having a hard time justifying switch to LiFePo4

[Steve_S]

Hmmm, simple enough, I am transitioning from 856Ah of Rolls Surette S-500's heavy Deep Cycle Lead Acid to 910Ah of LFP right now. The LFP is costing me no more than if I had bought all replacements S-550's ! But then I am NOT FOOL ENOUGH to go buy $1,000 Battleborn Batteries... I'd be 9 Grand deep !

I'm in Northern Canada and I see -30C / -22F in winter as a matter of course (Colder too is not unusual). Powerhouse has a Recovered RV Furnace that uses 12VDC for power and is fuelled by Propane and with electronic ignition it is frugal (set to 10C / 50F). Being direct vent, it presents no issues. 40Lbs of LPG per winter and still have left over.... The Powerhouse is well insulated so it keep the heat nicely in winter and keeps the heat out In summer as well. The furnace came from a 3 year old wrecked RV and cost me $300 with all the extra bits and dual tank regulator too.

What LFP's I am using, it's simple, see the XUBA Electronics link in my signature. Yes, you have to build the packs yourself but for 1/3rd less than the cost of Battleborns. 4x280AH cells = 12V/280AH = Total $591.56 USD delivered. PLUS BMS & a box to put the cells in. NOTE, that is 280AH NOT 100 or 120.

 

[mvas]

Going the DIY route ( with XUBA cells or other mfr ) does make LiFePo4 more attractive.
So, approx $700 for ... 4 @ 280AH Cells + BMS + Container ?

SOAR brand ...
5.5 Years = Rated at 2,000 Cycles / 365 day per year

 

[Steve_S]

The XUBA link here: https://www.alibaba.com/product-det...4520d22qNJc8&bypass=true&fullFirstScreen=true

BMS & Box is extra and depends on what you want.
I'm making Battery Boxes from 3/4" Purebond Plywood but other options are available for folks depending on their needs / abilities / capabilities.

 

[Ped]

It is very difficult to cost-justify a $900 100AH Battle-Born vs 2 @ 215 AH GC-2's cost $200 total when the GC-2's last for 7 - 10 years.

Yes only $200.... + $400 in extra solar + $700 generator + $100 for a charger + $150 controller upgrade + 100 in watering and test equipment.

 

[NoSmokeYet]

That test does prove that LiFePO4 can provide 2x to 3x more CYCLES, but the test contradicts this statement ... "well proven they last 6x to 20x longer than FLA", as claimed in message #2. Actually, that TEST proves that message #2 is a FALSE statement. And there has been no testing to prove that
any LiFeP04 can perform over a 20 year to 30 year AGING period to verify they can last 2x to 3x longer in time, than a 7 - 10 year old GC2 FLA battery bank.

It is very difficult to cost-justify a $900 100AH Battle-Born vs 2 @ 215 AH GC-2's cost $200 total when the GC-2's last for 7 - 10 years.

Heck....who wants the same old batteries for 20 to 30 years. P.S. got my golf cart batteries today, I'am cranking out the Wh's?

 

[orangeminnie]

It is very difficult to cost-justify a $900 100AH Battle-Born vs 2 @ 215 AH GC-2's cost $200 total when the GC-2's last for 7 - 10 years.
[/QUOTE]

Well, more like 300-600 for a pair of quality GC-2's, even from Wallmart. For those of us who are not carrying around a generator, I like the ability to run the LiFePO4 batteries way below 50% and not worry about needing to charge them back up right away. As to the horse analogy: horses overlapped with cars for at least 40 years in the U.S., and 60+ years in other parts of the world. The transition away from FLA for deep cycle use may be a long process, and lead-based batteries are still great for engine starting. As to safety: any known cases of recent-design BMS-protected LiFePO4 causing fires or explosions? The hazards of explosions from FLA offgassing are well documented, and I've witnessed two of them.

