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Old 11-19-2008, 04:31 PM   #31
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Danny.

I am please this thread has been started,

I do find this post of your as a very good marketing tool for your products

I have asked the question now several times in relation to the "35c " rating of the higher packs and how can this be so, To my understanding , as you have mentioned, a pack with these physical dimension CANNOT SUBSTAIN the 35 C rating given, But no reply has been forward thru to me??? Hence i never purchase this size or capacity pack.

Also in reality is this size or C rated pack really necessary or is it more an ego trip tHat racers are on. "Mine is better because it is bigger"

I beleive if racers were too actually sit down and do proper load tests and give some thought a smaller capacity pack will more than likely be as effective as a larger capacity pack, Lets face it in honesty, How many people can actually notice the difference in reality when the sycological aspect is removed??

[QUOTE=Danny/SMC;5069984]I

Now that Lipos have become the power of choice and most of the Lipo manufacturers come out of China it's very easy for companies to purchase and sell Lipos.

Do SMC cells come from here also??

As testing C rate requires expensive equipment the Lipo manufacturers and resellers know this so they can claim any C rate as they know it's very hard to test. So some rely on this to claim higher C rates which keeps the cost down so they make higher profit margins and it makes there pack more marketable.

I really dont think this can be solely directed to the manufactures. I beleive this would be more the majority of OEM sellers esculating the "C" when labels are being produced

Our supplier which we feel makes the best performing Lipos with true C rate has told us that true 35C packs are fairly hard to do and the technology wasn't possible until recently. I also asked him how some can claim 5200 with 35C in the ROAR case size which limits the cell size and he told me it was impossible to make a pack with true 35C with 5200 in that case size. This lead me to buy one of these 5200/35C packs so I could test it.

My comments above



QUOTE]

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Originally Posted by Dawn Sanchez View Post
How interseting this thread pops up..... and I'm so glad to read it!!!

ROAR is currently working on and will be implementing a system that would clearly evaluate C rating in submitted batteries to force truth in labeling of ROAR approved products....

also, ROAR will be working on truth in the future of labeled products.. meaning, verifying things don't change after the approval is posted.

Thank you Danny for writing this thread! I'm glad your the first to be on board with ROAR's upcoming policy.

Dawn
I find this some what disturbing from ROAR, That C rating isnt tested with their approvals. To me this is giving racers a false sense that they are purchasing packs that are true to their word, Especially seeing they have been given this approval

They have only appeared to be more interesting in whether the "HARD Case" meets drop tests or what brand of cells are used. I would of thought the specs of a pack would of been a higher priority ??? to of tested.
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Old 11-19-2008, 04:36 PM   #32
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When I put a 5000mah 20C pack in a car I don't worry about it, I'\ know I'm nowhere near drawing 100 amps continuous. The difference between a 5000mah 20C pack and a 5000mah 30C pack is that the 20C is safe to run at 100 amps the 30C is safe to run at 150 amps. My car is pulling maybe 25 amps average, so the C rating doesn't really matter to me. What does matter is higher average voltage and lower internal resistance. Those numbers tell me how much punch I'll get from the pack.

All that being said, I'll go on to say that higher C rated packs should tend to have lower internal resistance, but I'd still want to see those numbers on the packs I buy.
Finally someone hitting the nail on the head and usuing common sense
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Old 11-19-2008, 04:39 PM   #33
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It would be nice if all the "battery companies" would start cycling their packs and providing the numbers from a GFX. You know, say a 35 amp discharge and give the runtime, average voltage and IR.

There's only one company out there that I know of putting actual numbers on their packs... Don't ya think that there might be a reason that the others don't?
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Old 11-19-2008, 04:40 PM   #34
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Originally Posted by lauri View Post
Correct me if I'm wrong:

3T 540-size sensored brushless is less than 900W. LRP says its X12 3T is 797W but at what voltage? So lets say it is maximum 900W which at 7.4V makes 121A. When we consider ESC's internal resistance we can say that the MAXIMUM current can go up to 125A.

For 5Ah battery it has to be 25C to give out the 125A. So we don't need more than 25C capable 5Ah battery. Newer hardcase LiPos go up to 5300-5400mAh capacity. To get 125Amps from 5400mAh LiPo it has to be only rated at 23C.


When you run 5-minute races you can't use more than avg 12C without completely discharging the battery
(60min / 5min = 12)

When you run 8-minute races you can't use more than avg 7.5C without completely discharging the battery.

I admit that the C-rating is quite weird and we just have to trust the manufacturer. Only stating C-rating doesn't really say anything. I've taken it as the maximum amperage the battery can handle without blowing up

To make the C-rating count as a real value we should have more information on how it has been measured.

- How many % of capacity do you get when discharging with the C-rated amperage?
- Down to what voltage do you dischage the cell?

I hope ROAR will test the rated C-value and publish the results or not accept the battery if it fails. Of course we need to know what the limits are ie 80% of rated capacity, under +30 delta degrees temperature rise, discharged down to 3.0V

Lipo manufacturers have established guidelines to figure out the C rate of a Lipo cell.

