Why shouldn't I buy a 120AH Deep Cycle Battery at COSTCO for half the price of a GEL ?

coil1002 said:

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So, since the OP apparently is in Canada, what would one need to do for the comment regarding using them in climates where freeze protection is a concern for these batteries - just curious since many of us live close enough to the Canadian border and also fall under similar low temp climate concerns…

Lt.Dan said:

I also want to add to the discussion, its pretty common knowledge you can get roughly 500-800 cycles out of a healthy FLA battery, and roughly 5000 cycles out of LiFePo4. Now the numbers say roughly 10x the life right there, but you gotta also count in the fact that after 500-800 cycles, a FLA is DEAD. BUT, after 5000 cycles on a LiFePo4, the battery will still carry roughly 80% of its capacity, meaning it could last 10,000+ cycles before it is DEAD like the FLA.

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That is 100% valid.
It is, however, only half the point.
For completely off grid applications such as mine.
If you have solar replenished batteries every day, great. I’ll Call that summer.
If winter reduces your solar to basically nothing then you must rely on a generator. To do the least amount of damage for any chemistry of lead and get that 5 to 8 year life span it needs to be recharged as soon as possible. Best treatment would be running generator every day. Basically defeating the purpose.
For the same amount of LFP power used and returned over a 5 day span FLA needs almost 2x as much generator run time.
To have enough lead for a 4 day run to 50%, may as well buy LFP
If your bank is large enough for 4 days, you will be getting a real 50% as opposed to a large draw on smaller system with a bit of bounce back.
Once again. Feel free to leave your Lithium at 30% soc for a month or 2.

Mia said:

So, since the OP apparently is in Canada, what would one need to do for the comment regarding using them in climates where freeze protection is a concern for these batteries - just curious since many of us live close enough to the Canadian border and also fall under similar low temp climate concerns…

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You can freeze them. Even use them. Just don’t charge them.
Repurpose your battery shed to growing mushrooms and move them inside.
Temperature cut off is not difficult with a multitude of modern electronics, not to mention the addition of a few heating pads. If solar isn’t putting out enough to heat the batteries, it’s not enough to make that much difference.
If it is a weekend cabin in the woods.. Take the batteries home and bring them back nice and warm fully charged.
If it is freezing, there isn’t likely to be much sun in our climate. I count amp minuets, not hours for 4 months of the year.
If they are inside with you and still below freezing……. You really need to rethink being off grid.

Mia said:

So, since the OP apparently is in Canada, what would one need to do for the comment regarding using them in climates where freeze protection is a concern for these batteries - just curious since many of us live close enough to the Canadian border and also fall under similar low temp climate concerns…

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I've heard many people have had good experience using the water anti-freeze heating pads. They just stop water from freezing, not heat up a lot like a foot warmer. e.g. i bought this one https://www.amazon.com/gp/product/B077VLB1KK/



It just so happens that this thermostatically controlled temperature range is perfect for preventing freeze damage on LFP batteries and low complexity.

They should be fine to use just connected to 12V but I would feel safer with an arduino reading a thermometer and disconnect the 12V power to pad if the temperature reading became too high.

Off Grid Thad said:

You can freeze them. Even use them. Just don’t charge them.
Repurpose your battery shed to growing mushrooms and move them inside.
Temperature cut off is not difficult with a multitude of modern electronic, not to mention the addition of a few heating pads. If solar isn’t putting out enough to heat the batteries, it’s not enough to make that much difference.
If it is a weekend cabin in the woods.. Take the batteries home and bring them back nice and warm fully charged.
If it is freezing, there isn’t likely to be much sun in our climate. I count amp minuets, not hours for 4 months of the year.
If they are inside with you and still below freezing……. You really need to rethink being off grid.

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I know that you can still use them below freezing - I was inquiring more for recommendations from those that are boondocking in such climates as to how to keep them warm enough for safe charging!

curiouscarbon said:

I've heard many people have had good experience using the water anti-freeze heating pads. They just stop water from freezing, not heat up a lot like a foot warmer. e.g. i bought this one https://www.amazon.com/gp/product/B077VLB1KK/

View attachment 58452

It just so happens that this thermostatically controlled temperature range is perfect for preventing freeze damage on LFP batteries and low complexity.

They should be fine to use just connected to 12V but I would feel safer with an arduino reading a thermometer and disconnect the 12V power to pad if the temperature reading became too high.

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Ty! This is why I was inquiring! To find out how people are keeping their LiFePO4 batteries from freezing and safe to charge on the go! Are you using this currently?