 

[Rbertalotto]

This is a great post. I’m building a converted to electric garden tractor. Looking to decide between LA and Li.
I need roughly 75 usable AH at 48v to be able to run the tractor for 1 hour.
Four 12v / 150ah Concord GC batteries are $189 each, delivered. $756 total.
Try as I may, I can’t get anywhere near this price with a DIY Li system. Please show me I’m wrong here if im
The tractor will get about 50-70 hours of use a year. And at my age, if I get 5-7 years out of the batteries, I’ll call it good.
Weight of LA batteries in this application is very desirable for improved traction. Heck I’m adding hundreds of pounds to the tractor with wheel weights, lead hag on weights and fluid filled tires!
So in this case, I’m thinking LA is a better way to go......yes?

 

[Ped]

This is a great post. I’m building a converted to electric garden tractor. Looking to decide between LA and Li.
I need roughly 75 usable AH at 48v to be able to run the tractor for 1 hour.
Four 12v / 150ah Concord GC batteries are $189 each, delivered. $756 total.
Try as I may, I can’t get anywhere near this price with a DIY Li system. Please show me I’m wrong here if im
The tractor will get about 50-70 hours of use a year. And at my age, if I get 5-7 years out of the batteries, I’ll call it good.
Weight of LA batteries in this application is very desirable for improved traction. Heck I’m adding hundreds of pounds to the tractor with wheel weights, lead hag on weights and fluid filled tires!
So in this case, I’m thinking LA is a better way to go......yes?

Yes. Its continuous draw solar systems where the differences matter.

 

[JAS]

Hey everyone, It's been a while since I've checked this thread. Lots of good info! Thanks!

So I am currently mulling a solar "generator" like the Jackery or maybe the upcoming Bluetti AC200... Reason being is that I can cart it back and forth (as someone had mentioned in this thread regarding the Titan). I like the Jackery because of the light weight and I know I won't complain about lugging it. (But, waiting to catch a sale and see if it drops to $700). The Titan is just too expensive and while it is "portable", it's not light and convenient enough. Thus, I know I won't enjoy lugging it back and forth.

I'm also thinking along the lines of what someone else mentioned about using the FLA pack to run a heating pad to keep the LI pack warm.

Right now, I'm just watching prices and waiting for a sale. (Not interested in DIY packs).

 

[iceledoar]

Hey all,

So currently I have (2) 6V Golf Cart Batteries in series, (1) 240W 24v Solar Panel connected to a Renogy MPPT Tracer charge controller, (1) 100W 12v solar panel connected to a Renogy PWM charge controller, and a Xantrex ProWatt 600W pure sine wave inverter. This entire setup is outside in an unheated shed about 50' away from the cabin. I'm in central PA and the winters can occasionally get down to around zero degrees F for several days at a time. Yes, I have to water the batteries. But, only about 3-4 times a year and it's not really a problem...

This system has been running my entire recreational cabin for 6 years now and the batteries are still going strong. (I've only run them below 80% charge maybe twice and those two times not below 70%). My normal routine is to run our Champion 2000W inverter generator when running our freezer/fridge conversion, the vacuum, taking showers that uses our Shurflo water pump, and watching movies or the kids playing xbox. So for the most part, the batteries are only there for nightime lights, and flushing toilets, washing hands, etc. When I'm up by myself, I do use it more mainly because I don't always need the fridge and the batteries can easily handle my quick showers, plus no xbox

So at this point, I don't really "need" any more power. But, I would like longer runtime, such that we could watch a movie without having to worry about draining the batteries too far too fast. So the easiest and least expensive upgrade is to just get (4) GC2's and wire them up in series/parallel and as such double my runtime. This will cost me about $450. (I already have a 2nd 240W 24v panel that I can add to the MPPT as well)

Now, if I switch to LifePO4, I would be looking at (1) roughly 240AH 12v LifePO4 to match the (4) GC2s safe runtime. Looks like I could possibly find one of these in the $600 - $800 range (more if I buy from a more "trusted" source). Now I know the theoretical lifetime of these "should" be much longer than FLA. However, if I go this route, I also need to upgrade my charge controller to one with a low temperature cutoff and also setup some way to heat the batteries in the winter. (This could add another couple hundred.) So let's say to be safe, I'm looking at $1500 to go LifePO4 and let's say I can expect 20 years of use (I know maybe more). But, I'd have to deal with the low temp problem in the winter.

Currently, I have no worries about using and charging my batteries during the winter. If I switch, I imagine I'd have to be careful and pay more attention to making sure they're warm before charging as well as being careful not to drain them too far if I know I can't charge them... For $1500, I can stay with (4) GC2's and replace them 3 times. With my low usage, I expect to get 7-10 years out of the GC2's. So about the same long term costs as the LifePO4's... And that's assuming the GC2 prices stay the same

So am I missing something?

Thanks for any thoughts...

Jeff

Jeff I’m in a similar position, but on the new end of the spectrum. My place is way out there and not always kept warm in the winter. I decided to go with FLA’s. Having run the place for the last couple years off of a old trolling motor battery and finally upgraded to the Trojan Solar’s 6vdc’s is a huge difference. I know they are slower to charge but usually are full by noon the next day. Im sticking with FLA’s and keeping my money in my pocket. I did add a watering system so I should be able to leave vacant for a month or so during the summer. Avoiding the Arkansas heat and humidity.

 

[iceledoar]

Well... GCB’s need regular maintenance you know... distilled water, full charge, monitored capacity, keep discharge to 50%max... those cut it and forget it plans go bad rapidly if not maintained.

Adding water every couple months is not that labor intensive. 10 mins max

 

[JAS]

Jeff I’m in a similar position, but on the new end of the spectrum. My place is way out there and not always kept warm in the winter. I decided to go with FLA’s. Having run the place for the last couple years off of a old trolling motor battery and finally upgraded to the Trojan Solar’s 6vdc’s is a huge difference. I know they are slower to charge but usually are full by noon the next day. Im sticking with FLA’s and keeping my money in my pocket. I did add a watering system so I should be able to leave vacant for a month or so during the summer. Avoiding the Arkansas heat and humidity.

It's my understanding that the majority of the water evaporating/misting out happens when charging. Thus, if just sitting for a month or two fully charged and just being maintained won't really use any significant water...

 

[JAS]

Yes only $200.... + $400 in extra solar + $700 generator + $100 for a charger + $150 controller upgrade + 100 in watering and test equipment.

As of now... I haven't purchased any extra solar than I would have one way or another. The generator was/is necessary anyway for power tools, well pump, etc. Don't have an AC charger. (use solar only) Don't understand the controller upgrade? Never bothered with watering/test equipment so that didn't cost me anything additional...

Don't get me wrong, I understand your point and probably most people with very large banks of FLAs do have all those additional costs...

 

[JAS]

Well, more like 300-600 for a pair of quality GC-2's

If you're talking about Trojan or Concord, yes. However, the Costco Energizer GC2's that I have were about $90 each (and still the same price the last I looked). I can't say they're not quality since they've lasted 6 years and still going...

 

[Fred S]

Also remember that if the lithium bms has a low temp disconnect, that will protect the battery. But for a cabin that sits idle, I'd just disconnect the battery before I left. Down side is that you couldn't reconnect the battery when you return, if the battery is at or below freezing.
Or, just take the battery home with you.

Or #2 - I don't think a battery heater needs to be expensive, if you don't mind diy-ing it. You just need to have a reliable low voltage disconnect to keep it from over-discharging the battery.

 

[JAS]

Also remember that if the lithium bms has a low temp disconnect, that will protect the battery. But for a cabin that sits idle, I'd just disconnect the battery before I left. Down side is that you couldn't reconnect the battery when you return, if the battery is at or below freezing.
Or, just take the battery home with you.

