This is def true. When I was trying to get my Crt.5 to hit 60 (4S 30C Neu 2500 pack) I had a hard time doing it until the cells got warmed up. It was ~40F outside, so it look most of the packs life in spd runs to get temp up. Consequently the fresh cool pack was only doing ~55, but the hot half-discharged pack got over 60. You could really feel the diff in the punch too.

From alot of my tests, I see ~2.65V @ 50A on a half discharged pack.

They do have a greater V drop than lipos, but they tolerate it better and don't get hot like overstressed lipos, so its not quite apples to apples. A123s are really a whole 'nother beast.

Update
 

Received the 5000 lipo from bdebde today. He said that one cell had puffed, and it certainly had. Check out thepics below.

http://i206.photobucket.com/albums/b...p/DSCF2051.jpg

http://i206.photobucket.com/albums/b...p/DSCF2052.jpg

http://i206.photobucket.com/albums/b...p/DSCF2053.jpg

http://i206.photobucket.com/albums/b...p/DSCF2055.jpg

On a side note, gotta love the copper tab claim, only one tab is copper, the other is al. Plus the tabs are attached to each other in some method, looks like crimping to me. Does not look like resistance welding to me. I easily seperated them with a razor blade, and just popped them apart. No cutting or sawing thru the crimps. I really cannot see how this can transfer much power, and most likely indincates why the shrink melts off the wire end of the pack (happened on most of my maxamps packs too), heat from resistance.

The other 3 cells in the pack look fine, and all of them are in balance. I will try a load on them and see how they do.

http://i206.photobucket.com/albums/b...p/DSCF2056.jpg

http://i206.photobucket.com/albums/b...p/DSCF2057.jpg

Ok, pack is fixed, and it is on charge at the moment. I wil leave it fully charged and balanced over the weekend and check it on sunday to see if any of the cells have dropped voltage. Not going to be here tomorrow, small vacation for me!

I have also decided to switch test platforms. I have a HB LS10 that is setup for this size battery. I will put my variety of motors in it and test the batteries. Same size/weight as the crt.5 so it should provide the same results. I also have a pede that can run both of these packs, so that will be used too.

lincpimp... I hope you are not using this maxamps pack as a test pack?

It's not likely that the remaining cells are in 100% condition.

Also, the bottom cell in the pic above actually looks like it might be slightly puffed. A good cell is completely flat... no curve to it.

One of those cells has to be swelled...

I had a pack that had a very slight puff to it... barely noticeable. It lasted a long time like that but eventually did get worse and puffed more. That was a pack that got taken out with an ESC meltdown.

I think the non-copper tab is tin, not aluminum...? Alum is very soft and requires special flux to solder.

I am going to run this pack, just to see how it does. All of the the other cells are fine, no bulges, or puffing. I had a good look at them. Plus they were all in balance when I got the pack, a bad cell would lose voltage slowly. I will leave it fully charged and see how it does. The tab looks to be just like MA old cells, and they had al tabs, and required zinc sloder and the correct flux. Plus they were very fragile, and fell off easily.

Vehicle is a CRT .5 geared i think 16or18/46 with a 7L on 2.8 talons.

First pack is an old maxamps 5000 3s - Second a used 5000 2s

Now if someone can help me interpret that would be great!

Humbug - done!

Chris, any chance you could get a clearer pics of that. I cannot read it!

Question, on your 3s run, was that with the 3s pack the entire time? Looking at the bottom of the graph it lists min voltage at 6.11v! Not sure if that is right.

The 2s pack shows a max draw of 105 amps, and a low voltage of 6.01v. If that is correct, then the cells cannot keep voltage over 3.5v at their rated constant.

Well the graph is all from that run - I selected session 1 so i would assume the max/min are updated...

Looks like the newer 5000 cells were at least able to hold a better voltage than the old ones in the 3S pack - they showed a lot more votlage drops into the sub 10 volt range.

Let's how that Neu pack compares now..........

hhhhmmmmm seems to me that one could do a better test of load vs. amperage with a carbond pile load tester (used in auto applications to load test a vehicle battery). You could hook it up to a lipo (one cell at a time would be best), then raise the amp load until LVC is reached. That would give you a solid number as to what the cell will put out. Beyond that I think you get into (controlled) tests that could potentialy damage the cells.

