I'd posted this up a while back but hadn't mentioned which batteries... These were 6500mah 150C's

And everyone please keep it civil...

http://i168.photobucket.com/albums/u...k/1c0eed2a.jpg

So is that 5000 watts @ 27.6V. So .5 Voltage drop per cell under that that peak amperage. Any chance of you pulling a brick to keep the ampdraw high?

What size is that lipo pack that was tested- kinda difficult to tell / determine the voltage drop per cell & generate some actual c ratings without knowing it; 32.3v starting voltage is odd...

Imma pretend that its an 8s lipo pack ( seems if 32.3 / 4.2 = 7.6s, and its several minutes into the run, so... ) for the purposes of this post:

8s lipo = 33.6v

minimum voltage recorded is 27.6v, so thats 3.45v per cell ( minimum voltage, under maximum load )

The highest current ( load ) recorded is 178.1 amps

So, 178.1amps / 6.5amps ( 6500mah lipo ) = 27.4C @ 3.45v per cell

Thats pretty shockingly bad considering these are rated for 75C @ ...3.2v per cell say? ( since MA dont specify the cell voltage held under the 75c load ).

Well, there you go, more false claims by MA, what a suprize. :smile:

Chris, it's hard to see the numbers on the graph so could you post several current/voltage points at various points (preferably not at the very beginning or end)?

Ideally, it would be nice to have the voltage/current immediately before a current spike, and then the voltage/current during a spike.

I'd like to calculate pack internal resistance at various current levels. This will give up an inkling of what to expect at various loads. If we see IR increase dramatically at X amps, it means the pack is getting close to its max discharge value so we can then use that as the "true" C rate.

Could you also confirm cell count and wire gauge and length from battery to ESC. Normal 12GA wire can introduce substantial voltage drop at 178A and would be nice to take that into consideration.

Neil, you math looks good, but the max load will probably happen when the cells are freshest and are able to deliver that, while min voltage will happen towards the end of the discharge cycle where the pack is weakest. This is why we need a number of current/voltage samples across the cycle to get a better data sample.

If you look at the time series this is about 10 mins into play time hence battery voltage down... However this is where the largest amp spikes were - I zoomed and increased the upload resolution.

In real world terms these packs do seem to work well with the MMM-XL in this application.

http://i168.photobucket.com/albums/u...k/e44d0152.jpg

And the first large spike of the run...

http://i168.photobucket.com/albums/u...k/32dc4f4b.jpg

Ehh dropping to less than nominal voltage

Going by the max wattage (assuming that max amp draw coensides with the lowest voltage)

3958/30.0= ~132amps.

30/8= 3.51v per cell if I have you setup correct


What are these cells rated for?

kids today 30/8 = 3.75V @ 135 amps

they are 6500mah packs which probably means 6000mah usable i.e. 135/6000 = 22.5C spike

my mistake I was going by the 28.2v Min voltage. was looking at the wrong graph and did my wattage calculations off that one.

Those cells don't seem too bad. It's still hard to get exact V/A testpoints, but I calculate pack resistance somewhere between 1.4mOhms-3mOhms.

We can't forget that's pack resistance, and includes the wires and connectors. I don't know why they'd use 12AWG on cells with 150C claims, but 200mm of 12AWG wire will introduce around 1mOhm of resistance by itself.

That brings pack resistance to between 0.4mOhms and 2mOhms. Not bad at all for an 8 cell pack IMO.

Although, I still don't think these are truly "150C" rated. Given the price, I know I still won't be buying them anytime soon.

Yes our 150C packs can handle the load. We have tested them at a higher amp draw then that.

Brandon

Can we see?:whip:

Well. Well.

Where've you been Brandon?

It's kinda funny that you "show up" when some "proof in the pudding" is on the table.

IMO, it's too bad that it wasn't you, that offered real world graphs up, like you said you would do.

You might have won some respect here.

Thank You MaxAmps.
 

Awesome, Thank You Brandon.
I truly appreciate your continuing to post onto this thread. I know the forum owner has asked a few times for members to keep their post civil. And I certainly respect Monster Mikes Forum :)

PS. I'm looking forward to your data, test & graphs and videos. Any information on these race lipos will be extremely valuable and interesting to see and learn about. Thank you for being so open about doing this for us. I've never heard of Thunder Power doing any test for us racers, and those are also quite expensive lipos, and I personally would like to give other lipos a try- such as these 6500mah. The way I see it, if your Lipos can compete with the Thunder Power LiPo(Thunder Power Does not yet offer a 75c continuous Battery) I would rather go with the MaxAmps LiPo because I get a warranty. Whereas Thunder Powers warranty is not as flexible. For example- With a Thunder Power LiPo- for the first two years of ownership- we qualify for a 50% crash replacement. Which means we pay 1/2the new cost of the same battery. That is primarily for crash damaged batteries but Thunder Power can decide if they wish to allow a customer to have access to this crash replacement discount if it is determined by Thunder Power that the lipos were overdischarged or otherwise damaged by the owner of the lipos.

