Maxamps and Neuenergy lipo testing
 

Ok, since I have converted to enerland cell based packs and noticed large difference between them and my maxamps paks I figured that some testing will be in order.

I have a neuenergy 5000mah 3s 25c lipo, and bdebde is sending me a maxamps 5000 3s lipo (thanks). Maxamps claims to have a 20c constant rating, and that has been the basis of alot of conjecture.

Heres a link to each battery:

http://www.rc-monster.com/proddetail...eu3s5000car25c

http://www.maxamps.com/Lipo-5000-111-Pack.htm

I know that this is an apples to oranges comparision since the neu pack has a higher rated C value. My main intention is to show voltage drop under load, and see how the pack's actual performance compares to their advertised ratings.

Test vehicle will be a crt.5 with a variety of different motors. Currently setup with a MM and a plett maxximum. It has the rcm ext chassis, stock susp, diffs and center spur. I am currently running a maxamps 4200 3s pack, but will move the equipment around to fit the longer lipos. I also have a few other vehicles that can use the packs. I may also test using them, but will first focus on the crt.5. Gearing will be listed for each test, as well as my subjective thought on the performance.

Test equipment will include a voltmenter, eagle tree datalogger, bushnell radar gun, IR non-contact thermometer, and the seat of my pants! Charging will be done on either a hyperieon 5i or a duratrax ICE. I may test the setups twice and use each charger to make sure that my charge times and mah used are correct/accurate.

I plan to test both packs with the plett, a novak hv 6.5 with the 5mm shaft, and a hacker c50 6l. Both the plett and novak have similar kv ratings, around 3100kv. The hacker has a kv of 4400 and will be used if the batteries prove strong enough for the other motors, or I just need more load than gearing can provide. I will gear all of the setups up as testing goes, in order to place more load on the equipment.

Testing site will be a mixture of street and grass. My main intention is to get a decent load on each pack and determine voltage drop. I will radar each setup to verify loaded kv and attempt to match each motor/gearing combo. The eagle tree will be used to record data during the run, and graphs will be posted. If time allows I may also run each pack to the lvc to validate the pack's capacity claims. I do set my lvc to 3.1v per cell, just to be on the safe side. Keep that in mind if I post any capacity results.

Any and all info, questions, suggestions, and other test results (and critisism) are more than welcome. It is my hope that this testing will help validate the mfg ratings and give potential buyers some addl info about their planned purchases. I will do my best to minimize the variables and provide an unbiased test of each pack. I will also be honest with my findings, so I would appreciate it if non fact-based comments be left out of this thread. Not to sound harsh, but I really do not care how great you think x brand lipo is unless you have tested everything else.

And I will TRY (note the prvious word) to get some videos together of the runs. This is dependent on my painter bringing me his camera.

I for one will be eager to see your results. I have been using the MaxAmps 5000 mAh packs in 3S and 4S for a while now and am curious to see the differences.

When the MMM comes out, I want to get a 5S pack for my XB8EC and would like to have some data to justify a purchase of the Neu packs over the MaxAmps.

No prob, I should have some tests done next week. I can safely say that ypu wil have better results with the neuenergy pack. I replaced my maxamps 5s 5000 20c pack with a polyec 5s 3700 25c pack and it gives better punch and the same runtimes. The poly rc and neu are made with enerland cells, which are viewed by most to be the best available. Even with this info I will still do these tests, just for some hard data!

Finally!!!! Now when I get in this argument over max amps not holding up to what there rated for, I know where the graphs are LOL!

Thanks linc!

looking forward to it, i have only been running maxamps 5k cells in 4s and 3s and want to go to a neu 4s 5k pack , keep us posted

Sounds like a good test! I've got a few 4s 5000 polyquest packs, so it'll be interesting to see how their enerland cells stack up against maxamps.

Looking on Neu's site I have thinking of getting either the 30C - 3300mAh cells (99A constant) or the 25C - 3900mAh cells (97.5A constant).

Mike had made a custom battery tray for me with the exact dimensions to fit the MaxAmps 5000mAh packs for my XB8EC - both of these cells would fit the tray perfectly.

