Real Time A123 review

[Chris_The_Battery_Man]

This may be long so bare with me. I am not in any way trying to sell anything here... just supply cold hard FACTS about batteries we test. First to nip being called biast in the butt...

I want to start off by saying we DO NOT carry any house brand cells, just all name brand. We are builders... Not a factory like Thunder Power or GP. We just make packs out of already reputable brands of cells. No different than working in a hobby shop and saying that this part sucks and this one is better. We will not carry something unless its either something we would use or is in high demand from our customers. Even so there are still a few things we would still not use that we carry. Everything we carry you can buy elsewhere if you want.


Like JRH we are testers too. Nothing will show up on our website for sale like I said unless it's kick ass or there is an extremely high demand for it. Everything gets severly punished in testing before getting released. We actually stumbled across Enerland back in the day before Pollyquest and Thunderpower was around and were the first place to carry those cells.... Then they sold out. But regardless they're still some of the best cells in lipo to date with the exception of the 30C Elite lipos that are hands down the BEST lipos on the market.


So enough Rambling and on to the facts about A123.... As I have ranted before there are alot of places that have FALSE RATINGS on their packswhich means that their ratings are done in a un usable fashion to RC. They might have a better place in the world of electronics... But as far as high performance RC is concerned.... They're not what the lable says.

A123 claims 30C 60C burst. Well in a real time situation for RC that is not true. Most electric RC cars will stop running at about 6 volts if I am correct depending on the application. We believe that A123 tests down to 1v per cell. Below is a graph of a 2000 mah A123 brand cell tested at 10C down to 2.7v compared to an Elite 2200 30C cell. This is pretty much a real time voltage stop on the pack if it were to be used in an RC car.


As you can see the A123 2000mah(red curve) at 20 amps discharge which is 10C is averaging under 3v per cell which is where Lipo cuts off. The top blue curve is an Elite2200 30C at 20 amps discharge down to 2.75v. Its averaging 3.6-3.5v under a 10c load. The middle blue curve on the Elite is at 40 amps and the bottom curve is at 60 amps.

if you do the math the 2200 Elite will put out 72 watts at 10C and the A123 only puts out 55 watts....


I will post more graphs of the A123 at its rated 30C claim under the same conditions. I am pry forgetting a few details and will post up later tonight.
Now A123 has its advantages like faster charging, safer and longer cycle life... but for raw power.... they just dont hold up to their ratings not to mention they're heavier than lipo and consume more space thann lipo...


Feel free to ask away

[mattnin]

Your graph and review is all wrong, I give you a D-, here is why:

1) Speed controls will run at 6V, 5 cell nimh anyone? As I understand, 5 cell racing is big in touring car and even in some situations, off road.

2) There are blatant discrepancies in the cell capacity. As I recall, 2300mah is the capacity of an A123, so are you calculating the 10C current draw from 2000 mah, 2300 mah, or some other arbitrary current draw?

3) You are comparing batteries of different voltages, therefore your comparisons of power (watts) are only reflective of the current draw you are imposing on the cells and not a true representation of the performance of the cell.

4) Call us back when you finish the graph showing *correct* current draws from the A123, and completed like you have shown with the Elite.

5) You are showing me a graph comparison concerning the LIPO at differing current draws, however they are all in the same color so are meaningless.

6) Also, you have an error where you are saying 3V is where lipo cuts off, which is true, but that is not where A123 cuts off. A123 cuts off at 2V per cell

[mattnin]

Here are graphs showing A123 voltages at specified current draws from everydayflyer @ rcgroups.com

[Coligny]

When I see their website and list of corporate clients (GM, DeWalt, BAE)...

To put it frankly... if they are wrong, then I don't want to be right...

[Chris_The_Battery_Man]

Let me clarify a few things on what my point is because I think you may have missed it.

the A123 is 2200mah as is the Elite 2200 (and we could have picked any 30C Lipo to use for testing just these were handy).

We picked 60,40 and 20 amps because they are easy round #'s. It really does not matter what C value I use as long as they are the same for each cell. So for a 2200mah cell @ 60amps (60,000/2200= 27.27C). We can do the math for the others to get the C rating but it does not matter. But for those that must know the exact C ratings you can use the above to help figure the C rating used. But C ratings are irrelavent its the fact that both are tested the same way and are the same capacity.

