How low are you guys draining your battery per flight?

I have been testing it slowly, 20%...8% etc...

What I am wondering is if this smart drone will leave enough juice to return home based on how far away it is from that location?

I have been hitting the 20 min mark when I land below 10%

Next flight I will hover 1-2 feet off the ground above home and see how low will it go.

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What I am wondering is if this smart drone will leave enough juice to return home based on how far away it is from that location?

The short answer is... no it won't. 

You will need to make sure you have enough power left to RTL all the way back to home. If the power becomes critical, it will land. Which normally happens anyway as the power drops so much that there is not enough to create enough lift and the copter will descend

Thanks Bill!

So the smart part would be the LED indicators and the fact that it cuts off when fully charged I guess...

Looks like I would need 6 batteries to keep a constant survey/land cycle going.

You will destroy your batteries if you play with low power too much. If 20 minutes were my expected or published platform flight time I would not fly for more than 15 minutes. 

My thinking was that 0% on these batteries would represent 3.4-3.5v per cell so that someone picking these things up at best buy with no lipo knowledge would be in the clear, or at least have to try hard to ruin them from flight.

Next flight I will note the voltage and verify with the multi.

That would seem a sensible way to do it. I don't have a SOLO so can't really comment!

I read either on the 3dr site or in the manual that at 5% RTH is initiated as long as it is fly under GPS lock. I typically start bringing it in at 25% and pop in another battery. I haven't been in a situation where time was an issue push it any further.

I'm pretty sure the feature to reserve enough juice to come how is coming in a future release.  It's hanging around in a dev branch already but I suspect it needs more testing.

nice pic by the way.

The smart part is that it not that it only protects against overcharging, it should also protect against over-current, over discharge. Count the number of charge cycles and the amount of mAh discharged to how much charge was added to full charge. This gives battery health statistics.

I don't have a solo to play with, so I don't know the details for sure, but that's what other SMB batteries can do.

This is all done automatically. You can with RC LiPo charges measure how much charge you put into them etc... but it's all extra manual work.

I'm not so sure I'd want that feature. id probably just disable that and keep track myself. I suppose a verbal warning would be helpful, something like: "You no longer have enough battery to make it home you idiot. Please find an alternative landing site"

I'd rather see something like "you still have enough battery to make it home if done within the next 30 seconds. After that, you're on your own".

Seriously, I really need to study the manual more thoroughly for these issues. Thus far I haven't landed with less than 30%.

Forget the % remaining. It's the voltage that matters. If you routinely get the cells to 3.5 or below under load, you are shortening the life of the battery more than normal use should. I know this from personal experience. You should try to be on the ground before the cells are at 3.5 volts. AS the battery ages from cycles the amount of flight time it gets at a given current decreases but the % remaining value doesn't know about any of that. It's calculation is making assumptions based on some static values.

If you check the temperature of a battery that gets discharged to 3.5 or below versus 3.7 there is a noticeable difference. That extra heat does damage.

% remaining is a calculated value by determining the current draw for a given amount of time. It's also assumes you started with a fully charged battery unless the Solo is making a correction based on pack voltage but the normal arducopter code doesn't do that. It just goes by the parameter setting for a certain amount of mah or the pre-determined / assumed size of the battery.

The voltage is the true measure of how much fuel is left in your tank. Not the % remaining calculation. 

mp

Lots of great info here. Thank you!

A distance from home based battery RTH feature could be really helpful. If not a full FS then a warning. There is a lot to monitor especially if you are focusing on a shot and it could be hard to judge in some situations.

For battery % I was not thinking of it in that way, really good points.

Tonight I kept the solo close at 20% and flew it until the battery remaining showed 8% then next time I looked it was displaying N/A so I landed.

Measured 14.6v after the flight and it was showing 16.6v  in the app before the flight. I never timed it exactly but it was very close to 20 mins. I love flying this thing aggressively with the performance all the way up it is rock solid.

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