20 minutes flight from Stock Solo

[mike_kelly]

I got the idea to use a standard multistar 8000mah 4s battery that fits perfectly in the Solo batery tray in place of the stock 5200mah battery. Doing the numbers it should yield a 20 minute flight. I had to turn off the normal Solo smart battery sense.

I made an adapter from a connector in a bad battery I bought off ebay. I can not recommend this procedure to anyone else. It is dangerous to try and open a 3dr solo battery. Mine caught on fire during the process when I touched the circuit brd inside with my blade. So don't try and reproduce this.

I will regain battery monitoring by using a CANbus UC4H battery power module designed by OlliW which is not installed on the adapter in the picture yet.

I can't do actual flight tests because it is -22 below zero and the tests would not be useful and I am a woos.

 

[pyrate]

interesting, what is that doing to COG?

 

[carpy]

I got the idea to use a standard multistar 8000mah 4s battery that fits perfectly in the Solo batery tray in place of the stock 5200mah battery. Doing the numbers it should yield a 20 minute flight. I had to turn off the normal Solo smart battery sense.

I made an adapter from a connector in a bad battery I bought off ebay. I can not recommend this procedure to anyone else. It is dangerous to try and open a 3dr solo battery. Mine caught on fire during the process when I touched the circuit brd inside with my blade. So don't try and reproduce this.

I will regain battery monitoring by using a CANbus UC4H battery power module designed by OlliW which is not installed on the adapter in the picture yet.

I can't do actual flight tests because it is -22 below zero and the tests would not be useful and I am a woos.

Warmer here in MSP--only -1 below.

 

[Pedals2Paddles]

So that weighs about 30% more than the solo's battery, but also has about 55% more capacity. Should be interesting to see how the added 150g of weight balances out with the added capacity.

I'm sure you know this. But for the benefit of the others here... the multistar batteries get their light weight due to that lower C-rating... meaning they cannot dissipate heat as fast as the higher rated batteries... meaning their maximum steady and surge current specification is less. So they're generally very good for slow photography flights. And generally very bad for aggressive high power flight. The solo hovers at about 18-20 amps. Cruise flight (10-15mph) and descents are less, more like 14-16 amps. These batteries do well for that. But if you decide to punch it and fly around at flanking speed pulling 30-40+ amps, the batteries will suffer from excessive heat.

I'd like to take the SMBUS board out of an old battery and repurpose it is as a more generic SMBUS battery monitor. Write a modified driver for it in ArduPilot that does not monitor or use the smart capacity, since it can't do that if you interchange batteries. It would monitor volts and current, and you'd have to enter the capacity manually like on a traditional UAS battery monitor.

 

[mike_kelly]

That is what I am using the CANbus power module for which already has the battery monitor functions in Ardupilot now. It would be interesting to have a generic I2C monitor for easy plug and play. My flying is always AP slow so I never even consider the need for high C batteries. But it would certainly be an issue for hot dogs.

Weight difference is not too bad because with the low C battery there is no hard case or smart charging circuits inside.

The original smart bat probably was hardwired for the 5200mah capacity. So re-purposing would not be as easy as it could be if it were designed to be used with multiple battery sizes at the time.

 

[mike_kelly]

Warmer here in MSP--only -1 below.

You get extra heat from all those bodies in MSP! Low density out here.

 

[mike_kelly]

interesting, what is that doing to COG?

MY balance is pretty good because the 8k bat does not have all the plastic case and I have my HERE gps and mount on the front.

 

[fpvsteve]

Mike you will easily exceed the 20 min during normal cruising.
The Multistar 10C labeled batteries are good for real 6C continuous discharge, which means close to 50Amps continuous current in your case with an 8Ah battery. So heat will not be a problem even if you decide to fly end to end in Acro mode ;-)

 

[RichWest]

I'd like to take the SMBUS board out of an old battery and repurpose it is as a more generic SMBUS battery monitor. Write a modified driver for it in ArduPilot that does not monitor or use the smart capacity, since it can't do that if you interchange batteries. It would monitor volts and current, and you'd have to enter the capacity manually like on a traditional UAS battery monitor.

PM an address and I'll ship you one...less the battery.

 

[Pedals2Paddles]

PM an address and I'll ship you one...less the battery.

I actually have a pile of defunct batteries, including one opened up already. More than I know what to do with. Thanks though.

 

[mike_kelly]

I think it is a potential way for folks who desperately need more flight time for jobs to possible get what they need.

 

[sbrown]

I had to turn off the normal Solo smart battery sense..

Hi Mike. Can I ask what issues you ran into that were solved by turning off the Solo battery sense? I've flown a stock Solo with a similar setup, and I could take-off/fly without having to change any parameters. One thing that was different was the "Fly" button wouldn't work to arm/takeoff, but I could use the left stick down+right to arm, then raise it to take-off.

 

[mike_kelly]

Hi Mike. Can I ask what issues you ran into that were solved by turning off the Solo battery sense? I've flown a stock Solo with a similar setup, and I could take-off/fly without having to change any parameters. One thing that was different was the "Fly" button wouldn't work to arm/takeoff, but I could use the left stick down+right to arm, then raise it to take-off.

The arming issues are one but also the RTH issues with no or incorrect battery monitoring.

 

[sbrown]

The arming issues are one but also the RTH issues with no or incorrect battery monitoring.

RTH as in it would try to RTH to you as soon as you took off/or randomly throughout the flight? Interesting, I wonder what's different between yours and mine. I took a new Solo from B&H and slapped a LiPo in without modifying anything on the Solo and it worked (with no telemetry obviously, but it never tried to RTH). Do you have a green cube?

 

[mike_kelly]

Arducopter will not RTH within a radius of a 10-20ft of home. I don't remember the exact distance. So you would not see it until you flew far enough away. Just better to clean up the parameters that are germane to the issues.

 

[KDan]

Smart battery sense issues aside, I believe the cells in the stock Solo battery are also only 10c rated. Same as the Multistar. I've noticed that the Solo batteries get quite toasty after a normal flight - even when landing at 30% - which is when I typically land. The stock Solo battery cells are definitely not high C discharge capacity. They have a relatively high internal resistance based upon the heat being generated.

 

[Pedals2Paddles]

3DR specs list the battery as continuous 20 amps and surge 120 amps. Of course neither of those are an even multiplier of 5.2amps. Normal flight cruising around and hovering will range from 15-25 amps. Flying balls to the wall at 40-50mph will have you bouncing off the limiters (The stock solo uses MOT_BATT_CURR_MAX to limit current at 40 amps. For green cubes running master, it's set for 50.). And the voltage sags dramatically when doing that kind of flying too. The battery is clearly not designed for continued high current flight.

 

[drislio]

Heyo...let us know how it goes with the power module and post some pictures...

 

[fireflyer451]

Mike, can you provide a picture or two, and details on how you made the battery connector/adapter to plug into the Solo? I'm brand new to this 3DR bird and while the used Solo I bought flies fine, 4 of the 7 batteries I got with the deal are no good. I would be happy to work on the alternatives.

Thanks

 

[mike_kelly]

There are multiple ways to do it. I did not want to modify my Solo, since I was playing, and did it the hard way. Which I do NOT recommend because it is dangerous. I took apart a Solo battery to get the connector, then I simply soldered onto it XT60 leads. You could also open up the Solo and permanently solder to the circuit board that the Solo battery plugs into.

It is very easy to cause a fire messing with a Solo battery. The cells are right next to the plastic case. They are a vacuum and lithium will ignite when exposed to air. So a simple puncture while you are trying cut the case apart will cause a fire. Ask me how I know