Future of DIY LiFePO4 looks bleak…

[toms]

Meaning ‘only 7 years’ or ‘wow, a full 7 years!’ ???

Sorry, that was pretty ambiguous. I meant people will be happy that they are getting 7 year battery life out of a battery that should last twice as long as that.

It is clearly not in the best interests of commercial manufacturers to have a battery lasting too long.

 

[fafrd]

I've ordered a few things thru aliexpress over the years, and frankly I think it's a crapshoot. It's like Harbor Freight on steroids. Having a recommended vendor with a warehouse in the US to land product and distribute from there is worth a lot to me.

For sure.

Powerwholesale.net - Amy and her husband - have more cells coming in to their Houston warehouse. Seems the trend is for larger capacities, the 300A+ sizes seem to be most popular - I think those users are off-grid home-based users. Rather overkill for what I need for my RV, so I was happy to find 230-size new A+ cells for $108 without having to wait for them to come from mainland China. I have no doubt I'll get good product that will test up to par and can build a pack reliably. The 4 eve 230A cells with bars were $454 all in, shipping, payment fees, everything.

OK, so $0.155/Wh. That’s still 10% below the best price I’ve seen on Amazon and Amy and her husband seem to be going about things right as far as focus on quality and customer support, so I think you made a wise decision.

But still, +10% for a 2-month no-questions-asked return policy/period starts making one think twice…

They're due in a couple of weeks, not a couple of months. Then $140 for a bms, and I'll buy a bench-power pack and the rest of the ancillary items to build a pack, like a hydraulic crimper, wire, terminals, etc.

My GC2's are 7 years old this year. One cell is dropping gravity just a bit, so I figure it's just a matter of time now and I would have had to buy another pair - a decent set runs about $325-$375. For about twice that I can get much more power reserve and much longer life. This is an investment in better performance and longevity, likely for the rest of the RV's life. Installing an inverter for the wife's electronics really kind of launched this whole quest for more power -more solar, more capacity. Besides, it's fascinating as hell. ?

I have no idea what a ‘GC2’ is…

[b\I don't see the commodity offerings like you see on Amazon getting any cheaper[/b].

Well, my main point was not that the commodity cells on Amazon would get cheaper but that the Off The Shelf finished LiFePO4 batteries would get much cheaper a year from now. One year ago you could but find commodity LiFePO4 cells on Amazon…

I do see the bigger players like Battleborn and Dakota dropping their prices in order to compete. I think the cheaper options are really chipping away at their market share.

This is exactly my main point - OTS LiFePO4 battery costs through channels like Amazon will decline far more over the next year than commodity LiFePO4 cell costs…

I think overall cost won't go down simply for raw materials cost, but higher volumes brings economies of scale, and settled formats or uniformity, and so then costs come down a bit for mass production. The technology becomes more mainstream, users see the benefits, so the market expands.

Exactly. As well as the fact that, as the market matures and expands, Chinese vendors find the motivation to organize domestic inventory (allowing bulk/volume shipping economies of scale).

Everybody finds sources like Battleborn - they and Victron seem to dominate the quality high-end market. But not everyone is willing to commit at that level to enter the field, so they go looking for cheaper alternatives, without benefit of an understanding of why the cheaper offerings are cheaper.

Markets in transition are always a ripe field for con artists, but as the market matures, I believe we’re going to see more and more examples of quality OTS offerings approaching budget DIY price points.

That battery from Powerporter I linked to in the lead post just posted their manual. First of all, they have a relationship with GroWatt (and may even be an affiliate of GroWatt for all I know). So you can look at the delta between Victron and GroWatt in the inverter space to see what’s starting to happen now in the LiFePO4 OTS battery space.

And second, they are offering a pretty solid 5-year warranty. US-based warranty versus China-based warranty needs to get sorted out, but the key point is that it seems clear they will be budget OTS LiFePO4 battery offerings delivering GroWatt-like warranty, service, and quality reaching the US market over the next year or so…

If companies like Ampere-Time can get their 100A packs down in the $200 level they'll sell millions of them. And 200A packs for under $500. I don't see that happening in a year, but maybe so. If there's a high failure rate people won't adopt the technology.

These were posted by another poster: https://www.amazon.com/LiFePO4-Batt...rds=12v+LifePo4+battery&qid=1638487429&sr=8-3

255Wh @ $0.27/Wh is still a ways away from the 2.5kW @ $0.20/Wh your talking about but is a pretty good reflection of the state of the market in December 2021, and by December 2022, I won’t be surprised to see prices on Amazon much closer to your target.

I got interested in some of the more boutique builders like BigBattery, and then you find more like them, like Battery-Evo. The latter had a 180A pack on sale for black-friday for their $799 with 10% off shipped.

2.3kWh @ $0.35/Wh doesn’t seem especially attractive in today’s market, especially since those Battery Evo offerings are almost certainly using substandard or even used cells…

I nearly pulled the trigger. But [b{there are enough reported problems with all of these alternatives to make me give pause[/b], and products a step up like BigBattery Owl are still a grand for a 170A pack.

Yes, as I said, substandard and/or used cells. Personally, I’d take a chance on one of those new batteries from Powerporter before I’d purchase anything from Battery Evo.

