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Discussion Starter · #1 ·
This thread is not EV related, but its battery related, so I figured its not entirely out of place.

In my quest to erase Lead Acid technology from my life I am working on upgrade of my home UPSs to LiFePO4 batteries. Brief power blackouts and brownouts are not uncommon in my area, so I try to protect my electronics investment with small UPSs of various sizes strategically located around the house :). Since power loss is usually brief, few seconds to few minutes, I am not interested in large expensive whole house UPS, I have a gas generator I can use in case of real emergency, so the focus here is on small, computer type, UPSs you can get at any retail outlet. They are rated by their power level and come with sealed LA batteries of various capacity and voltages of 6V, 12V or 24V. Usually LA batteries in these units are capable of just a few minutes of max power output and have limited life span. I typically end up replacing UPS batteries every 2-3 years, which I find to be a waste of money, hence this project.

As most of you know, 4 LiFePo4 cells in series have nominal voltage of 12.8V, which happens to be in the same range of 12V LA battery. This makes it very easy and convenient to swap LA batteries with LFP batteries. In this project I need small capacity cells and 2C-3C rates, so UPS can run for 20-30 minutes. Obviously prismatics are too large for this purpose and even Headway cylindricals are too big for most small UPSs, so I went on Ebay looking for cells in 1-3AH size range. Oh boy, plenty of choices, most direct from China, some are individual cells, some are pre-assembled packs of various P and S configurations. I am cheap and handy enough to build my own 4 cell pack :), so I am only looking for individual cells. Auctions offering genuine A123 cells get my attention :D. I can't resist to pay $10 including shipping for 4 1.1AH genuine A123 cells. Here is the seller. They offer variety of tab options, since I am not interested to spot weld my own tabs, I pay $.80 more to get tabs added.

Despite the holiday season, my cells arrived in less than 2 weeks, much sooner than I expected. Nicely packed, tabs as ordered, kudos to this seller, he is doing a great job so far. All cells at exactly 3.3V.

I whip out my trusted single cell LiFePo4 6A charger and within few minutes all cells are at 3.65V. They arrived at about 75% SOC based on my charge current/time measurements. Now they are 100% SOC and top balanced. I drilled tabs, so I can use #4 bolts to assemble them in series.

Now I have a 1.1AH 12V LiFePO4 battery that cost me $10 and looks like something terrorists in movies cobble up to blow stuff up :D

My smallest 325VA UPS which powers my Internet/VOIP/WLAN and has to fit inside of a small in-wall wiring cabinet died recently, so a trip to CompUSA and $35 later ( they had a good sale on $50 ULTRA model which is small enough to fit my cabinet ) I have a new UPS to boot.

I am disappointed that new UPS has 6V battery, not 12V as my old one had. So, I take apart my newly assembled battery and reconfigure it from 1P4S to 2P2S. Same energy capacity, just different V vs A ratio to match the UPS.

Bingo, UPS comes alive and kicking. I measured my load on this UPS to be around 20Watt, the battery is 2.2AH*6.4V = 14WH, so it will survive up to 40 minutes power outage, which is at least twice as much as the LA battery would do. Best part, this LFP battery will outlast the life of UPS and possible the house its in :D, so no more replacements, woohoo!

Pics attached.

DSC_3270.jpg

DSC_3271.JPG

DSC_3273.jpg

DSC_3277.jpg
 

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Discussion Starter · #2 ·
BTW, before I put the battery in the UPS, I was curious how it lives up to its specs, so I loaded it with 1 Ohm 50W resistor when it was still in 12V 1p4S config, which produced about 12Amp current, which is just over 10C for these cells. The battery proudly sustained 10C for over 5 minutes, just getting barely warm, which I can't say about my load resistor :eek:. I had to place it on aluminum plate or it would burn the hole in my wooden bench :D

I did not wait full 6 minutes to get to the bottom cliff of the discharge curve, I didn't feel like spending another $10 and wait another 2 weeks to get my UPS up and running. But even with 5 minutes at 10C for fake A123 cells its a decent performance IMHO. Voltage was above 3.0V per cell almost entire time. I think 20C could be sustained with appropriate cooling.

Cost per AH is about $2.50, twice as much as large prismatics, but it would be very labor intensive to build large packs for DIY people without proper equipment. Still, I think these cells have their place in various smaller applications.
 

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Kind of funny you brought this up. In 2007, long before I got interested in EV's, I bought 12 ANR26650M1 2.3AH cells from A123 Systems to test these new battery types. After they arived I checked the cells and they were all little above 3.3v. I left them on the shelf for over a year to see how much they would discharge in time, a year later they were all about the same voltages exept one was a bit lower, but not enough to even matter. To say the least, I was impressed considering my past experience with nicad's and nmh cells.

