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.

 

[Stimmy]

First position doesnt work because its covering the gps? Otherwise, keep experimenting.. I like the progress

 

[Rueben]

Ya. I was cursing at it because this is the same location I flew a few days before. I alway get a really quick lock and it was a few minutes with no lock. Eventually i stopped cursing at the solo and started cursing at myself.

Try the Zippy compact 1300 x 2 you will be surprise how much more time you'll get. With external batteries is all about weight

 

[Pedals2Paddles]

Have you tried it with those? I'm having a hard time believing adding only 2600mah will make that much of a difference given the weight they add.

 

[RichWest]

Really nice effort, I appreciate you sharing your findings here.

The trade off for the added weight is obviously flight time. Now I am curious with how the bird flew with that much added weight. Stock motors and props, correct?

 

[Pedals2Paddles]

It was clearly not as graceful, which is to be expected. The PID tuning, compas-motor calibration, etc is all for the stock weight.

 

[Pedals2Paddles]

Im wondering if this can do good for a extended flight time project
it's only 270gr pretty lightweight & 14.8mm thick 4 layers of 3.7v 14.8v 10000mah LiPo
Dimensions:width/66mm thickness/3.7mm length/125mm X 2 plate of battery Price $16 F/S for LiPO 7.4v 10000mah
Buy Products Online from China Wholesalers at Aliexpress.com

I think im going to give it a shot

I'm trying to decide if you're being sarcastic. Just in case you aren't, please don't do that unless you want your solo to catch on fire and burn down the whole neighborhood.

 

[User Name]

Maybe someone with more electrical knowledge could chime in, but would this potentially be a better choice? Multistar High Capacity Lightweight 4S 6000mAh 2C Multi-Rotor Lipo Pack

It's only 364 grams for 6000 mah, so more capacity for less weight. It's only 2C discharge, but since it's just supplementing the main battery, maybe it wouldn't need to be so high?

6000 mah at 2C is 12 amps continuous, would the Solo still draw more power from it if it had the main battery to do most of the work? If not, I suppose the danger would be that it would deplete the main battery first and then could start pulling more than the rated current from the secondary battery.

But maybe that opens up another possibility - a smaller capacity, lower discharge battery that would be depleted at approximately the same rate, but weight considerably less than basically a second Solo battery?

Again, maybe someone with more knowledge can offer some insights.

 

[Pedals2Paddles]

That's not really how it would work. The main battery isn't going to "do most of the work". With the extra weight, the solo will be drawing about 30-35 amps total. That will be split evenly between both batteries, which is about 15 amps each. Well over that 2C discharge rate. Plus, you never want to be drawing at or close to the maximum rating. The battery won't last long that way.

 

[RolandS888]

@Pedals2Paddles , try another flight with 430gr of dead weight, that will give you a baseline comparison flight time of what the stock battery can do at that weight.
Saying another battery gives 3 mins extra isnt correct due to the extra all up weight.
My guess is that the single battery and dead weight will run for maybe 10 mins, and with the extra battery you got your 18 mins, thus the extra battery IS a significant contributer to extending flight time at that weight.
Every copter is under the law of diminishing returns, where eventually the copter becomes so heavy with extra batteries that no flight time is added. You just need to find the sweet spot..
Id like to see a smart battery replaced with a 6600mah 4S (~600gr) as the sole battery, but the battery parameters will need to be altered so it doesnt FS on low capacity.
Possible lower kv motors and 11 or 12 inch prop needed to extend hover time too.

 

[RichWest]

@Pedals2Paddles , try another flight with 430gr of dead weight, that will give you a baseline comparison flight time of what the stock battery can do at that weight.
Saying another battery gives 3 mins extra isnt correct due to the extra all up weight.
My guess is that the single battery and dead weight will run for maybe 10 mins, and with the extra battery you got your 18 mins, thus the extra battery IS a significant contributer to extending flight time at that weight.
Every copter is under the law of diminishing returns, where eventually the copter becomes so heavy with extra batteries that no flight time is added. You just need to find the sweet spot..
Id like to see a smart battery replaced with a 6600mah 4S (~600gr) as the sole battery, but the battery parameters will need to be altered so it doesnt FS on low capacity.
Possible lower kv motors and 11 or 12 inch prop needed to extend hover time too.

Very good reasoning, to bench mark the added weight and stock battery. I was thinking a 1200mah sister battery would provide better flight time and better flight performance. win-win...maybe???

 

[Jubalr]

@Pedals2Paddles , try another flight with 430gr of dead weight, that will give you a baseline comparison flight time of what the stock battery can do at that weight.
Saying another battery gives 3 mins extra isnt correct due to the extra all up weight.
My guess is that the single battery and dead weight will run for maybe 10 mins, and with the extra battery you got your 18 mins, thus the extra battery IS a significant contributer to extending flight time at that weight.
Every copter is under the law of diminishing returns, where eventually the copter becomes so heavy with extra batteries that no flight time is added. You just need to find the sweet spot..
Id like to see a smart battery replaced with a 6600mah 4S (~600gr) as the sole battery, but the battery parameters will need to be altered so it doesnt FS on low capacity.
Possible lower kv motors and 11 or 12 inch prop needed to extend hover time too.

