lithium

Re: lithium

Plus I don't trust them yet, that they won't suddenly erupt into a 4'th of July fireworks display.
They seem to be great batteries if they can be economically controlled. AKA Boeing 787. And THEY have money to spend!

Re: lithium

People have been doing it for years, but perhaps not so much for fixed solar installations.

To be sure, they cost a pretty penny up front, but the lifecycle cost can be competetive when all the other aspects of the chemistry are desired. BUT, you have to do your homework in regards to your power budget. Slapping in an under-capacity bank will be a costly mistake. One valuable thread about house banks in a marine setup can be seen here:

http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069.html

Know that "Lithium" or Lithium-Ion batteries come in many flavors, much like specifying a "lead" battery without mentioning the difference between flooded, gel, agm, starting, deep cycle, long term float and what kind of doping material they use, (lead, antimony, tin etc).

The two most common are Lithium-Cobalt-Oxide (Li-Co-02). Think cellphones and laptops and RC model planes - and even some commercial ones. Charge is best done in a fireproof bag - or at the very least your fireplace to remain safe. If your charger, or bms system has the slightest of problems, then you will witness that pretty quick first hand.

The other common chemistry is Lithium-Iron-Phosphate (Li-Fe-p04). THIS is the chemistry that is much more stable, but gets commonly confused with the unstable ones above. Think advanced lifepo4 powersports batteries where they are actually placed under your motorcycle seat or even directly behind the gas tank. No fireproof bags. Lifepo4 is the chemistry to use in a house-bank.

How could this be? The tradeoff lifepo4 chemistry has over the unstable cellphone battery, is that is has HALF the power density. Thus lifepo4 are about 2 times larger than lithium-cobalt, but much safer. Essentially lifepo4 have a very strong valence bond to oxygen, and greedily holds on to them. They can also take some wider charge voltage swings than the cellphone battery chemistry. Because of their relative size, you don't find them in cellphones and laptops. However they are still about 1/3 to 1/5th the weight of comparable lead-acid. There are other differences but I won't go too far into that here.

The problem is that the average consumer is not educated on these differences, and may be fearful from sensational videos and articles that don't actually spell out WHICH chemistry was used, or the battery is undergoing insane amounts of abuse. Other than that, there are also spectacular stories from those using trash componentry, such as counterfeits, factory rejects, intercepted used cells from becoming recycled, etc. Poor hobbiest construction with a total lack of safety is also commonly seen.

Anybody here with the remotest interest in battery technology could prove it to themselves, rather than believing everything you read on the internet - like me! Instead of going large, you can make a good "learner battery" setup, like one does with walmart flooded batteries, with a simple, but high-quality powersports lifepo4 (Like a Shorai, or Antigravity - 2.5ah at least - that is to get "real" Ah if not stated directly, divide any motorcycle starting "PbEq" value by 3) and prove it to themselves. If you don't have a decent charger to test with, then an Optimate TM-291 lifepo4-specific charger will help you recover SAFELY from a mistake.

Re: lithium

All the above looks like good stuff. If you had a Lifepo4 bank, you'd be amazed at how less fuel your generator will burn as the internal impedance is so low, you'll ramp right up to 90-95% with full efficiency before hitting a miniscule absorb current time.

Lifepo4 is certainly what I'd run with in an environment with limited solar insolation. I mean I loved my TPPL Hawker Cyclons / Odyssey's, / Enersys agm's since I could just pound on them with current without missing a heartbeat, but man, these lifepo4's blew me away. Anyway....

However the average guy will probably end up with CALB, Winston, Sinopoly, GBS type cells from the EV market. If you got the bucks, then Genasun is worth looking into. When the budget allows, I'll be picking up a Genasun solar CC to replace my Xantrex and Morningstars. As always, avoid fly-by-night outfits and deals too good to be true, otherwise you'll end up with poor performing junk.

Unfortunately, the shark filled waters of patent litigation impede progress, but patent reform is best discussed elsewhere. However, that is one real-world consideration to think about if for some reason your 2 year old pack has a problem, and needs cell replacements.

As much as I like lifepo4, if you are doing it on a big scale, you MUST go into it with your eyes WIDE open.

Re: lithium

Seems that page is gone.

It may not be intentional but you bring up a good point - homebrewers had better know the difference in chemistries, as Lithium-Ion encompasses the whole spectrum of sub-chemistries which have different voltage and stability / safety / charging characteristics.

Consumers often get confused between the spelling and distinction between Lithium-Ion (as an entire class) and Lithium-iron, which is the lifepo4 sub chemistry. That little "R" makes a big difference! I'll bet that page was really intended for the industrial buyer or manufacturer, who actually knows what chemistry they are looking for.

Sloppy or uninformed journalism just lumps all Lithium-Cobalt accidents under the entire umbrella, and Lithium-Iron-phosphate suffers as an unintended or intended side effect.

Re: lithium

Got it now. Looks nice.

The data sheets *imply* that it is a stable Lifepo4, but I would not personally be comfortable if in fact it is LiCo02, or Li-Cobalt !

Of course they are covering all the bases, but the emphasis is not much different from the warnings for a typical commercial lead-acid battery.

The average consumer or even manager who directs his engineers to look into this, may not know or even care about the sub-classes of Li-Ion. In fact, spelling out the actual chemistry like lifepo4 may make some commercial purchasers think it is not as good as "Li-ion". Ah, marketing.