The point is this. You have two chemistries. A123 and Lipo. Many people are hearing that A123 are the best newest technology to use and assume this means they will go faster.

But this is not true. The Elite 2200 lipo, as per the graph, will out WATT the A123 by quite a bit. And it weighs quite a bit less while taking up less space.

If you have a set space in your model and need to pick a battery you want to pick a battery that will offer the best peformance for its size. The A123 do NOT do that. In fact they weigh 31% more then the same capacity lipo. (lipo weighs 55grams, A123 2200 weighs 72.4 grams)

So the fact is the for a smaller package and weight the Lipo offer a much larger power gain over the A123 cell of the same capacity.

It does not matter if the A123 can operate at a lower voltage. Who cares. What matters is wattage at a given weight and size at a given load.

The #'s do not lie. I will race anyone with a 3s A123 2200 pack against any true 30C 2200 lipos and win the drag race every time. The power is that dramatically different.

We will have 20,40,60 amp discharge graphs down to 2 volts for the A123 at some point tonight or tomorrow. It is very obvious, from the graphs, that the Lipo has a huge power edge.

A123's charge quickly and can handle over discharge. They also may have longer cycle life. So these are the only advantage you have to pick A123. It not a Power Gaining chemistry it is a Long life battery for certain applications (like consumer drills and possible for use in Real Autos).

Not sure why it is not obvious from the graphs so far on the huge power difference.


What this all boils down to is this:

You have an RC. You want more power. Under the EXACT SAME conditions the Elite2200 lipo is hands down better for putting out power than the 2200 A123. The graph proves this. I may have had a typo but it is still the A123 brand 2200mah cell(Not 2300) http://www.cheapbatterypacks.com/mai...=A123&cat=A123


But I am not at all saying that A123 is a crappy cell. They have their place.... Just not in high drain electric RC applications.

[Reflection]

Good info Chris,thanks. I want more. Always like reading things like this to learn about different products.

For me,I want the most power I can get from the smallest,lightest pack for ease of mounting on the car. Personally,I'll take a lipo over anything.

[JohnRobHolmes]

The LiFe cells (a123 type) have less voltage per cell, and hold less watt/hour per weight as compared to Lipo chemistries. In RC cars the advantages basically boil down to fast charge times and less worry of fires (which isn't really a worry IMO). I have been playing around with the LiFe cells, and I like them in my electric motorcycle more than R/C stuff. I don't want the risk of fire between my legs at 30mph. Motor controller goes bad, shorts the battery, bad situation, wreck, etc.


For power to weight I prefer Lipo, which is basically what the graphs are showing. Can you post up the cell weights Chris, and possibly dimensions?

[Chris_The_Battery_Man]

Yeah I am going to post updated graphs for mattnin... These are the closest cells to compare in the Lipo VS. LiFe arguement....

A123 2200mah 3.3 volts
Weight 72.4 grams
diameter 26.5mm
length 66mm

Elite 2200mah 3.7volts
Weight 55 grams
Length 98mm
Width 35mm
thichness 8mm

The only reason I post this up is because we get constant phone calls about people wanting A123 because they'think they are going to get a product that's "Better" than lipo. Its not a performance upgrade compared to lipo for people that want more power or go FAST....

I would even have to say a 8 cell Nimh 9.6v pack versus a comparable 9.9volt LiFe Pack would be a better comparison... The Life(A123) may have the edge over Nimh but not lipo. Lipo hands down is Factually a better performing cell.

You would actually be supprised to see how close in performance the LiFe and Nimh are in performance.... Thats my next project.

[Trikster]

Nice info. I wish the price would drop on the Lipos though... I only use lipo in my planes (and have for 6 or 7 years, Kokam 2s1p 1020mAh ring a bell?) but would love to get a nice one for my Slash.

[Chris_The_Battery_Man]

65 bucks on our site for a 25c 4800 2s Elite pack

[Coligny]

I switched to lipo for some RC (mostly Choppers... because it's the only way to go now). But honestly... I would have much better days without the spear of damocles that is handling lipo/charging/checking for low voltage or over C use. (and also, i'm running out of stainless steel trays to store them)

I tried a chopper lipo on my brushless TT gear (just to see) without checking the C rating... 20 minute later they were looking pregnant with twins. And here I don't even know how to handle these kind of hazardous waste... (yeah, I completly drained them, so now it might be a little less risky).

