everydayflyer

So the new 1100 mAh cells are available at HomeDePot,E bay ,Amazon etc. and there are at least 3 thread on RC Groups but no word here on the Official A123 Racing website.
Sure is a strange marketing strategy IMO.

http://www.rcgroups.com/forums/showthread.php?t=768455

Known as Black & Decker VPX .


Graphs of a 3S and a single cell

My weights:

2cell pack as purchased 123 gr. / 4.34 oz.

1 cell with 2 1/2" 14 ga. leads and APP connectors 48.6 gr. / 1.71 oz.

3S pack with 6" 14 ga. leads APP connector and PQ balancing leads. 137.7 gr. / 4.86oz.


Cells are .715" dia X 2.535 long , not counting tabs.





Charles

SS Pede

Strange marketing strategy indeed. Though we must admit that RC is not really A123's biggest thing going right now. Still...the sooner I know the details about these packs, the sooner I can look into potentially purchasing them. [8D]

I am curious about how much power these cells can provide compared to M1's. Are they still suitable for 1/10th scale brushless land vehicles?

everydayflyer

I know but this is their Official Support Forum after all.

Plenty of detail on the other site.

Charles

SS Pede

Sorry, I can't make much sense out of those numbers in terms of how my truck (Stampede) would perform (assuming I got the 2s2p pack). 25 amps from how many cells? [&:] Put it this way: do you think they'd work better, same, or worse in your Rustler compared to your M1's that you've mentioned on here?

everydayflyer

Parallel they would be about the same 2200 mAh Vr/ 2300 mAh.

Their advantage is smaller size .less weight.

Would you rather use a 6C 2400 mAh Nicad or a 6C2P 2400 Ni made up of paralledl 1200 cells or perhaps a set of 3S 2400s used in series (saddle packs) would be best.


Charles

SS Pede

Thanks. Looking forward to some user reviews of these cells. [8D]

Red Scholefield

My Feedback: (9)

I just picked up a Black & Decker VPX pack at Lowes. $19.97 for two cells in a plastic pack that is easy to dissassemble, just pry up the tabs on the connector end and remove that assembly pulling the cells out of the plastic shell.

These are marked A123 18650 and weigh 40 grams each. A discharge after charging to 7.2 volts with an Xtrema charger they gave 950 mA @ 1.3 amps discharge. Two cycles were run, no change in delivered capacity.

Under the paper sleeve is a normal heat shrink sleeve. I'm going to make up a 4S pack and see how it performs on an AXI 2208/34 with 10 X 5 APC-E prop.

One rather strange thing. The can is negative while the button is positive, just the oposite of the A123 2300 mAh cells we have been using.

Red Scholefield

My Feedback: (9)

duplicate post

flipflop

I picked up two of the VPX packs at Wal-Mart yesterday and went ahead and ordered a CellPro from FMA. I'm primarily planning on running them as 2 cell RX packs. Just wondering, until the CellPro gets here, can I go ahead and build my packs and charge them on a normal nicad/nimh charger if I monitor the voltage and stop at 7.2???

Thanks

Red Scholefield

My Feedback: (9)

That should work, just make sure you are monitoring the voltage and shut it down at 7.2 volts.

flipflop

ALLRIGHT!!! Gotta go plug the soldering iron in. I think for the initial test I'll put a deans plug on there so I can see how they perform with the Wattmeter.

Thanks a lot

dragon_no_fly

How fast are you guys charging them at? 5 Amps? Anyone try charging these new "A123" cells at up
to the M1 rate of 10 Amps? That would be very interesting, a theoretical 6.6 minute re-charge time.
I have seen zip charging on the M1 cells listed here which is extremely impressive. A123 NEEDs to
make an official comment on these new 1,100 mAh cells ASAP to dispel any disbelief in them that
they may not actually contain A123's patented nano lithium phosphate material. Assuming that they
actually are from A123 (probably manufactured in China) I can not imagine how they would have
any safety issues beyond what the original, well proven M1 cells have. I and I am sure a tonne other
flyers have been waiting for these cells for quite some time. I really hope they are TRUE A123 cells,
if so, good bye, good riddance to LiPO packs on my helis with all of their annoying safety issues!

everydayflyer

My first attachment shows them charged at 5A for all testing.

Yes they are official A123 tecnology ,the real deal.


I have charged a 4S pack at 10 amps. which equaly 9C.

