LFP or LifePo4: questions about using

Re: LFP or LifePo4: questions about using

I also understand some of the mfcts/sales recycle and/or refurbish the cells.
If I could point out:

Please do point it out. Who ??

I had a guy with some 700, A123 pouch cells ask me about it, they were all blown out on the sides. I had no answers but to ask my local guy. I do lead acid every week @ $.31 a lb for wet lead.

Re: LFP or LifePo4: questions about using

They speak 'Strine' in Australia and it only slightly resembles English. They do spell the words honour and colour in the English format. We replaced the 1st RAR in 173rd Abn in 1966 and I had an Aussie SAS platoon sgt as instructor at MACV Recondo School Class 03 in November.

I think he speaks of reading German because they are pushing solar further than the US.

$3500 is scarcely massive compared to the cost of a house and a large solar array. One chooses where to save and where to spend. If one chooses to spend their funds on trivial pursuits and not save for more meaningful uses, well that is just fine. And if one saves their funds to develop their home further, that is also just fine.

Re: LFP or LifePo4: questions about using

Blackcherry04 wrote: »

How about a name and number. I'd like to know the shipping requirements and get that free offer in writing.

It's not a service to ship in and recycle, it's a service for their customers, Want something for nothing, I'll send you some rubber biscuits....

Company is Battery Outfitters.

Re: LFP or LifePo4: questions about using

creeky wrote: »

From what I've read, it appears almost any good quality controller can be programmed to charge LFP batteries. I am contacting the battery provider about their recommended solar charge settings.

First, you MUST disable temperature-compensation which comes with most quality CC controllers designed for lead. Then, depending on how conservative you want to go, an absorb value anywhere from 13.8 - 14.2 is safe. Some of us prefer to use the lower end, 13.8 - 14.0, whereas those like Genasun, use 14.2v. I, like some others feel that is just a tad too high for naked-cells. You can finish absorb or not - it's up to you. Finishing absorb usually nets you little extra capacity, so many of us skip it.

Those driving external balancing circuits will usually have to take them up to 14.5 - 14.6v in order for the bleed off circuitry to kick in.

PNJunction and Reed. Could you share the solar controller/charging settings you use with us?

Reed and I differ in our setups. I'm only running 12v batteries. I personally never take any cell higher than 3.5v (14v on the battery) and don't have any balance issues of any practical major proportion. I have an external lvd set for 12.8v with a small timer. A hard lvd for me would be about 12.5v (3.125v per cell) for the oh-crap moments if I should forget. My CC or ac charger serves as the hvd. You see references to not going below 2.5v, but that is that start of catastrophic damage. Give yourself some headroom with 3.1v lvd or so.

IMPORTANT: If your cells start to drop into the deep discharge knee out of the flat area, like at 12.8v (just below 3.2v ), you should bring them back up to this point SLOWLY with no more than 0.1C current, whereupon you can apply higher currents when you get out of the knee. This will be quick usually, but the inability to control charge current to no more than 0.1C when below 3.2v per cell by most solar controllers means you shouldn't drop much below 12.8v overall in the first place. Some EV'ers that drag their battery down to 90% DOD or more, and apply full-charge current at that low a level risk swelling and eventual failure.

There is no need to float lifepo4. If you can't disable it, drop it to something benign, like 13.6v (3.4v cell), where after a full charge, this float value will have no current behind it. It may also serve as a parastic-load catch prior to draining your battery down to the lvd in case of neglect. Long-term study of this low-voltage, no current float affect has not been done to my knowledge, and only consists of anecdotal stories. So far, I've seen no harm when my Samlex charger drops to float / no current. Not that I want to leave it that way, so I pull it off, but don't freak out about it.

I'll have to let you do the math for this. You know that you can operate the cells from 0-80% DOD. There is no peukert effect to speak of, so you can draw nearly any current you like to that point. I would still suggest no more than 50% DOD to give yourself some autonomy or unexpected load capability. Or anything in between.

The big problem for you is that the *reasonable* operating range of lifepo4 is from 0C / 32F to 60C / 140F. You may be able to go colder, but with limited current. I have no first-hand experience with that, but know that when real cold, you do NOT want to hammer lifepo4 with heavy recharge current. Essentially, the intercalation slows down, receptivity sites are clogged, a "traffic jam" of ions occurs in the electrolyte, and now bad news on your hands.

