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gcrank1
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# Posted: 25 May 2022 12:45pm - Edited by: gcrank1
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Wow!
These 100Ah LFP bats have sooo much power to use and sooo user friendly. I still have not hooked up my solar, just hooked up a bat in-cabin, clipped on the psw inverter and have 120vac every time I want it.
Too Easy!
All that futzin with Lead Acid bats is NOT missed.
These are the 3rd best thing after getting the Champion 1700/2000W inv/gen and the PSW inverter for the bat-bank.
Seriously, anybody considering getting solar for small-scale I suggest getting an LFP battery first, using it for a while while you sort out what else you 'might' want to do. So much on tap and light enough to haul home to recharge.
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SCSJeff
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# Posted: 25 May 2022 02:55pm
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Agreed!
I just replaced my (2) 205AH Costco Golf Cart Batteries w/ a DIY 170ah LFP. Oh my, how much faster it charges 
Will have to see this winter if I need to do anything about keeping them warm enough to charge. But, for the most part, if I'm at the cabin when it is that cold, I'm either out hunting all day or doing work and would be using the generator anyway...
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Nobadays
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# Posted: 25 May 2022 03:22pm
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Been happy with my Chins LiFePo4 batteries I got to replace the Chevy Volt modules that went south last winter.
Bought 4 x 24v, 200ah and wired to 48v, 400ah. We are using right at 30% per day (should say evening/night) so theoretically we would have 2 maybe 3 days reserve.... more likely 2 days. We go to bed around 9pm and the batteries read 53.0v (55.2v is Float according to Chins parameters... a little low I think) and reads, often 53.0v in the morning.... sometimes 52.9v. That's with the satellite internet on all night! Impressed!
May add 2 more, when the budget will allow, to get 600ah and another day or two reserve.
Yes it's a lot of ah but we live here.... we jokingly refer to our place on a cul-de-sac in AZ as the "cabin" because we haven't spent more than 2.5 months there per year in the last 3 years. Here at this "cabin" we have an electric fridge, freezer, 40" TV, and satellite internet. Obviously lights, charging, etc.
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paulz
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# Posted: 25 May 2022 06:18pm
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Yep a big improvement, especially if you are hauling them back and forth. Besides the weight savings, when I was hauling FLAs back and forth all my jeans had acid holes where they rubbed on my legs. I still have 10 pairs of jean cutoffs.
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Brettny
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# Posted: 26 May 2022 09:29am
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Lithium is a definite if your hauling them. Granted I left my FLA all winter and came back to full batteries.
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gcrank1
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# Posted: 28 May 2022 09:31pm
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We spent the past two days at the cabin with a movie on the old tube tv c/w vcr (kind of an energy hog) before bed. We ran everything we wanted off the LFP with the low draw 300W psw inverter.
The bat integral dig voltmeter read 13.3v when we got there (that bat has been there for 3 or 4 day trips before) and when running stuff went down to 13.1v under load but was at 13.3 after resting today before we left.
Yeah, voltage is not the best way to evaluate an LFP, but bouncing back up to 13.3v sure shows Im not down at 13.0 or less.
Id run the water pump but the bucket works fine.
Fridge? Another hog; we use a Yeti clone icebox. My home-froze ice bottles last and last.
Enough beans to run a microwave? No, I start the little Champ gen for the few minutes IF we want/need to use it (700W unit) or any other high-draw, short use device; no big deal.
Wife is good with all of this too
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gcrank1
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# Posted: 28 May 2022 09:34pm
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SCSJeff, how about keeping an inexpensive 'marine/leisure' battery around to stick on there for the winter?
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SCSJeff
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# Posted: 31 May 2022 09:32am
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Quoting: gcrank1 SCSJeff, how about keeping an inexpensive 'marine/leisure' battery around to stick on there for the winter?
Maybe... But, I have the battery inside a dead chest freezer inside my shed. I'm thinking I can setup a 12v heater on a temp controller inside there and that will be enough. But, I'm going to wait and see just how cold it gets in there once the battery is being used.