This was what I was wanting to see tried as well. There are higher capacity 4s batteries available that are the same or less weight than the stock battery. So a higher cap battery with no weight change would obviously extend flight time.

 

[Pedals2Paddles]

I am aware of how all that works Been playing that balancing act with DIY multirotors for years. I just used the LiPos I already had lying around from my heavy lift Y6. Additional weight requires additional power to fly. At some point, you're adding so much weight, it counters the additional available fuel. It's very clear that this combination was more weight than it was able to make efficient use of. It is possible a battery that weighs less, but has less MAH, could result in another minute or two from what I had. There will be a sweet spot somewhere. We just need to find it.

But even if we find a sweet spot for adding MAH and weight, we still have a motor/prop combination that is not well suited to lifting additional weight. That will always be a problem. If we swapped out for lower KV motors and 11 or 12 inch props, we'd probably see a big bump in time. But then you're sacrificing some responsiveness and maneuverability.

I'm going to experiment by adding weights to the solo and seeing what the current draw in flight is for the given weights. Say 200, 250, 300, 350, 400 grams. That will tell us how much current the Solo will draw in flight with the given weight. Then it is just math. Take a battery, look at the weight it would add, and the MAH it would add, and do the math for flight time.

This was what I was wanting to see tried as well. There are higher capacity 4s batteries available that are the same or less weight than the stock battery. So a higher cap battery with no weight change would obviously extend flight time.

What i used was the same capacity and weighed less. The stock battery is about 490 grams. The add-on battery I used was 430 grams. That's about the lightest 10C 4S 5200MAH battery you're going to find today. If you ad the required hard shell and smart boards, you probably end up back at around 490. So I do not believe the 3DR battery is unnecessarily heavy, or that there are remarkable weight savings to be gained in it. We just do not have magically lighter battery yet. The technology doesn't exist. We all want it. But it simply hasn't been invented yet.

 

[Jubalr]

What i used was the same capacity and weighed less. The stock battery is about 490 grams. The add-on battery I used was 430 grams. That's about the lightest 10C 4S 5200MAH battery you're going to find today. If you ad the required hard shell and smart boards, you probably end up back at around 490. So I do not believe the 3DR battery is unnecessarily heavy, or that there are remarkable weight savings to be gained in it. We just do not have magically lighter battery yet. The technology doesn't exist. We all want it. But it simply hasn't been invented yet.

I'm looking more for a way around the 'smarts' to use a battery as we always have in the DIY world. I would be satisfied with just the traditional voltage/watts/current readings and I'll decide when to bring it in. This would then allow batteries of higher capacity with only little to no weight gain. Drop the weight of the 'Smarts' and set another battery in the tray with a strip of velcro. ie:
Specs:
Minimum Capacity: 6600mAh
Configuration: 4S1P / 14.8V / 4Cell
Constant Discharge: 10C
Peak Discharge (10sec): 20C
Pack Weight: 537g
Pack Size: 142 x 49 x 35mm
Charge Plug: JST-XH
Discharge Plug: XT90

 

[Pedals2Paddles]

That would be nice. There is presently no other means for the Solo to read and report on power. There is no connection for power module like we're used to. It gets it from the smart battery SMbus or it gets nothing at all. I didn't actually try to see what would happen if I tried to take off with just the external LiPo and no smart battery. My guess is it will say the battery is too low to take off since it will be reading -1% and 0 volts.

The smart battery design makes it incredibly impractical to do anything other than as-designed. Not impossible. Just impractical. It is frustrating for us who like to tinker. But it is also nice when I prefer simplicity in the field.

 

[pat-love]

I am curious: how many "c" the OEM battery has? Someone knows??

 

[Ralph E. Johnson]

Very interesting and enjoyable to hear all your comments. Makes me realize where technology comes from in the first place. The human mind is an amazing computer. Mine doesn't work that way I just enjoy the eyes in the sky pleasure of the closest experience I have ever had of flying!!!

 

[rassalas]

I think the obvious thing to do is take the smarts out of the smart battery and attach it to a better version battery.
I find it hard to believe the smarts is actually in the chemistry part of the battery.

 

[Ketch]

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.

It seems like the basic physic laws of energy and work never change. More weight, more power consumption.

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.

 

[Pedals2Paddles]

I think the obvious thing to do is take the smarts out of the smart battery and attach it to a better version battery.
I find it hard to believe the smarts is actually in the chemistry part of the battery.

You are correct. If one were to saw it open, you could remove the cells, install larger cells, and solder the power and balance wires back in. But you would also need to reprogram the brain with the new MAH capacity.

I am curious: how many "c" the OEM battery has? Someone knows??

I believe it is 20 or 30 C discharge and 2C recharge.