MaxAmps warranty- I've not read it in awhile but now comes standard with all lipos. It's a 3year 300cycle warranty and I believe within the first year it is a free replacement, and then a percentage added for use for the remaining two years depending upon how long the battery has been owned/used. MaxAmps has also lowered their prices allot- and removed there reduced price program which only gave the big spenders huge discounts. Now those discounts are applied to all the batteries. And I really like that move- great job MaxAmps- Well Done :)

Note: I recently purchased a 2500mah 2cell LiPo for my M11x and I asked Jason if he could make me one because at the time- they only offered the 3cell variety for the M11, whereas the newer model M11x takes a 2cell LiPo. Jason said no problem- he made the lipo and even add an additional wire for 5c quick charging- because MaxAmps uses the 5c quick charge cells for Transmitters as well. This means ten minute 12.5amp balanced charge times- and the LiPo only went up apx ten degrees from ambient/room temperature.

If these 6500mah MaxAmp LiPo's are competitive with the equivalent Thunder Power LiPo- the way I see it- the cool looking design on the MaxAmps batteries is just a plus. Most batteries have very little- if any design. And though the design on a battery has nothing to do with performance- I think MaxAmps is doing everything they can do- to satisfy the customer. And now that I think about it- I've never met anyone in person that has run or is running MaxAmps- that has anything bad to say about the batteries. And this is one of the reasons I highly recommend these batteries to my friends and family. Not one of us has ever had a problem that we feel MaxAmps didn't go out of their way to help us with. Even if it meant returning the battery within 30days for a full refund. That's MaxAmps. I don't know of any other battery supplier that offers anything near this kind of satisfaction guarantee.

I can also understand that paying allot of money for batteries is not possible for everyone. And for those of you that wish to pay very little for a LiPo- there is Hobby King with their Turnigy Line Of LiPo's- and many people run those and are very happy as well. Even though sometimes you will get a bad battery. The price is so low, it's still less to buy another one. I will also be giving the Turnigy cells a test this new race year as well. And I'll do a full review of the Turnigy cells vs the MaxAmp cells vs the Thunder Power cells. Thank You For Reading.

They arent 150C packs though, only 75C / 150C burst...

Still, holding nominal voltage at a mere 22C load isnt exactly great is it, I'd love to see what the voltage dips to with closer to a 40c load- I'd make these solid 30-35C packs at best, meaning they are overrated by about 120% :lol: ; nice marketing work but you cant fool us Maxamps!

numbers do not lie
 

THE NUMBERS DO NOT LIE. Look none of us are asking for a graph that shows fair performance. What we are asking for is proof that shows that these cells hold up to the advertised claims of TRUE 150C rated race packs. From our understanding that means 150C continuous load capability all while holding nominal voltage. If this is not possible, then I would think that the reasonable and responsible thing to do is correct the advertising to match the actual ability of these packs. Otherwise it still shows that Maxamps is falsely advertising its batteries.

It was nice to have one of your biggest race supporters drop in to post a nice retort in support of your batteries and your company in general, but it still does not show that your TRUE 150C claims are in fact accurate. We can sit here all day long and write posts for or against Maxamps, but that will not prove or disprove your claim. We as your consumers want to see proof of your advertised claims for a battery that holds up a "true 150C" continuous load. Until you are willing to do just that all of this is a waste of our time and yours. So please stop with the song and dance and provide what you promised to do in the first place. This is not a bash on your company or anyone elses. We could care less about your reputation one way or another, but what we would like is for you to be honest and do whats right.

150C is burst not continuous.

Then say that.
 

Can you provide the advertising that states that it is a burst rating? If that is the case, then there is the problem we are having with the advertising (TRUE 150C) race ready LiPos???? That does not read/sound like a burst rating. Plus from all of the conversation up to now there was nothing stated by Brandon that it was only a Burst rating either. This is what we are trying to get straight from the horses mouth. I do not think anyone cares to dispute with anyone else here. We just want some straight talk from Maxamps. Chris I appreciate you trying to support them, but we just want to hear the facts. specs on these batteries plain and simple. If 75C is the continuous rating, then how long will it hold voltage at 75C? And if that is the continuous rating then these packs are in fact TRUE 75C packs that will take 1 second busts up to 150C, not ture 150C. Are we all just not getting this, or is there something wrong with this whole marketing stradigy? I mean I am not a battery specialist or a rocket scientist, but why does this seem pretty simple to fix from our perspective but not from their end?

