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Old 10-16-2007, 11:30 PM   #526
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It seems we in R/C lack a standard method of testing these cells to determine how they'll work in our environment. I know for certain other market segments do massive amounts of battery testing to determine which is the best for for given application. Surely we can learn from them, and develop our own method for judging cells that not only gives us the best indication of how they'll perform on the track, but how they compare to one another.
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Old 10-16-2007, 11:38 PM   #527
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SMC set the standard for nimh years ago and is followed by most matchers across the world. Lipos are still new to a lot of companies and these standards will be ironed out. It's like anything else out there and just takes a little time.
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Old 10-16-2007, 11:51 PM   #528
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There is a standard to measure C rate and test safety for Lipos and the good manufacturers will use this standard. We sent some packs for testing to our manufacturer and we were surprised at some of the results as some companies list there packs at a certain C rate but when tested they were 5 to 10 C lower.

A company can claim a certain C rate just like they can claim a certain mAH but they know that very few people/companies can test the C rate of a high capacity cell. To test the C rate of a 4800 or 5000 pack you need a constant amp load of 96 to 110 amps which requires a special and expensive equipment that is not common.

SMC guarantees the C rate and mAH of the packs we offer based on the standard tests. If you look at the result I posted earlier about our packs cycle info at 35 amps you will see that our pack is above 5000mAH.
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Old 10-16-2007, 11:52 PM   #529
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Quote:
Originally Posted by Danny/SMC View Post
4. For the cycle life, in Kokam's data, its cell will remain 80% of its capacity after 60 cycle times. However, Kokam discharge the cell at only 8C. Our standard is to remain 80% of the cell's capacity after 50 cycle times but with 22C discharge rate. Thus, with only 8C discharge rate, our cell can do over 60 cycle times with 80% capacity remaining.

If our packs can hold 80% of it's capacity after 50 cycles at it's rated C rate which means they would easily do more cycles at a lower C rate like Kokam uses to establish it's test result after 60 cycles then I think we can assume our packs will hold up as well as theres if they hold up under the C rate test.
From the instruction sheet that comes with the Orions:

Quote:
For the experts: Kokam recommends limiting the discharge of the battery to 80% DoD (Depth of Discharge). Under these conditions,
the cycle life of the battery is greater than 1000 cycles.
and...
Quote:
• How long will Li-Po batteries last compared to Ni-MH? A few months? Years?
Under normal conditions, Kokam specifies a cycle life of over 1,000 cycles at DoD 80%. However, as noted above, this heavily depends
on how the battery is treated. After over a year of testing Li-Po batteries have shown to provide on average 30%+ more runtime then
Ni-MH batteries of the same capacity.
I know that they don't specify all the parameters, but there's a BIG difference between 50 and 1000 cycles.

I know I charged mine at least 300 (3 times a week minimum for two years) and it held the same capacity and ran substantially the same. They've never dumped on me and the damaged one pulled off two back-to-back 10 minute mains (1 mod, 1 stock) a couple weeks before it finally croaked.

Sounds like it might not be the "best" cell for me...50 cycles for $125 isn't as bad as NiMh, but it's not that much better.
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Old 10-17-2007, 12:09 AM   #530
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If you read the information supplied by Kokam and what our manufacturer tested on our packs then you will see that they seem to have similar results so I would expect ours to hold up as well.

I like the way they state under normal conditions.

If you were to only discharge or pack down to 80% it will have a longer cycle life as well.

I really don't know what you want me to say but I will not make a claim that our pack will last 10 000 cycles when used properly but I'm very confident that our pack will give great performance for many cycles.

Do you have the original discharge capacity of your pack versus what it's at after 300 + cycles ? If so what is the discharge amperage used to do your tests ?
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Old 10-17-2007, 12:17 AM   #531
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Originally Posted by Danny/SMC View Post
Do you have the original discharge capacity of your pack versus what it's at after 300 + cycles ? If so what is the discharge amperage used to do your tests ?
It's a Lipo...I don't discharge it.

Like I said, I damaged it a year ago and it still did 20+ (close to 25) minutes (10 stock, the rest mod) even after it was puffed up. I still have it here if you want it.
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Old 10-17-2007, 12:20 AM   #532
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Your the one claiming that it has the same capacity after 300 cycles then it did when it was new. I'm just asking you for your test results and how you tested this to make your claim ?
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Old 10-17-2007, 12:38 AM   #533
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Well...if it still has the same runtime...maybe I'm going out on a limb here....then I'm guessing that it still has the same capacity...no? 20 minutes of RACING, followed by another 5 minutes of bashing around and jumping before it dumped...on a damaged (a year ago) pack.

