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Old 08-20-2013, 12:31 PM   #1
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Default Benchmarking the Best 2S Lipos

I've noticed it can be difficult to find direct comparisons for information in our hobby, so I started to do my own. For this article, I tested over a dozen batteries and wanted to share some of the results of my findings so far:

http://its1204.com/content/lipo-batt...s-packs-update
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Old 08-20-2013, 08:31 PM   #2
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Quote:
Originally Posted by silencery View Post
I've noticed it can be difficult to find direct comparisons for information in our hobby, so I started to do my own. For this article, I tested over a dozen batteries and wanted to share some of the results of my findings so far:

http://its1204.com/content/lipo-batt...s-packs-update

25 amp discharge doesn't really tell if the lipo is good.

Should have used 30 and 35 amp discharge load, closer to real amp draw of a vehicle racing.

Also, 70-75F.
Temperature effects IR in lipos so reading can be off.

I would have used pack temp with IR and discharge curve at 30 and 35 amps

Last edited by Mr RCTech; 08-20-2013 at 08:41 PM.
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Old 08-20-2013, 09:44 PM   #3
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you need-

consistent charge voltage (4.22v/cell)
35a discharge on gfx
ir measurement
avg voltage
# seconds above 4v/cell
total run time
mah

anything less is silly...
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Old 08-20-2013, 10:29 PM   #4
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25 amp discharge doesn't really tell if the lipo is good.

Should have used 30 and 35 amp discharge load, closer to real amp draw of a vehicle racing.

Also, 70-75F.
Temperature effects IR in lipos so reading can be off.

I would have used pack temp with IR and discharge curve at 30 and 35 amps
Thanks for the feedback. Always glad to hear ways to improve.

Oops, that's a typo, the temperature range is supposed to be 70-72F (corrected). Yes, I agree there is room for some error due to temp variance. Just gotta do my best to ensure it's controlled.

Agreed, a higher discharge load would be ideal wouldn't it? I'm curious though, how did you arrive at 35A? What type of car/motor/track would that equate to?
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Old 08-20-2013, 10:38 PM   #5
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you need-

consistent charge voltage (4.22v/cell)
35a discharge on gfx
ir measurement
avg voltage
# seconds above 4v/cell
total run time
mah

anything less is silly...
Thx mike,

consistent charge voltage (4.22v/cell)
Yes, i'll have to get better at this as I improve the process.

35a discharge on gfx.
Yup, as in above post. 35A would be great. And a GFX would be awesome. haha.

ir measurement
IR measurements have been recorded, but they have not been uploaded yet. I have IR at full charge, storage charge, and discharge. What type of info would you guys like to see?

avg voltage
Average voltage of what presented in which way?

# seconds above 4v/cell
This is available in the raw file, but your comment is interesting, why 4v?

total run time
This is available in the downloadable raw file. I'll add that benchmark chart as well.

mah
Also in the raw file. Any ideas on how this should best be charted?

Best,
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Old 08-21-2013, 05:57 AM   #6
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I (when I had my gfx) would look at voltage at 360 sec into the cycle then would set my voltage cutoff slightly under that so I could get a realistic avg race discharge voltage and beginning and end ir #s.
This seems to be more ideal for my needs . this really shows the info i wanted to know about my voltage on the track.
I also used 35amps .
Its what all good old scrc/nimh cells were tested . and i like seeing the compairison.
+ doing 35a discharges tests the cells indurance with the heat . (temp of packs at end of cycle ) lower temp usually helps depermine which packs r better by seeing lower temps
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Old 08-21-2013, 07:53 AM   #7
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Originally Posted by silencery View Post
Thanks for the feedback. Always glad to hear ways to improve.

Oops, that's a typo, the temperature range is supposed to be 70-72F (corrected). Yes, I agree there is room for some error due to temp variance. Just gotta do my best to ensure it's controlled.

Agreed, a higher discharge load would be ideal wouldn't it? I'm curious though, how did you arrive at 35A? What type of car/motor/track would that equate to?
What you might need to do is to get each lipo to its lowest IR then graph in real time.

Everyone knows that the Sting packs are the highest out there for right now.
SMC, Trinity and others switched over to them.
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Old 08-21-2013, 12:22 PM   #8
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Originally Posted by jlfx car audio View Post
I (when I had my gfx) would look at voltage at 360 sec into the cycle then would set my voltage cutoff slightly under that so I could get a realistic avg race discharge voltage and beginning and end ir #s.
This seems to be more ideal for my needs . this really shows the info i wanted to know about my voltage on the track.
Thank for the note.