Off Grid Thad said:

That is 100% valid.
It is, however, only half the point.
For completely off grid applications such as mine.
If you have solar replenished batteries every day, great. I’ll Call that summer.
If winter reduces your solar to basically nothing then you must rely on a generator. To do the least amount of damage for any chemistry of lead and get that 5 to 8 year life span it needs to be recharged as soon as possible. Best treatment would be running generator every day. Basically defeating the purpose.
For the same amount of LFP power used and returned over a 5 day span FLA needs almost 2x as much generator run time.
To have enough lead for a 4 day run to 50%, may as well buy LFP
If your bank is large enough for 4 days, you will be getting a real 50% as opposed to a large draw on smaller system with a bit of bounce back.
Once again. Feel free to leave your Lithium at 30% soc for a month or 2.

You can freeze them. Even use them. Just don’t charge them.
Repurpose your battery shed to growing mushrooms and move them inside.
Temperature cut off is not difficult with a multitude of modern electronics, not to mention the addition of a few heating pads. If solar isn’t putting out enough to heat the batteries, it’s not enough to make that much difference.
If it is a weekend cabin in the woods.. Take the batteries home and bring them back nice and warm fully charged.
If it is freezing, there isn’t likely to be much sun in our climate. I count amp minuets, not hours for 4 months of the year.
If they are inside with you and still below freezing……. You really need to rethink being off grid.

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I have also contemplated a mobile option such as a trailer to take LiFePO4 with us on the road when we are not at the “cabin location” when/if we switch over - currently we have FLA which get trickle charged over the winter and checked and filled when we are there, but once we retire, we may not be around to fill them, but they will be trickle charging in our absence… but my husband isn’t so keen on towing them in a trailer and we have a truck camper with no place to put them….

Short_Shot said:

My statement was that he is making this out to be apples and oranges when it's still a matter of proper handling.

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Actually I said YOU were making an apples and oranges comparison. Whatever.

FLA just don’t up and die in two years.
I had a couple walmartha DC batteries that gave up at 9 & 10 years old. I didn’t expect that long, and I don’t expect that long out of their replacements. Also walmartha.

But telling people their FLAs won’t last like you did- is false- that was MY point. I’ve got 2-1/2 years on some right with no signs of struggle. I expect they’ll do as well as numerous others in the past did. Five years or so? Don’t know yet. I made sure I’m not going to be deep cycling them by adding two and assuring I have plenty of panels.

I note you mentioned proper handling. The costcoland batteries are unknowns to me so I can’t speak for them. Heavy 6volt golf batteries often go ten years for not much more per Ah than ‘marine’ DCs.

the original question was valid:
Does a lfp battery make sense? Or lead?
A lot probably most of the time especially for bigger systems lfp wins.

Lead acid can make sense, too (mine are outside and it does get to zero often here)

I’ve got just $350 in five deep cycles- i am willing to accept the lifespan I get. The OP wanted to know how to make that decision for themselves. Lfp might be best for them- I don’t know that answer. Just please don’t tell my batteries they are already no good- they’re doing great.

Mia said:

Ty! This is why I was inquiring! To find out how people are keeping their LiFePO4 batteries from freezing and safe to charge on the go! Are you using this currently?

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I am not currently using one of those thermostatically activated pads in an operating system.

If you search around the forum with terms like "thermostatic" "heating pad" and stuff like that, there should be some posts about other people's real world experience.

I personally think they are best paired with insulation, but it's important to do an analysis of what temperature/humidity locally is expected year round and stuff before going too far. Good luck!

12VoltInstalls said:

Actually I said YOU were making an apples and oranges comparison. Whatever.

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Yes.

That's what I said.

12VoltInstalls said:

the original question was valid:
Does a lfp battery make sense? Or lead?
A lot probably most of the time especially for bigger systems lfp wins.

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The original question was why go with spendy gel when Costco has 150.00 FLA.
It then turned into
FLA vs LFP with a pinch of gel.
I am guilty of a thread hijack I guess.
But lead is so……. yesterday, ya know?
It is absolutely valid to compare apples to oranges. If you think you can’t make a great pie from oranges, you need to meet aunty Amy. Both are food, good, sweet, semi nutritious, mostly liquid, packed with sugar and grow on trees.
Thus compared, I like fresh apple cider better. Completely subjective.
It is also absolutely valid to compare energy storage systems regardless of chemistry.
If two different objects do the exact same thing their ability to do that thing must be compared, measured and evaluated. Eeehhhhhhh,,, not so subjective. Such is advancement and evolution. Thus we have progress.
I don’t want to walk 20 miles to work tomorrow, I’ll drive instead. But sometimes walking is what’s called for. You’ll have that when you compare most century+ old technology to current scientific achievements.