Charles

rmh

All things being equal-- I would expect a charger such as the FMACellPro 4 to charge these in just under 1/2 the time spent for the 2300 size cells
assuming 1/2 the mah for the 1100

so--I will also see if it takes the same time to put the same amount in each type. (1100/2300)
If so - the impedance is the same . I have a pair of the new CellPro 4 chargers -- so this all can be easily verified.

dragon_no_fly

Thanks everydayflyer for your as usual great info, I missed the 5 Amp charging rate data.
dick Hanson, that makes sense, I am going out on a limb here, since I do not currently
own these new 1,100-sized cells, but if the raw material inside them is *identical* to the
original M1-sized cells, than the only thing that I could possibly think of that may cause
a 9C (10 Amp charging rate) into these cells as *possibly* damaging or cell life reducing
would be the smaller size of the "can" that holds the chemical powder that is less efficient
at dissipating heat as compared to the larger sized cells. I have personally charged the
M1 cells at 10 Amps and they are room temperature at the end of the charge which by now
has been well documented by many R/C users. So, in essence, (I can be totally wrong about
this), same material as in the M1 cells, just stuffed into a smaller-sized can; that is, the new
1,100 mAh cells. If we prove that the new 1,100-sized cells have the same electrical im-
pedance as the M1-sized cells, I will be charging my 1,100 mAh cells @10 Amps for a
phenomenal re-charge time of 7 minutes or less.

everydayflyer

Well I have Zip charged a 3S A123 2300 pack many times

http://www.rcuniverse.com/forum/m_6477096/tm.htm

and the average charge time is 6 minutes with a starting current of approx. 30A and tapering to around 5A at which time I stop the charge most of the time. This ends up being a 16A average charge as shown on my logged charges.

These smaller cells being just under half the capacity should really most like be charged at a somewhat lower rate (amperage) . It would be nice if A123 Racing would at least state if their standard 10A charger can be used with these cells also. I have a few 10A charges on my 4S pack of 1100s and they show no signs of abuse but then only time will tell.

8 amps. on the 1100s is equal to approx.16.7A on the 2300s so I feel ,based on my experience that they can handle this but then A123 Racing has not approved great than 10A charging for the 2300s either.


Charles

dragon_no_fly

everydayflyer, have you taken temperature readings on these various charging schemes?
For instance, see below (note: assumes A123 cells; that is, both the standard M1 and the newer 1,100 mAh cells):

[Pack capacity mAh] [Temperature of pack] [Charging rate]
2,300 ? 10 Amps
2,300 ? (Your zip method) --> ~16 Amp average
1,100 ? 5 Amps (standard 4.5C, actually 4.95 Amps)
1,100 ? 10 Amps (basically 9C)

If you have not taken detailed temperature readings of the various packs at various
charging rates, have you at least physically felt the difference in the pack's temperature
directly after it was charged at the high charging rates over the "standard" charging rates.
If so, how do they compare? IMHO (again, I can be wrong on this and there may be some
danger involved), but if the 1,100 mAh cells are only slightly warm after a 10 Amp or 9C
charging rate, then you will probably only see about a 5 or so percent decrease in the cell's
life holding all other things constant, but the cell or pack is inherently safe during this rapid
charging regime.

SS Pede

Yeah, I'm curious about this too.

Physically, wouldn't these smaller cells have a greater surface area to volume ratio, thus helping cooling a bit? I don't know how this affects anything chemically though. Obviously there's a reason why, for example, AA's can't be charged as rapidly as sub-C cells.

everydayflyer

There is a lot more deatiled info in my post on RC Groups however.

Charging 2300 at 16 amp. average causes an approx. 15F increase in temperature as in from 70F room to 85F. After a flight where they are at 100 F they cool down during the charge.

The 1100 never went ove 95 F while being charged at 10A and were at 70F at start of charge.

The 1100 reached 120F while being discharged at around 20 amps. and at higher rates up to max. of 30amps. I used a computer fan to keep them at around 125F.

http://image2-4.rcuniverse.com/e1/fo...87/Bz77764.jpg

Cells would never get this hot during a normal flight. Highest temp. I have ever recorded on the 2300s in flight is 128 F and that was in 85F weather and a total discharge (2100 mAh plus) during a 4 1/2 minute flight (13C average) with burst to 70 amps.

I ran a 3S 2300 pack in a MambaMax powered traxxas rustler Truck back to back 6 min. run( 100 amp. burst) till completely discharged and 10 amp. charges in 90F temps. and pack reach 140F .
Pack is a year old has over 200 cycles on it. Has been charged from empty to full in 4 1/4 minutes a few times, charged from empty to full in 6 minutes approx. 30 times and charged at 10A most of the time. it has been stored fully charged from day one and still delivers over 2100 mAh capacity.

Posted attachment showing 3 Zip charges.