Or #2 - I don't think a battery heater needs to be expensive, if you don't mind diy-ing it. You just need to have a reliable low voltage disconnect to keep it from over-discharging the battery.

Yep, if I were to go the Li route, I'd go with Battleborn (currently the only battery with low temp disconnect that I trust)

 

[thenewtbaron]

So to be on the conservative side, an FLA will last 5 years. You're saying the lifepo4 will last 30 - 100 years?!?! That sounds a bit exaggerated... (especially with the risk of charging under freezing temps causing it to be bricked)

I don't think "affordable" lithium batteries have even been an option for DIY people like off-gridders for the last 30 years (let alone 100). How have they been "proven" to last that long?

In fact batterystuff.com claims only 5-7 years. (Yes, I agree that contradicts everything I've been reading as well)

https://www.batterystuff.com/kb/articles/battery-articles/lithium-battery-overview.html

It depends on how you use the batteries and how much you discharge them. That website states else where that AGM can get 300 charge cycles at 60% DOD - that means you'd get like an actual 150 full charge cycles but AGM batteries can be damaged by larger DOD.

LifePO4 can get 1000+ charge cycles at 100% DOD and won't get damaged by the larger DOD. If you ran it to only 60% DOD, you'd probably get like 2000-3000+ charge cycles.

Now, I don't know if this is correct or not but after that 2000+ charge cycles, the lifepo4 will not be useless but should be at 75-80% capacity while the AGM/FLA would be pretty done.

I also don't know the usage case/DOD of that website's estimates are based on. If it was based on daily full cycling, 5 years at 365 days is about 1800 cycles. If you needed the same amount of power of the lifepo4 from FLA, you'd have to have 2.5 batteries, and they would be used up in 300 cycles...or less than a year. You'd have to replace the 2.5 batteries 6 times while still being able to use the LifePo4. so15 FLA batteries vs one lifepo4.

I just googled 12 v 100ah, and the first SLA battery that showed up was 150$/battery or 1800$ of batteries for over that 5 years vs the top of the line battleborn 12v 100ah is around 1000$

 

[JAS]

I just googled 12 v 100ah, and the first SLA battery that showed up was 150$/battery or 1800$ of batteries for over that 5 years vs the top of the line battleborn 12v 100ah is around 1000$

Yep, sounds like a no brainer if cycling batteries daily... In my case, they only get slightly discharged about 2 days every month on average...

 

[gnubie]

LifePO4 can get 1000+ charge cycles at 100% DOD and won't get damaged by the larger DOD. If you ran it to only 60% DOD, you'd probably get like 2000-3000+ charge cycles.

There's a lot of old figures out there for lifepo4. Things have improved since their initial commercialisation. It's not unusual to see quality battery manufacturers upfront rate their batteries at => 2000 cycles at 80% discharged, but if you look a little deeper and get the spec sheet the expected lifetime is ~2000 cycles at 100% discharge with 80% discharge yielding a lot more cycles. This isn't done by understating the capacity of the battery either, but there is that option of course.

Battleborn state their batteries will do > 3000 cycles at 100% discharged, and then be down to 80% of original AH rating. There's been a lot of debate over BB setting their BMS to cut off before true 100%, ie they over provision their battery which isn't a bad thing, but the ultimate answer to that is to add up the watt hours in all the cells and do a discharge test.

 

[thenewtbaron]

Yep, sounds like a no brainer if cycling batteries daily... In my case, they only get slightly discharged about 2 days every month on average...

Do you leave them trickle charging or just let them set in the cabin? LifePO4 has a pretty low self-discharge rate compared to some other chemistries.

I think you'd be fine. It just becomes a a balance between ease/safety vs cost for you. LifePO4 have a lot less fiddle work, have to charge it up less often because of self-discharge, don't have to worry about acid or fumes, and if you push it to its limits rarely it won't burn out it capacity.

BUT

it does cost a lot.