Yes, that's how the 6 minute chart was setup. Have I not defined that clearly or overlooked something?
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Old 08-21-2013, 12:26 PM   #9
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What you might need to do is to get each lipo to its lowest IR then graph in real time.

Everyone knows that the Sting packs are the highest out there for right now.
SMC, Trinity and others switched over to them.
Interesting idea. I'm not sure if i wanna take it that far though since my goal is to help people know what to expect when they pull a lipo out and just start running it.

I do agree all the environmental conditions need to be tightly controlled in order to ensure unbiased results though.

Actually, i didn't know about the Sting packs. Have a link? I'll have to see if i can get my hands on some to test
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Old 08-21-2013, 01:29 PM   #10
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Sting Batteries

http://www.trinityrc.net/shop/index....ry&path=71_128
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Old 08-21-2013, 01:31 PM   #11
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Quote:
Originally Posted by Mr RCTech View Post
What you might need to do is to get each lipo to its lowest IR then graph in real time.

Everyone knows that the Sting packs are the highest out there for right now.
SMC, Trinity and others switched over to them.

No one switched over to the "Sting" packs. The sting packs are simply the owner of the factory where most of us get the good lipos from, his own brand. The owner sells the same high end packs under his own sting name. They make different grades of cells and some of the people that buy from him buy the exact same cells as sting and some do not. Some buy cheaper cells and label them as the higher ones. It just depends on who is honest and who is not. Go with a reputable manufacture and chances are your getting the same cells as a "sting" without the sting in your rear end when paying for them.

EA

P.S. And if you really want to get serious there is one company that sells 4 lines of batteries. 3 of them are all the same lower grade cheap C rating and one line is not. Just a way to sell more lipo's to people....
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Old 08-21-2013, 02:57 PM   #12
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OR
you could count you time as money and just buy EA's batteries

I ran his VTA pack in my VTA car for the first time Sun and won the Speedworld Cup race in Sacramento, TQ'd as well

I had every car on the straight by 1.5 to 2 car lengths and had the only car to run in the 19secs lap
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Old 08-21-2013, 03:27 PM   #13
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Originally Posted by silencery View Post
Interesting idea. I'm not sure if i wanna take it that far though since my goal is to help people know what to expect when they pull a lipo out and just start running it.

I do agree all the environmental conditions need to be tightly controlled in order to ensure unbiased results though.

Actually, i didn't know about the Sting packs. Have a link? I'll have to see if i can get my hands on some to test
SMC packs -

http://www.smc-racing.net/index.php?...ory&path=67_90

http://www.lefthander-rc.com/catalog...hp?cPath=23_64
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Old 08-21-2013, 03:37 PM   #14
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http://www.trinityrc.net/shop/index....ry&path=71_128

Sting batteries for you if you really want to spend extra and try them.

EA
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Old 08-21-2013, 03:37 PM   #15
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OR
you could count you time as money and just buy EA's batteries

I ran his VTA pack in my VTA car for the first time Sun and won the Speedworld Cup race in Sacramento, TQ'd as well

I had every car on the straight by 1.5 to 2 car lengths and had the only car to run in the 19secs lap
I could

I'm certainly not doing this to save time though. My aim is to provide a resource with objective information to help all enthusiasts, old and new.

When I got back into RC a few years ago, I had so many questions and I wasn't even coming in as a noob from the ground floor! As awesome as RCtech is, the unstructured nature here makes it a huge clusterf*ck. It's almost impossible to pick through the good info from bad, particularly for new people. I don't know this will ever happen, but it'd be nice if I could help lower the barriers of entry, provide good information to share with everyone, and let people make informed decisions to help grow the hobby.

For example, with batteries, there are TONS of choices from cheap China packs to high end race packs. Offhand, I can think of lots of questions people might have with no concrete answers:
  • If I buy a cheap pack, how much of a measurable performance difference can I expect? Will it last?
  • Is it worthwhile to save 1/2 price for a racer at my level (rookie/sportsman/expert)?
  • Will spending $160 on a battery make a difference for me?

Everyone's circumstances are different, so it'd be great if we could speak to everyone at the appropriate level and answer the right questions. Actually, the example you mention is great: maybe you're already at a skill level where you can take advantage of an expensive pack, but a newbie might be happy concentrating on completing laps with a budget rig.

Anyway, i'm not sure where this site will go. I guess we'll have to see

P.S. I have some new material benchmarking fans coming down the pipeline too. Might be interesting for some.
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