Since then I have put four together to make a 12v pack and used it for several little bench projects to test performance, and I was surprised with the performance of the cells. I used an FMA Cellpro 4 to do some charge and discharge tests just to see how they behaved under load, btw the Cellpro charger is a remarkable little device.

Since then I have used some of the cells for things like powering up one of those remote weather stations with radio clock, got tired of replacing the two batteries in the base unit and having to reset it everytime I changed batteries. Also used one of the cells and build me a eCigarette out of some PVC fittings, I charge the eCig with a switching ac/dc 3.3v wall wart I found from a supplier on the internet, it surprisingly charges the cell to exactly 3.6v.

I also have two APC XS1300 UPS's here in the office/shop, one server and two work stations, and was thinking about doing the same if those batteries ever go bad.

The A123 ANR26650M1 were a bit expensive since I had to get them from A123 in order to be assured I was getting the real thing, they were about $19 each including shipping, but it is what it is when one wants to test stuff...lol


Roy
 

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I've also bought cells from the same seller, but in 26650 size.

Fake or not(how to tell?), I was rather satisfied with them. Cordless drill got a new life with 4S-pack:)
 

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I don't think these are "fake" A123, rather they seem to be "B" grade rather than "A" grade A123 cells - just don't pass QA in A123 manufacturing (which is now located in China?)

Roy Von Rogers - can you tell me the ebay user that sells the switching ac/dc 3.3v wall wart, you mentioned or what make it is? I'm looking for a cheap single battery charger - doe sit have auto shut-off & what current?
 

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Powerstream.com....PST-AC0330W

Its rated as a 3.3 wallwart, I tested and it stoped at exactly 3.6 volt on an overnight charge.

Roy
Thanks Roy, much appreciated - I see they can output 3A current so it shouldn't need overnight to charge a 2.3A A123 single cell. I see also that this is a CC/CV charger great!
 

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Discussion Starter · #9 ·
I don't think these are "fake" A123, rather they seem to be "B" grade rather than "A" grade A123 cells - just don't pass QA in A123 manufacturing (which is now located in China?)
I don't buy such theory. If A123 doesn't sell directly to DIY market, why would they risk their brand value by selling "B" grade product, yet not selling their "A" product, makes no sense.

In any case, the thread name was a "tongue in cheek" comment, I really like these tiny cells for small applications, in fact I ordered bunch more to replace Lead Acid in all my UPSs and my friends and relatives's UPSs, these are wonderful for the job, I don't care who makes them.
 

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I don't buy such theory. If A123 doesn't sell directly to DIY market, why would they risk their brand value by selling "B" grade product, yet not selling their "A" product, makes no sense.

In any case, the thread name was a "tongue in cheek" comment, I really like these tiny cells for small applications, in fact I ordered bunch more to replace Lead Acid in all my UPSs and my friends and relatives's UPSs, these are wonderful for the job, I don't care who makes them.
Sure, I understand where you're coming from & it seems logical but on the other hand, what do you think A123 do with the batteries that don't fully pass QA? I've read that they allow them to be sold as long as they are not identified as A grade - i.e the "fake" part is that they put another green plastic sleeve over the underlying one with the barcode on it. This new plastic sleeve says A123 & this is not what A123 want, AFAIR. Anyway, if you strip off the green plastic sleeve you will see embossed on the metal casing of the battery IDs which identify them to A123 manufacturing process. Why would fakers bother to do this & then cover them with 2 plastic sleeves? The tests on these batteries show them to be pretty much bang on the capacity & performance of all A123 batteries - I don't know what the QA failure condition is?

So in essence, you are correct, they are fakes but only in the sense that they are mis-labeled as "A" grade. Once people know this, there is no fakery & nothing wrong with them. I hav ebeen using these for a long time & have never found a problem with them.
 

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I bought thirty 18650 cells from this seller and do confirm that batteries are of good conditions. Yes, it is B-grade product (I like the price though), but is way way better than any other "alternative powder" based China manufacturers - none of no-name batteries is capable to provide high currents like these A123 "lower grade" cells.
http://s.dealextreme.com/search/lifepo4 - buy "real fakes" and compare to the subj cells.

Also I am interested how can you tell that such a store don't sell same accus screened out by A123 quality control?
http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=6444 - $17.96/pc vs $9.25 directly from China.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190459815991&ssPageName=STRK:MEWNX:IT

I guess the only confirmed source for A-grade cells is Dewalt packs.

My question is - does anybody know where to buy larger AHR32113 batteries?
This chinese guy posted some promises
http://cgi.ebay.com/16A123-systems-...830095543?pt=US_Batteries&hash=item3a66a384b7
"And A123 32113 will be provide in the future!"

Please share info on AHR32113 sources. Thanks.
 
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