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sikeston34m
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10.15.2010, 05:52 PM

The 150C rating is ludicrous considering current technology.

Let's just run some numbers. Simple Math.

We have a 150C 6500 mah Lithium Polymer cell.

At a 975 amp discharge rate, each cell is capable of 4095 watts of power.

If we discharge our fully charged cell at the 150C discharge rate, it will be fully drained in 24 seconds. (If anyone is interested in the formula for calculating any of this, I'll post them up.)

I am a Refrigeration/Maintenance Engineer for a Distribution Center here in Missouri.

It's very common for me to deal with Techs and Sales Reps from industrial battery companies such as IBP and Deka.

Batteries have always fascinated me, so I ask alot of questions and stick my head in the books.

Here is a comparison for you. The battery in question is a 36 volt 1000ah lead acid Industrial Truck battery weighing in at 2850 pounds.

Each main power lead is about as big around as a fat cigar. Cross sectional area comparable to a Nickle.

It takes a well co-ordinated forklift driver about 6 hours to drain one of these batteries. Obviously alot of energy.

The question that I posed to IBP and Deka Techs:

What is the maximum discharge rate limit before damage occurs?

Answer: Right around 750 amps. It is at this point, it blows the jumper bars off the cells.

Jumper Bars are the intercell connections. Each unit is made up of 18 - 2 volt cells connected in series. Total of 36 volts.

They use pairs of jumper bars to jump from one cells positive posts to the next neighboring set of negative posts.

EACH jumper bar is around 2" wide and 1/2" thick and about 6" long. They are made of lead.

I've witnessed several accidents where the main power leads were crush/pinched to the point where a dead short condition occured.

Never have I seen the jumper bars blow off, but a battery this size can discharge enough amps to snap 1/0 leads in a shower of sparks. I have seen this happen. It's quite scarey.

Now, back to the 150C rating. We are going to discharge a 6500mah Lipo Pack at 975 amps continuous?

How are we going to test that since the entire discharge process will only last 24 seconds?

These numbers are off the scale and highly impossible IMO.

Last edited by sikeston34m; 10.15.2010 at 05:55 PM.
   
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  (#32)
molak
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10.15.2010, 05:58 PM

Thirth party or nothing .. is well known that we cant trust MA ...

Just to give an example. A while back i bought 2 factory remanucatured packs from MA ebay user. I got a puffed pack and an unbalanced one...


975 amps over a 12awg... lol.

An awg 12 wire will explote into sparks with such a discharge...

Last edited by molak; 10.15.2010 at 06:06 PM.
   
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  (#33)
sikeston34m
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10.15.2010, 06:47 PM

Quote:
Originally Posted by molak View Post

975 amps over a 12awg... lol.

An awg 12 wire will explote into sparks with such a discharge...
That's kinda like saying:

"I'm gonna pull your truck outta the ditch with this piece of fishing line."

   
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What's_nitro?
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10.15.2010, 08:37 PM

I just figured I would add this as the OP...

I did not start this thread with the intent of taking shots at MA's new product. That being said, I still think the rating of 150C is quite ridiculous for ANY battery pack that small, not just this one from MA.

If we are talking about a <5ms spike rating then yes, the cells probably can do that. Any longer and the tabs would most likely melt off.

A [universal] method of rating the continuous AND peak discharge of a battery is the way to go. Rating a cell/pack for just one or the other does not provide enough information.


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mistercrash
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10.15.2010, 11:56 PM

I have to ask this question. How long has it been since anyone here has bought a brand new Maxamp lipo? Has anyone bought a Maxamp lipo very recently? I'm just thinking of Hyundai. They've come a long way since the Pony and Excel. Maybe Maxamp has changed. I doubt the 150C claims are true for now. Like it was said, if a lipo capable of that kind of discharge was available, the military and automotive industry would get hold of it way before the RC industry. Let's just wait quietly and see if everyone here has to eat their hat or if we're in for a good laugh.


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Electric Dave
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10.16.2010, 12:51 AM

I've got to say, numbers and charts are meaningless. For me, the only things that matter are performance, price and safety. I have used new MaxAmps batteries recently and been very pleased with the performance. I'm not crazy about the numbers they use to describe their packs performance...clearly sustained 150C is not even possible given the wires and connectors in use. I am however pleased with the performance I'm getting out of my new MA 5250 packs. They feel great from the first lap to the last and I know that if something does go wrong, I can always make use of the 3 year warranty.

I've run many different brands of battery in my buggy and truggy, honestly I don't feel much difference at all across all the brands when the packs were fully functional. I think the current state of LiPo technology is such that they almost all deliver enough performance for all our hobby needs. MaxAmps offers a broad spectrum of products, they make it easy for consumers to get the right fit for their vehicle and they backup their claims with a great warranty. Why all the negativity?
   