I never had these kind of worry with NiMh... and for crawlers... LiPo seems to be like hunting mosquitoes with a bazooka. Lots of drawbacks for little gain.
I's really wish the Eneos where available as C cell, because sometimes my rigs stay put for quite long... and then I have 2 hours free to get some action... but the standard NimH are discharged... or the lipos are at their storage voltage.

[mattnin]

Now you are changing the argument.

The point is this. You have two chemistries. A123 and Lipo. Many people are hearing that A123 are the best newest technology to use and assume this means they will go faster.

But this is not true.

If you want to make another point where A123s will propel your R/C vehicle slower than a LIPO, I will not argue with you because I know this already. I have raced 2S A123 in stock class vs. LIPO and I am definitely slower. However, that is not your original point.

Your original point is that you are claiming the battery company gave false ratings and the A123 cell is not a true 30C battery continuous and 60C burst (which you have not proven).

You also claimed that speed controls stop working at 6V which is wrong. You claim that A123s cut off at 3V which is wrong. You claim that A123 batteries are 2200mah capacity which is wrong, they are 2300mah.

You are also comparing the wattage at a given current between the batteries which is a poor comparison because the A123 operates at a nearly a whole volt less than a LIPO. This is like comparing a 12V battery and a 6V battery and drawing 1A through them and saying " the 12V battery provides 12 watts and the 6V battery only provides 6 watts @ 1A that means the 12V battery is better" which is a false statement and proves nothing in terms of performance. Bump up the 6V battery to 2A and then it provides 12 watts, and so on and so forth.

If you plan on disproving A123 claim of 30C continuous and 60C burst, you better have some really good evidence of it, all the way down to your test equipment, conditions, etc...

[Chris_The_Battery_Man]

No they are 2200... atleast the ones we tested. Which are A123 brand unless there is a typo on our site... But that is such an in significant point... If they were 2300 that wouldnt make them better, it would actually make the test results worse. And they are absolutely still not 30C I have to post graphs of our tests at 60 amps down to 2 volts. And we are going to RE test The Elite2200 just for the benefit of the doubt at 60 amps down to 3 volts.

If you were to argue that they will "Handle" 30C constant that maybe I would agree... Would you be able to use the pack with that kind of voltage sag... Probably not... Atleast not in the majority of the applications these are being sold for anyways. Will they work fine in a crawler, sure or any other low amp draw application for that matter. But I have guys wanting these for their E-revos and otheer cars that will draw some good ammounts of current.... And this is what I said when I started this thread...

So enough Rambling and on to the facts about A123.... As I have ranted before there are alot of places that have FALSE RATINGS on their packswhich means that their ratings are done in a un usable fashion to RC. They might have a better place in the world of electronics... But as far as high performance RC is concerned.... They're not what the lable says.

A123 claims 30C 60C burst. Well in a real time situation for RC that is not true. Most electric RC cars will stop running at about 6 volts if I am correct depending on the application. We believe that A123 tests down to 1v per cell. Below is a graph of a 2000 mah A123 brand cell tested at 10C down to 2.7v compared to an Elite 2200 30C cell. This is pretty much a real time voltage stop on the pack if it were to be used in an RC car.

Yeah maybe I was wrong about the 6v cutoff and I made it clear that I was un sure of that.... A123 is marketing these towards HIGH PERFORMANCE RC and these are not a high performing cell. They may be a good reliable chemistry to an application that does not ask much of them... but when you have guys wanting to put them in big brushless cars or planes or whatever would require 60 amps continous out of them.... they are not up to the test. Plus there is this rumor going around that A123 is somehow a higher performing chemistry than Lipo and that is not true.

As far as our equiptment goes thats all been validated. We test everything on the same stuff and are testing the 2200 A123 against the Elite2200 under the SAME CONDITIONS ie amp draw. Even with the cut off set at 2v the results arent going to differ much from the graph above... thats just a stopping point ot doesnt effect the graph at all except where it stops.


For those using A123 for bashing or in an a high performance application..... What are you guys setting your cutoffs to?

[JohnRobHolmes]

2v/ cell cutoff is safe for the chemistry. Any lower and it will damage them and shorten lifespan. The useful voltage under low current discharge is 2.8v/ cell. Anything below that on low current discharge doesn't give much more mah at all.

