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Naza low voltage settings.

Discussion in 'Other DJI Multi-Rotors' started by discv, Jun 13, 2014.

  1. discv

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    First set up flights on my F450 build are going well.

    But I'm bogged down on understanding the alarm voltages in Naza assistant. Many searches have only increased my confusion :?

    Bare machine, 2200 3s, 8" props. Default settings give 3 mins 30 secs till first red LEDs. Battery takes 692 to full recharge.

    Can anyone suggest a starting point for improvement of default values.

    [I'm totally baffled as to why the 'no load' voltage has anything to do with it]
     
  2. ladykate

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    All this is 'under load' - specifically, with motors running. That is what your NAZA assistant is using.

    The low voltage recommendations are not usually too bad. Be careful about adjusting them. Your battery shouldn't go below 3.15 volts per cell under load (that's a guess based on my experience with ESC low voltage cutoff on one of my machines which essentially shut down a couple of motors and allowed the platform to spin in at 3.15). So, if I was doing it, my final voltage setting should be above that - typically, I have that one set to descend and land at 3.5 volts (lower than recommended!). That is getting pretty low but it will bounce back to about 3.6 or 3.7 (unloaded) before I get it to the charger. If you are flying high and miss it - you might not have enough juice to descend gracefully so watch it closely. First warning should probably be about 3.8 per cell which, according to most charts, is about 40% useful battery left. Note that both these voltages are lower than the DJI recommendation on my NAZA.

    In no case should you go below 3.0 volts per cell but that is actually hard to do (I've tried) since everything starts turning pear shaped about 3.2 volts.

    As in all things, your mileage may vary a bit. Don't be overly quick to radically lower the cutoffs. Bad things happen sometimes. Trust me. Batteries do not discharge linearly - typical results seem to be a quick loss at the top followed by a relatively stable and slower discharge followed by all out panic and undershorts cleaning.

    You can up the battery to 2700 or so with no problems. That will give you more time.

    As far as what your battery is taking on recharge, it seems like you aren't using it down low enough but your battery may not be the most efficient. If it has a high internal resistance, then you will get the warnings and auto-land but, upon putting it on the charger, find that it only takes 30 or 40 percent to charge it. Also, it is not unusual for the battery to 'bounce back' after it sits for a while. The true measure of battery state is to measure it under load or just after landing. What make battery do you have?
     
  3. ladykate

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    Just as apocryphal evidence, I was flying RC today using a 3D foamie. The wind picked up (tough on foamies) and I was proud to be able to handle it using a heavy handed throttle and no aileron turns (aileron turns means your foamie turns into a kite in the wind) - but suddenly the plane just quit in the air and full throttle didn't bring it out of a dive. On checking, the battery was reading 3.7 per cell but I cranked up the motor and applied full throttle and it died to an idle almost immediately. I had run out of juice because I was putting a heckuva load on the motor. Even though the 'no load' state was fairly good, the 'under load' was below flight standards. This can be mapped to what I've seen with our multi-rotors. Be careful of approaching the bottom end and expecting to have any reserve. It won't be there when you need it the most.
     
  4. OI Photography

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    discv, what are your default settings in the NAZA? I know what they are on a Phantom but I'm not sure if that's what the retail NAZA has set from the factory as well. If your settings are above 10.7/10.6 (loaded values for 1st/2nd level) then lower them to at least that to start.

    Also, do you know what the total weight of your 450 is? I'm guessing that it's a bit more than a Phantom, which means you aren't going to be able to get a lot of time out of a 2200mAh batt...but you should still be getting better than 3.5 min. Since you're battery is only recharging 600mAh it's clear that you're just not set up to use all the available juice.
     
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  5. ladykate

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    Just checked: I need to do an update on mine but my default values are 11.5 and 11.1 which is high. I have them set lower than that.
     
  6. ElGuano

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    Common advice for the Naza low voltage settings is to ignore the no-load numbers, and as described above, focus only on the final, loaded value.

    Set your line loss to 0.0, and input your desired loaded number into the no-load fields. So for level 1, it's common to select something like 10.7v, or perhaps 10.6v if you fly by timer and are sure to have your quad back at home and ready to land immediately after seeing the first red flashes. If you actually use your blinking LED to tell you when to come back home from distance, you want it higher.

    10.5-10.6 is a reasonable level 2 setting, though I never want the quad to take control of throttle from me, so I set it down to 10.4v with the understanding that I will never let it get that low, barring some exigent circumstance.
     
  7. discv

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    Wow-thanks to you all. Lots of info to absorb.
    I will be fitting a better battery and try changing to the bigger props. But as a newbie- I want to go one step at a time!

    Meantime, here is my Naza page with the battery fully charged.
     

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  8. ladykate

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    Yep. Those are the default settings. You can adjust them down from that. My voltages were slightly more conservative but you can try any of the others. Just keep it in the area the first couple of times to get a feel for it.

    Get a bigger battery. Be sure to get a good one - the cheaper ones will usually show their value.

    There are many good ones out there, though. GensAce, Pulse, Onyx and others. Generally, if they are too cheap to believe, then don't believe it.
     
  9. ElGuano

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    So from your picture, your level 1 is 11.2v loaded. That's using maybe 50% of your battery. I'd start by changing those values to 10.7 and 10.5, respectively.

    Your calibrated voltage looks fine, so long as the battery is fully charged up.
     