To get the C rate it consists of loading up the cells at various C rates. So if you think it's a 20C you would do it at 15C and if you get more than 90% of it's rated capacity you then discharge it at 20C and if it's at 90% then that cell is a 20C cell. If it's below 90% at 20C you can try 18C to try and figure out what the C rate is.

So there is industry standards for Lipo suppliers but they seem to know that it's very hard for the consumer to test so they will rate them higher as this equals to better marketing and more profit margin.

C rate is the way you can measure a Lipos performance and it doesn't need to be changed we just need to learn who puts real C rates on there packs unless you don't mind paying for something your not getting.
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Old 11-19-2008, 04:40 PM   #35
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Originally Posted by FFR1 View Post
I find this some what disturbing from ROAR, That C rating isnt tested with their approvals. To me this is giving racers a false sense that they are purchasing packs that are true to their word, Especially seeing they have been given this approval

They have only appeared to be more interesting in whether the "HARD Case" meets drop tests or what brand of cells are used. I would of thought the specs of a pack would of been a higher priority ??? to of tested.
As I understand it, ROAR testing so far has only been limited to whether or not the pack is safe, not whether or not they live up to their advertising claims. If ROAR is going to start regulating truth in advertising, it's going to open up a huge can of worms for other r/c products (engine HP, brushless motor wattage, speed control amperage ratings, etc.)
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Old 11-19-2008, 04:44 PM   #36
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Originally Posted by Fred_B View Post

There's only one company out there that I know of putting actual numbers on their packs... Don't ya think that there might be a reason that the others don't?
Fred this can also be taken as a very good marketing tool by doing this, Seeing the markets are hugely competitive any extra labelling, info etc etc is always good and can give you a leading edge, Then this can also been used against your competitiors!!
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Old 11-19-2008, 04:47 PM   #37
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As I understand it, ROAR testing so far has only been limited to whether or not the pack is safe, not whether or not they live up to their advertising claims..)
Are you saying then , That a falsified/ over inflated 'C" information?? is safe?? and is acceptable with ROAR approved packs
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Old 11-19-2008, 04:50 PM   #38
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FFR1: Yes our packs come from China. What I'm getting at is that it's very easy to get Lipos from various suppliers from China so this leads to many different types of Lipo packs for RC cars. Like I said my goal is to open peoples eyes and yes it also gives SMC good publicity but trust me we have no problems selling our packs so it's not only about publicity.


Whether it's the manufacturer or reseller that claims a false C rate or capacity rating it's still false and the consumer is not getting what he paid for.
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Old 11-19-2008, 04:51 PM   #39
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Originally Posted by Danny/SMC View Post
So if you pay for more for a pack that should be able to provide a certain C rate you don't matter if it isn't as long as it has good IR and voltage ?

Does this mean we should call our 24C/5200 a 40C pack since it has good cycle numbers ?
I'm not saying the C rating doesn't matter at all, but I think in addition to telling us the truth about C numbers(which it appears your company does), it would be useful information. Mostly because this is something racers are used to seeing and can relate to.

I would imagine that the punch from a higher C capable pack would be much better. At the same time, if I am hunting for a pack and brand X has an avg discharge voltage of say 7.21 vs SMC avg discharge voltage of 7.30, I would look at buying the SMC. For those in spec motor classes, ie stock and super stock, the higher avg voltage seems to be what most people want.

I am not a battery guy, and certainly don't work in the industry, just stating things how I see them. Maybe the true C rating is how we need to be looking at Lipo's, if so, then again, thanks for the information.
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Old 11-19-2008, 04:58 PM   #40
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I'm not saying the C rating doesn't matter at all, but I think in addition to telling us the truth about C numbers(which it appears your company does), it would be useful information. Mostly because this is something racers are used to seeing and can relate to.

I would imagine that the punch from a higher C capable pack would be much better. At the same time, if I am hunting for a pack and brand X has an avg discharge voltage of say 7.21 vs SMC avg discharge voltage of 7.30, I would look at buying the SMC. For those in spec motor classes, ie stock and super stock, the higher avg voltage seems to be what most people want.

I am not a battery guy, and certainly don't work in the industry, just stating things how I see them. Maybe the true C rating is how we need to be looking at Lipo's, if so, then again, thanks for the information.

We do cycle our 28C packs and print the info on the packaging the problem is that were the only one doing it. We can easily change the numbers by hooking up the voltage sensing leads at different places. The pack temperature also has an impact on numbers and then there is the way the pack was charged discharged that impacts the number. This means it would be hard to compare numbers.

I'm not sure how long you have been racing but back in the day you could match cells with a Turbomatcher or a Lavco system and they would both provide numbers but they couldn't be compared. Even if companies would use the same matching equipment the way it was programmed could change the numbers. An example of this is when we would match 4200s lets say the highest cell was a 440 with 1.23 voltage there was one of our competitors who would sell the same 4200 cells but all there cells were 470-490 with 1.25 voltage. So comparing numbers isn't always useful.
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Old 11-19-2008, 05:00 PM   #41
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Originally Posted by Danny/SMC View Post
FFR1: Yes our packs come from China. What I'm getting at is that it's very easy to get Lipos from various suppliers from China so this leads to many different types of Lipo packs for RC cars. Like I said my goal is to open peoples eyes and yes it also gives SMC good publicity but trust me we have no problems selling our packs so it's not only about publicity.