I've found my average max current draw to be ~78A. So if the votlage drop of either pack was less than that of the MaxAmps packs would be a great advantage - the 5S packs with either cell is only aout 25grams heavier than the MaxAmps 4S packs.

For your setup the 25c 3900 5s pack looks good, it has enough cont rating and will have longer runtimes than the 3300 30c pack. Plus I read that the 30c cells were not as good as the 25c cells. Not sure if it was all of the 30c cells though...

I am sure that you will see that the Neu will hold voltage better than the maxamps pack.

Sounds good. Are the packs of similar age and type of use? It wouldn't be really fair comparing a newish pack against a worn out pack. I'm going for the enerland cells though of course.

Well, the neu pack has a handful of cycles on it. Not sure on the maxmaps pack, but lipos are supposed to be good for quite a few cycles before they start to lose potency. I guess that I could buy a new maxamps lipo for this test, but I do not think that I want to give them any more money.

Maybe if maxamps believe their packs are as good as they say (I have read a post with a maxamps guy saying their cells are superior to enerland cells) then they could give you a free pack to test, since it would be good advertising for them when you prove how good their packs are. But on the other hand...

Well it is nice to see that you are putting your free time to good use linc, and with the assistance of a few good butler monkies it should not take long at all. This matter could actually end up being a good subject to get published into one of the R/C magazines for circulation so everyone could read it. I would be willing to bet that the entire community would love to see/hear the results of such a test. Especially for consideration of any new purchases that are being considered at this point. With the pending release of the MMM and the Tekin Pro1MT I know I would like to make sure that I am buying the best packs available for my money. We appreciate the selfless sacrifice that you are about to embark upon in an effort to help us all. Thank you pimp and keep us posted Sir.

Yeah right... It would be nice... They have the meane to test their cells performance, but they chose to let the ad dept do the talking. If the maxamps guy was saying that their cells puffing ability was superior to enerland cells than he is right on!

Thanks Jerry, I had to let the monkey butlers go after an unfortunate accident involving feeces and my slippers. Never mind, I will ge tht ehouse sprayed for fleas and move on...

In all likelyhood I can image the critisism that this test will draw. I am biased, as we all knowe (sarcasm) so I am sure that the various lovers of maxamps will have something to say. I may make a duplicate thread on the nitrokillers forum, but that may be going to far. I wonder if the admin (jason) would delete it? Here I go again, stirring the pot!

Like for like compare will be difficult - best thing i would have thought is to use a drag race. Same car, setup and gearing - 4.2v off the charger on identical life, capacity, rating batteries.

Back to back 200 yeard drag race WOT - 250 yards - brake and check amp/volt graphs.

Then random non logged driving to 3.7v on both packs and repeat drag run...

Just an idea...

Thanks Jerry, I had to let the monkey butlers go after an unfortunate accident involving feeces and my slippers. Never mind, I will ge tht ehouse sprayed for fleas and move on...

In all likelyhood I can image the critisism that this test will draw. I am biased, as we all knowe (sarcasm) so I am sure that the various lovers of maxamps will have something to say. I may make a duplicate thread on the nitrokillers forum, but that may be going to far. I wonder if the admin (jason) would delete it? Here I go again, stirring the pot![/QUOTE]

OK heres the thing linc. Anytime you match up two competitors that are battling for their piece of the pie you are going to stir up some controversy no matter how fairly you run your testing:yes:. You are going to get some criticisum and arguements from one side or the other:rules:. Especially if one side comes out looking like S*$& with egg on their faces:whistle:. All you can do is try your best to remain impartial in your lab work so to speak:whistle:. Once your analisys is completed, no matter what the results I think you should post up on the nitrokillers and any other site who is involved with or uses these cells. The worst they can do is lock out the thread:gasp:, but it may just force whoever comes out looking bad to change something in the way they are making their products to compete for their place at the table:na:. Lets be real here. What you are about to do (testing) has the ability to cause some serious problems $$$$ for someone out there:diablo:. The truth will set thee free. This is surely going to be ineresting from the cheap seats:lol:.