Well, if any of the batteries let go during my tests, at least I will know what not to buy next time.

I will start off with low gearing and slowly try to creap up on the correct load.

I agree that this would produce a very "controlled" test, but it's also what you usually see in the graphs that manufacturers produce. (And at that - probably from a brand new cell that is in it's best condition) In general none of our buggies are going to run at over 20A continuous and they really high amp draws will be seen during hard accelerations and at top speeds. It's important to me how the Amp draws at top speed effect voltage drops as that's where you'll feel the most impact.

I kinda like this testing comparison as it's showing what these cells will be doing after being run for a while - a little more real-world.

My test
 

here is what i just did

i ran my truck and i came in and checked V and both of my 2s packs were at 7.5v , my lvc is set at 12.4 so 3.1v/p/c

i decided for fun to try something, i hooked up my volt meter and it read 15v, my truck is on a stand and the wheels were allowed to free spin, my set-up is a mm/9xl with maxamps 2 x 2s 5k lipos wired together , geared 14/46 with heavy basher badlands

anyway on to the good stuff.............:rules:

with basically no load my V dipped from 15v to 11.88v under full throttle:yes:

i will try this again once i have recharged my packs and my V will be at 16.8V

:rules:
i will be tring the neu energy packs or at least something rated higher then these in the future, but as far as i can tell a 30c discharge pack would give great runtime and also be better for the batterys, i guess i am pushing these:whistle:

just tested 5s, same except for battery V

new 20.5v to 14.9 @ full throttle=2.98v/p/c on a fresh charged and balanced battery

i think i just puffed another 5k m.a. today

Thats sucks, I'll hand you an oar, as we are in the same boat!

What size pack is it?

I have done this on my lipo's and they all have come up short. Maxamps 4s6000mah 20c tests at 70 amps @ 12 volts which makes it 11.66c . Trinity Lipro 2s 4500mah 20c tests at 40amps @ 6 volts which makes it 8.88c. The trinity packs I tried to get the rated 20c (90 amps), 70 amps was max I could get and the voltage went down to 2 :gasp: I only held it there for a few seconds. Basically you could dead short the Trinity packs and 70 amps would be all you would get. I don't have alot of faith in the manufactures numbers.

Great info! Any specs, or info about your test gear? How was it setup? Any chance of a pic?

Trinity LiPro's are the worst I have run. fresh pack in a Traxxas VXL will trigger the LVC 50% power mode when punching the throttle to full. Even the MA batteries did not do this. We tested 3 Trinity LiPro's on 2 different VXL's to make sure it was not a isolated issue.

I had the same issue with a maxamps 4000 pack. When it was fully charged it was fine, but it did it after a few mins.

it was one of my 2s packs, it may not be as bad as i thought, but well see once i put a charge back in it

This is what I'm using. It's very simple. It is just a ammeter and a voltmeter with adjustable load. You just hook your battery up to it and turn the knob. As amps go up volts go down, just watch the gauges. You can adjust it for any load you want. If you want to do a long test like 40 amps for 10 minutes I would put a fan on it

Nifty. That looks like a good piece of equipment.

Some more MaxAmps 5Ah 3S pack puffing.....

I've got 2 3S MaxAmps 5Ah packs that I've been using for not even a year. They've got maybe 30 - 40 cycles each. Since I've put in the RCM extended chassis on my CRT.5 and went up to 30 series tires my Amp draw has gone way up and runtime gone way down. I know peaks are hitting the high 90s, but the packs are lasting no more that 10 minutes. That's an average of (60/10)*5=30Amps.

30 Amps continuous (really a 6C rating) and at the end of one run a pack was reading 130* and was puffed out on both side. The puffing went down as the pack cooled - but I sat there and watched th pack for about 30 minutes - I was afraid to put the pack in the car for the ride home.

Very disappointing - I have already ordered a 3S 3900 (25C) Neu pack - so we'll see how much better it does when it comes in.

Both of my 3s 5K MaxAmps packs have puffed. Neither had more than 15 cycles, and both were taken care of very well with regard to charging and storage. Neither was ever even run to LVC.