[BritCrawler]

Chris, your website's wrong. A123 cells come in 1100 or 2300mAh ratings. I also checked www.a123racing.com and they list those packs as 1100mAh and 2300 mAh.

http://a123racing.com/html/racingPacks.html

Also I thought one of the attractions of A123 was it held up at lower voltages and didn't need as high a cut-off as LiPo packs in order to preserve the cells' chemical integrity. I could have read wrong though.

[JohnRobHolmes]

Even with a lower cutoff the a123 woudn't hit 2300mah at 20 amps.


On larger rigs a 2p setup is needed. An emaxx would be pretty fast on 6s2p a123.

[mattnin]

Chris, I am not arguing that they will handle 30C. I am simply saying you have a lot of errors in your review.

I feel they are high performance cells. I have been using 2S1P packs for well over a year now in modified 1/10 truck, buggy and 4WD using a 2S1P saddle pack in a BJ4WE and now I am using a 2S2P pack in modified touring car. I race at www.highdesertrc.com track in Grand Junction. I have also been using them in my rock crawler for over half a year. As matter of fact, I only own one lipo, the rest are A123. I don't bash, I race or otherwise compete using these cells. You may say they are not high performance, I would have to disagree.

I am just as fast as anyone else out there and no one is taking me on the straights that is for sure. The cells usually stay completely cool in offroad, but they do get warm in touring car, I have measured 140F. But they held up like a champ, no swelling like an rc common sense 4400mah lipo did a week before. I charged that pack up at 10A and I was ready to go for the next heat. As matter of fact, I took only one battery with me to the track, and that was it. So I relied on the fast charging and performance of that battery to do well.

I'll be seeing how they work in a large vehicle too. I have a guy here going to make me a 1/8 scale Gravedigger monster truck tube chassis using maxx diffs revo shafts and I am going to be using a 5S2P A123 pack in there. I think they will work just fine, even a 5S1P pack I believe would work just fine, but I'll see.

I have A123 cells for the safety aspect and long life. I have seen way too many youtube videos of lipos catching fire that it has me scared.

[sloppy]

Originally Posted by JohnRobHolmes

Even with a lower cutoff the a123 woudn't hit 2300mah at 20 amps.


On larger rigs a 2p setup is needed. An emaxx would be pretty fast on 6s2p a123.

really fast from what I have seen.. and seem to be pretty cost effective to..

[mattnin]

I don't set a voltage cutoff with the A123 packs. I just run them until the car stops. It is really easy to see when they are discharged. It is very sudden, and the car pretty much just stops.

[Chris_The_Battery_Man]

EDIT: Ok yes I am dumb and didnt realize that the 2200mah/4600mah was a 2p. My bad there. I have the worse ADD. But as I said that extra 100 mah doesnt help its cause... it actually makes the results worse for its size


And let me back up for a minute.... Because those who know me... I am tarded and word things poorly:?... mattnin The A123 may be 30C 60C burst for that chemistry... under the right conditions... You are right there, I guess my saying they're not 30C technically is incorrect and I appolagize there... but as far as real time performance in a high performance application that demands alot, I have a hard time believing that. I mean the Elite4500 30C lipo(Which i know your going to say is not even clost to the 2200 A123) will handle a true 135 amp constant discharge and still maintain 3.6-3.4 volts at that load where as the A123 4600 mah pack for example(If we were testing 1 cell) will handle 138 amps contant but be at about 2.6-2.4 volts per cell. We could argue all day long that "Well A123 is a totally different voltage" Yeah and I agree that we are not comparing apples to apples here... But those who claim A123 is better than Lipo are not correct.


Now correct me if im wrong but isnt the idea of a high performance cell to be lighter, smaller, and faster or more powerfull than the chemistry its up against? These A123 cells are being sold with the idea that they are a better performing cell than a similar Lipo... and that is not true. Lipos are lighter, smaller, and deliver WAY more power than a Life cell... Unlike all the claims and questions we get about A123 being better.


Below is a thing the owner wrote up thats going to go in our FAQ's soon after it is read over...

A123 vs. Lipos


There is a lot of buzz about A123 products and have been for some time now. The most common questions we get asked on the phone are:

1)Do you have A123 cells/packs?
2)How much will they improve my models performance over the lipo pack I currently have

For #1 the answer is “YES” we do carry A123 and they are grouped with the Lipo products. So go to lipo packs and you will see them listed.

For #2 the answer is “They will not improve your performance”.

WHAT!?!?!