In the last few months, I had dumped it down low enough a few times that it took over 4000 (4200-4300 or so...). Again...it's a Lipo, so I don't do all that discharging stuff.

I'm not pitching anything, I'm just relating my experiences. It's obvious you think your stuff is the "best", I'm just trying to figure out why, because you don't seem to want to tell us.
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Old 10-17-2007, 04:39 AM   #534
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Danny have you done any testing as far as large groups of Batteries and checked on how close each of your batteries are in performance?
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Old 10-17-2007, 05:09 AM   #535
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Quote:
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Well...if it still has the same runtime...maybe I'm going out on a limb here....then I'm guessing that it still has the same capacity...no? 20 minutes of RACING, followed by another 5 minutes of bashing around and jumping before it dumped...on a damaged (a year ago) pack.

In the last few months, I had dumped it down low enough a few times that it took over 4000 (4200-4300 or so...). Again...it's a Lipo, so I don't do all that discharging stuff.

I'm not pitching anything, I'm just relating my experiences. It's obvious you think your stuff is the "best", I'm just trying to figure out why, because you don't seem to want to tell us.
I think he already proved it. Did you see the GFX results? He proved it has better performance. That hardly qualifies as "you don't seem to want to tell us". I think you don't want to believe what he is telling us. Instead of constantly arguing, just be content to run the Orion pack. It really is a simple solution. I don't know why you feel compelled to constantly disagree.
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Old 10-17-2007, 06:26 AM   #536
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Danny have you done any testing as far as large groups of Batteries and checked on how close each of your batteries are in performance?
We checked 6 random packs and they were all virtually identical in performance.
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Old 10-17-2007, 07:15 AM   #537
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For you guys worried about not having a hard-case for your lipo, why not simply take a thin sheet plastic/lexan/aluminum and double-tape stick it to the top and/or bottom. I know its backyard engineering, but something is better than nothing. It would add an extra layer of protection from bending, denting, or puncture.

It's not like that case on the Orion/Peak hard-case LiPo's will stop a fire or explosion. They are simply a clam-shell container using double sided tape on the top and bottom of the battery.
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Old 10-17-2007, 07:18 AM   #538
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Putting a piece of lexan on the top and the bottom of the lipo pack to protect it:

What about the sides and the ends? Why should rc racers have to backyard engineer an obvious oversight? The case is not there to prevent fires, it is there to protect your $150 battery from scrapes and collisions.

I will look at the smc packs when they release a hard case version.
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Old 10-17-2007, 07:23 AM   #539
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The smc 5000mah lipo pack will out perform the orion 4800 pack. It is that simple. They put out better numbers on the GFX and they feel better in the car. I think you guys are splitting hairs on this.

When any new item comes out it is always a risk with the longevity of the item. But that is where I look at the company whose name is on the product. SMC has given me good stuff in the past, and I am willing to take the plunge on thier lipo becouse of it. I look at anything I buy the same way, whether it is a motherboard for a computer or an engine part for my real car. If you want the latest technology you sometimes have to take a leap of faith based on the companies track record. And with these batteries you are getting known performance (GFX tested) from a known good company. What more do you need.

Do you guys really give Novak or LRP this much resistance when they build a new speedo. Or do you guys just like to watch yourselves type?

Thanks for another great product Danny and Jack.

Also I am all for a hard pack I think the 3200 carbon lipo has the best case design, but the 4800 has alot of fitment issues in cars, some of these cars the SMC pack will fit like a glove, and some cars it is more difficult. But until car manufactures start taking lipo into consideration then that won't happen. And until we can all get along and work as a group to make the lipo racing the class to be in, then the car manufacturers will still design cars around sub c cells.
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Old 10-17-2007, 07:24 AM   #540
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Originally Posted by Jack Rimer View Post
I think he already proved it. Did you see the GFX results? He proved it has better performance. That hardly qualifies as "you don't seem to want to tell us". I think you don't want to believe what he is telling us. Instead of constantly arguing, just be content to run the Orion pack. It really is a simple solution. I don't know why you feel compelled to constantly disagree.
I'm not asking for a couple tenths of a volt for a few cycles, I'm asking about longevity amd cycle life. Danny says it's better than the Orion, because it's good for 50-60 cycles. That doesn't sound the same or better to me...

IIRC, Linger (the only Lipo expert on this thread...) has also said that Kokams can do a few hundred cycles with minimal degradation.
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