On the other hand, I have 4 2s 6K packs and they're all doing great after lots of cycles.

I got two flights on a MA 4s1550 before it puffed, bought a FP evo20 4s 1500 the same day to compare. The MA has been dead for over a year and the FP evo is still fine. At this point I dont care if they do hold voltage at rated amps if they dont last they aren't worth the few bucks saved.

If you guys ever come across DN Power packs avoid those also, buddy bought two, one puffed after the first flight the other puffed in storage with less then 10 flights on it.

We have both decided that it isn't worth the few bucks saved on these so called bargain brands.

I was just looking at that car battery load tester- $520 is rather a lot of money, but worth it if you owned a garage I suppose. Would it be possible to build something similar using a normal battery discharger, perhaps modified so you can vary the discharge rate (load?), and add a voltameter & ameter shunts somewhere in the circuit? Beyond me, but there are lots of clever electrical guys around here that might have some thoughts.

Just thought that I would let you guys know that my maxamps 4200 3s pack let go. 3 out of the 6 cells (2100, 3s2p configuration) died. Well 2 just died with no apparent reason, or damage, and the third puffed like a balloon, but still had decent voltage. Oh well, the 3 good cells are now a 3s1p 2100 pack. I will set the crt.5 up for a full size tray and test it with some of my other 3s packs.

Don't breath on those MA packs... they may puff!

Oh no, I was pushing them hard. 82 amp rated pack trying to turn a novak hv6.5 motor in a crt.5. That is a heavy truck, and geared for 40mph. Way too much load for a 82amp rated pack. I think I need and 8000 3s maxcraps pack, maybe 160amps would be enough for this beast...

160 amps is just the Continous Rating. Those 8000mah packs are good for a 400 amp Burst Rating.

It says so on the website! *rolling eyes* :whistle:

Only 400 amps, the crt.5 can easily pull that. I think that maxamps are underestimating their cells a bit. 400 amps at 11.1v is about 6hp. A trx 3.3 can make that easy...

Well.... here's my very techincal :lol: prrof of concept on MaxAmps vs. Neu cells.

I've been running a 4S 5000mAh MaxAmps in my XB8EC and got a 5S 3900mAh Neu pack in preparation for the MMM.

Though I would try out the 5S pack in the MM to see how it would work or i I would send the MM up in smoke. Needless to say it works fine and temp were no higher than 130* (w/ ccbec, fan and no extra caps).

I had lowered the gearing on the XB8 from 17/48 to 15/48 in preparation for the new pack and with the Maxamps 4S 5Ah pack I was getting about 10 minutes before the pack would dump (pack less than 3 months and 10 cycles).

I ran it today with the Neu pack and WOW:surprised: unbelievable. I ran the car VERY HARD for 15 minutes and the pack hadn't even dumped yet. First time I ever saw a 1/8 buggy pull a full wheelie :gasp:.

Anyway - you would think with same gearing a buggy on 5S would pull more Amps and last last time with a lower rated pack than on 4S, but the 5S pack only pulled 3.355Ah during the run and took 3470mA back in the charge.
This is compared to the MaxAmps 5K pack dumping around ~3.5Ah in a run and taking back over 4 during charge.

Needless to say - MaxAmps are going up on e-bay after this experience.

I have a maxamps 6000mah 5s pack and after I bought my polyquest it just doesn't get used anymore. I want to get rid of it since it will probably never be used again but really how much do you ask for a crappy pack? :rofl:

I've put plenty of Maxamps pack up on ebay - post it for a low pasting fee (like around $15) for 1 week and by the time it sells you will probably make at least $100 on the pack.

Most people on ebay think maxamps are gold. That is due to their overzealous advertising. Good for you! Just start it at 1 dollar and let it go, you will get a price for it!

Testing issues...
 

well I ran a few easy cycles on the 3s 5k pack, and another cell puffed. Not only that but the pack would go out of balance overnight, just sitting.

Guess that it is toast, I will remove the puffed cell and make a 2s pack and see how it does. Not looking good though.

Also having issues with the mm in my crt.5 test bed. Not liking the novak hv6.5r motor at all. I have another esc, and will try that out. This is taking longer than I expected...