  10. EMCSQUAR

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    Your battery warnings are WAY to high. As El G stated above set first level at 10.6, 2nd level at 10.4 - you'll almost double the flight times you're currently getting.
     
  11. discv

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    Reading carefully the advice- here are the changes I shall start with- if I get your [collective] approval ;)



    The AUW. incl. 2200 battery is 1063g.

    Batteries;
    Started with a Nano-tech 2.2, 25-50c- very poor times- got soft to the touch- scrapped.

    Currently experimenting with Overlander 2.2, 25-35c, 170gr.

    I also have a Nano- tech 2.65, 25-50c, 213gr. COG will need changing to fit this.

    My battery options here in UK is mostly limited to HK [UK warehouse] stock holding.
     

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  12. rilot

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    IMO, Naza battery warnings are more trouble than they're worth. Monitor with the iOSD or better yet, get some proper telemetry with a current meter. Then you know exactly how much juice you've used.

    Yes, your warnings are too high but you have 0 in your loss. You need to calculate your loss for the craft.

    Do this as follows:

    Charge batteries to full and connect to Naza assistant
    Set first level voltage to 1V below the measured voltage in the Naza assistant
    Fly until first warning (it won't very very long) and land
    Connect to Naza assistant and see what the measured voltage is now
    The difference between the measured voltage and the voltage you set as first level is your voltage loss

    Example, you set 13V for first level, landed when you get the warning and your measured voltage is 13.5v. This would make your flying voltage loss 0.5v.

    Then you can set your warnings back to sensible values.

    Then to work out what your actual warning values should be, set them to something sensible like 3.75v / cell, fly until first level warning then charge your batteries, monitoring how much juice you are putting back in (you need a charger that can do this). Keep dropping or raising your voltage warnings until you are putting 80% of the capacity of the batteries back in to them when you charge.

    Then, you have your voltage warnings and loss set properly.
     
  13. discv

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    Thanks Rilot- now I am really, really confused.

    Referring to my first screen shot, the Naza default settings- the first level is set at 11.20.

    I flew till first red LEDs- landed- returned home [10 mins]- and got a measurement of 11.80 [no load]

    WTF.
     
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  14. ElGuano

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    Discv,

    10.7 / 10.5v for low voltage alarms is fine. Knowing your line loss and testing for it is all good, but it doesn't help you on a Naza because it can be off by 0.2v. or so depending on battery. Nobody adjusts the line loss in assistant every time they swap out batteries.

    If you land at 10.7v loaded, when you cut the engines the battery will start bouncing back. After 5 minutes, it will likely read 11.2v. That's the line loss again, and what you are seeing is the recovery voltage. But here it gives you a better sense of what percentage you used. 11.2v is just about 80%, give or take 5%.

    So rule of thumb: land at around 10.6-10.7v loaded. After a few minute to a few hours after the flight, the recovery voltage should be around 11.2 unloaded. If that is what you are seeing, you are doing well!
     
  15. ladykate

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    +1 Although messing with the line loss values is fun and can help you discover a crappy battery, you really want to cut to the heart of it and set your voltage warnings correctly. Do that first.

    Also, if you REALLY want to play with this, you can get a cell count voltage meter (used in RC flying a lot) for less than a couple bucks delivered. With this, you can shut down the motors and get an immediate reading - while they are shutting down if you want. No chance for bounce back errors. They even make them with audible low level warnings - tie them to the battery and you get a screeching noise when it drops down below the voltage per cell that you set.

    Here is the alarm version: http://www.ebay.com/itm/1S-8S-Buzzer-Al ... 338618aa08

    You can shop around and find them on sale (I got five of the alarm versions for $11 shipped). The non-alarm version is also handy for quick checking in the field. If you buy them, buy two of whatever you buy. For some reason, they go off and hide just when you want to use them. Sort of like ink pens.
     
  16. discv

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    Ok, I will have a test flight with the 10.7/10.5 settings- loss ignored. Have ordered a couple of the suggested alarm/meters to try and gauge voltage on landing.

    No flying today- the field is full of people kicking balls etc.- baa humbug :evil:

    Of 6 fairly new batteries- 4 [all Nano-Tech] are all puffed up. I now know were the term 'Nano Puff' comes from.
     
  17. ladykate

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    That seems strange. Are you over-charging them? One person was pushing the charge to 4.2 per cell and it was causing puffed up batteries - which is a bad thing.

    Over-charging or charging too fast will cause them to swell and the common advice for a puffed battery is to dispose of it.
     
  18. discv

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    I have an Accucell 6 charger and I always balance charge at 1 amp. The default setting is 4.2!!! Hence the 12.6 in screen shots.
    This puffing up is unique to the Nano-techs.

    So, to be clear, are you saying that the default 4.2 is too high?
     
  19. ladykate

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    Nope. 4.2 but not over. I wasn't clear in my post. One person was pushing it to .1 over 4.2. My bad.

    Double check the voltage if you can. The other instance was with a charger that was over-charging very slightly. The Nano batteries get good reviews from our local RC world. They all suggested I convert to them for the multi-rotors. Hence, if they are swelling up, I would suspect a snake in the woodpile somewhere.
     
  20. discv

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    LK, thanks for clearing that up. I am fairly sure that the 'snake in the woodpile' is the Nanos- the other brands are fine.

    * Being an old geezer, expressions like the 'woodpile' one, have to be avoided. All to easy to trot out the original :eek: