Discussion A123 M1 Charge Graphs

[everydayflyer]

This post will be multi charge graphs in an attempt to show the difference in resting voltage versus charging methods.

My AF-109 has always read a little high and these charges are from 109 throught LiPoDapter ,through Eagle Tree Micro Power Logger.

After the third graph I placed back on AF-109 and while monitoring the cells voltage I ran voltage up to 3.65 per cell and held there until stable. A total of 50 mAh was added. 15 min. after this the pack is holding at 10.81 volts.

Fourth graph charge on stock AF-109 ,charge stop after 45 sec. in stage 3.

12-7-06 Added fifth graph which shows 3S being charged on modified AF-109

12-7-06 Added sixth graph .
The resulting resting voltage after 15 min.was 3.459 / 3.429 / 3.429 (10.317)
I added 40 mAh and after 30 min. cells 3.595 / 3.561 / 3.585 (10.741)

Update: After setting overniht for approx. 10 hour in an unheated room voltage checked at temp. of 58F 10.671

I think it is safe to save that this modification results in a 22:40 charge that should be considered a full charge.
Modification Thread here.

http://www.rcgroups.com/forums/showt...t=602445&pp=15

My Radio Shack did not have correct Resistor so I used 10K + 22K + 47K all 5% 1/2 watt. Total in series was 77.6K.

12-11-06
Added another 2.2K for total of 79.8K and posted resulting graph.
Prior to charging pack was ran flat in my Traxxas Rustler / Mamba Max 5700.
Resting voltage 5 min. after run 8.0.

Higher cell voltage during charge 3.697
At end of charge 3.585 / 3.571 / 3.60
7 min. later 3.483 / 3.468 / 3.483

AF 109 indicated
2,140 added at end of stage 2 ( 17 min. )

2,280 added at end of charge.(21:55)

12-30-06 Added two TP 1010C Rev. 2.0D (Beta) charge graphs. One with and one without amps. ,both are of the same charge.
While ET Micro Power indicated 10.74 V max. TP 1010 and a seperate DVM both displayed 10.95 .
A123 cells quickly settle to the 3.4XX range after charging to 100% capacity.

As noted in TP 1010C Thread I received error [1} Low Voltage and had to add a few mAh to get voltage up a bit before charge would start.
Post here:
http://www.rcgroups.com/forums/showp...postcount=1382

TP 1010C Ver. 2.1A Firmware elinates the low voltage problems and will now charge a 3S at 7.4 volts without issue. It will also do a Recovery mode on a pack with cells down to 1.5 V per cell..

2-12-07 Added a Graph using AF 112PK charger and Dapter (latest version).

Dapter available here.

02-13-07 High speed charge graph added.
Ignore spike at the very beginning.

Charles

[everydayflyer]

There is a Support Forum on RCU at

http://www.rcuniverse.com/forum/m_4667864/tm.htm

wherte I posed the following about their Turbo Charger

What is the resting voltage of a 3 cell pack 30 minutes after charging?

No response fro A123 Racing however a member / user posted.
I underlined / bold-ed part of text.

Post #13

I read this and forgot I had a 3s pack on the A123Sonic charger for ~1.5hrs. I took it off and measured 10.98v. 30min later I measured 10.97v. 60min later that pack still reads 10.96v! I had another 3s pack charging during that time and took it off when it was finished. It measured 10.95v and 30min later measured 10.38v. The A123Sonic charger will keep repeaking the pack if you leave it connected.

and in another post (#16)

Update #2: All packs were recharged and left on the Sonic charger for at least 1hr minimum. The voltages are from the 3s1p packs sitting at rest for about 1.5 days. A-10.79v, B- 10.70v, C-10.92v, D-10.89v. The Sonic charger is not a typical Lipo CC/CV charger. It has no CC charge from what my Medusa meter shows. The initial start has the highest amp rate then shortly after that it settles to around 55w-58w for most of the cycle. Once the pack hits ~10.8v the "Charged" light comes on and almost all of the mah have been put back into the pack. The Sonic continues to charge much like a CV from that point until the pack hits 11.1v or 11.2v (the Medusa I have only has 00.0v resolution). Then the charger stops all charging. But when the pack voltage settles to ~10.8v (from resting and/or from powering the Medusa meter) the charger starts charging like a CV cycle again to the 11.1v-11.2v. This cycle of peaking/resting will continue for as long as the pack is connected.

