LiFePO4 - The future for off-grid battery banks?

[PNjunction]

LFP does not work worth a damn in cold weather, and by cold with LFP I mean 32 degrees or lower. Once you get to Zero degrees, LFP is almost unusable. FLA and AGM are usable down to -40 F, just reduced capacity. -40 with LFP is a cold dark day without any power.

Agreed. I wouldn't want to take them below 32F. However, at our "Sub-C" rate, one might be able to have a bit more tolerance especially for discharge. But yep, sub-freeze is a bummer.

We're all just in an endless absorb cycle here. Same stuff every day. FLA rules. AGM and Lifepo4 suck and should be avoided at all cost.

Frankly, I'd just ban all threads about anything but FLA to keep the peace.

[Living Large]

Before I forget I wanted to say I think you are doing a great job doing your homework. It will payoff because you only have to do it once to get it right.

Thanks. After I got done with a draft solar design, finding an economical POCO solution became a higher priority. That was its own lengthy process, in dealing with the POCO to figure out how encumbrance works, the state DEC and Army Corps for wetlands, the town for floodplain, and now finally getting through my HOA - which could be my downfall "just because". Just because someone with power 1 mi away in the development doesn't want us on the fringe to have the luxury of power by running a line 50' over an impassible creek - a crossing nobody can see because it is all private property except the impassible creek. And the adjacent lot owners are all in approval. Oh, the the feds just listed a brown winged or brown nosed bat or some such, and you can only cut trees from Oct to Feb or some such. Oct 1 is coming - I have my chainsaw warmed up if the HOA gives the green light! It's been a long haul, but background work has been critical. Both for solar and POCO in this case.

[Sunking]

You did that Dereck, and I am very grateful for all the advice you have offered. I have it all on file, just in case. Correct - mine is a niche case. That's my life story.



Yep - absolutely it applies. My intent from the start was to never have my basement going below 40 degrees, worst case.

40 and higher to 70 is no problem for any battery really. Only difference between battery types would be percentage of capacity loss. Capacity Loss may bee the wrong term because it is only temporary. Perhaps Not Available would be better. When the battery warms up, that capacity now becomes available again. So take that into consideration when sizing batteries.

Edit:

Before I forget I wanted to say I think you are doing a great job doing your homework. It will payoff because you only have to do it once to get it right.

[Living Large]

I can only give you the facts so you can make an informed purchase decision.

You did that Dereck, and I am very grateful for all the advice you have offered. I have it all on file, just in case. Correct - mine is a niche case. That's my life story.

One more thing you need to know because it applies to you. LFP does not work worth a damn in cold weather, and by cold with LFP I mean 32 degrees or lower. Once you get to Zero degrees, LFP is almost unusable. FLA and AGM are usable down to -40 F, just reduced capacity. -40 with LFP is a cold dark day without any power.

Yep - absolutely it applies. My intent from the start was to never have my basement going below 40 degrees, worst case. That was with FLA. I was shooting higher for LFP. But that assumes all the backup systems are in place, and I have unlimited time to babysit. That plan is on hold.

[Sunking]

Generally true, however everyone's situation is a bit different.

You are a niche case that can justify the expense, and you know damn well you are taking a huge Risk with LFP. I can only give you the facts so you can make an informed purchase decision. One more thing you need to know because it applies to you. LFP does not work worth a damn in cold weather, and by cold with LFP I mean 32 degrees or lower. Once you get to Zero degrees, LFP is almost unusable. FLA and AGM are usable down to -40 F, just reduced capacity. -40 with LFP is a cold dark day without any power.

EV folks know this fact and why they install heating pads inside ventilated battery boxes for their EV batteries or park them in a heated garage using AC power. Look at commercial EV's and they use both heating and cooling for their batteries. One company tried it without thermal management, and got burned. Ask Nissan what it cost them to learn that fact.

[Living Large]

EV crowd can justify LFP batteries because weight and energy density are the two most important characteristics of an EV. Means nothing to a solar system.

Generally true, however everyone's situation is a bit different. I have to tell you my eyes lit up when I saw the weight of LFP compared with the 330lb FLA batteries I was considering.

I have removable steep basement stairs, which while have an external Bilco door, are not close to code. There is also a 2' rise to the stairs because the house is built above grade 3-4'. I would have had to have rigged a boom to lower the 330-pounders straight down where the removable stairs are. 8 trips carrying an LFP under each arm down the stairs without removing them was a very positive attribute.

That said, I am very close to getting electricity for about $10,000, compared with what was well over $100K when I was solo. I found 2 other neighbors to get electric, and we have all approvals except my HOA to go over a remote creek that nobody can see. And if one more of multiple lots goes on the same line within 10 years, I get $5000 back.

I should mention it was Dereck's advice that I bang my head against a rock and wake up that caused me to redouble my effort to get electricity. It has been a Herculean effort, but one that may pay off.

