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creeky
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# Posted: 26 Jul 2015 09:57am
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I just want to update some of the Lifepo4 info. With some changes and improvements to the chemistry, recently there have been updates to the Lifepo4 lifespan specs.
Rated lifespan is now:
* 3000 cycles at 70% discharge. (8 years. identical to lead acid at 20% discharge)
* 7000 cycles at 50% discharge. (20 years -- aaaaaaaaa)
* 17500 cycles at 20% discharge. (50 years. holy hanna)
to put this in perspective. this means you can now build a solar system that has a complete product lifespan of 20 years.
for me. my lead acid battery pack which gives me 2kw of useful power (we can quibble and call it 3 without taking derating into consideration). It will last a maximum of 8 years.
so a 10 kw/h lifepo4 would give me 5kw (double the useful power). and last 2.5 times longer. for about 50% greater initial cost. and comes with a host of performance benefits. the top being not needing to have the battery fully charged on a daily basis. and second, for me, no maintenance. jeez. not to mention the lack of toxic fumes. anyhoo
for those with seasonal battery use. can you imagine putting in a battery and not needing to replace it, nor worry about it when yer gone for the winter, for your lifetime.
the whole off grid solar equation is now complete.
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bobrok
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# Posted: 26 Jul 2015 12:14pm
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What I'd like to see is a side by side specs comparison between these lithium batteries and that aqueous hybrid ion battery I posted earlier.
Rated vs. each other on cost, efficiency, expected lifetime, etc.
As you know I'm soon embarking on my propane line project, but, as fate would have it, I finally found a solar installer who is willing to make the trek up to my camp to look at my system with an eye towards upgrading.
I don't want to pass up this opportunity, so if I have to stop the propane and talk solar I'm willing to do it.
Having comparison info like this would be valuable not only to me but anyone else who is doing solar upgrades.
So far my take on the specs is the aqueous hybrid ion battery is less costly than the lithium, but has a somewhat shorter life span. I think I read 3000 cycles? Other than this are they about equal in performance?
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MtnDon
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# Posted: 26 Jul 2015 12:38pm
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Quoting: bobrok What I'd like to see is a side by side specs comparison between these lithium batteries and that aqueous hybrid ion battery I posted earlier.
If I was looking and talking to an installer / sales person I would want to know the names of folks who have already bought and used the aqueous batteries he's selling.
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creeky
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# Posted: 26 Jul 2015 01:01pm
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bobrok. I'm with MtnDon.
I think in your previous post I outlined the very real problems with aqueous hybrid.
primarily very low charging amps. very low discharge amps. in english this means you need a long slow charge (not ideal for solar). and you can use only low powered devices.
discharge is 10 amps at 48v: meaning you can use devices up to 480 watts. but wait! aqueous batteries are even worse than lead acid when it comes to dropping voltage under load. so you can use 400 watt appliances. or two 200s. etc. see.
that means no fridge (start up surge), no water pump, no blender, no microwave, no dishwasher, no electric hot plate etc etc etc.
this might not be a problem for you I don't know. perhaps you're only planning on some lights, a laptop and a tv.
right now. lithium in the form of lifepo4 appears to be the most cost effective solution you can order right now.
i look forward to your comparison chart tho! 
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cspot
Member
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# Posted: 26 Jul 2015 01:25pm
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Creeky,
How well would these batteries work for charging from a generator only? In other words if you don't have a good spot for solar or just use the cabin infrequently could you recharge with a generator when there? I know with traditional batteries that I have read on here that one issue with the generator is it is hard to get a full charge on them.
Just wondering. Don't have my cabin yet as we are still looking for the right place. Just been looking at various options for when we do.
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bobrok
Member
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# Posted: 26 Jul 2015 01:45pm - Edited by: bobrok
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I'm hoping to schedule the installer for around end of August/early September unless she craps out on me (due to scheduling on her side; she's pretty busy and covers a very large area).
I plan on picking her brain for all its worth and taking copious notes which I will share here.
FYI, she has an engineering degree, has lived off grid for 20 some years, and has had her solar business for the last 7-8 years.
She sounds as if she knows her stuff.
...but then again, so do you know yer stuff  very well, so I'm looking very much forward to this exchange of ideas.
Thanks for the reminder about charge rate and discharge; yes, I hope to run my 12 v. demand pump off this as well. No other major appliances in the future other than charging tools, small tv, led lighting.
I'll reserve the generator for use when wife uses hair dryer or for vaccuuming.
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MtnDon
Member
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# Posted: 26 Jul 2015 03:18pm - Edited by: MtnDon
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Key questions are about the maximum charge rate and the maximum discharge rate. My interpretation of what I have read is that these batteries can not take high amp charge rates or supply large surge discharges.
Also how fast does the voltage drop when a large load is applied? That could play havoc with some inverters.
Solar charging most often relies in high charge rates to make up for the few hours of really good sun. In a similar way most folks will want to have high charge rates when using a generator, in order to save fuel and actual run time on their generator.
