How To Build a Battery Pack from A123 Cells - Page 29 - RC Groups
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Feb 26, 2012, 05:47 PM
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I don't mean to rain on your parade here but the DC9096 is comprised of NiCd cells (not A123 or any other LiXX cell). As such, the cells will be useless to use for receiver packs (unless you want to use 4 or 5 of them for each pack, which will make for a pig of a pack).

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Feb 26, 2012, 06:17 PM
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N1EDM's Avatar
Another thought would be the discharge rate of the cells. They might be enough for a household appliance/tool but will they have enough discharge current for a plane if you were going to use those for an electric motor. I'm not saying that these won't, just voicing that these would need to be tested to find out.

Or did I miss the point and that these were only going to be used for a receiver/servo setup?

Just my $.02

Last edited by N1EDM; Feb 26, 2012 at 06:36 PM.
Feb 26, 2012, 09:43 PM
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jwilson32's Avatar
Gotcha... I think I'm just going to buy some new cells... Thanks again for the help.
Old May 07, 2012, 11:59 AM
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Oct 10, 2012, 12:39 AM
rc crashburn's Avatar
Sorry to try to revive a dead thread but are any of you folks still purchasing the 26650 or 18650 A123 cells and packs? If so, where are you sourcing them from?
Oct 10, 2012, 05:23 AM
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Ken Myers's Avatar
I still have 2 DEWALT 24V packs, a 36V pack and several cells already harvested but not used. I am considering this source for a flyer who wants to switch this winter.
Oct 10, 2012, 06:45 AM
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Highlander's Avatar
Originally Posted by rc crashburn
Sorry to try to revive a dead thread but are any of you folks still purchasing the 26650 or 18650 A123 cells and packs? If so, where are you sourcing them from?
Assuming those are the 2300 sized ones, I get mine from Great price, too!
Oct 10, 2012, 07:05 AM
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Ken Myers's Avatar
I had considered EP Buddy as well. Not sure why he's showing two prices. I'd emailed him when he was out and asked when they might be back in stock and NEVER received a reply. Always good to know another source in the USA with a reasonable price.
Oct 10, 2012, 07:57 AM
jackerbes's Avatar
They were like a blight on eBay some months back, down around $3-4 per cell if I remember right. It must be a commodity market though. It still has a lot of listings (search for A123 battery) but the prices seems to have stabilized around $8 per cell and up depending on the quantity. Here is a typical listing:

Like Ken, I stocked up a little a couple of years ago when DeWalt was transitioning from using A123 cells to something. At that time I think I harvested new cells from DeWalt DC-9280 18V power tool packs for less than $3 a cell. I was getting the packs from Tool King back then and now they don't even list the DC9280 pack any more.

The 1100 mAH (18650) cells don't seem to be common or easy to find at all any more.

And all those various CR123 cells are not A123 (brand name) LiFEPO4 (battery type) cells. No other cell has ever shown the same performance that was seen in the round, metal cased, A123 26650 and 18650 cells.

If you can find old stock DeWalt DC9280 packs they each have eight 2300 mAH cells in them. At least some of them did.

Oct 20, 2012, 09:08 PM
rc crashburn's Avatar
Thanks, you guys, for your replies!

I realize that the CR123 is a flashlight type battery and won't supply the current we need for most RC high power usage.
Have checked-out Ebay and once the smoke clears, most of the Dewalt Power tool battery packs fetch prices comparable to bare cell prices.
Sadly, it seems that the price still remains up on the real A123 2300mah bare cells right now.
Observed that here are only a few venders supplying the new bare cells on Ebay.
I found that these new cell prices begin at approx. $8 per cell on ebay, shipping is included.
$10 per cell (voltman & epbuddy) and higher does not interest me so much, especially when some of these cells are old new stock and shipping is added to the order.
Am not sure as to the shelf-life or cycle-life of used batterys made 5 or more years ago.
Lastly, I see that HobbyKing sells new stock for $7.99, tabs are included, but shipping is NOT included.
Users of these branded "OlevinPower" cells say that they are the real deal.

Am still looking for some new real-deal cells that are better value.
Oct 21, 2012, 05:16 AM
Card Carrying Old Fart
Rickochet's Avatar
Originally Posted by rc crashburn
Am not sure as to the shelf-life or cycle-life of used batterys made 5 or more years ago.
I tinkered with A123 when they first came out. I think I remember reading that they had a 10 year shelf life.
Oct 21, 2012, 09:57 AM
Registered User

A123 cells

Here's a link to a forum I visit regularly, $6 a cell shipped.
Oct 21, 2012, 10:59 AM
jackerbes's Avatar
That is about as good a deal as you'll find on the genuine A123 26650 cells.

I have five year old 1100 cells (new, sealed, B&D VPX packs) and they are still holding steady at the storage charge they were packed with over five years ago. I have several year old,brand new, B&D power tool packs with 26650 cells, also new and unused, and they are holding the storage charge too.

I have been using 1100 and 2300 mAH cells for four to five years and have not seen one expire from age yet. Out of about 30 cells in use, I have had two cells that failed for unknown reasons.

I stupidly managed to kill three more cells by trying to charge them with the polarity reversed.

If there is a service life limitation on these cells in terms of charge and discharge cycles, years of use, or years of storage, it is still unknown.

As long as I can fly the 40% or so extra weight (over LiPO) and have room for the cells in the place they are being used I'll use A123 cells. With all things considered, they are simply one of the best cells on the fface of the Earth for some conditions and purposes. There is no such thing as one type of cell that is best for every purpose and user.

May 16, 2013, 03:16 AM
Registered User
Originally Posted by LBMiller5

Although interesting, this tutorial about bulding an A123 pack, has, in my opinion, a major flaw.
I didn't read it around, it's just my opinion, based on some physics and some math, anyway here it is my conclusion:

I think these tabs are not suitable and maybe not even safe.

I can't determine from pictures their thickness, so I cannot decide about it, but about MY tabs which I found attached to A123 cells I bought, they're totaly inadequate:

They are 1 cm (10mm) wide and 0.3 mm thick; this means 3 mm^2 area, which as far as I know, can tolerate a maximum of 12 Ampere!
To tolerate 60A we'd need 60/4=15mm^2, which for a 1cm wide tab means 1,5 mm thickness.
Hence I bought these tabs:

They didn't arrive yet and there's no datasheet to check the thickness, but from pictures they look at least 1mm thick.

A second issue on the tabs is how they are soldered to the cells: I see just 4 welding spots around 0,5 mm wide (0.25 mm^2 ?), which means a total contact area of 1 mm^2 How is this supposed to be able to carry 60A?!?
What I think is that these tabs are welded to the cell just to make it easier to perform a complete welding using tin; in other words, I think the 4 welding spots are there just to keep the tabs in place until you complete the soldering; this because filling the whole tab perimeter with tin leads to a wider contact surface.

BUT don't forget to leave the center spot of the cell free from tin! The center of the cell is an emergency venting valve: it lets internal gas spread out in case of short circuit, overvoltage or whatelse. In such a circumstance, the cell will be definitely damaged and unusable... but it will not explode! Instead it can explode if shortcircuited and the venting hole is covered.
May 16, 2013, 05:08 AM
jackerbes's Avatar
The close physical contact make the current carrying area of the tabs to be about the same amount of material as is in contact.

You are apparently a newcomer to the cells, I can understand your concern about the apparent deficiency of the tabs. But the cells have been used with the factory welded tabs by many people and for a long time and I don't recall a single incident of the tabs failing or even overheating as a point of high resistance.

There are some pros and cons to getting the old tabs off in order to replace them with better tabs. It is impossible to un-weld the spot welds and almost any method of removal runs some risk of putting a hole or creating a weak spot where the weld was. So all tings considered, just using the tabs because they were already there proved safe enough.

Just out of curiousity, where are you getting your cells and which ones are they as far as the size and markings? The sources for these sort of dried up a while back...


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