Maybe it has something to do with my battery monitor and less to do with how much the battery is actually discharging. Perhaps I should invest in a charger that lets me see how many mah’s are going into charging the battery as was suggested by Shawn.
Yea, any decent one will do that.
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I would probably try for a genuine ISDT charger, since a lot of the others that appeared for my search were cheap copies of old B6 chargers, or something totally unknown.
The lower end ones like this (in the link) still need an external power supply to run the charger:
https://www.amazon.com/ISDT-Touchscreen-Battery-Charger-Discharger/dp/B0823DGJXS/ref=sr_1_27?crid=ZJSSB3PJYU09&keywords=lipo+charger&qid=1686451496&sprefix=lipo+charger%2Caps%2C410&sr=8-27
The chargers that plug into mains power (and dont need an external power supply) are quite a lot more expensive. You might be able to order from Hobbyking too, the old Turnigy Reaktor chargers were very good but you cant get the single model anymore, only the dual chargers - and they have a range of ISDT too.
I have one of those. A300w version powered from PC power supply. Bulletproof.
Yes same here 
I know of commercial operations using them and swear by them.
I ordered a new charger this morning. Hopefully it will be good enough to give me the information I need to tune things.
I wonder also if perhaps I should find a battery that discharges at a lower rate. My current one is rated at 60C, and I’m wondering if something like this one linked below might extend flight time. While it is not a lighter battery, the discharge rating is 12-24C, and I am wondering if that would make a difference here. I always thought current was drawn as-needed and that the rating should be higher than the actual load, but I am hoping for your thoughts.
https://www.amazon.com/gp/product/B07MMTVP1G
Also, here’s a new log from a test hover following the changes to P/I/D and harmonic notch settings from last night.
Thanks again for all the assistance here.
None at all. In fact it will have less available max current capability which is what the C-rating is. But if the battery you have is shot…
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That’s what I thought originally, thanks for verifying. As for these, I will not defend a battery. All I can tell you is I purchased the two 6500 mah batteries I am currently using for this build, so they are at least brand new. So maybe a few more cycles and they’ll be in their prime.
I just tested again without any changes and hit 10 minutes in the air in a hover. I was in alt hold for a while and then switched to loiter. It was tiring of fighting that and switched to loiter. It seemed pretty solid. There was some breeze activity in the last half and I felt it was responding to some of that as well, but otherwise it seemed good. I’ll go ahead and post that log here.
At what rate you are charging your battery ? I would suggest from my experience charge it at 1C rating which would improve the battery performance.
I have seen significant improvement after changing my charger and charged at 1C rating.
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Do you mean increasing charging current to 1C or decreasing it?
Increase it to 5A or something based on C rating.
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Arun is correct, the best charge rate is usually “1C”
which means if your battery is rated at 5800mah, for example, your charge current would be maximum 5.8amps
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Check out this old RCG thread: Flight time calculator spread sheet. It contains a spread sheet that will calculate your flight time. The math was worked out by a cat with the user name of renatoa. Oops, the spread sheet can be found here: Spread Sheet
I seem to have the mAh reported in the logs roughly matching what my new charger is saying it takes to re-charge after flight. So that’s a bonus I suppose.
Because sometimes I like living on the edge, I pushed my low and critical voltage levels down some more. Doing this I got my flight time closer to 10 minutes. Still based on all the math I’ve done so far, and initial looks at what you’re showing me through this spreadsheet, I should be seeing closer to 15 minutes.
I appreciate the information, it’ll just take me more time to digest and understand it to figure out where I’m going wrong.
I was able to get through autotune for pitch, roll, and yaw. After getting those new PIDs saved, it seems to fly better. It’s been really a lot of fun working through everything.
The biggest disparity I found for power system components was the grams of thrust per watt (g/w) of a given motor and prop combination. Having a “good” prop on a “bad” motor and vice versa will throw the actually flight time off. Having a prop that is too large or too small does the same thing.
Do you have any experience with the Hexsoon EDU-450 v2 frame kit? That’s what this one is built on. On the one hand having the thinking all done for you on what props, motors, and ESC’s to use is maybe nice (obvious caveats aside). On the other hand, maybe I could have done a better job had I picked things myself based on what I want to do and how much I expect it to weigh.
But this is also my first custom drone build, so I wouldn’t be able to get to the next level without going through this one. So there’s that.
I appreciate your input. If you happen to look at this kit and have any feedback about things I could do to optimize what I have going on, I would certainly appreciate your insight.
Basically what you have is a re-hash of the DJI Flame Wheel f450 with a NAZA flight controller. Back in the day they were every where. As I recall the most you could get was 15 minutes and as I recall there was lot of whining and crying over flight times. My first quad was an X525 with 1000kV motors and an APM 2.5 flight controller. It was a decent inexpensive learning platform and it taught me quite a bit about motors and props. The fun started when I built a Tarot 680 Pro hexacopter with Pixhawk… I chased that endurance demon and I ran into a limiting factor: Prop size. For endurance you need a “light” aircraft with low KV motors swinging big props.
The frame came with 2216 920KV motors. I don’t know who made them. The ESC’s have a generic “20A” label on them. Props are most certainly t-motor 1045’s with built in nuts. The kit also included LED’s and a Hexsoon PDB. I’m using the power module that came with my FC because voltage and current readings from the PDB were not meaningful.
Other equipment not included in the kit that I have installed:
Cube Orange+
Herelink v1.1
SIYI A8
5 x TF-Luna’s
Plus I have about 10-12 grams of 3D printed parts I designed for mounting the antenna’s and the gimble.
My total weight on the scale with props but no battery is right at 1357 grams.
My expectation was that I could get this to fly 15 minutes. I’m hitting about 9. I maybe just have a less than good battery. It’s a 6500 mAh 4s. One indicator to me is that I get a little more variability than I expected trying to tune the BATT_AMPS_PERVLT. One flight it’ll be within 30mAh, the next it’ll be out 150mAh. The only way I got it that high was pushing it all the way down to 14 volts, too. If I had any sense I wouldn’t do that, I guess. Anyway, at that voltage it logs about 2300-2500 mAh used. If I went all the way to 12 volts, which is technically the limit for a lipo, manufacturer notwithstanding, I still don’t think I’d hit 1300 mAh left in the tank. So I’m thinking maybe these just have less than good chemistry. Plus with the 4s at that rating, I’m 560 grams worth of battery weight, and that takes it a little bit high, I think.
you might be able to check here to see if your battery brand is a bad one, or find a good one: Battery Load Test Comparisons - RC Groups
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I’ve been reading there a ton. Nothing with my label on it, but the dreaded “cheap amazon battery” stuff in there makes me super sad. I was thinking of trying one of the LiHV batteries, but wasn’t sure what might need to change in the tuning of it all.
I have a couple 5200mAh 3s batteries from my old IRIS+ that I was thinking of retuning for. Just to see how awful that might turn out.