Well, as far as comparing the two mfg packs, that is not really the point of my test. I am comparing the stuff inside the heatshrink, to the little sticker with the writing on it that is stuck to the heatshrink.

My main point is to esablish what kind of discharge these packs can hadle and still retain voltage. My seat of the pants testing seems to point to the enerland cells holding voltage better under load, but I would like some hard data to support this. I may continue testing past these two packs, but lack the variety of maxamps packs I once had.

I think that linc has more than enough experience for us to draw reliable conclusions based on his methods of testing. All I really need to see is an Eagletree plot showing how far the voltage dips on high current peaks. A few data points of that and it's quite easy to determine which pack holds voltage better under load.

And this is what you shall get. I hope that my test vehicle and methods will yeild enough load to properly test these packs. I can always gear for 80mph or something stupid like that. That should provide enough load...

This isn't the first time a Maxamps pack has seen a datalogger. I have posted several here before in a similar "test" session.

I don't even recall what the #'s were or what thread it's in, but I do recall that some were skeptical because the Maxamps packs did better than they were "supposed to", based on their very low opinion of them, lol. *cough*serum*cough* hee hee

My Kokam 20C 4800 posted better #'s than my Maxamps 5000, but it wasn't night-and-day between them.

I would expect a good 25-30C pack would also perform better than the maxamps pack.

Off topic: I do find it interesting that some here tend to say the TrueRC packs are ok but Maxamps are not. Of course, the TrueRC are a lot cheaper.... but certainly are not better packs. Perhaps you should pick up a TrueRC bargain pack to compare also. ;)

Do you remember what maxamps cells you tested? Their 4000 cells seem to be decent, still not 20c, while I did not think that the 5000 cells were very good, maybe 15c before the voltage dumps. My trakpower 4900 packs easily outperformed a pair of maxamps 5000 2s packs in series. And the ratings of both are almost identical (my trakpower packs are the older 20c rated ones). The differnece was very obvious to me, and I did not think it would be that obvious. I must have picked up 2-3mph top speed, and acceleration was much better.

I have a feeling that Truerc packs are consider good due to their price to performace. I may have to pick up a truerc pack for testing, any idea what to buy?

The True R/C guy said that he uses the same cells as MaxAmps when I talked to him a year ago or so. I think the difference is that he advertises them as 15C at a lower price compared to MA's 20C at a higher price for the same cells.

This is very interesting. I may have to pick up a 4000 3s pack to test, and maybe a 5000 3s pack if they sell that. I may have to give him a call and talk to him about his matching methods, or whether he buys the packs pre-assembled.

Linc, how do you determine what the true C rating of a pack is?

I have an Eagle Tree now and I'd like to test my MaxAmps packs to see how they do.

Do I just run them hard from full charge to LVC then do some kind of calculation from the data pulled?

get a 2P pack of the true-rc packs; Dans 4000 mAh cells are good. (for a very low price)

Well, from what I have read, run a full pack thru and post the graph. What I am looking for is what amp load pulls the cell voltage down below 3.5v. I figure that if the pack cannot handle its rated load with cells dropping below 3.5v it is not correctly rated.

What maxamps packs do you have? And what setup do you run these packs on.

I ran 5000, 6000, and 8000 Maxamps packs. The 5000 had the edge in general considering capacities and voltage drop. But the 3000/4000 based packs were not too bad.

I was running them in my 8ight I believe.... just brief tests to get some amp spikes.

The big thing is the temp of the packs. Cold packs put up crappy #'s. Nice warm packs like on hot summer day put up much better #'s.

I actually hesitated to recommend maxamps packs until I ran those tests and was pretty happy with the results, on top of the fact that they seem to run great in my cars and I've never had one get hot/puff on me. (except a pack that I shorted out.... my bad, and the reason why I don't have a 4s 5000 pack anymore)

(4) 2s 6000
(1) 2s 5000
(1) 3s 5000 - A cell appears to have died, so this will likely soon be a 2s 5000
(1) 2s 2100 - Axial AX-10/bl-RC18MT
(1) 2s 1550 - Vendetta ST(currently stock, bl on order)
(1) 3s 1550 - Axial AX-10/bl-RC18MT

The larger packs run in a few different vehicles:

-Stock 3905 E-maxx
-BL-Revo (MM/9XL)
-Kyosho Kanai 3 (MM/8XL)
-CRT.5 (MM/CC4600)
-RS4 (Sidewinder/CC5700)

I just confirmed with Dan of TrueRC that his cells are the same as MaxAmps.