Worst case, I'll bring the battery home (or even inside the cabin in a pinch) to charge
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gcrank1
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# Posted: 18 Oct 2022 08:04pm - Edited by: gcrank1
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Looks like winter is setting in early here.....I was so hoping for a long, pleasant fall but we are 'unseasonable cold'. And my wife is recovering from a total knee replacement so we arent making cabin trips, thus my 'cabin year in review'.
This past year I never did re-hook up any of the 6x102W panels in any config; discon'ed it all about a year ago, got the LFP's around the 1st of the new year and put into service asap last spring. Our winter afternoon trips were few. Rotating the 2 bats with home charging worked a treat. I think their internal BMS shuts each down well before the LVD of the inverter. The clue is typically when an led light shuts off for a bit (actually the inverter), rests, then comes back on. If I discon the bat then there is no trouble re-starting the BMS and the recharge. Iirc that all happens about a 12.8/12.9 volts under the load. Let the bat rest and the voltage rises a bit.
If I just swap bats at 13.0-13.1v it is seamless. There isnt a lot of Ah's under 13.0 anyway, unlike the Ah's per 'tenth of a volt' above that.
Im pretty much shooting for about an 80% use, not going below the bottom 10% or trying to even recharge the top 10%. (though it may be more like the bottom and top 5%?). The learning curve wasnt steep with the help of those with experience here and over at diysolarforum.com, especially Steve_S.
I doubt the BMS is even registering a total 'cycle' the way I use them; they should outlive me (headin toward 70).
Getting rid of the pain and suffering of LA was a good thing for me! And if starting anew I would seriously consider going 24v right off; the downside is you have to get more expensive 24v bats and a low-freq 24v inverter. Many/most? 12v LFP cannot just be hooked up in series like LA to make 24, the BMS's cant take it (think feeding your computer with dbl its design voltage). LA's are Dumb, LFP's are Smart, some smarter than others though.
Not a deal breaker for me as is because I can/do put the LFP right in the living quarters with the PSW inverter feeding currently to the outlet and lights circuit.
KISS Principle. No need to have them remote, close to array and SCC, as with LA, inverted to 120vac there to be able to make the long 100ish' run to the cabin.
As the commercial used to say (havent seen it in a good while),"Just Do It".
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paulz
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# Posted: 19 Oct 2022 09:37am - Edited by: paulz
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Quoting: gcrank1 If I discon the bat then there is no trouble re-starting the BMS and the recharge. Iirc that all happens about a 12.8/12.9 volts under the load. Let the bat rest a bit and the voltage rises a bit. If I just swap bats at 13.0-13.1v it is seamless. There isnt a lot of Ah's under 13.0 anyway, unlike the Ah's per 'tenth of a volt' above that.
This morning mine are at 12.9 with a 5A load, first time I can remember being under 13. I know they are safe all the way down to 12, but as you say not a lot of time left in that range. Going to fire up the genny when it gets light out. They also get down to 12.6 while the 120A coffee maker runs for 15 minutes.
Could be that my 10+ year old Valence batteries are starting to tire, although I checked via the software and all are equal VPC. Sure hope they last awhile longer.
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gcrank1
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# Posted: 19 Oct 2022 10:23am - Edited by: gcrank1
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During this summer's use I resolved to not use heavier loads after mine hit the 13.0v. The event that caused that was 2/3 way through an evening movie on the old tube tv with integral vhs player (kind of a hog). On that occasion I didnt have my swap battery along even though I knew the cabin bat was 'getting low' (duh). My ancient 'jump-pac' saved the movie, also could have the inv/gen.
Ive since proven to my satisfaction that using that 13.0ish threshold Im still good for led lights and usb charging for a good bit.
Yeah, hammer some amps back in Paul and keep on rockin
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Steve_S
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# Posted: 19 Oct 2022 11:13am
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Just a reminder. There are TWO Voltage ranges for LFP.
The Allowable Voltage Range is 2.500-3.650.
