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bldginsp
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# Posted: 17 Jul 2014 08:52am
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I briefly googled lifespan of lithium batteries but came up with nothing conclusive. Cel phone and laptop lithiums generally are only good for a few years if that, but they usually get severely abused. I would only invest in a lithium battery for PV if I had a real assurance about its longevity, all other factors aside.
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old greybeard
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# Posted: 17 Jul 2014 09:02am - Edited by: old greybeard
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Quoting: bldginsp Can any lead acid battery last over ten years?
We'll see. I use USED 4D batteries I pull off our emergency generator at work, After service for 1.5 years, maybe 15 generator starst, I keep the core and take them to camp. Oldest was bought in 2009. I'm running 2 batteries each fed by a 80w panel and individual pcm controller. At camp 100+ days a year. Light usage, lights and TV, except in winter when I can fall below 50%. So far holding up fine.
And we pay about $130 new.
Hard to justify $3500.
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Steve961
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# Posted: 17 Jul 2014 02:56pm
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Quoting: bldginsp Can any lead acid battery last over ten years?
According to Northern Arizona Wind & Sun, a solar company I trust, certain industrial forklift type batteries can last 20 years in a typical solar system.
A Crown industrial (forklift type) battery, 12 Volts at 530 AH would provide about 2.9 Kw at 50% DOD. The cost for one of these is about $1,550. Comparable in cost and capacity to the 2.6 Kw lithium mentioned previously, but with a proven history of longevity.
The major disadvantage to one of these is the weight - 465 pounds vs. 94 pounds for the Lithium. One advantage to the extra weight is that thieves would have a hard time stealing it. 
Crown Industrial Battery - 12 Volt, 530 AH
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creeky
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# Posted: 18 Jul 2014 02:17pm - Edited by: creeky
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thx all for the laughs. oh my stomach is sore.
Not to pick out just Steve. but. A 500 lb battery. that's hilarious. Oh. Again. Whew.
Tech note: The warranty is 1,500 cycles at 80% dod. lead acid solar battery systems that last for 20 years probably use a 10-20% dod. So you'll need a few of those things. Wheeze. Gasp.
And, $1540 before shipping 500 lbs. Excuse me while I wipe my eyes. Man. That is funny.
On another note: Buggy*, horse** and whip for sale. Proven technology. Thousands of years in use. Google the automobile: cars kill thousands. Tens of thousands of mutilations. Don't be fooled. A **reindeer and *sled is the better alternative. Free first bale of hay included. Send 1/3rd less than the price of a Prius to: Santa Box. 101 at h0h 0h0 North Pole, Canada.
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Steve961
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# Posted: 18 Jul 2014 02:48pm - Edited by: Steve961
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Creeky:
Even you should know that warranties do not reflect the typical lifespan of a product. The warranty on your beloved Lithium battery is only 5 years (prorated), so should we assume that's its lifespan?
500 pounds for a battery is a disadvantage, which is why I specifically mentioned it. It's not a deal breaker though as most people live near a large enough metro area where industrial batteries can be purchased. You will need a pickup truck or trailer and some burly friends though.
In the end a Lithium battery is still just a battery. It's not some revolutionary product that obsoletes all existing battery technologies in use for solar power storage - contrary to your buggy vs. automobile analogy.
I will always choose a technology with a proven track record when it comes to my hard earned money and personal safety. In 10 years or so when I'm looking for my third battery bank, I may very well choose Lithium.
Edited to add that I only brought up industrial batteries in response to a question if lead acid batteries could last more than 10 years, which they can. I personally use smaller AGM batteries that weigh much less.
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creeky
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# Posted: 18 Jul 2014 04:30pm
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Steve, I was having a laugh. I too have a lead acid battery pack (720 lbs). i must have misread because I thought you and old greybeard were kidding and using exaggeration as comedy.
As I've stated: I put this post up because some folks may be actually building a solar system this year.
For a cabin where they expect, as I do, to spend many happy years. With kids (grandkid!) that play video games. and parties with a tv and lights and a fridge running all night long. and living life in the modern age.
