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Old Jul 24, 2015, 07:25 PM
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Quote:
Originally Posted by GryphonRCU View Post
Look at your per cell voltages.......something looks weird there.
V = W / A
V / 6 = per cell voltage

Other than per cell voltage numbers under load being very high (possibly great battery) , why are they the higherst under most AMPs when they should be lowest.
And in fact, under most AMPs, its so high that I Doubt it. 3.94V under 130A load???

G.
I remembered to log the 6.5x6 and 6.5x6.5 tests, so I am posting the graphs and raw data files from the OpenTx Companion logs. The batteries are Revolectrix 427 blends charged to 4.2 volts. I guess the batteries are pretty good after all.

I have the Frsky battery telemetry sensor, but did not bring it out. I'll make sure I get cell and cells telemetry next time.
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Old Jul 24, 2015, 09:04 PM
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Only comment I can make is regarding data plucking.
Don't take the very first set of peak values. Try and move forward about 1.0 to 1.5 second past that and read all values from there.

7 data points, that means changing over 6 periods.
Consumption changing by 23 , I assume mAH
Average AMPs = 130A

I assume your logging rate is every 1.5 seconds if I did not screw up my math.
So use the next set of data values after peak initial AMP.

23.5V changed to 22.1V
22.1 V / 6 cells = 3.68 Volts per cell

3.68 is way more reasonable compared to 3.9V

Not sure how accurate the voltage values are but it seems like a pretty good battery.
Since you are holding higher voltage under load, your motor will draw more AMPs and Watts and turn a bit more RPM too than folks who were getting those premature cutoffs.....and produce more waste (heat).
I believe reports were that 130A were about max for speed runs.


Hopefully that battery will serve you well for a long time.
Please report back after its long term use.

Good luck and have fun,

Gryphon
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Old Jul 25, 2015, 08:57 AM
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Quote:
Originally Posted by GryphonRCU View Post
Only comment I can make is regarding data plucking.
Don't take the very first set of peak values. Try and move forward about 1.0 to 1.5 second past that and read all values from there.

7 data points, that means changing over 6 periods.
Consumption changing by 23 , I assume mAH
Average AMPs = 130A

I assume your logging rate is every 1.5 seconds if I did not screw up my math.
So use the next set of data values after peak initial AMP.

23.5V changed to 22.1V
22.1 V / 6 cells = 3.68 Volts per cell

3.68 is way more reasonable compared to 3.9V

Not sure how accurate the voltage values are but it seems like a pretty good battery.
Since you are holding higher voltage under load, your motor will draw more AMPs and Watts and turn a bit more RPM too than folks who were getting those premature cutoffs.....and produce more waste (heat).
I believe reports were that 130A were about max for speed runs.


Hopefully that battery will serve you well for a long time.
Please report back after its long term use.

Good luck and have fun,

Gryphon
I appreciate you leaning in. I guess peak values are not really where it's at, unless one wants to cherry pick the data. Just wait until I get and post a GPS peak speed >215 mph!

All kidding aside, the 6.5x6.5 was still pulling ~2600 Watts after 8 seconds of wide open throttle. I hope a few limited full throttle runs won't kill a battery. What would be the fun in that? I'll be monitoring the battery's health.

Again, thanks for the information. The 22 series Mega upthread certainly looks interesting...

LSO.

P.S - Logging is at 0.1 second intervals
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Old Jul 25, 2015, 02:03 PM
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LSO,


Thanks for the post. 0.1 sec it is.
That is not a calculation I Normally due since logging rates are usually seen/known.
Double checked a 130A range file for similar mAH.
Then reached in the trash can and pulled out my scribblings from last night to see what I had screwed up. Started inversed, and if that was not bad enough, left out the 6 periods too. Laughing at myself.


I like learning about different loggers.
Do you have a link for yours?
A friend needs one for hotlining pending max AMP capability.


Gryphon
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Old Jul 25, 2015, 02:21 PM
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Quote:
Originally Posted by GryphonRCU View Post
LSO,
I like learning about different loggers.
Do you have a link for yours?
Gryphon
I am using the telemetry logging that is part of the OpenTx Companion 2.0 software. It won't help unless you are using an OpenTx transmitter, such as Frsky's Taranis.

OpenTx Software
USA distributer for Taranis

Additionally, voltage and amps through Unisens-E telemetry sensor (software is in German, but there are english translations on the web)
Unisens-E thingy

HTHs.

LSO
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Old Jul 25, 2015, 03:47 PM
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LSO,

Thank you for the reply.

By the way, that Transmitter's USA distributor is a nice guy.
Since they are just 10-15 minutes North of the Golden Gate Bridge, I dropped in once. Completely blown away by the insanely low prices for 16 and 32ch options that he was talking about. Hard to wrap my head around 16ch, let alone 32chs.



Gryphon
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Old Jul 25, 2015, 07:36 PM
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Quote:
Originally Posted by GryphonRCU View Post
LSO,

Thank you for the reply.

By the way, that Transmitter's USA distributor is a nice guy.
Since they are just 10-15 minutes North of the Golden Gate Bridge, I dropped in once. Completely blown away by the insanely low prices for 16 and 32ch options that he was talking about. Hard to wrap my head around 16ch, let alone 32chs.



Gryphon
You need to use your fingers and toes to use all 32 channels!
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Old Jul 26, 2015, 05:07 AM
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LSO
Is that a new battery? Have you conditioned it? Holding ~3.6V/cell would be a game changer.
Did you also buy their new charger? I was looking at these batts a few months ago but couldn't find many reviews.... decided to get a cheap Turnigy instead.

Let us know how that batt comes around. I'd be interested to see how it holds up.
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Old Jul 27, 2015, 07:43 AM
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You'll need more than 2600 watts for 215mph....
Quote:
Originally Posted by lordsirob View Post
I appreciate you leaning in. I guess peak values are not really where it's at, unless one wants to cherry pick the data. Just wait until I get and post a GPS peak speed >215 mph!

All kidding aside, the 6.5x6.5 was still pulling ~2600 Watts after 8 seconds of wide open throttle. I hope a few limited full throttle runs won't kill a battery. What would be the fun in that? I'll be monitoring the battery's health.

Again, thanks for the information. The 22 series Mega upthread certainly looks interesting...

LSO.

P.S - Logging is at 0.1 second intervals
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Old Jul 27, 2015, 08:20 AM
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Originally Posted by rimripper View Post
You'll need more than 2600 watts for 215mph....
Hence the use of "all kidding aside"
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Old Yesterday, 05:34 PM
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finally got off the ground

I got my bungee launcher together and the heavy 6 cell FJU finally got airborne (after a few tries- now have the correct tension figured out). Bummed out, telemetry iffy, no 215+ mph on gps:

The first landing took two tries and I still managed to overrun the runway (takes forever to bleed off speed).

I had one 5 minute flight just taking it easy and only used 1600 ma on my 3000 ma packs.

I will post telemetry on my next weekend flights.

Ultra fun with this FJU!
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