Tell you what - if anyone wants to see safe and sane specs for charging coming from other than the battery manufacturer or internet forum chat, look up the Tecmate-Optimate Lithium 5A charger manual available online. Although intended primarily for powersports users, (I used it to initially balance and TEST my larger prismatic GBS batteries), the information contained within the manual is invaluable. It may also be one reason it is recommended by a few powersports guys like Antigravity, EarthX etc. It is always nice to get a second opinion. When I saw that they operate much the way I do, I added it to my battery maintenance toolchest. They are also much more than a CC/CV charger, but enough about that. The main thing is that the manual has some very important information in general.

Re: LFP or LifePo4: questions about using

Prior to disposal, one should totally discharge the battery. You have effectively "de-lithiated" it, so no more lithium. Mark it as "bad" or "do not recharge" as the cell has been purposely abused for this purpose, and attempts to recharge them are now going to cause problems for dumpster divers. Parasitic reactions at total discharge, especially for a period of time, eats away the battery internally.

All that's left after a total discharge is plastic, graphite, copper, aluminum, and some inorganic solvent in the small amount of electrolyte. The lithium, as such, is for the most part gone after a total discharge.

Any attempt to discharge them, put them in salt water, wrap in towels, bury underground, and perform various witches spells over them mean that one is looking at the hobby / toy model industry, which are not using lifepo4, but a different chemistry.

Re: LFP or LifePo4: questions about using

PNjunction wrote: »

I'll let Professor Jay Whitacre from Carnegie Mellon explain it as he did to a group of those who were using the old Thundersky lifepo4 cells.
http://www.ri.cmu.edu/video_view.html?video_id=60&menu_id=387

Many thanks for the link, I hadn't seen this before.

Very good and accessible explanation about LiFePO4 batteries. Certainly shows that the devil is in the detail, and that all batteries and manufacturers are not the same.

Thanks!

Re: LFP or LifePo4: questions about using

While the class is primarily intended for those students of lifepo4, he does branch out into generics of other chemistries, like LiCo02, which we don't use at all. It is also a favorite among EV'ers to disect to prove their own point of view with religious fervor, hanging onto syllables for meaning. What they miss entirely is to just use a common-sense approach and one should do fine. Going overboard with hobbiest related ideals may prove to be technically correct, but impractical in the long run. Much like obsessing if you should use 14.4 or 14.4555v in absorb for agm.

The quality of the separator is important, and just like lead-acid manufacturers, there can be variables in manufacturing quality. That is one reason to stick with the major players, like GBS, CALB, Winston, Sinopoly, Balqon, Hi-Power. But we won't know how well their separators stack up for another 10 years.

Another class by Prof Jeffrey Dahn at Dalhousie U goes deeper into the study of the electrolyte itself, along with heat-related issues, the fallacy of repetetive cycle-testing, and together with Jay Whitacre's class, one can get a real education:

https://www.youtube.com/watch?v=9qi03QawZEk

For me, the biggest take-away from both of these is that keeping the charge voltage low (like 13.8 to 14.0) and letting it absorb (or not), is better than constantly driving these cells to 14.4 to 14.6 to satisfy the needs of the external cell-balancers, even though technically you might be within spec. What may be waiting for us is the sudden-death syndrome down the road due to electrolyte oxidation, exacerbated by both high-heat, time, and high voltage. THAT is why I run mine conservatively.

Always keep in mind however that we are using the least energy-dense version, lifepo4. Many fires from lifepo4 are not due directly to the battery itself, but to the infrastructure connected to it with poor wiring, high-resistance/loose connections etc. Unfortunately, that is used to denigrate the technology of the battery itself.

It is much like the turn of the last century, where those with horse-drawn vehicles quickly point out how lead-acid technology in the new-fangled electric vehicles which may have caught fire blame the battery, and not the owner's own abusive charging / lack of maintenance which set his infrastructure on fire. And in the case of NiFE, which was (and still is!) a far more advanced version of lead-acid, was an expensive investment to lose.

Re: LFP or LifePo4: questions about using

Alaska Man wrote: »

Watched that which led me to the UltraBattery® from the engineers at Ecoult and the EastPenn Manufacturing Co. buy out.

Interesting. When you get your hands on one, let us know how it goes. You had me until I saw the sales / investor pitch. Maybe a separate thread would be the better solution.

When I talk about lifepo4, I do so generically, from established competing companies, like GBS, CALB, Winston, Sinopoly, Hi-Power as some of the major players. I dislike single-vendor, locked-in solutions and prefer the amount of choice one has with lifepo4 - and also the ability to get them next-day if you need them that badly.

At any rate, I'd hate to see this thread diluted with vaporware batteries, those available only to OEM's, the hundreds of improvements in labs of all chemistries "available any day now" and most especially investor pitching. But that's me.