So you're not. Okay. But (and you aren't the only one) why try to run it down?
and you're wrong. it does, completely, change the dynamics of solar storage. 3x lifespan. 12% and up more efficient charging. What???
so to turn my post about a small full time off grid system into a weekender light use system and sniff. ya okay. I get it. different needs. tho to make crazy comparisons with 80% discharge rates. well. you know. that's pure h.s. So ... no high horses right.
this whole longevity/proven thing is also simple diversion. Really. You're going to put your family into a car without seat belts or child seats? what did that comedian say? "when I was a kid we weren't too good to sit in the back window of the car"
This post is about making cabin life, off grid, easier and more fun and cheaper. Here's a battery that may have a slightly larger up front cost but offers (if you read my posts) amazing advantages in cost, lifespan, easy of use, temperature handling (man this thing works from the hottest desert to the frozen arctic better than lead acid) ... and the capacity is nutbars huge.
If you were spending thousands of dollars on an off grid power system for your family wouldn't you want to see somebody point out this tech, available now, free shipping?
jeez. i see folks post pics with nice trucks, big families, all kinds of toys (I've lost track of how many four wheelers i've seen) and building lovely cabins. I can't think that 3,500 bucks for 25 years of electricity storage is unlikely.
and a 500 lb battery. sorry. but that is still funny. cheers.
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MtnDon
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# Posted: 7 Nov 2014 04:05pm
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These LFP or LifePO4 batteries have been mentioned in more than one thread on the forum.
Over time I have done some searches for more info on the topic. Recently a link was posted to what I consider to be one of the better, if not the best, internet postings on LFP. I don't know the professional background of the author but this is an exhaustive piece. Points are made here that I never saw anywhere else. The author is a user of LFP in a marine application, about as close to being the same as an off grid cabin as you can get. IMO, this should be required reading for anyone thinking about LifePO4 / LFP batteries.
This is the link to page 1.
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Steve_S
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# Posted: 7 Nov 2014 05:13pm
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Geez, they even have 1000 Ahr batteries !
Looking @ the HIQAP Energy Storage Systems and now pondering options...
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creeky
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# Posted: 7 Nov 2014 06:50pm
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Steve_S. I've seen quite a few systems since my first posts. I've made some good friends. Two fellows in particular who have off grid systems with LFP battery packs. Both of them have had no problems for going on two years. And would never go back.
You can read about a fellow (not one of the above) who has been a test case. ron jones. also Technomadia, Gone with the Wynns.
in Australia you can find rare posts by folks who have been using LFP for 4 years. And loving it.
but they are hard to find, largely due to "leadites" who attack them online with, well, one fellow called it "nitpicking".
The neat thing is they don't require the maintenance or the special storage conditions. They are not toxic. Heavy. Nor do they self discharge and ruin themselves.
They are a bit pricey. They don't like being overcharged/undercharged. but neither do lead acid.
I still think it's a bit ... pwm vs mppt. Solar keeps improving. These are "mppt" ... aka, better batteries.
For myself, my FLA pack continues to work well. But I will never, under any circumstance, buy a large lead acid pack again. There is no need. They're buggy whips.
imho.
And if I needed a reminder. The cold season has arrived and my FLA pack is derating (losing power) as we speak. And needs watering.
btw. the hiqap systems come complete with over/under charge protection. battery monitoring etc. they look pretty sweet.
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MtnDon
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# Posted: 7 Nov 2014 08:06pm - Edited by: MtnDon
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The main disturbing detail I have read in a couple of places is that they should not be charged when frozen and when at low, but above temperatures it is recommended to slow down the rate of charge.
Our batteries spend months of their life in freezing temperatures, in an unheated and unoccupied space. That does seem to be an additional complication.
It just seems that the technology may not be ready for prime time use by people who need/want a plug 'n' play battery solution. I still recommend reading the info I linked to. It's not hyperbole from someone who has not actually used the technology.
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beachman
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# Posted: 7 Nov 2014 08:52pm
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This is a great thread BTW. I see the LFP as any new technology and they certainly sound encouraging. I suppose it is like buying a new TV that will be outdated once you plug it in. Only time will tell from those that actually move to LFP whether the move was worthwhile. This whole solar thing is moving quickly and I think every upgrade has to be progressive. Keep this thing rolling and I look forward to more comments.