I know very few people whose off grid use does not include some high amperage loads. Refrigeration usually means there is a surge. Power tools. Virtually everyone I know uses a microwave at some time. Or at least the wives want one.
All I'm saying is that I would want the maximum discharge rate known to me in very clear language. Guaranteed. I would want to know what happens if I exceeded that rate. And I would have to be very certain my future needs will not exceed the batteries maximum rates. Serious talk required with life partner if there is one. I know our electrical use increased beyond our original expectations. )But I also knew a microwave was very high on the required device list. All that before plunking down my money for something that is supposed to be of long term use.
There are advantages to these batteries. From what I read though, there are also disadvantages. Of course those are not going to be mentioned by the manufacturer and many re-sellers. That's why I fall back onto my original thought..... show me the happy off grid users I can talk to.
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MtnDon
Member
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# Posted: 26 Jul 2015 03:26pm
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My concerns stem from info like this
$1200 (round numbers)
2.4 kWh capacity (round numbers)
450 watts usable continuous power
@48 volts nominal that is 20 amps; in or out of the battery.
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Julie2Oregon
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# Posted: 27 Jul 2015 05:28pm
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Yeah, that discharge rate for the aqueous batteries is a huge downer. You need a LARGE string of the batteries just to run some electronics, according to their very own blogger who put them to the test.
On the blog, I posted a question asking if adding more solar panels would help, instead of having a string of 6-8 of those batteries just to run a laptop, printer, some lights, etc. IIRC, he only had about 600 watts of panels but something like 8 KwH of battery storage!
The answer I got wasn't an answer. A company rep told me to contact one of their dealers/installers to assess my needs. Um, no. I just wanted some info and I don't want a salesman hounding me!
Creeky, do you have a lifepo link?
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creeky
Member
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# Posted: 27 Jul 2015 06:00pm
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i've been looking for suppliers.
the best price and tech I've found is balqon. you can google them. they have an online store.
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offgridjunkie
Member
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# Posted: 27 Jul 2015 08:13pm
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Quoting: Julie2Oregon Creeky, do you have a lifepo link?
Yep, this is the next step Creeky. They are not easily found.
If anyone else reading this thread knows of suppliers of lifepo4 batteries, please post them up here.
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bobrok
Member
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# Posted: 27 Jul 2015 08:29pm
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Would this be of help?
URL
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Bret
Member
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# Posted: 27 Jul 2015 11:07pm
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http://www.balqon.com/balqon-battery-cells/
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creeky
Member
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# Posted: 28 Jul 2015 08:57am
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cspot. sorry. missed your post. Yes. Lifepo4 is excellent for charger only as it is far more efficient accepting a charge than Lead acid (LA).
The high efficiency (90%!) and the fact you only need to partial charge without losing lifespan. sweet.
thx Bret for posting the link. I've talked about Balqon so many times I'm afraid to link to their site lest it seem like I'm spammin'.
The have an online store. Look at the RV or Marine batteries. Or house batteries if you're looking to build a larger system.
The thing I like is the battery packs are complete with BMS (battery management system), fuse and disconnect. So while the price looks high, it includes everything. Plug and play.
Compare that to lead acid where you still have to buy/make interconnect cables, add fuses / disconnects etc.
So there are some savings there also when doing a price comparison.
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Bret
Member
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# Posted: 28 Jul 2015 11:13am
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This is what I am waiting for.
http://electrodacus.com
Going to be an interesting ride, this off grid solar.
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creeky
Member
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# Posted: 28 Jul 2015 12:40pm
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I'm rooting for him too. I've been following his build for many years. His home made BMS is suitable for small installations.
If you need a solution today:
The Balqon come with BMS installed. Similar to dacus, but engineered for the specific batteries and size. They are mated with probably the best lifepo4 battery out there right now. And will handle the larger battery size.
One thing I really like about the Winston battery Balqon uses is that they are huge. It appears that fewer larger amp batteries in series is a better solution than more smaller amp batteries in series/parallel.
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Julie2Oregon
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# Posted: 28 Jul 2015 04:08pm
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Ah, OK, thanks, guys! I didn't equate lifepo4 with the Balqon site. I guess because on some of their batteries listed, they require a few week build time, it says, and I guess I figured they'd be all assembled and ready for sale.
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creeky
Member
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# Posted: 28 Jul 2015 06:27pm
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Julie2. if you go to the online store at Balqon you will find the ready made packs.
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cspot
Member
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# Posted: 28 Jul 2015 08:09pm
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Thanks Creeky!
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MtnDon
Member
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# Posted: 28 Jul 2015 09:13pm
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Quoting: Julie2Oregon I figured they'd be all assembled and ready for sale.
Sometimes they are in USA stock. Very often not. They seem to price reasonably low because they don't carry inventory. Boat shipments from China are cheap. Good solar systems are well planned. It should be possible to finalize a system, then order everything and wait 3 to 6 weeks.
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