Charles

dragon_no_fly

Thanks everydayflyer, that's exactly the information I was looking for.
I know that cell temp. is not 100% accurate or relational to cell life
or cell premature death, since I have personally witnessed (NiMH)
cells die prematurely at nothing near being hot. 95F seems to me
to be within a "tolerable" range for the 1,100 mAh cells when being
~ "Zip" charged at above 5C (9C or 10 Amps), but this is only a guess,
since I do not have the actual raw specs of the cells. Not too sure that
these cells can tolerate a 140F max threshold as the original M1 cells can,
my guess would be, probably not. From your charts, we can somewhat
infer that cell heating above 120F may lead to more rapid cell deterioration;
would you agree? I wish the A123 tech rep, Brian I believe his name is,
would pipe up in here stating officially about the authenticity of the cells,
some more detailed specs, whether or not A123 Racing will be releasing
a new "fast" charger for these cells or can users currently use the original
M1 charger they released and if there are any more sizes coming out soon.

everydayflyer

I believe heating any cells LiPolys A123 2300s or 1100 to over 125F will reduce their life by a substantial amount. They can stand 140F short term without undue stress and I for one do not expect to get as many cycle from them bing charged at anything above 1C. To me not having to wait an hour for the pack to charge and thus being able to fly continuously with only two packs off sets any decrease in pack life.
I know my 2300 which has been charged over 160 time in approx. 6 min. owes me nothing but still delivers same volts under load and over 2200 mAh usable capacity.

Even at approx. 4.5C chatging (10A for the 2300s) flying is almost non stop.
With one plane two 4S 2300 packs and two charger I flew 7 flights in 1:35 this afternoon.
Mosyt I had to wait on a battery was 2 minutes. These were 6 min. flights.

Charles

dragon_no_fly

Yeah, I agree with you everydayflyer, heating can definitely kill a cell of any type
of battery. From your posts and other posts, it appears (at least from my per-
spective of the information currently out there about these new 1,100 mAh cells)
that they are good for a steady 20-22 Amps and seem to handle the "standard"
4.5C (4.95-5.00 Amps) charging rate fine, but apparently can handle up to or
perhaps, even higher than a 10 Amp or 9C charging rate, however, there is not
enough long term data yet concerning charging these 1,100 mAh cells at 9C
or 10 Amps (rate at which the original M1 cells are charged at) and what that
does or more specifically, the percentage of reduction in the cells' charge/dis-
charge cycles before reaching the standard 80% general capacity rule. 20
Amps is good enough for all of my current heli needs, although the voltage
is somewhat lower and the weight is a bit up unfortunately. I was thinking
that, it is possible to use A123 Racing's original M1 charger on these cells
beyond charging them at the *possibly* damaging 9C rate by making a
current shunt or some sort of current limiter between the charger's output
and the 1,100 mAh pack so that the current reaching the pack is at a more
"normal" 4.5C or 5 Amp rate. It would be really slick to make a selector
so that one position would allow the 9C or 10 Amp rate hit the pack for
6 minute re-charges when you have to charge them as fast as possible
while at the field and another selector position that cuts the current in
half to 5 Amps for more "normal" charges. That would be very slick in-
deed.

everydayflyer

See post

http://www.rcuniverse.com/forum/m_6569864/tm.htm


CellPro 4 will charge a 2S,3S at 4A and a 4S at 3A.

One never has to many chargers.

A123 Racing

Hello All,

Sorry I was not able to Pipe in earlier, but I don’t spend a great deal of time on the Forums over the weekends. The VPX packs from Black and Decker do indeed have our newest 18650 cell. It is the same M1 chemistry that is so popular in our 26650 Cell.

To answer a few questions that have popped up so far:

1. Beware that the Cathode (positive) is now on the button end of the cell, like a normal battery. The case is negative and Live, so watch out for shorts.
2. Charge rates over 5C will most certainly have an impact on Cycle life.
3. Normal use cycle life is up to 1000 cycles similar to the 26650.
4. A123Racing will be offering standard packs with these cells soon.
5. The charging of these cells will be addressed, Most likely a new rev of the Sonic Charger, with a 5A/10A switch and 4S capabilities.

I guess that does it for now, let me know if you have any other questions.


Power . Safety . Life

Brian

[link=http://www.a123racing.com][/link]

Red Scholefield

My Feedback: (9)

Flew the 4S18650 this morning in my Tantrum - AXI 2208-34 APC 10 X 6 E prop, WOT 16A gives unlimited vertical. Most flying done with reduced throttle. Got 4 min plus and CellPro indicated 50% charge remaining. Charging on CellPro at the fixed rate of 3A for A123.
We may heve another winner here for smaller sport planes.

Discharge on CBA II at 1 amp gave 950 mAh.