MaxAmps Voltage Drop Graph

[kulangflow]

You may have seen me start testing some of my MaxAmps packs in a Li-Saver thread, but I thought I'd put the testing in it's own thread.

I have four 2s 6000mAh MaxAmps packs, none of which have more than 20 cycles. Since I've had them, they have always been used with an LVC and balance-charged with either a Hyperion 1210i + LBA10 or a Hyperion 0610iDUO w/ built in LBA10 balancers.

I tested them one by one in my Kyosho Kanai III with a MM/9XL/UBEC. I also tested a True R/C 2s 8000mAh pack just to compare it because it's rated roughly the same as the others. I tried to run for the same amount of time on the same terrain.

Keep in mind that the True R/C pack is new and the MA packs are used, but they haven't been abused, never been over 100F, never been run without an LVC, and can't have more than 20 cycles on them.

MaxAmps 2s 6k:
# 20C Constant(120 amps)
# 30C Sustained(180 amps)
# 50C Burst(300 amps)

True R/C 2s 8k:
Up to 120A continuous
160A Max burst

So, what are your thoughts?


PS. I'll be posting this in the Traxxas forum too, so you might see it twice if you frequent that place too.

[aqwut]

Wow, I'm surprise the trueRC performed that well...

[TexasSP]

I have heard several people swear by the truerc packs, I guess it wasn't BS after all. Thanks for the graphs, that was good to see yet disappointing and great at the same time. All in all it makes me glad I am selling the last of my maxamps packs off.

[johnrobholmes]

So is this a chart of 10 full pack cycles, plotted to a line for each pack? We are seeing the average voltage over the discharge of the pack, or some other finite time period?


Good info, I like to see data like this.

[kulangflow]

Originally Posted by johnrobholmes

So is this a chart of 10 full pack cycles, plotted to a line for each pack? We are seeing the average voltage over the discharge of the pack, or some other finite time period?


Good info, I like to see data like this.

It's the average voltage for every point that the pack hit a specific range of current.

It was nowhere near that scientific. I noticed that the Li-Saver LVC kept tripping on my Revo even when the packs were fresh off the charger. It did it with any combination of my four 2s 6k MaxAmps packs. I thought it was a problem with the LVC, until someone on here suggested that I test the packs to see if they were just dropping voltage that badly under load.

I tested each pack seperately in my Kyosho buggy for about 10 minutes each. Each pack was fresh off the charger when the test run began. I used the first 1000 mAh of each test for the graph. I tried my best to run the car the same for each test on the same "track" in front of my house. I basically did laps through my lawn and my neighbor's lawn across the street, stopping hard at the end of each lap and starting hard again at the beginning of each lap.

If I were trying for a lawsuit or something, I'm sure better tests could be performed. The only real test I need is the fact that I can't run these packs in my Revo without tripping the LVC on take-off.

Now I know, at least for myself, not to spend any more of my money on MA packs. I also had two 3s 5k packs of theirs puff a cell within the first 10 or so cycles each. I guess I can't sell these packs, so I'll just keep them around for smaller lighter vehicles. Maybe I'll run them in parallel if I can fit them in a different application.

I wish I had the time to do better testing, but this small test was proof enough for me.

[MetalMan]

I moved this thread to the General Electric section.

Interesting comparison! Did you use an Eagle Tree recording device? If so, could you post up graphs straight from the data?

[kulangflow]

I did use an Eagle Tree. I'll have to see if I kept the raw files for the actual ETree graphs. (They'd be on a different computer.) I can't read them very well which is why I make my own.

If I saved the raw files, I'll post the ETree graphs.

Thanks for moving the thread. I wasn't sure which section it belonged in.

[Serum]

Wow, I'm surprise the trueRC performed that well...

here it comes aqwut.............

I told you so.. :)

[sikeston34m]

Originally Posted by kulangflow

You may have seen me start testing some of my MaxAmps packs in a Li-Saver thread, but I thought I'd put the testing in it's own thread.

I have four 2s 6000mAh MaxAmps packs, none of which have more than 20 cycles. Since I've had them, they have always been used with an LVC and balance-charged with either a Hyperion 1210i + LBA10 or a Hyperion 0610iDUO w/ built in LBA10 balancers.

I tested them one by one in my Kyosho Kanai III with a MM/9XL/UBEC. I also tested a True R/C 2s 8000mAh pack just to compare it because it's rated roughly the same as the others. I tried to run for the same amount of time on the same terrain.

Keep in mind that the True R/C pack is new and the MA packs are used, but they haven't been abused, never been over 100F, never been run without an LVC, and can't have more than 20 cycles on them.

MaxAmps 2s 6k:
# 20C Constant(120 amps)
# 30C Sustained(180 amps)
# 50C Burst(300 amps)

True R/C 2s 8k:
Up to 120A continuous
160A Max burst

So, what are your thoughts?


