Anyone familiar with LFR/Tenergy LiFePO4 32650 5500mAh 3.2V Rechargeable Batteries?

AaronAnder said:
Hi Aaron! I just picked up 640 of these batteries! I'm am testing them now. So far, the first cell gave me 5000mah of the advertised 5500mah
PM me, let's keep in contact. I'll also keep posting here as well.
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I have purchased and tested some of these cells. The discharge capacity tests (Powerlab 8) show about 4850mAh, ~88% of rated capacity. If you apply the Peukert Effect with a Peukert exponent of 1.07 and a 5500mAh capacity rated at C/20, you get 4950mAh at C/5.

These cells were in storage since 2013. My research about the effects of longterm storage of this duration was inconclusive. I suspect that these cells were overrated at C/20, instead of the C/5 standard.

I haven't found a datasheet for these cells. Datasheets for Tenergy 5000mAh 32650 put the rated discharge at 2C or 2.5C. These cells are most likely Energy Cells, as opposed to Power Cells, which should make them appropriate for power walls.
 
http://www.all-battery.com/datasheet/30069-0_datasheet.pdf
http://www.all-battery.com/datasheet/30071_datasheet.pdf

Even if the tests at C/5 show lost capacity during aging, the tested remaining capacity, which coincidentally happens to be ~5Ah at C/5, coincidentally yields ~5.5Ah at 0.275A (C/20 at 5.5Ah C/20 rating). Since deep cycle batteries are usually rated at C/20, that's what we want for a house bank.

https://planetcalc.com/2283/

How much usable life remains after 3.5 years of storage at full charge? That is the question.

Here's a shot of my 10p test bed with the 32650s.

Oops! I tried to upload a photo, but it didn't take. The new post appended as an edit to my previous post, and now it won't edit to redacted the edit to reflect the attachment failure.
 
image_ftmfuo.jpg



image_fekrde.jpg


Balanced parallel wiring.

I have charged and discharged the 55Ah 10p battery at 11A, and nothing even gets the slightest bit warm.

Voltage drop across each contact is about 5mV.

The contacts are Keystone Electronit's 1016-1, gold-plated.

*Keystone Electronics
 
Pretty kewl :) I love that setup. Gives me more ideas.... :idea:
 
Korishan said:
Pretty kewl :) I love that setup. Gives me more ideas.... :idea:
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Thanks for the compliment. I used what I had layingaround. Other than the Powerlab and cells,I only had to buy the contacts and ring terminals. I even had a brand new box of screws that I bought four years ago and never used, and they were perfect for the ring terminals.
 
Sweet! Where did you get the contacts?
 
Korishan said:
Sweet! Where did you get the contacts?
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Digikey 36-1016-1-ND. They're actually sized for AA/AAA/N (universal), so I came up with the risers to offset the height. Some 1/4" woodstrips underneath the cells made it a perfect fit.
 
I like DIY designs and this is exactly that :) Looks good.
 
daromer said:
I like DIY designs and this is exactly that :) Looks good.
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Thank ye. And thanks for fixing the text for me. I've had difficulty with the text interface on the Galaxy S6 on various forums. Changing the keyboard helped with the jumping cursor bug, but now autocorrect is doing strange things.
 
There is little to no information (independent) about those cells and it looks a wonder, because they seem to be 2013 stock. I just ordered a box of Tenergy 32650 and hope for ~ 90% of stated capacity. I have a reason to believe that Tenergy is = LFR (unlike Fullriver, with some bad reviews but similar price and appearance), markings on the metal shell of the cell seems to be almost identical, some numerical variation in date and 2 more digits vary from sellers pictures. Have contacted a guy who purchased a box and he says it must be about legit capacity. Fingers crossed, will report back.
P.S. There are Fullriver 26650 7p blocks (spot-welded) from 2014 (as it looks like from the pictures) 3.3Ah cells. Very nice assembly for future pack build but, I am afraid of the 2 ES posts, stating they are real BS.
 
parabellum said:
There is little to no information (independent) about those cells and it looks a wonder, because they seem to be 2013 stock. I just ordered a box of Tenergy 32650 and hope for ~ 90% of stated capacity. I have a reason to believe that Tenergy is = LFR (unlike Fullriver, with some bad reviews but similar price and appearance), markings on the metal shell of the cell seems to be almost identical, some numerical variation in date and 2 more digits vary from sellers pictures. Have contacted a guy who purchased a box and he says it must be about legit capacity. Fingers crossed, will report back.
P.S. There are Fullriver 26650 7p blocks (spot-welded) from 2014 (as it looks like from the pictures) 3.3Ah cells. Very nice assembly for future pack build but, I am afraid of the 2 ES posts, stating they are real BS.
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Before I pulled the trigger at eBay, I chatted with someone at insightcentral.net who has purchased, tested and used the Tenergy (LFR, whatever) cells to build a motorcycle battery. In the forum, he estimated the capacity at about 2.6C at about 4800mAh, in a very crudetest. Chatting with him gave me some confidence. I think he bought his back in October .

I also spoke with Doug'sDeals. They acquired the cells in June of last year and stated that after 3 cycles the cells tested close tofull capacity, though they weren't more specific than that.

I saw a couple of negative comments about the Fullriver cells too, so I shied away from them.

88% is close to 90. ;) The single cell capacity tests I did were in a first attempt at a battery holder, and the contacts were loosey goosey, so the contract resistance undoubtedly affected the results.

In the 10p test on the V2.0 rack, the contacts are super tight. However, with 20 contacts, even though the total resistance would be the reciprocal of the sum of reciprocals, it could still affect the results.

By the way, the cells I received have Tenergy on the box. My micrometer measures the length at ~70mm, so they're 32700s.

Also, regarding my capacity tests:

The single cell tests were charged to 3.5V down to C/100 A and discharged down to 2.8V.

The 10p test was charged to 3.65V to C/20 and discharged down to 2.5V, per Tenergy's 5000mAh 32650 datasheets.

All things considered, they could have 5000mAh, as stated elsewhere, given the flaws in my procedure. I reported 4850mAh based onmy 10p test.
 
By micrometer I meant measuring caliper. Why do I want to call it a micrometer? I don't know.
 
skyfridge said:
By micrometer I meant measuring caliper. Why do I want to call it a micrometer? I don't know.
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Because it also measures "micro meters" :p just slightly differently
 
That's when inspiration is at its finest!! Or, is that perspiration? Hrmm....
 
Korishan said:
That's when inspiration is at its finest!! Or, is that perspiration? Hrmm....
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Exhaustion, too. But I did find some inspiration last night and came up with the Battery Sandwich. See Jack'sBuild Thread for details.
 
Hey! Let's watch paint dry together. I started the C/20 test 2 hours 44 minutes ago. There's only about 17 hours to go.

I'm too excited to sleep!


image_qctgzl.jpg
 
LOL

what program/gear are you using to monitor/test with?

And why are you in airplane mode? ;)
 
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