This is the voltage range that the cells can operate in without harm. "The Safe Zone"
For "12V" that is 10.0V-14.6V
The Working Voltage Range is 3.000-3.400.
This is the Voltage Range that delivers the AmpHours the cells are rated for. This is why everyone calculates LFP Battery at a Nominal Voltage of 3.200 Volts per cell (50% SOC)
For "12V" that is 12.0V-13.6V very flat curve
You are quite safe to have a Low Voltage Disconnect @ 2.700 Volts per cell / 10.8V. Note that if a heavy load is applied when the pack is low the voltage sag will be greater than if the pack is full. Most BMS' will allow a certain amount of time before triggering a Low Volt Disconnect (it's in seconds to accommodate surge pulls, like a water pump/fridge/freezer start surge and the like).
Because the BMS in an LFP Battery Pack is millivolt sensitive it's quite accurate to "itself". There is always a voltage difference between what the voltage BMS sees and versus what an Inverter or Charger see at their terminals. Line loss is part of life, every connection, switch, lug etc adds a little loss and it adds up fast... death by a thousand pricks, as it were.
I strongly suggest that you take a Voltage Reading at your battery pack Terminals and then at the Inverter Input Terminals and Solar Charge Controller out terminals to the battery (2 decimal accurate DVOM/DMM strongly suggested). Adjust/Compensate on the Inverter & SCC for the difference, so if the inverter is set to Low Volt Disconnect @ 11.0V (2.750 Volts per cell) that it really is 11.0V @ the battery Terminals.
Gotta say it....
The keep it between 10% - 90% Shtick is more about keeping within the "Working Voltage Range" as the bottom 10% is 2.500-2.800 (short lived cliff fall) and the top 10% is that (cliff climb) from 3.425-3.650
Hope this is helpful and clarifies a few things.
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gcrank1
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# Posted: 19 Oct 2022 10:41pm
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Guess I'll just bite the bullet and see how many more hours I can get going down to 12.5v.
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Steve_S
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# Posted: 20 Oct 2022 06:48pm
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LOL for me, I've always wanted to know what the "Edge Cases" are so I know what to expect if/When stuff happens.
Like a GAS Car, When I've gotten a new one (for me), I like to top it up and fill a 5 Gallon gas can and chuck that in the trunk, then drive it till it beeps/bleeps and finally runs out of gas to get an idea of just how much mileage I can figure on. But then I have lived in some pretty remote and sparsely populated areas and never wanted to get "stuck".
I even did something similar with my Solar Battery System to know what the real "bottom" is which might spook a few folks but where I am I hafta know ! Luckily I have a couple of generators, so it's a matter of powering one up and push 80A to the batteries... After that I increased my battery bank to give myself elbow room cause winter can be quite hostile at times up here. Like last year, I was Very Sickly and after 3 days of heavy snow, it was piled above my 4x4's bumpers and I could not manage the blower in that mess, a quick call and I had a snowplow arrive to make a path for me and get me dug out.
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gcrank1
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# Posted: 20 Oct 2022 07:48pm
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Living into the wilderness certainly underscores the old Boy Scouts motto,"Be Prepared".
Im pretty content to stay off the very edges though I do like to know where the shoulders are and how wide and steep 
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gcrank1
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# Posted: 23 Mar 2023 12:20pm - Edited by: gcrank1
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Last fall when we 'locked up' I brought the LFP home that we had been using for our last trips, maybe 3 weeks on/off. Bat went into 50ish*F basement for winter. This morning, in prep for opening up I pulled it out. Good VOM read 13.31v, really good I think for the use we had last fall and a no maintenence winter lay-up. Onto the Meanwell PS and after 45min the cheap a-meter was down to close to -0-. I let it run for another 15min and shut off. Looks like it is 98+ % now, or 'topped up enough for me' anyway.
Too Easy!
