Big LI-FE Lifetime?

[VidPro]

Tell me a story of LI-FE and TIME
Ok you have had your Big Li-Fe things for enough years. I know some of you even do RC and Hotwire where your harsh on every battery you get your hands on. :grin2:

Please show me a thread, or Post, or please post HERE your wonder stories of BIG Li-Fe batteries that have lived forever.
AND
Please tell me about anything you can come up with where you have TIME and Capacity still. or where you have seen X% of drop.
Time, Cycles, Storage, Power tool, EV , Guesses, asumptions, Anything.
does your li-Fe robot still run for 5 minutes on a charge?
Is your Drill in need of a replacment pack even if it was Li-Fe?
Does your flashlight you moded with Li-Fe still run as long today as yesterday?
Did you crash your li-Fe airplane before the battery ever died on it ?
are the Li-Fe batteries in your hybrid working well?

I have a good idea about how long my specific Li-Ion and Li-Poly will last, (never long enough) and i have some little snot nosed li-fe Rcr123 things doing fine. but i want to know about POWER and Life and TIME especially.

 

[45/70]

Well Vid, I don't think my comments or observations are exactly what you were looking for, but anyway.

I've been using some DX RCR2 LiFe cells for a little over a year now. They seem to be just as good as when new. I also have some DX RCR 123 LiFe cells. I've had them probably six months, they too work as when new. Recently (2-3 mos.) I obtained some DX 18650 Life cells. Half of these arrived with screwed up shrink wrap, but after some neanderthal repair work, they seem fine as well. OK, so none of this really comes as a surprise. They aren't old enough.

Just going by what information is available for LiFe chemistry cells, for example "2000 cycles vs. 300" for LiCo cells, and a usually estimated 10 year calendar life for LiFe cells vs. 5 years for LiCo, it's hard to come to a decisive conclusion as to how long they will last. Of course, I don't imagine DX LiFe cells to be comparable to A123's, so none of this probably means anything. :) All the same, I'm figuring LiFe cells to hopefully last about twice as long as LiCo's. This will make up, in part anyway, for their comparatively lesser capacity (most noticeable when you see a LiFe powered Tesla Roadster with a battery cart in tow).

For me, it's not the safer chemistry of LiFe cells, or their supposed longer calendar and cycle life. What is important to me, is the lower voltage that makes them compatible with certain devices that are voltage sensitive. LiFe cells are the only rechargeable alternative in a Li-Ion cell for some applications, except for diode voltage corrected LiCo cells which appear to be being phased out, so I'm stuck with them.

The biggest problem with LiFe cells, is determining the SOC, as you and I discussed before. The voltage is so consistent during discharge, that you can't really estimate their capacity, with or without a load applied, with any kind of accuracy.

It will be interesting to read other's responses to your questions, as I'm curious as well.

Dave

 

[mfm]

I obtained some DX 18650 Life cells. Half of these arrived with screwed up shrink wrap, but after some neanderthal repair work, they seem fine as well.

What do you use the 18650 LiFEPO4 cells for? My imagination only came up with a Solarforce low-voltage pill and a P60 host.

 

[45/70]

What do you use the 18650 LiFEPO4 cells for? My imagination only came up with a Solarforce low-voltage pill and a P60 host.

Neofab Legion II, 3s 18650. It starts warning somewhere below 7.5 Volts and cuts out around 2 Volts/cell under load, so it works well with LiFe, except for the runtime, of course (around an hour @ 600 lumens, ~10-12 hrs @ 85 lumens). With protected LiCo's the protection circuits could trip, leaving you with no light, and unprotected LiCo's could discharge too low if you don't check the "battery gauge". I'm not sure about that, as I've never run any cells that low. I figure the LiFe's will spring back some, and you could run at a lower level for a while. I use both chemistries.

Dave

 

[Hrvoje]

Have a look here:

http://www.rcgroups.com/forums/showthread.php?t=672512

Hrvoje

 

[VidPro]

Well Vid, I don't think my comments or observations are exactly what you were looking for, but anyway.

Dave

it is thanks

 

[BlueFusion]

I did some research before deciding i REALLY wanted to have LiFe.
From what I found, nobody really knows just how long they last, because nobody's actually ever used one for long enough to find out. Talking 10+ year lifetimes... guesstimates are around the 20 year mark at 80% capacity. YMMV