Yes that is correct. A123 cells will not make your model go faster or run longer. They will actually make your model slower and heavier.

Why?

A123 cells are heavier by about 30% then current high C rate lipos (30c). They have lower average voltage then 30c lipos of the same capacity and A123 cells physically take up much more space then Lipo cells. Actually A123 cells take up more space then a same sized NIMH pack of the same voltage and capacity. We could not believe that either until we asked a factory to make us a custom 9.6 volt pack to fit in the same space as our 9.6volt NIMH Elite 2/3A 1500mah packs. They said they could do custom cells to make it the same size but the capacity would be only 1000-1200mah tops. Now this factory was not A123 so perhaps A123 has better energy density so at best A123 will match the same space as a equivalent NIMH pack in voltage/capacity.

The reason there is so much confusion is because of the C ratings these cells get. We hear ratings as high as 60C. But 30C is most commonly seen. People think that a C rating is like a power rating that is comparable to any other battery on the market. Many people think a 30C Lipo and 30C Lion/A123 cells would be of equal power.

THEY ARE NOT.

A123 cells operate at much lower voltage. At 22amps (10c) they run at 3.00 volts per cell. If that were a lipo we would throw it away and never use it. But people seem to accept this power level from A123 because the cells can take it and were designed to operate at the lower voltage.

Now that is fine. And for cordless drills who cares what the operating voltage is as long as it does its job.

For RC it is a little more important to understand the differences between these two technologies.

The bottom line is the Lipos are more energy dense and operate at a higher voltage under any load versus the same capacity of LiFe (A123).

So the question we ask the customer is what do you want: A pack that is lighter and more powerful at a lower cost or one that is heavier and operates at lower voltage and costs more? Then we usually have to add: “Oh yeah, A123 are safer and can charge in 15 minutes though and might have longer cycle life”. Now that last bit is important and very cool. But to be honest those 3 things don’t win races or make your jaw drop when doing high end acrobatics.

I can honestly tell you that I don’t see the big deal. We did some graphs which we will make available but at higher C rating the A123’s actually drop to near 2.5 volts where as the similar lipo holds 3.4-3.6 volts. That is 1 or more volts per cell on average. That is huge! I understand A123 are not supposed to operate at 3.6 volts but that does not matter. We are talking about two technologies and the space they take up. So to me it is very important to compare those differences. Some will claim it is not a fair comparison. Why not? It about how much power I can get out of a certain sized object that I can choose for my model.

So don’t get caught up in the hype. A123’s are neat and gimmicky but they are no “Holy Grail” of R/C batteries. If your A123’s are out performing a 30C lipo of the same capacity and cell count let me know because that lipo must be a piece of crap J LOL.

So bottom line: Save your money and buy a good lipo and charger. If you are really concerned about safety stay with NIMH or buy a couple lipo bags and charge in a big flower pot. If charging in 15 minutes is super important to you then you may need more battery packs to begin with. I can fly all afternoon with a couple good lipo packs. I don’t need to keep charging all day. Also consider that as of right now A123 retail prices are much higher then equivalent Lipos. We know that pricing on LiFe is coming down in a big way and some factories in China tell us that LiFe will be cheaper then NIMH very soon. But all you will end up with is slow and cheap which is better than Slow and expensive.

Oh and something to keep in mind about A123 4C charge rates. It requires a charger that can deliver a lot of wattage. If you have a paralleled setup you will probably still take 1 hour to charge due to charger limitations. Many common chargers are only 50watts. You will need a 180watt or better charger and those are in the 180-220 range. Although the A123 charger seems to be a good value and is supposed to handle the smaller packs with out problem.

Customers are now starting to ask about using A123 as RX packs. I think the 1100mah packs would work great for that as they are lighter than Nimh and you don’t need to worry about them over draining. But for Transmitters you can’t really get a large capacity A123 pack to fit. It might be worth it if you could I think. But I will stick with 2000-2700mah AA cells for now. If you have seen what a 2200mah A123 cell looks like you will understand why there is no chance those are going to fit in many small devices. Think Long SC cell.

Hope not to rustle too many feathers. We do sell it for those that are strong believers or just have the ideal situation to use them. I know I would consider them for a real car electric conversion if they were not so expensive but that is why I have my eye on the Chinese LiFe versions. 10ah cells will be available for very little money. But they are only 3C cells do don’t get too excited.