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Julie2Oregon
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# Posted: 8 Nov 2014 05:17am
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So, I AM going to be living year-round in my cabin and having an off-grid solar power system put in. About 1,500 watts. How many of these lithium batteries would I need and would it still be possible to use a wind turbine to help charge them, do you think?
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Steve_S
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# Posted: 8 Nov 2014 08:53am
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FYI on Lithium Batteries: Operating Temperature -45 - +65 deg C and -45c = -49f, so unless your in the Arctic Circle (where solar would be pointless 6 months of yr) the temp issue is a NON-ISSUE. Mis & Dis-information abound from various sources. We have similar "packs" in military equipment and that stuff runs in the Arctic @ -50C and have done so for a number of years... Experience says that in "normal / non arctic" conditions these should present no issues. Can't speak to High Heat regions but never heard a peep about problems from anyone using the packs in the Middle East.
@Creeky we are just working out our Solar Needs for our current -> future build and the material here seems to fit the bill as it were... Will start a thread on that in a moment.
Yes a little more pricey BUT when you look at High Quality AGM with similar capacities, the price difference isn't really all that much when you consider maintenance & replacement costs.
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creeky
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# Posted: 8 Nov 2014 09:28am
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Thx Steve for the operating temp input. Look forward to your build.
Julie I have seen some of your posts about your needs. I would look at 9-15kw based on lithium (LFP). That gives you a regular fridge etc. One of the nice things about LFP, because of the longer lifespan, you can add to the battery pack, even years later.
A 15 kw LFP gives you around 7 kw usable. With 11kw in time of need.
And yes to the wind turbine.
You just set your battery charge voltage to 14.1 (in a 12v system) and avoid the possibility of overcharging.
I did see a post on an Aussi site where a LFP user talked about what he runs. He heats water electrically. He uses an induction cooktop. This is an attribute of LFP I had overlooked. It sustains higher power output (more amps!) than FLA. Which means it changes what kind of appliances you can use.
From my research I've also discovered LFP is best run between 40 and 90% charged. This should give you around 4000 cycles. Or over 10 years. This also neatly avoids the problem of over or under charging.
The hiqap system comes with a over/under disconnect for another layer of safety.
In my case: I'm of two minds with LFP. Do I go to a 9 kw system and kick the heck out of it (although at 4kw available that would be double what I get from my now cold FLA pack). Or do I spend another $2k and get a 15kw system that I rarely stress. Either system gives me more usable power than my FLA pack. (Or do I go for an 18kw 24v pack and buy a new inverter/charger spending $10k (taxes shipping etc in)? It would do me for the next 10-15 years.)
It's an interesting conundrum.
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Julie2Oregon
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# Posted: 9 Nov 2014 05:06am
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Creeky,
How many solar panels (and what wattage) would you need for that size of a battery bank?
I did find an energy-efficient 9.2 cu. ft. fridge. Aside from 3 small lights and a TV, I figured everything else would run on propane (or be a solar device already). If I could do electric on-demand hot water, though, that would be magic. Propane hot water, with the venting requirements, is a pain.
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creeky
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# Posted: 9 Nov 2014 03:12pm
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Julie, I do propane on demand for hot water and when time permits I will add solar preheat. The tagaki jr lets you use preheated water or cold and adjusts automatically. I see them around $600. I have an Ecotemp L12 (250). Same deal but you have to adjust the gas manually for the desired temp. Sounds reasonable until you're in the shower and you want the temp up/down
Venting is actually pretty easy. It takes one hole. The outlet pipe is inside the intake pipe on a good system. In my area, by code, the vent must be 3 feet from the corner of the house, 6" away from non opening windows and 10' from the gas tank. But you should check your code...
For solar
You may live in a better solar irradiation zone then I do. My zone is amazing Jan thru Oct and crap Oct thru Dec. So ... if I didn't have the 2.5 bad months... The fellow who heats water electrically is in a high solar irradiation area (australia) and heats water in the afternoon after his batteries are recharged.
***
Solar panels are so cheap compared to when I started with my system I tend to get carried away. Your idea of 1500, with your described loads, sounds really good.
