ROAR Maxamps 4200 pack? - RC-Monster Forums

05:13 PM

Anyone hear about these yet? Supposedly rated at 35C!

I just found a discharge graph at 3C, and it seems a bit bogus...

Tell me what you guys think. I keep reading that a lot of people on here, and some on other forums, believe the maxamps packs are utterly overrated. I'm inclined to agree with them after seeing this graph.

http://www.nitrokillers.com/attachme...8&d=1217350427

So am I, too, right in thinking that these cells are overrated?

BrianG · 07.29.2008, 05:20 PM

Are you sure? I think it's like their 5Ah graph where you multiply the A reading by 10...

07.29.2008, 05:46 PM

Just found out it's through a CBA amplifier, so the load is 126 amps.

Even still, wouldn't voltage drop substantially under such a high, continuous load?

MetalMan · 07.30.2008, 01:24 AM

I find that graph bogus, as well. First off, if I read correctly elsewhere, Deans connectors were used, but they wouldn't handle that kind of load. W.S. Deans themselves rate them at 60amps, I think.

Second, the average voltage looks like 3.7v/cell... There's no way Maxamps could be the ONLY company selling cells that are so "seemingly" capable of 30C.

As usual this is my opinion.

02:32 AM

They're 35C capable cells supposedly. Not even flightpower has 35C cells out yet (at least I haven't found any enerland based 35C packs yet!).

He said the pack only ran about 106 degrees too over at RCZ (I was the one to ask for graphs... and also asked for an eagletree which hopefully he'll get around to).

Glad to see I'm not going crazy thinking these are bogus claims...

I also made a little comment about the copper/aluminum (not sure which these cells have) terminals the cells have handling 126 amps... I don't think a battery bar for NiMH even handles that kind of load continuously, and those are considerably thicker (albeit not 126 amps continuous type thick...).

Methinks a rating standard/system needs to be implemented by ROAR, complete with cell information (almost like when companies match NiMH cells, they put a sticker on the cell with voltage and stuff; internal resistance would be nice too, so we can compare packs based on resistance and get a more accurate idea of C ratings)...

Dagger Thrasher · 07.30.2008, 07:04 AM

Agreed. That graph just seems too good to be true, especially with the quality of MaxAmps' other cells. None of the high-end brands yet have cells rated at 35C like you say, MetalMan, so I'd love to know where MaxAmps have magic'd these up from. Perhaps they are true 35C cells if that graph is completely accurate, but it's gotta be unlikely.

hoober · 07.30.2008, 09:29 AM

Ask where the voltage for the graph was picked up , and why the graph is not flat (steady) is typical of a very very slow discharge graph OR one that is not even close to the rating of the cell.

In otherwords what I'm saying is that according to the graph and temp the battery should be able to be pulled on a lot harder (maybe twice as hard).

The test should take less than 2 minutes.

hoober · 07.31.2008, 06:36 AM

Quote:

Originally Posted by hoober

Ask where the voltage for the graph was picked up , and why the graph is not flat (steady) is typical of a very very slow discharge graph OR one that is not even close to the rating of the cell.

In otherwords what I'm saying is that according to the graph and temp the battery should be able to be pulled on a lot harder (maybe twice as hard).

The test should take less than 2 minutes.

The graph is laughable and can't be close to a 30C or 2 minute discharge.

lutach · 07.30.2008, 11:59 AM

Wow, what is MA doing? I would rather play it safe than sorry. This will turn out to be a marketing scam and how will they explain when people are blowing their vehicles up. They need to be careful with claims like that. The highest I've seen so far is 33C and the manufacturer of the cells even told me it's really not mature yet and they just recommended the 30 and 25C cells. Even if I had legit 30C cells, I would just go 25C max just to avoid the ones with less common sense who will over gear there system just to utilize the 30 or in this case 35C rating of the cell. I hope MA know what they are doing, but it looks like they haven't learned anything from the current cell they are offering.

Arct1k · 07.30.2008, 02:36 PM

This for me is much more interesting....
http://www.hobbycity.com/hobbycity/s...cing_Lipo_Pack

othello · 07.30.2008, 06:56 PM

>None of the high-end brands yet have cells rated at 35C

Actually Kokam will start a new line up of 35C cells - they are already listed at webshops in Europe (not in stock yet). Kokam further developped their 30C cells and labelled them as 35C cells. Looking at first graphs shows that they are not quite that capable.

Kokam 3600 (35C cell)

hoober · 07.31.2008, 06:52 AM

Apparently the test really wasn't a 126 amp test. The replacement graph is now flatter, less capacity , more temp increase and has a current of 60 amps (which I can buy)

It looks like about 15 or 20C will max out the temp and give a flat graph. I would like to pull either 30-35C on a pack and see what happens.