Whether it's the manufacturer or reseller that claims a false C rate or capacity rating it's still false and the consumer is not getting what he paid for.
Danny,

I am not having a go at yourself or your company It is not my intention , I use SMC packs myself and find them very good I also use another brand of pack and find these to be as equal too yours, I also have used cheaper packs and have found these to be the same.

I do applaud you for being on here and being open and answering questions.

I just think there is toooooooo much hype and stupid thinking by racers in relation to " I need big because bigger is better"

In reality with on -road the loading required would barely reach 1/2 te c rating of cells.

What i would like to see is sensible "c" ratings and bring back the Burst current rating that used to be supplied to packs, In my opion the BURST Current is being used as the constant current in some case.

But then if the manufactures arent supplying the time factor for the burst rating i guess this would again lead to these type of discussion
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Old 11-19-2008, 05:02 PM   #42
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Are you saying then , That a falsified/ over inflated 'C" information?? is safe?? and is acceptable with ROAR approved packs

It doesn't really make sense for ROAR to worry about C rating or mAH hour as a manufacturer can submit packs with true C rate and mAH and then sell packs with lower C rate cells. Unless ROAR wants to start buying packs from every company from time to time to check as see what they are selling but that could get pricey.
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Old 11-19-2008, 05:02 PM   #43
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Are you saying then , That a falsified/ over inflated 'C" information?? is safe?? and is acceptable with ROAR approved packs
I'm saying it's not ROAR's job to regulate advertising (although they appear to want to go that way). They approve packs based on their ability to handle a drop, an overcharge, and an over discharge. None of these say anything about if one pack is faster than another or can handle more current than the other, just that the pack can be used safely and won't cause a safety hazard if a common user error occurs.
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Old 11-19-2008, 05:03 PM   #44
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SMC is the only battery company putting true GFX 35 amp numbers on there packs!

danny does this because his packs are the best...

think of it like buying a high end sports car

company A says they have 650 hp and run a 1/4 mile in 11.3 seconds for 75,000 you can buy company A car

company B comes along and says they have 700HP and can run a 1/4 mile in under 11 seconds for 50,000 dollars

you buy company B only to find out later that there numbers were over inflated and you cant beat a moped with a 400lb guy on the back of it!


every new lipo that gets released claims they are the best pack and they buy from dannys supplier blah blah blah 6000mah and 75 c.......yet when you take it home and put it on a gfx it is junk......


honestly if they all put a gfx number on all there packs it would go a long long way in policing this problem....

a "racer" is going to spend his money on the best pack....

when you have 10 different lipo packs in a case at a hobby shop and they range in prices and voltage and IR at the very least the consumer can choose to buy what lipo fits his needs or budget...this C rating and bogus claims just leave a bad taste in the "racers" mnouth when they do put it to the real test...

you guys can buy so called "super" lipo packs from all the other companies...i'm going to buy lipos from a matcher who puts his numbers where his mouth is! right now only SMC has put cycle numbers on his lipos...that should speak volumes

and let's not forget danny has been doing batteries for years and has always stood up for his product!

do you see the yeah racing matcher on here helping the customer? nope...

go ahead buy brand X and put it on a gfx....your not going to be happy if you "race".
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Old 11-19-2008, 05:08 PM   #45
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Danny,

I am not having a go at yourself or your company It is not my intention , I use SMC packs myself and find them very good I also use another brand of pack and find these to be as equal too yours, I also have used cheaper packs and have found these to be the same.

I do applaud you for being on here and being open and answering questions.

I just think there is toooooooo much hype and stupid thinking by racers in relation to " I need big because bigger is better"

In reality with on -road the loading required would barely reach 1/2 te c rating of cells.

What i would like to see is sensible "c" ratings and bring back the Burst current rating that used to be supplied to packs, In my opion the BURST Current is being used as the constant current in some case.

But then if the manufactures arent supplying the time factor for the burst rating i guess this would again lead to these type of discussion
Don't worry about it I have been on these boards for awhile and I don't take things to personal.

As a racer myself I know that in RC cars there are many packs that will run fine and in the hands of the best racer they can win. Our 24C pack is the perfect example it runs very well and is cheaper than our 28C packs.

We will never change the minds of the racers that they need the best or else they can't compete but then again if you have the money and you don't mind paying a bit more there is nothing wrong with buying the best you can afford.

We could put the burst C rate on our packs but that would lead to even more confusion. I'm pretty sure some must be using the burst C rate as the constant C rate but they should say so. Like I said this thread is just to help and yes it will also be good for us as we do put a true C rate on our packs but my main goal was to open peoples eyes.
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