I have taken an experimental approach to my system. I started with 1 kw. Worked great. Got a deal on .5 more. Worked better. What I like about the bigger system is I can use bigger loads in the afternoon on a sunny day. What I mean is, once my batteries are pretty well fully charged, I can run a dishwasher, laundry, etc without my batteries coming into use at all.
I've said this many times. But I prefer high voltage (48v) panels. They are easier to wire for long distances on smaller cable and are often cheaper due to the large volume of production.
I think Steve_S is talking about 320 watt panels. Bigger is better. imho. I have 250s as that was the best available at the time I bought. I would go 320s now, ahem, if the price was right.
enjoy.
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creeky
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# Posted: 10 Nov 2014 01:50pm
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I found this excellent reference on LFP battery suitability from Princeton U. https://www.princeton.edu/~spikelab/papers/101.pdf
The final paragraphs sum up : "studies suggest that LFP batteries may last many times longer than lead-acid cells in off-grid wind and solar applications and have significant potential to reduce energy storage costs over the lifetime of intermittent renewable energy system"
LFP also won hands down with "the best voltage performance" and showed "the least degradation" and overall rated the highest in this article.
Worth reading.
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MtnDon
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# Posted: 10 Nov 2014 04:09pm
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First, let me say I do realize the many benefits that LFP have. They are not without some potential issues, though.
Quoting: Steve_S Operating Temperature -45 - +65 deg C and -45c = -49f,
i guess it depends on how the word "operating" is defined. Does it include recharge or only include discharge?
After wading through some websites and some user manuals on LFP's I have found several references to the topic of temperature and charging. One of the respected marine suppliers of LFP batteries is Genasun. In their user manual there is a section on temperature. Their battery packs are fitted with sensors in different locations throughout the pack. When the sensor reads 0 Celsius it turn off the charging buss. When the temperature sensor reads -20 Celcius it turns off the discharge buss. There is also a note that they offer a heater package that can be programmed to come on when necessary.
See section 8
starkpower, scroll down FAQ list, 2/3 the way
Valence, chart top of page 2
So I don't know how that reconciles with the -45 C to +65 C statement. It is aparent that all the LFP battery info mentions the upper limit but many decline to mention anything about the lower limits and especially regarding charging.
So I still believe that LFP is not for everyone and that everyone who might be interested forget all they know about FLA and start asking all the questions anew. After all, vendors and manufacturers often have sales first on their list of priorities.
As the LFP battery thing sits now, I am more concerned about cold weather charging than I am about the price.
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creeky
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# Posted: 10 Nov 2014 05:11pm
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Temperatures for charging are still a concern. especially for me. One of the main reasons I was interested in LFP was because my batteries get cold.
Some online writers are saying you only have to tone down your charge rate below 0C. To C/10. Others are saying stop charging altogether. I have read little from a reliable source on this issue and I am eager to iron this question out.
(btw. the genasun manual was excellent on this point I thought). I do know folks who have charged LFP batteries at below 32F/0C and used them even lower without apparent problem.
As for using the power. That continues to be a LFP advantage. There is little of the derating as you see with lead acid (FLA). And using the power in the batteries remains acceptable.
Note that Crown, the FLA batteries I use, say do not use below -18C. So LFP at -20 or FLA at -18 ... cold is bad.
And FLA is in serious trouble at a mere 35C, aging at double the cycle rate.
The nice thing about the Princeton paper is it once and for all refutes the leadite arguments one hears. It states categorically that LFP is the current best choice for "reduce(d) energy storage costs" and has the "the best voltage performance".
This, I think we would all agree, are the key factors in off grid energy storage. Cost / Lifespan. Effectiveness.
What I hope is this definitive paper will allow us to move ahead with working on the off grid issues with LFP. Sure, with LFP we can give up worrying about sulphation, dod, watering, a safe box with ventilation, etc. But we still need to be careful not to overcharge, undercharge, top vs bottom balancing, and charging temperature.
One key advantage to LFP is that it doesn't off gas. So you could store it indoors. And due to a wider dod and a lower mass, an electrical heater inside a well insulated box might be just the ticket for many in colder climates.
But what about the reliability of the BMS solutions?
The reason I post on this and other sites, maintain my blog, is to forward RE knowledge. And have fun of course.
But it's nice to see a real dialogue beginning.
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