Maxamps: clear this up and post up the specs on these batteries. Please explain what you mean by "TRUE 150C race ready".

MaxAmps Continuous And Burst Amp Ratings.
 

This is an exact copy of one of Brandons post on this thread. Brandon said he will back this up with video and pictures of the test being performed. I'm looking forward to those results.

Who was that? Did I miss something?

Wow, retailers must get away with a lot in the USA.

Retailers have been stung for far less than this under misleading and deceptive conduct in Australia. The general consensus is that a stated C rating is that of the continuous load, so a 65C pack can do 65C Continuous. If you advertise a pack as 150C and you know (or ought to have known) the public would take this as a continuous rating, and it's not, then it's a deliberate misstatement.

I mean a V8 F150 can get 1l/100km if I roll it down a hill and cut the engine....

The new MA V8 Can get True 100 miles to the gallon
if I roll it down a hill and cut the engine....

Hands up who wants to start a class action against maxamps? :diablo: :rules: :whistle:

FYI from the maxamps site

The use of Lithium Polymer batteries in radio-controlled models is to be considered experimental, and there is no warranty, expressed or implied, by the manufacturer, distributors, or retailers with respect to the capacity, life in cycles, storage, or discharge characteristics of lithium cells in RC use, nor any other use nor aspect unless otherwise stated.

Yet they give you a 3 year 300 cycle warranty on their lipos! Which they will fight you about telling you that your setup draws to much current. I want to see them argue that with these 75C batteries!

Exactly. The warranty issue is why I only owned one maxamps pack I mean brick. It's all bull just like their advertising. Lawsuits abound in the future. Companies have been sued for less....

It's real easy. Don't like it? Don't believe the claims? Don't buy.

Missing the point
 

I believe some people here are missing the point of this thread. "TRUE 150C" race ready LiPo packs in the eyes of most R/C hobbiests reads to be a battery pack that can hold 150C continuous. If these packs can only do 75C continuous then advertise them that way. Stop using advertising tactics that try to fool everyone into thinking that their batteries are more than they really are. Great some people are impressed that they now have a pack that can do 75C continuous, and 150C one second bursts. Then advertise them that way. We are trying to watch out for everyone in this hobby, not just our own wallets. If this were a Chinese company you guys would be having a fit and contacting the Department of State over the matter. Claiming a TRUE 150C status on a LiPo pack is shady at best when we all know very well that it will not hold up to that claim. Personally I was glad to hear that they are now offering the 3 year warranty on all of their packs. That was a good move. Whether or not they honor that will have to be seen.

Really? Who appointed you, us, whatever as guardians of the industry? If you were really that interested in "guardianship" you'd be doing more to test and verify the claims of ALL battery manufacturers/distributors, including the Chinese, Taiwanese, etc. ones too, and not just harping on one.

Frankly most of the LiPo battery manufacturer/distributor, etc. out there don't do anything to back up their claims with solid information and technical specifications that can be verified. It's a free-for-all.

Yes except
 

Yes except you forgot one thing. Most of the LiPos being used out there today have been tested over time and all of them have some level of reputation to back them up whether it is performance, durability, specs, of bad claims processing. This one in particular has not done so well over the last two or three years in the eyes of most of the people in here because of puffed cells, none respect where warrenty issues are concerned, and the highest prices in the business. That is what started this discussion in the first place. I am not asking to be appointed for or by anyone for anything. Like everyone else in here I am merely posting my opinions, experience, and concerns about this issue, because people want to know if Brandon is going to breath new life into this company or just keep following the same previous reputation. No need to boil over here. This is a fair and open discussion requesting real world specs on these LiPos. Don't lose respect just because you may not agree with my posts. This is what forums are for.

I'm with Jerry! First I don't think these will do even 75C continous but if thats what they are claiming then that's the way they should be advertised. Not as True 150C

Meee too! Finally we make some progress in the MA thread. Juice is good. :party: Any thoughts on milk?

Smoothies
 

Well I prefer strawberry smoothies with real ice cream. Adding tequilla is always a nice treat too.

I don't see anything on the website that explains anything of the rating. All they say is True 150C.

It doesn't qualify it as 1 sec, 10 sec, or until they catch fire.

I think any reasonable person would interpret this as continous, or at least longer than 1 sec.

They may well all be god's gift to lipos, but claiming they can do 975 amps without any qualifiers seems rather rediculous.

Otherwise I have no opinion on these and never plan on buying them.

Haha wow, when they started talking about Juices I thought in my head "what about milk?"
Milk is good, very good. But I gotta get me one of them chocolate cows...

Borden Milk is Best.

Never heard of Borden milk :oh:
I usually get whatever organic Milk that has the best expiration date on it at the store, never seen Borden Milk though, maybe they don't sell it here.