I can help too if you you don't have any of the following batteries I have:

(2) 3s2p 4200
(2) 3s 5000 - 1 brand new
(2) 2s 5000
(1) 2s 4000
(1) 2s 1100

I can run any of the bigger packs through my CRT .5 / 7L 16/46 with an eagletree...

LMK

Certainly, any info that you guys can provide will be very useful. I only ask that you try to load the batteris as much as you can. At least to the cont rating for a few seconds to get a good measure of voltage drop.

Most factories rate continuous at around 3.3 to 3.4v/cell under load, FYI. The nicer, newer cells do better of course.

example http://www.allerc.com/hp-lvx-lithium.htm


Really you could rate it at X continuous discharge if it didn't hit LVC until the rated capacity had been spent, even if it was at 3.01v the entire time.

I have a feeling that this is the way certain companies rate their lipos. Problem is that if you do this on a continuous rating, what happen at the surge rating? I would say that it would dip below 3v per cell, kicking in the lvc. So I figure that the cont rating has to be measured higher than 3v per cell, to allow for the momentary surge rating to still be effective.

Some batteries don't even have a surge rating....


Good point though. The temp of the battery is also very important. I have some 25C lipos that won't put out 25C at 3.35v until I push em hard for a few minutes. Once they warm up the voltage actually bounces up a bit from 3.3 to 3.4v. It is with a prop load, not in cars but you get the idea.

I tested 5s2p a123 in my stock 3905 E-maxx. I used a method learned from tiran_rw on the Traxxas forums to manipulate the data like this:

-Sorted the Amps (ascending)
-Dropped the digits after the decimal (forced round down)
-All the voltage points that have the same current get averaged into one sample for that amperage point. (eg anytime 15.00 - 15.99 amps occurred, add all the voltages together, and divided by how many occurrences)

This is what I came up with.

10C - 46A - 14.42V - 0.82V / cell drop
15C - 69A - 13.55 - 0.99V / cell drop
20C - 92A - 13.13V - 1.07V / cell drop
25C - 115A - 12.73V - 1.15V / cell drop

So, what would you say a correct rating for these cells are?

http://i192.photobucket.com/albums/z...123FullRun.png

I agree. I have spoken to FP on several occasions and they state that lipos do there best around 100-110 degrees.

That graph looks pretty unpleasant to me. At 10C, they're already under 3V/cell and at 20C, they're under 2.7V/cell. This would lead me to believe that either you have some bad cells or A123 was smoking crack with their 30C rating. Sure, they may be able to be discharged at 30C, but the voltage drop is horrendous.

You have to remember that they are rated at 3.3v per cell.( Anyone correct me if I am wrong here...)

Yes, I know that. Quite a few Lipos do >3.4V/cell at 10C easily, so logic would dictate to me that 3.0V/cell shouldn't be unreasonable for the A123's at 10C.

If I only count the first 100 mAh and include the fact that the max voltage of the pack at the beginning is 18.1V (as opposed the theoretical 18.5V I used initially), then the numbers look a little better:

10C - 46A - 15.6V - 3.2V / cell
15C - 69A - 15.0V - 3.1V / cell
20C - 92A - 14.0V - 2.9V / cell
25C - 115A - 13.0V - 2.7V / cell

Do they usually factor in the whole run? If you're averaging in the low voltage at the end of a run, it's going to drop everything, right?

Most of the charts that I've seen from the mfgrs. have been a constant load measured until LVC or around 3.0 volts per cell or milliamps used over time on constant loads. I have never seen any graphs of real world use in RC cars or MT's, helis and planes sometimes but nothing with the serious current spikes that land vehicles create.