With the cost of LFP at roughly just double FLA and the same or less than Gel, there is almost nothing left to compare.

Well. In their defense, lfp4 isn't necessarily the same cost depending on the product. The cheaper lithium packs often have a BMS that is sub par and means the user needs to watch out for additional concerns.

The one that comes to mind is low temp charge protection, but this can be obtained with a quality charger.

That said, you spend 220 to 250 for a 100ah deep cycle lead acid and effectively get half the capacity, or spend 500 on a cheap 100ah lfp4 and get the full 100ah.

Thus making the price essentially the same but not practically the same.

The up front investment is still higher, but you are buying twice the capacity. If your original plan accounts for this and you were going to buy "two" lead batteries anyways... then there's simply no reason for lead in your situation.

There's also 50ah lithium batteries out there in the wild that are only slightly more expensive than the "equivalent" lead one.

However, just to throw a wrench back in it.

You don't need to buy "two" lead acid batteries for 100ah.

If you only need 100ah usable then things get dicey on the cost when looking at 200ah lead (and likely the larger ones too). These are then again cheaper than a 100ah lithium and you start questioning the matter once more. In this case the up front cost comes into play again. Do you have money *now* or are you going to try to offset the system install cost by deferring the battery upgrade a few years? This line of reasoning can be valid if you simply don't have the funds available.

Of course we all know the increased lifespan puts lithium at a vastly lower lifetime cost.

Lead isn't entirely dead yet, but it's very close to it.

It all definitely goes out the window when you go towards a diy pack for usable capacities over 100ah (maybe even a bit lower), but I don't assume everyone will do that.

Just thinking out loud here ,
The new LFP battery’s are space age and all but cost a lot of money up front .
I use gell battery’s in my sail boat
I just don’t wand wet cells tipping when sailing for obvious reasons .
But off grid I’m one of those guys that like cheep sams club battery’s
I use 16 215 has golf cart battery’s for48 volt bank.
I use 10% of my capacity over night
I’m sure I can get 5 years out of them I allways do. They cost me 89 bucks each .
No core charge when I bought them .
So I payed less the 1500 bucks out the door .
The charging fumes get vented out side
My battery box is 30x72 “ in my garage .
It get down to-20 for a few weeks every year .
Last year my panels where covered with snow so I just charge for 1 or 2 hours more or less every day and get a full absorb charge on the 4th day ..
I service the bank twice a year by check SG in every cell adding water and EQ ing if It needs it but it really never dose .
And cleaning and tightening battery cables
I do get between 20and 40 dollars back when I scrap them 3 or400 bucks soooo
They cost me 11or 1200 dollars for 5 years
If I lose 20% I can still run fine .
I know guys that have 10 years on cheep golf cart battery’s and still use them ,
Here is the rub I really don’t know if you can get HO insurance or pass inspection
With LFP battery’s ?
And most of this forum tragic is people
Trying to figure out how to make up battery packs of use them hmmmmmmm

Lithium prices have fallen greatly recently to the point where lithium is often only marginally more expensive. In some cases lithium can actually be cheaper when comparing big brands of lead to Chinese lithium packs.

Diy is *definitely* cheaper than lead acid.

This was not true just a few years ago.

But you might be right on the inspection point. A UL listed lithium pack is not likely to be as cheap as lead and if that matters then it comes back to the previous point of up front cost.

I’m just not seeing any lith battery cheaper the my go batterys ?
If the price never went up my battery’s would cost me 2700 bucks for 10 years
And I think they would last a few years longer .
I bought some 280ah cells for thin money from China with bms but that was for a 12 volt system for my buddys travel trailer .
He has had them for 4 months on his work bench and has not figured out how to balance them or build a battery pack out of it yet .
So not as easy as will makes it sound ?

Personally I strongly dislike the investment risk of needing to water batteries or check specific gravity. Miss a check up and suddenly need to move hundreds of pounds of equipment.

I’ve built a 100Ah 12V LFP pack and honestly It Was Easy. Get a JBD BMS and follow overkill solar BMS manual. It works.

Just chiming in. It’s still running and charging from solar every day for a year now.

Of course equipping oneself with new information is itself a cost. That’s what we are here for ?

