Solo smart battery % at end of flight

Posted by RPM on July 9, 2015 at 10:28am

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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Replies

    • Art Stroud Jr. > Bill Bonney July 9, 2015 at 4:20pm
      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.
    • RPM > Bill Bonney July 9, 2015 at 11:09am

      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.

    • Developer
      Bill Bonney > RPM July 10, 2015 at 11:09pm

      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.

    • Moderator
      Gary Mortimer > RPM July 9, 2015 at 11:19am

      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. 

    • RPM > Gary Mortimer July 9, 2015 at 11:30am

      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.

    • Mark Prince > RPM July 13, 2015 at 6:15pm

      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

    • Moderator
      Gary Mortimer > RPM July 9, 2015 at 11:33am

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

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