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Old 01-31-2012, 03:15 AM   #46
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Quote:
Originally Posted by Danny/SMC View Post
Have you personally tested a 3000mAh cell at 180amps ? If the info comes from the factory you should do your own tests as I got fooled by the factories claims. I think they understand that very few people have the equipment to test at these high rates so they will claim what they feel will sell more packs.
Im with you on this one and i understand what you have been through and believe it or not Danny i know the factories your talking about .

Like i said there is only one factory in china they are expensive but they have all the equipment even temp altitude chambers for testing for military specifications .

From start to finish there is only one factory in china with all equipment that is needed and beyond for battery manufatured to elliminate contamination etc .

Ive been to factory which i wont mention any names that they were mixing the electrolyte with a cement drill type mixer in a bucket and painting the eletrolyte on the copper sheeting with a paint brush .The proper way is a dust free sealed room with a plasma spray system which no factory in china uses bar one .Most who claim are factories are not at all but trading companies with a small room as an office but like i said will not mention any names or brands .
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Old 01-31-2012, 03:27 AM   #47
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Originally Posted by Potato View Post
What are you talking about? What you're saying doesn't make sense.
Nominal voltage for a lipo cell is 3.7V.
3.7V is one cell
7.4V is two cells in series
14.8V is four cells in series
They all can use the same cell, which would have the same capacity. If the highest single cell capacity available is 6000mAH, then putting them in a series would have the same pack capacity (1S, 2S, 4S). There's no distinction between 3.7V, 7.4V, 14.8V.
Sorry dude i confused you all i was saying as complete packs say 7.4v 2s ,14.8v 4s etc the highest capacity reached so far for these packs from the biggest factory in china thats owned by government with endless research and development budgets is 7.4v 2s at 6000mah 14.8v 4s at 5200mah etc so how do these other backyard factories reach the c ratings and the capacities they claim they must be magicians when the big boys with the research and the big money can't.

thats all sorry for the confusion
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Old 02-16-2012, 06:48 PM   #48
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Hummm, nice read as i agree that i also have not seem much over a real 30c continuous discharge battery.
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Old 02-17-2012, 02:37 AM   #49
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Mainly aimed at Danny/SMC;

What is a rough figure for internal reisitance of a 2s lipo pack compared with the old 6cell NiMh pack's. I know lipo's are more efficient, just wondering how much?

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Old 02-17-2012, 03:48 AM   #50
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Its about time manufacturers started adopting a process to "show off" their true product performance.

Kudos to SMC for doing this.

I think its time others followed suit, or STFU about 90c or whatever ratings, unless they have some true measurements to back it up...

Kinda like Traxas and the XO-1... 100mph? O rly!!!!! I must go out right now and buy one of those...
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Old 02-17-2012, 08:09 AM   #51
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Watching with interest........
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Old 02-17-2012, 08:51 AM   #52
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Quote:
Originally Posted by COBRARACING View Post
Ive been to factory which i wont mention any names that they were mixing the electrolyte with a cement drill type mixer in a bucket and painting the eletrolyte on the copper sheeting with a paint brush .The proper way is a dust free sealed room with a plasma spray system which no factory in china uses bar one .Most who claim are factories are not at all but trading companies with a small room as an office but like i said will not mention any names or brands .
Out of interest, were the Chinese factories company suppliers to any well known brands, or just the 'unbranded' style of lipo's you can easily find on Ebay etc.
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Old 02-17-2012, 09:13 AM   #53
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Quote:
Originally Posted by CarbonJoe View Post
Some of the blame for the charging limits can be placed squarely on ROAR. Their rules state a charge limit of 1C.
Actually ROAR lifted that last year....it just has never been updated on their website but if you look under the rule changes it is not listed any longer. It lasted for about 2 years. But now they REQUIRE the use of a balancer type charger at all ROAR races.

Quote:
Originally Posted by Danny/SMC View Post
Thought some of you might like to see my C rate tester. I'm able to pull over 200 amps with this setup. All tests are done on one single cell.
Braver than I am Danny! LOL

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Old 02-17-2012, 06:46 PM   #54
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Quote:
Originally Posted by Skiddins View Post
Out of interest, were the Chinese factories company suppliers to any well known brands, or just the 'unbranded' style of lipo's you can easily find on Ebay etc.
All battery lipo cells are made in china .Some buy materials from Japan some from inland china .Some have high quality machines for manufacture and state of the Art factories and some are garages in the back streets .

Government funded factories are the best as they have access to the best engineers from the universities and other government departments but there product is all performance and quality last longer but is also sometimes twice the price but your paying for a high grade non contaminated product that will give you between 500 and 800 cycles .

But as i said all cells are made in china and rebadged.

Your cheap cells you find on ebay are grade F cells thats why they are cheap they are from the bottom of the production run.The you have Grade A cells which are hand picked from the top 10% of each batch .
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Old 02-19-2012, 05:53 AM   #55
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Great thread.

Sure am glad I'm racing an M05 with a silver car motor and cheap NiMh cells.
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Old 02-19-2012, 06:03 AM   #56
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Quote:
Originally Posted by EAMotorsports View Post
Actually ROAR lifted that last year....it just has never been updated on their website but if you look under the rule changes it is not listed any longer. It lasted for about 2 years. But now they REQUIRE the use of a balancer type charger at all ROAR races.
Good old ROAR. Glad to see they're keeping the web site updated.

What's the ruling on charging 1s LiPos then? Still require a balance type charger, even though most 1s LiPos don't have a balance port, nor require one?
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Old 02-19-2012, 07:52 AM   #57
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I notice one company is advertising their lipo batteries,at least this one I am looking to buy(6s 6500mAh), as "True 150c rating". Not putting a name out,but maybe it's known already....what's with that number(150c), must be some advertising gimmick?! Thanks

Last edited by Huck50; 02-19-2012 at 08:02 AM.
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Old 02-19-2012, 08:18 AM   #58
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Quote:
Originally Posted by taz00 View Post
Great, another vague measurement to compare packs...
Why on earth is it so difficult to hook up a battery to a known load (eg light bulbs) and measure the voltage sag?
IR of a pack depends on too many values to be used for comparison.
Apart from measurement method you have state of charge, temperature, gauge of the wires etc that have an impact on IR.
It seems that most car battery manufacturers do not want to use a proper measurement because they will lose their marketing advantage.
+1.

Another meter to hookup to my lipos and tell me how bad there really are??
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Old 02-19-2012, 08:29 AM   #59
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I think there was a usefull information for racers, a list of the best lipo brands based in racers experiencies, don't you?

I will start it with my experiences.

GM Maxx 6200 60C. The best I'd used.
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Old 02-19-2012, 08:46 AM   #60
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Quote:
Originally Posted by Huck50 View Post
I notice one company is advertising their lipo batteries,at least this one I am looking to buy(6s 6500mAh), as "True 150c rating". Not putting a name out,but maybe it's known already....what's with that number(150c), must be some advertising gimmick?! Thanks
Most C ratings are marketing gimmicks. And as Danny stated above, the solder, wires, and connectors can't handle these continuous "ratings" anyway. Short runs of 12ga wire is only rated for 60A. Your motor is only going to draw what it needs, and no more. For example, in 17.5 blinky TC, I use around 2000 mAh in 6 minutes, for an average current draw of 20A. It doesn't matter that my battery is capable of over 360A continuous, the max the motor will draw is around 60 A, rught from a dead stop. Down the straight, it might only pull 7A.
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