I was at cabin yesterday to get tractor started, clear the drive and prep for open up (read: figure out how to do this cabin thing all over again). The JD 2025R popped right off, spent 1.5 hrs clearing snow (biggest snow we've seen there in 3 winters). Expect to be heading up to burn the slash pile and get a go for this year in the next few days
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redwolfguild
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# Posted: 23 Mar 2023 01:43pm
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The storage discharge (or should i say "No Discharge") is great on these batteries.
Paulz - How are those Chinns holding up? I was cautious about buying them.
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gcrank1
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# Posted: 23 Mar 2023 04:50pm - Edited by: gcrank1
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Fwiw, imo....
The products are changing pretty quickly and 'what was' even 2yrs ago, def pre and post 'supply chain/covid' issues, and now may not be the same.
Even the tear downs of products to show what of and how 'well' they are made a short while back and now may not be the same inside.
Point? Considering where all these reasonably priced bats are coming from ya pays yer money and makes yer choice (and takes yer chance).
Buy something that has been in business a good while and has a facility on this continent. A 'good sounding warrantee' that requires you to ship a bat (or anything) to China does not sound good to me.
I paid a bit more for my 2 China bats from an actual brick&mortar store that says "iffn ya have trouble come back here"; that have me some comfort.
But today, thinking on this, I believe Id order a 100ah 12v LFP off Amazon (we have Prime).
1) because now I realize one 100ah LFP is all I needed for our modest requirements.
2) They are a fair bit less money for someone to give a go. Im sure Battleborn's are great but if that was my only choice Id have never gone there.
Also, if I thought I needed 3 or more paralleled Id really consider going straight to a higher ah bat system as wiring batteries, even LFP, past 2 is fraught with issues of cabling, fusing and too many connections (each a potential trouble spot).
Also be aware that not all LFP bats can be series wired together to make a higher voltage system, think it is the BMS that has to be able to recognize its 'more than 12v and Ok'.
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Nobadays
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# Posted: 24 Mar 2023 12:05am
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Quoting: redwolfguild Paulz - How are those Chinns holding up? I was cautious about buying them.
Not sure if Paul has Chins batteries but we do. We have 4x24v/200ah .... 2s2p for 48v @ 400ah, or 19.2kw. Extremely happy so far! We locked up the cabin the middle of January and went back to AZ (currently in Cairo, Egypt, doing some traveling) so we'll see how they stood up to winter in about a month when we head back up.
The discharge curve on the LiFePo4 is so flat! Before we had MNC lithium, used Volt batteries, and these LiFePo4 stand up to daily usage, especially during no charge periods way better! I can't recall numbers off the top of my head but one period of 3 days with little/no charging we were only down like .2 volts! I'm sure at some point it would have started dropping but haven't seen it yet. BTW we average about 4kw a day usage so we theoretically have ~4 days storage.
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gcrank1
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# Posted: 24 Mar 2023 07:33pm
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Something I forgot in my reply.....
Because of the far more 'cycles' available in LFP, amounting to years of use (10 is often mentioned) we are not yet at the 10yr mark to examine the claims. There seems to be some aging degradation though even that is not a big issue or issue at all afaik.
So, lets say you take my idea of 'buying cheap LFP', get 2x, or 3x the power out of one compared to Lead Acid but they die off in only 7years. In that time it is quite likely there is going to be a leap forward in battery technology that may make the LFP as 'out of date' as LA is now.
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Nobadays
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# Posted: 25 Mar 2023 12:36pm
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Quoting: gcrank1 There seems to be some aging degradation though even that is not a big issue
I think the numbers that get kicked around are 3,000 to 5,000 cycles. If you are like us we generally only use ~30% of a cycle per day, meaning we rarely go below 70% so if my math isn't flawed it would take 3+ days to consider 1 cycle. The other thing is that at the end of that 3k-5k life, they are likelying to still have 80% of the rated capacity. My neighbor opted for Battle Born batteries and they are warranted for 11 years and they state you will still have 80% capacity for a few more years.
If you are more or less full time, or spend significant stretches of time at your cabin I'm convinced LiFePo4 is the way to go.
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travellerw
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# Posted: 26 Mar 2023 08:16pm
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Sigh.. I wished..