PS. I'll be posting this in the Traxxas forum too, so you might see it twice if you frequent that place too.

Very interesting data. Thanks for posting.

So 2 packs aren't even living up to 10C.
1 Pack is barely doing 10C
The best pack out of the 4 is barely doing 15C?

The Best performing pack on the chart is made from 10C cells!

I realize you didn't want to destroy what is left of your packs.

But if you had your LVC set at 3.0 for this test. Then this explains the bottom of the graph.

If testing were done with No LVC, there's no telling where the bottom lines would be.

[kulangflow]

Originally Posted by sikeston34m

So 2 packs aren't even living up to 10C.
1 Pack is barely doing 10C
The best pack out of the 4 is barely doing 15C?

The Best performing pack on the chart is made from 10C cells!

The True R/C packs are the 15C cells, but your point definitely remains just as valid.

I was running the MM LVC at 3v/cell. Yikes, right?

[TexasSP]

You know, I was just thinking back to some other problems I had 2 years ago when using MA packs, I was chalking it up to the BEC being a problem, but after these graphs, it looks to me like this could very well be the problem. This was using an old EVX with MA LVC's. I ended up using a receiver pack to fix the problem, but I still got odd behavior now and then.

[GriffinRU]

Originally Posted by kulangflow

You may have seen me start testing some of my MaxAmps packs in a Li-Saver thread, but I thought I'd put the testing in it's own thread.

I have four 2s 6000mAh MaxAmps packs, none of which have more than 20 cycles. Since I've had them, they have always been used with an LVC and balance-charged with either a Hyperion 1210i + LBA10 or a Hyperion 0610iDUO w/ built in LBA10 balancers.

I tested them one by one in my Kyosho Kanai III with a MM/9XL/UBEC. I also tested a True R/C 2s 8000mAh pack just to compare it because it's rated roughly the same as the others. I tried to run for the same amount of time on the same terrain.

Keep in mind that the True R/C pack is new and the MA packs are used, but they haven't been abused, never been over 100F, never been run without an LVC, and can't have more than 20 cycles on them.

MaxAmps 2s 6k:
# 20C Constant(120 amps)
# 30C Sustained(180 amps)
# 50C Burst(300 amps)

True R/C 2s 8k:
Up to 120A continuous
160A Max burst

So, what are your thoughts?


PS. I'll be posting this in the Traxxas forum too, so you might see it twice if you frequent that place too.

Just couple thoughts:
If you do the math than you find out that on individual cell level all packs have similar performance with reasonable standard deviation of given measurements.
Keep in mind discharge rate and voltage drop do not have linear relation and these 2 packs(4 of one kind) have 8000/6000 mAmp difference in capacitance, thus in internal resistance.
Not to mention startup voltage, and connectors material and condition, but that is setup conditions and I was doing math on normalized data to avoid complication to some extent.

Bottom line, MaxAmps claims are inflated while batteries are not that bad, from this graph.

And for the end-user the most important fact would be that True R/C 8000 mAmps packs are better than MaxAmps 6000 mAmps.

[lutach]

Good point Artur. I think MaxAmps should start getting better cells soon. There are plenty of places now that have awesome cells. If I was MaxAmps, I would just get some CBAs and pound through the cells they might be getting and post some real discharge for what they sell. They are a very well stablished company, especially if they are getting second quality cells at rock bottem prices and making a big profit on them. One example: I think I was the first one to actually use a large mAh pack, I had 2 12000mAh 3S packs and a lot of people thought it was pointless. The price back when I got them was $30 a cell. That was in 2003 http://www.rctech.net/forum/showthread.php?t=26840. Now MaxAmps should get rid of this packs they have with what seems to be low quality cells and get some cells that have proven themselfs.

[lincpimp]

Originally Posted by lutach

They are a very well established company, especially if they are getting second quality cells at rock bottem prices and making a big profit on them.

Why change, you just explained their business philosophy.

I will attempt to make a point here:

I wonder how many maxamps lipos are sold to people doing MT nitro conversions? And how many are sold to people with rustlers and other electric 2wd 10th scale vehicles? While I can tell the difference, the benefit of better cells is not that obvious in the 10th scale 2wd segment. Lower weight and less traction produce less load, even with a powerful setup. I even compared a maxamps 4200 3s to a neuenergy 5000 3s in my crt.5 and did not see much difference. So their batteries are fine for that application, and that may be their main market right now.

Since they have opened the nitrokillers forum, it may be necessary for them to upgrade their cells, or else they will have to recommend the 8000 packs to everyone...

I don't have any MaxAmps products so I've not made any comments in any of the various threads about their stuff however I've got to say it's very disappointing to hear all the bad new about MaxAmps, mainly because they are the "flagship" LiPo vendor - if all you do is read the various RC car Mags. They get plenty of ink when the Mags do a conversion and they have a big advertising budget.

Based on my reading on this forum, I'd never buy a MaxAmps product but lots of uneducated folks will.

DM