Charles

[everydayflyer]

Resting voltage versus capacity
Using an AF-109

At a resting of 10.3 volts( 3.43 per cell avg.) I added 40 mAh and voltage reached 11.72 and was 11.30 resting right after charge.(3.766 avg. per cell)
After 15 min. 11.08
After 30 minutes 11.04 volts (3.68 avg. per cell)

Dsicharged 100 mAh and resting voltage after 15 minutes 10.05 (3.35 avg. per cell).

100 mAh is 4-5% nonimal capacity of a full (?) pack.

Toped off a with 110 mAh./ balanced durning top off.
Cells 3.751 / 3.746 / 3.770
After resting for 15 min.
Cells 3.683 / 3.668 / 3.697


Charles

[Marv829]

I just wanted to post new numbers for the A123 Sonic charger as I forced myself to pull up a chair and watch the cycles start to finish. I also took the charger apart to see what it's made of. I discovered I could achieve 14 minute recharges with my A123 3s1p packs simply by providing forced air cooling on the heatsink. They must lower the charging watts to keep things in check heat wise. These are the numbers with active cooling.

For 3s1p packs - 14min charges - stays above 90w charge power for most of the charge - "Charged" light comes on at ~10.9-11.0v - peaks the pack to ~11.1-11.2v - repeaks the pack when voltage drops to ~10.9v.

For 2s1p packs - 13min charges - stays around 75-85w charge power for most of the charge - "Charged" light comes on at ~7.2-7.3v - peaks the pack to ~7.4-7.5v - repeaks the pack when voltage drops to ~7.3v.

-Marv

[everydayflyer]

Marv thanks for sharing that with us. Nice to have such numbers from an A123 charger and a number of packs to use as a baseline.

I just did the mod. to my AF-109 today and added another charge graph in post #1 to show the results.


Charles

[Marv829]

Your welcome Charles. I will be purchasing a data logger in the future. I'm leaning towards the Eagle Tree MICROPOWER E-LOGGER as of today because of their new brushless RPM sensor.

[Marv829]

Here is my charger now after a fan mod.

[everydayflyer]

I increased the total resistors value to 79.8K and graphed a full charge at 8A.
Graph added to post #1.

Charles

[everydayflyer]

Two more charge graphs added to post #1.
Both graphs from same charge but slightly different.

Charles

[aeajr]

If it is not taking this discusson off line, could you share your overall impression of these cells vs. Lipos or Nimh for power, weight, whatever? I am interested in using them in electric planes that are in teh 1-3 pound range flying brushless motors.

Any overall impressions would be of interest.

[aireze]

I would also like more info on battery type comparison.

[everydayflyer]

There are many Thread on A123 cells compaing to LiPoly,NiMH,eMolie etc.
A Search on A123 will return many Threads / post. At 2.5oz. for a single 3.3 nominal voltage cell they are to heavy for most foamies.

I would prefer this remain a charging thread.

Charles

[aeajr]

Thanks everyday flyer and I respect your desire to keep this about charging.]

I have started a new thread. For anyone wanting to understand A123 technology, I have started a thead here:
http://www.rcgroups.com/forums/showt...71#post6636420

This thread should be focused on charging.

[everydayflyer]

An addational charge graph added to post #1.
That was charge # 162 for that pack and was right after being ran in my Rustler till flat.
These cells continue to amaze me.


Charles

[bjpaul]

I have a feeling that these posts are counter productive to the A123 early adopters as they are probably driving up the price of DeWalt packs on eBay

Oh well......... now if A123 would just get an intelligent marketing plan for loose cells .

Brad