I lived 3 years on FLA, and then 2 years on LiFePo4. The LFP were a game changer.... However, the cold weather performance is a killer here. We like to use the cabin in winter and want our system operating year round for camera's, security system, ect. Unfortunately, LFP isn't the answer....
And yes, I looked into the heated ones, but damn they use a lot of power for heating. Its not off the table for the future, but I would have to add panels and I worry about cloudy days. Winter can have like 5-10 days of cloud here!
So.. With spring here, I will be off to the cabin soon to install our full solar and 48V FLA battery bank. I made sure to go WAY overboard on Ah to limit the SOC I take them too. Its the key to long life in FLA. Our RV batteries are 15 years old and still going, they actually powered the cameras and security system in the cabin this winter with a 340W solar panel.
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Nobadays
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# Posted: 27 Mar 2023 09:50am
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Trav... yeah I get where you are coming from. We wanted to run our security camera this winter while gone, couldn't take the chance of running my LFP so dropped a cord from my shop system with FLA to the Starlink, camera is self powered. Unfortunately I lost the internet several weeks ago.
My friends peeked through the door to the shop, said the inverter said "low" which tells me the Victron Battery protector probably shut the flow off... I'm hoping the batteries are good and not dead! I'm kind of thinking I need to shut the inverter down and restart it. I trust the Victron Battery protector to have done its job, just confused why the inverter would have any power at all.
But yes, for unattended winter use I'm with you. Just not sure about using LFP. That said, CHINS makes a Smart Battery that has an internal heating unit. It diverts incoming power from the solar to the heater until the battery is warm then allows charging. I don't believe it continually tries to keep the battery warm, only when a charge is going to it. Seems ideal. If I can scrape up the cash I might try them next winter.
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gcrank1
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# Posted: 27 Mar 2023 10:19am - Edited by: gcrank1
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Well, yeah guys, there is 'that'....
The last year I had my old FLA I let it idle along on the solar (4x100w array, down from my 2s/3p, 6x100w panels).
I bought my 2x100ah LFP 12v bats that Dec/Jan. For any winter short term visit the FLA was going to be fine. As it was, having no solar running at all makes more sense for me as we have nothing to power until we get there and turn on the lights and a fan to circulate the heating air within. Sledding in my little jump-start pack for that is no trouble, it rides the sled with the other stuff on a man-haul easy enough.
If full timing it I see no downside to LFP in a heat stable (34?+F) space, but for your needs/uses having at least a skeleton FLA for over winter makes sense, IF at 12v; that 48v would be an expensive over-winter only pack.
I left my one LFP at the cabin Sat after spending the day burning my monster slash pile. While burning I had the LP furnace and ceiling fan running, cozy but not near as warm as near the fire!
Battery could have wintered over there fine even in the sub-0- temps but I liked it better in my 50F basement at home.
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gcrank1
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# Posted: 5 Apr 2023 10:15pm - Edited by: gcrank1
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An observation when topping up one of mine:
I use a 40a Meanwell power supply set at 13.8v, 8ga. wires with 50a Anderson con's. When on charger I have a voltmeter and ammeter attached and do check it about every 1/2 hr. Once amps start to fall I check more frequently.
My #2 bat was at 13.1, then rose steady to 13.8, charging at around 35a on my cheap, old auto clamp on meter. It started to fall off and when I returned the second time it was 0-5a (hard to read). Suddenly it spiked up (12a?) Ran about 10sec then fell to 0-5 again. After about 45sec it repeated, etc, etc.
Im sure what I was seeing was the BMS tripping the HVD (high voltage discon), I must have a 'runner' cell in that bat.
Certainly a good place to stop and not over-work the BMS function.
After sitting overnight it settled to 13.43, sure looks like a full 100% charge. It may have balanced the cells internally so maybe the cells are all in sync now.
Im putting it to some light use and keeping my eye on it.
So, if you ever see that charge current drop to minor current watch it a bit for any spike to indicate the BMS trip. This is a good reason to not leave a charging LFP unattended.
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