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thzero
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10.16.2010, 11:05 AM

Yes, would be nice to see every reputable battery manufacturer step up and document the individual cells in the pack, supply graphs for the pack as a whole, etc. and work together to come up with a standard testing package.
   
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thzero
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10.16.2010, 11:08 AM

Go for it. Better to be more transparent than the next guy. Formulas, unless wrong, are hard to argue with. Numbers and claims can always be manipulated.

Quote:
Originally Posted by sikeston34m View Post
If anyone is interested in the formula for calculating any of this, I'll post them up.
   
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Bondonutz
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10.16.2010, 11:26 AM

Quote:
Originally Posted by mistercrash View Post
I have to ask this question. How long has it been since anyone here has bought a brand new Maxamp lipo? Has anyone bought a Maxamp lipo very recently? I'm just thinking of Hyundai. They've come a long way since the Pony and Excel. Maybe Maxamp has changed. I doubt the 150C claims are true for now. Like it was said, if a lipo capable of that kind of discharge was available, the military and automotive industry would get hold of it way before the RC industry. Let's just wait quietly and see if everyone here has to eat their hat or if we're in for a good laugh.
I have 2 3s 5200 MA packs that are new(4mos old, have dated reciept), I aquired them via trade.
My Turnigy 30C 5000mah Packs perform better and charge/balance better
The MA packs are very warm and slightly puffy after run, the Turnigys in same RC are ambiant temp and normal after run.
NO B.S. !

My expectations are not high at all but I will not pass judgement till I see facts/graphs on these new 150C packs


I retired from RC, now life is all about guns and long range shooting.
   
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suicideneil
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10.16.2010, 05:06 PM

Quote:
Originally Posted by Electric Dave View Post
Why all the negativity?
Cost vs performance ratio
Attitude of Jason and Austin to queries or legitamate concerns

The CastleCreations reps are a shining beacon of how you should deal with your customer's concerns, complaints & queries; calling people haters and bullies and deleting their posts/ threads to hush them up never exactly gives a good impression of a business, albeit one run from a guy's garage.

Funny thing- I referenced a discharge graph ( re: 35c performing as ~20-27c ); that graph has been removed when I took a look-see over at the nitrokillers forum, funny that...

Quick check... yup, no flaming there, just facts and geniune points
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Semi Pro
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10.16.2010, 05:49 PM

Quote:
Originally Posted by mistercrash View Post
I have to ask this question. How long has it been since anyone here has bought a brand new Maxamp lipo? Has anyone bought a Maxamp lipo very recently? I'm just thinking of Hyundai. They've come a long way since the Pony and Excel. Maybe Maxamp has changed. I doubt the 150C claims are true for now. Like it was said, if a lipo capable of that kind of discharge was available, the military and automotive industry would get hold of it way before the RC industry. Let's just wait quietly and see if everyone here has to eat their hat or if we're in for a good laugh.
i have and i am not happy with it, max amps does not stand behind there warrenty on the 5250 packs, i would love to test out the new packs on my high kv topspeeder but im sure that would void the warrenty on the new packs too


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......maybe they want to be more like novak
Quote:
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I'm telling Patrick you said that!
   
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  (#42)
Bondonutz
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10.16.2010, 06:37 PM

Quote:
Originally Posted by brandonwilcox View Post
I should go update my post. Yes, I was an editor for RC Car Action magazine for almost two years. I am now the Marketing Director for http://www.maxamps.com
You my friend have stepped into the Lions den and your wearing RoastBeef Cologne.
Good luck with your new endeavor


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reno911
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10.16.2010, 08:09 PM

I don't understand how more people don't question this.

If say a car manufacturer came out with a car that had 1000 horsepower on a 4 cylinder naturally aspirated motor. There would be a shit storm. People would be demanding a dyno graph.

How is this any different?

Heres something for Maxamps. Give me proof and I promise to buy a 2s pack!
   
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What's_nitro?
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10.16.2010, 11:20 PM

Brandon has said he would get some graphs up when they were available. I would hope that would be sooner, rather than later, otherwise they may lose quite a few sales. If these batteries really do hold their voltage that well I'll be buying some, too.


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Industry standard
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_paralyzed_
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Industry standard - 10.16.2010, 11:34 PM

Instead of ripping on MA (which is quite easy to do) We as consumers need to DEMAND an INDUSTRY STANDARD for lipo testing, similar to wattage ratings on home stereos. (x watts at x ohms at x thd)

So much time and energy is wasted on bickering and mud throwing, why not use that time and energy to solve the problem?


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