Discussion How are you going to charge your A123's?

[bjpaul]

With the release (finially) of the DeWalt 36v battery packs, we will have A123 cells to try. It is my understanding (from somebody testing A123 cells) that they absolutely will not stand a charge greater then 3.6v per cell. As our Lithium chargers are currently set to 4.2v per cell what will you use?

It may be time to spring for a good regulated CC/CV power supply.

Brad

[charge1(ds)]

You could use the supplied charger. Just wire up the in pack regulation circtui to the output of the charger and make a balancing tap and just set it up like it would be in th enew state still but use plugs.

[RC Man]

I plan on using my Astro 109 – if that won’t work I have no interest in these cells.

I was under the impression that lithium cells are charged to 4.1 or 4.2 volts but the nominal operating voltage is 3.6 to 3.7 volts.

[Neil Walker]

PowerCube charger. The LiPo function allows you to set whatever pack voltage you like.

[bjpaul]

Originally Posted by RC Man

I plan on using my Astro 109 – if that won’t work I have no interest in these cells.

I was under the impression that lithium cells are charged to 4.1 or 4.2 volts but the nominal operating voltage is 3.6 to 3.7 volts.

RC Man... you will not be able to use your Astro109 for A123's except for a high cell count series pack where you may be able to fool the charger that the cell count is less then the actual count. But I would not advise that.

The A123 chemistry is different then common Lithiun Polymer and they cannt be charged over 3.6v.

Brad

[Neil Walker]

More details on the PowerCube: http://www.lomcovak.cz/charger/powercube1.html

Available in the U.S. at http://www.yntdesign.com/

Definitely not for beginners, as the voltage for LiPo charging is set manually, e.g. if you want to charge your pack to 17.8 volts, it'll let you. The LiPo mode is just a dead simple CC/CV where you pick the C and the V.

It does, however, have the best software I've seen yet - and I say that as someone who develops software for a living. The software could actualy be used with any charger (or any whattmeter, for that matter). It's even got a provision for writing a user-supplied filter (using regular expressions) to accept input from anything you like, as long as you can express the data stream in some form of current, voltage and time. Multiple dataset overlays. And user-defined functions for the graphs, e.g. want to compute the area under a curve between two points on the graph? Make your custom function, click the two points on the graph and away you go.

Expensive, and definitely not for someone who wants the full auto-everything setup, but quite powerful. Makes a very nice combo with my TP-1010C and TP205/210s. I bought it with the A123s in mind well over a year ago.

[rick.benjamin]

Build an adjustable charger/balancer
http://www.rcgroups.com/forums/showthread.php?t=270580

Rick

[GoatZilla]

Originally Posted by RC Man

I plan on using my Astro 109 – if that won’t work I have no interest in these cells.

I was under the impression that lithium cells are charged to 4.1 or 4.2 volts but the nominal operating voltage is 3.6 to 3.7 volts.

Great idea, let us know how that works out for you.

[thermlin']

so uhh....anyone tore a pack up yet?

[RC Man]

I’m really not interested in some new oddball cells that require a new oddball charger I already own way to many chargers. I will just buy some of the new TP batteries when they come out next month


RC

[JKos]

If you compare the fully charged voltage of packs made with the A123 cells (assuming a real full charge voltage of 3.6 V) and LiPos, there are few that are either dead on or very close. Here is what I came up with...

A123 S# | A123 V | LiPo V | LiPo S# | Delta per Cell (V)
  6S    | 21.6   |  21    |   5S    |  0.1
  7S    | 25.2   |  25.2  |   6S    |  0.0
 12S    | 43.2   |  42    |  10S    |  0.1
 13S    | 46.8   |  46.2  |  11S    |  0.046

So, at 7S, the A123 could be charged perfectly as a 6S LiPo pack. The 13S is pretty close at an under charge of only 0.046 V per cell.

- John

[charge1(ds)]

John if you call 0.046 v per cell undercharged then yes.

[yakman]

I have a Hyperion EOS 7i Speed 5S25N CHARGER. It charges Li-ion at to 3.6v.

The improved new revision apparently does not.

[everydayflyer]

How are you going to charge your A123's?

American Express ,of course.

[sjslhill]

3.6V and your going to need parallel? Hum, what will be the advantage?