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Joined Mar 2011
43 Posts
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Wayne,
When i look for a lipo one of the criteria i try to look for is consistency. While some of the packs reported in the database for the Loong-Max look great some of them are not up to par and inconsistent. Of course i can only conclude my decision based on the info provided but overall they seem like a good brand with some inconsistencies. Do you think these packs are consistent or is there some disparity between the packs. Here is one tested by bobSmith, (Row 42) which is rated at 25C but true C is 19. BobSmith Loong-Max 2250 25 19 23 7.24 22c ESR meter 0.74 43 19 |
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Joined Mar 2011
43 Posts
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I created a "C" Delta column using the database and I was pretty clear to see how inconsistent some of the packs are. I can conclude easily what packs not to purchase but the ones that showed a Delta in a favorable manner had much less inconsistency even though not a single manufacturer was 100% consistent. I won't name the mfg from the list but there is really one that shows a favorable Delta consistently between all the testers, however even this mfg had a few questionable packs.
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Rugby, UK
Joined Feb 2007
723 Posts
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Quote:
Have alook at http://static.rcgroups.net/forums/at...EG%20Table.jpg Bob has probably used his packs a lot. Not saying they are very long lived but if you put my Measured IR figures into the calculator they give 27C In a hurry will post more tonight Wayne |
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Rugby, UK
Joined Feb 2007
723 Posts
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Quote:
I know Bob and he is a careful and knowledgeable modeller with a particular interest in lipos. The Loong Max are the original types which have not been available for some years and will be ageing. If you look lower down you will see that the 1800 20C Tipple is showing a real C of 22 ie 10% up on spec as is the 25C Tipple I tested. My original testing from some years back showed that Loongmax packs outperformed nearly all the competition and thay all met their C rating claims. See. http://www.rcgroups.com/forums/showt...php?t=1087725p Wayne |
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Rugby, UK
Joined Feb 2007
723 Posts
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Quote:
Suppliers change, chemical makeup changes so that the short answer is probably 'No' Nonetheless, Loong Max Tipples still show very low IR values so they should be worth a punt. Wayne |
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jets, you might be interested in this post from another thread about who makes LiPo cells and how they are marketed.
http://www.rcgroups.com/forums/showp...8&postcount=15 John is a vendor promoting his product but he has a long history in the LiPo business (he worked on the original Kokam batteries) and I think from all the evidence his assertions are correct. In another post somewhere (going from memory here) he stated that of the 100 LiPo cell manufacturers in the world all but two are in China and the cells we see in our batteries are all supplied by only 4 of them. All the brands we see are just assembly operations. Haiyin may be an exception as they sell directly and are a manufacturer. John |
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Joined Mar 2011
43 Posts
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I think you must have me confused with someone else, I was never dealing with RevoJohn?
I'm well aware of where the cells come from. I actually wrote a paper on LiFePO4 and the cells just like Lipos come from a few sources overseas and everybody else assembles them and throws their label on it. The Lipos are just more popular in the RC world hence the scrupulous marking is not as bad with LiFePO4 batteries unlike Lipos with vendors/MFGs making ridiculous claims all in an effort to falsely market their products and pull one over the consumer. |
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Orange, California, United States
Joined Nov 2001
640 Posts
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Ok here are a few graphs a boat customer of mine sent me of some 6s 5000 mah packs he runs in his race boat. The graphs shown are a 6s 2P configuration which is what he runs in his boat. These are from the 10, 11 and 12 charge on the packs.
Mark |
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Joined Mar 2011
43 Posts
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That is nice of you to post the graphs but it just goes to prove your claim of selling only 65C lipos are false advertising as shown in the data from the graphs for example Cell 3 puts your continuous current at 25-27C Real value not 65C. Which would mean the smaller packs that usually have an even higher IR probably closer to between 15-20C not 65C.
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