The cost was 620 usd for the cells (1280 Watt hours) and 140 usd for BMS.

760 usd for 100 real usable amp hours 12V

Wellbuilt said:

I’m just not seeing any lith battery cheaper the my go batterys ?
If the price never went up my battery’s would cost me 2700 bucks for 10 years
And I think they would last a few years longer .
I bought some 280ah cells for thin money from China with bms but that was for a 12 volt system for my buddys travel trailer .
He has had them for 4 months on his work bench and has not figured out how to balance them or build a battery pack out of it yet .
So not as easy as will makes it sound ?

Click to expand...

It can be though if a person takes the initiative to put the components together

curiouscarbon said:

Personally I strongly dislike the investment risk of needing to water batteries or check specific gravity. Miss a check up and suddenly need to move hundreds of pounds of equipment.

I’ve built a 100Ah 12V LFP pack and honestly It Was Easy. Get a JBD BMS and follow overkill solar BMS manual. It works.

Just chiming in. It’s still running and charging from solar every day for a year now.

Of course equipping oneself with new information is itself a cost. That’s what we are here for ?

The cost was 620 usd for the cells (1280 Watt hours) and 140 usd for BMS.

M760 usd for 100 real usable amp hours 12V

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For $849.99 I can have the following UL certified lithium battery delivered to me assembled:

12V 100Ah Smart Lithium Iron Phosphate Battery w/ Self-Heating Function (or $50 less without the self heating function) [sorry for the typos and edits …using a very crappy ipad with an inaccurate and improperly responsive touchscreen with it’s own mind at times…]​

Wellbuilt said:

Just thinking out loud here ,
The new LFP battery’s are space age and all but cost a lot of money up front .
I use gell battery’s in my sail boat
I just don’t wand wet cells tipping when sailing for obvious reasons .
But off grid I’m one of those guys that like cheep sams club battery’s
I use 16 215 has golf cart battery’s for48 volt bank.
I use 10% of my capacity over night
I’m sure I can get 5 years out of them I allways do. They cost me 89 bucks each .
No core charge when I bought them .
So I payed less the 1500 bucks out the door .
The charging fumes get vented out side
My battery box is 30x72 “ in my garage .
It get down to-20 for a few weeks every year .
Last year my panels where covered with snow so I just charge for 1 or 2 hours more or less every day and get a full absorb charge on the 4th day ..
I service the bank twice a year by check SG in every cell adding water and EQ ing if It needs it but it really never dose .
And cleaning and tightening battery cables
I do get between 20and 40 dollars back when I scrap them 3 or400 bucks soooo
They cost me 11or 1200 dollars for 5 years
If I lose 20% I can still run fine .
I know guys that have 10 years on cheep golf cart battery’s and still use them ,
Here is the rub I really don’t know if you can get HO insurance or pass inspection
With LFP battery’s ?
And most of this forum tragic is people
Trying to figure out how to make up battery packs of use them hmmmmmmm

Click to expand...

Because…. this is a DIY forum for people to learn from others and to ask questions

Longer cycle life of lithium batteries is a key part of the value.
If sized so small you cycle 80% every night, that makes a difference.
If sized for 3 days autonomy without sun, most nights it only cycles 15%. In that case, quality FLA can give 15 years and is still a reasonable alternative.

The other concern is maturity and reliability. Someone mentioned BMS is often cheap and unreliable.
A cycling test of dozens of brands of battery had only two or three that lasted several thousand cycles without failing.
If LiFePO4 looks good assuming 3500 cycles, it is only that good if it actually lasts that long.

Of course, if you can buy LiFePO4 (DIY) for same purchase price per usable kWh as lead-acid, you break even when it reaches 10% or 20% of anticipated life.

Me? I went with AGM because for grid-backup I doubt I'll use 200 cycles.
I was unware of DIY options (and they weren't as cheap 15 months ago), so I compared to commercial lithium. 5x the price for 5x the cycle life. AGM already offered 3x the cycle life I expected to use.
Within a year, the LG RESU battery I had considered was recalled due to fires (actually the RESU-H 400V, not the RESU 48V, but still ...)

Hedges said:

quality FLA can give 15 years and is still a reasonable alternative.

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Huh. You gave me a chuckle.
I celebrate but don’t hold my breath at five years with the martha stewart batteries.

However, you used the word, “quality.” I don’t know if Johnson Controls walmartha batteries are ‘quality,’ probably not, but they are fairly inexpensive and last…ok. Quality seems to be ~$250+ so basically 3 times the price three times the life!