[Sunking]

the EV guys go for a more of the 'Duct Tape' approach which I dont mind in itself as my batteries will be indoors so no need to pay for all that metal.

Not sure how you came to that conclusion, but most the EV crowd is very savy and leaps and bounds ahead of Solar. The EV guys are the Pioneers, the solar crowd are a bunch of tight asses who really do not know much, and just following the crowd like sheep to be slaughtered.

EV crowd can justify LFP batteries because weight and energy density are the two most important characteristics of an EV. Means nothing to a solar system.

You can buy and operate a FLA battery for 5 and a few up to 10 years. There are a couple out there. A really good FLA cost around $200 to $250 per Kwh. If it last say 5 years means just in battery cost alone you paid $1250 / 1825 days = 69-cents per Kwh just for the batteries. You want AGM or LFP? They cost twice as much and last half as long. That means $2500 / 913 days = $2.74 cents per Kwh or 4 times more than FLA.

This should make you stop and ask yourself:

Hey Stupid; why do I want to pay $0.70 to $2.70 per Kwh taking something off-grid when I can buy unlimited amounts of power from the greedy ole Power Company for 11-cents per Kwh. I hope you can answer yourself without embarrassing yourself.

[jedics]

Are there some Aussies who know of people they have dealt with that will do the right thing when I go to purchase?

Ive found a few places ev-power and Lithium Batteries Australia, seems to be a big difference in price although the LBA guy says the batteries are made here and they come in a very sturdy looking metal case, the EV guys go for a more of the 'Duct Tape' approach which I dont mind in itself as my batteries will be indoors so no need to pay for all that metal.

[PNjunction]

the only biz I am doing is trying to learn from people who know more than me so I can make the best decision when Im ready to buy, thats why Im here.

I'm not sure you'll ever have the lifetime required to weed through all the bunk to get to the facts in time. This is a global phenomenon more or less on all boards when dealing with lifepo4, not just here. Personal politics, outside interference from those outside our low-voltage/low current use in the EV/Ebike/RC modeling field, hackers using inappropriate cells of different li-ion chemistries held together with duct-tape, junk-dealers trying to pawn off vehicle crash batteries to newbies all add to the confusion.

It's a conspiracy I tell 'ya!

Interestingly enough, do you ever see lifepo4 cheerleaders interjecting into lead-acid threads at every turn? Thank goodness that is not the case, but the reverse is always true.

While I do not like FLA at all, and could counter much of the broad brushstrokes applied to their favor, you won't find me trying to dissuade anyone from using it if they want to. Instead, I'll provide some of the minimum generalities such as a current spread from C/12 to C/8 for newcomers and leaving the rest to those who actually own them.

.... wait, here comes a pat on the back ... (ugh)..

Sad really. I don't know if there is a good cure that is not so draconian that it defeats the purpose of a public forum. Wait- what? Private forums perhaps or a public one with totalitarian rules stated up front for participation? hmmmm...

[jedics]

. The most expensive option you can choose with the shortest life time is AGM and LFP. Some 400% more at end of product life.

I found this sentence a bit confusing, your saying AGM is the most expensive and shortest life, LFP is the most expensive but 4x the life of AGM?

HOW MANY WATT HOURS IN A DAY. Until you know that, you have no biz doing anything.

Ok relax Sunking, the only biz I am doing is trying to learn from people who know more than me so I can make the best decision when Im ready to buy, thats why Im here.

[jedics]

The only thing specific was the "sales" pitch with "I have a friend who works at Tindo Solar" !

Thanks for listening to my opinion

No pitch, actually I want to be told that I should just get the cheapest ones I can find as warranties are'ent worth anything and the extra efficiency can me made up for with just a couple of extra panels

[inetdog]

Sure, I can do that. With the name calling that is promoted here it's hard to have one.

We are trying to reduce that component of the Forum ambience. Please be patient.
It may be tolerated, but it is certainly not promoted.

Note: Positive attitude does not mean "I am positive that I do not like that."

[Willy T]

Word of advice, how about a more positive attitude?

Sure, I can do that. With the name calling that is promoted here it's hard to have one.

[inetdog]

That must have been you that offered a picture of your system. After being called a liar by Sun whatever, I posted the invoice, thats more than he deserved.

Word of advice, never post a picture on here, the nit pickers will give you plenty of harassment.

Word of advice, how about a more positive attitude?

[Willy T]

Willy, you replied to this poster:
Quote Originally Posted by Iron Bran - Lots of chatter, very few photos. Anyone have actual install photos to share???

I know you must have intended to upload a photo of your LI system, but I don't see it. Could you supply one?

That must have been you that offered a picture of your system. After being called a liar by Sun whatever, I posted the invoice, thats more than he deserved.

Word of advice, never post a picture on here, the nit pickers will give you plenty of harassment.