07.31.2008, 07:30 AM

I gotta ask, why so much hate on maxamps? I have one of their packs and it seems to be a terrific performing pack. Everyone always seems to dog on them, unless I have an exceptionally good pack from them. I don't have any graphs or anything like that but in a 5.15 lb rustler with a mamba max 6900 geared extremely high (28/83) it provides every bit of torque it needs to flip the car backwards at any speed, be it take off, mid, or top end with a pull of the trigger. Or maybe my system doesn't draw as many amps as I thought, I don't know. Its a 20c 2s2p 6000hv pack, the only other pack I can compare it to is a 10c 8000 true rc pack, but that isn't a fair comparison. I've had it since February and its as good as ever, I did do a full charge on it the other day and it took 6655 mah. Not to sound like a maxamps thumper, but I've no regrets buying the battery and it satisfies my needs. Are there that many failures out there?

Just go Play · 07.31.2008, 11:02 AM

Quote:

Originally Posted by 1maxdude

I gotta ask, why so much hate on maxamps?

LOL why is it that anything less then being in love with MA is considered hate?

But since you asked... I personally feel the practice of over rating a product that is widely considered to have a high degree of inherent danger even when used as designed to be highly irresponsible of such a large US company that sells their products to a target market group consisting largely of children.

Theres any number of other reasons but w/e

lincpimp · 08.02.2008, 01:42 AM

Quote:

Originally Posted by 1maxdude

I gotta ask, why so much hate on maxamps? I have one of their packs and it seems to be a terrific performing pack. Everyone always seems to dog on them, unless I have an exceptionally good pack from them. I don't have any graphs or anything like that but in a 5.15 lb rustler with a mamba max 6900 geared extremely high (28/83) it provides every bit of torque it needs to flip the car backwards at any speed, be it take off, mid, or top end with a pull of the trigger. Or maybe my system doesn't draw as many amps as I thought, I don't know. Its a 20c 2s2p 6000hv pack, the only other pack I can compare it to is a 10c 8000 true rc pack, but that isn't a fair comparison. I've had it since February and its as good as ever, I did do a full charge on it the other day and it took 6655 mah. Not to sound like a maxamps thumper, but I've no regrets buying the battery and it satisfies my needs. Are there that many failures out there?

I have sent back 90% of the maxamps pack that I bought. That is 9 out of 10. I would have sent the other back, but missed the 30 day window. I had at least one cell puff in each pack, and actually received a pack that had a puffed cell in it. Maxamps packs are fine in a 10th 2wd vehicle. 2wd just can't pull the load, or sustain it like 4wd can. Your 6k pack is 20c rated. I would love to see it produce 120amps... Therein lies the problem, false advertising...

Quote:

Originally Posted by hoober

From what I've read , the problem seems to be with the truth in advertising or marketing. I like all my Maxamps packs. I got a good deal on them , and the ratings are about half of what they are sold as.

If one uses a 20C pack at 10C or less (like 90% of users will) then niether maxamps or user will detect that anything is wrong. I don't expect to get anything close to the rating out of my maxamps packs , so I simply compare said pack to competitors packs at whatever ratings/cost they actually are and make my choice to buy.

The trouble starts showing up when a user thinks it is ok to pull the amount of current that the pack is said to withstand. The pack will overheat, puff up and not last a few cycles , even become a danger to have around.

Best to compare weight and size. That seems to be the best bet in comparing lipo ability. I was suprised when I got my first neu lipo. 3s 5000mah 25c battery was almost twice as big as a maxamps 5k 3s. After running it I can safely say that the maxamps was no where near the quality of the neu, and damn close in price. Maxamps has to pay for all of that advertising somehow... And the NitroPuffers forum...

Quote:

Originally Posted by Just go Play

LOL why is it that anything less then being in love with MA is considered hate?

But since you asked... I personally feel the practice of over rating a product that is widely considered to have a high degree of inherent danger even when used as designed to be highly irresponsible of such a large US company that sells their products to a target market group consisting largely of children.

Theres any number of other reasons but w/e

The only reason that people say that there is maxamps hating here is becasue they just do not understand the difference. Going from nimh to a maxamps lipo is a huge step, and I think that many wonder how much better can a different lipo be. I have personally tested and owned at least a dozen different brand lipos, and know the difference. Most people do not have 5k to drop on battery testing. I have found that repeatedly that enerland cells perform, and last. I even went as far to buy the oldest 5s 3700 polyrc pack that I could find. It was maintained correctly by the previos owner, but had over 100 cycles on it. I have had it for about 8 months now, and it is still good, capcity and output are right on spec. I just cannot say the same for maxamps.