And BigBattery Owl for 2.17kWh @ $0.46/Wh? The Singnsture Solar GYLL delivering 5.1kWh @ $0.29/Wh looks like a much better bet in today’s market.

I also have trouble trusting used/reconditioned cells that are basically a recycled product. Seems like more of a gamble to me - I would rather start out with factory-new A+ grade cells. So that's kind of what I'm shooting for - a step up from these in performance reliability and capacity at a similar cost, without completely blowing my wad with the likes of Battleborn. My neighbor drank the koolaid - he's got five grand just in batteries for his delivery van conversion!

You are taking a chance anytime you purchase cells from a reseller. If you pay up to get cells directly from a manufacturer like EVE, you can have high confidence you are getting what is advertised.

Your chances of getting true factory Grade A cells from an outfit like Signature Solar that has their OTS batteries asssembled by the actual cell manufacturer themselves is higher than purchasing from any reseller, even a well-reputed one like Amy.

Forum members like @time2roll and @HRTKD are so encouraging and supportive, and Will of course blazing the trail, making the choice to learn more and take the plunge less scary. I have quite a bit of experience with lithium polymer packs for RC cars and that stuff is downright dangerous. I had fears of nuclear bombs sitting in my RV living room. LOL I have a lifetime of experience with 12v systems for boats and RV's, going back more than forty years, so this then becomes and extension of that. Bigger and better. ?

This thread was directed primarily at those users going DIY because it is so much more economical - I believe that motivation will start drying up within a year from now.

Of course, the outlook for DIY hobbiests who plunge down the DIY route because of the adventure, the learning, and the fun is not at all bleak. For those who choose to go the DIY path because they enjoy it, their hobby is just going to get cheaper and cheaper with each passing year…

 

[robby]

Agree with everything you’ve posted, but want to add that you overlooked the used EV cells. There will just keep being more and more of them.

I have to agree with that one. Used Cells will always be available on a delayed time line and in almost the same quantity as new cells are being manufactured. Recycling cells into base minerals will always be the secondary option versus trying to sell them used.

I would not even attempt to try and predict the future of DIY battery packs as there are to many variables. The whole thing could collapse under certification regulations as green energy becomes more popular there is almost certainly going to be more regulations. That might even effect off grid users via home owner insurance or clearer regs on liability to manufactures for product failures.

On the flip side it's more likely the used cell market will spur DIY projects just because it will become super cheap to build 60KWh or more of capacity OR there could be new cell formulations that reset the whole market. If someone develops cells that are twice as good as LIfePO4 then you can expect them to be expensive at the start and once again factories have to find a market for B grade cells.

Then we also have to factor in the other effects of exponential growth in battery manufacturing. Can they really mine the quantity of minerals that are needed? This is not just a market for rich countries, I am seeing videos of people in the poorest parts of the world hobbling together a pair of panels and a small battery bank plus inverter. Electricity is becoming so expensive in many parts of the world that people are willing to spend a significant part of their annual income on getting basic solar. That low and middle end global market will probably guarantee that DIY parts are always available.

 

[fafrd]

Sorry, that was pretty ambiguous. I meant people will be happy that they are getting 7 year battery life out of a battery that should last twice as long as that.

It is clearly not in the best interests of commercial manufacturers to have a battery lasting too long.

Ah, OK. It’s a bit OT for this thread I’ve started, but I’m interested in your experience.

Looking at datasheets from manufacturers like EVE as well as papers like this: https://uwspace.uwaterloo.ca/bitstream/handle/10012/12177/Catton_John.pdf

It seems as though LiFePO4 cells can suffer significant capacity fade of as much as 3% per month (EVE’s datasheet) or ~4% per year (that paper) even if the battery is not being cycled.

So I’m curious what limitations you’re placing on your battery use to achieve 15-year lifetime (5500 cycles @ 1 cycle per day).

EVE’s latest cells will give you 6000 cycles to 80% capacity (if you clamp them at 300kgf and maintain them at 25C), but it’s not at all clear that they will maintain 80% capacity for more than 3.1 years even if not being cycled…

 

[fafrd]

I have to agree with that one. Used Cells will always be available on a delayed time line and in almost the same quantity as new cells are being manufactured. Recycling cells into base minerals will always be the secondary option versus trying to sell them used.

I would not even attempt to try and predict the future of DIY battery packs as there are to many variables. The whole thing could collapse under certification regulations as green energy becomes more popular there is almost certainly going to be more regulations. That might even effect off grid users via home owner insurance or clearer regs on liability to manufactures for product failures.

On the flip side it's more likely the used cell market will spur DIY projects just because it will become super cheap to build 60KWh or more of capacity OR there could be new cell formulations that reset the whole market. If someone develops cells that are twice as good as LIfePO4 then you can expect them to be expensive at the start and once again factories have to find a market for B grade cells.

Then we also have to factor in the other effects of exponential growth in battery manufacturing. Can they really mine the quantity of minerals that are needed? This is not just a market for rich countries, I am seeing videos of people in the poorest parts of the world hobbling together a pair of panels and a small battery bank plus inverter. Electricity is becoming so expensive in many parts of the world that people are willing to spend a significant part of their annual income on getting basic solar. That low and middle end global market will probably guarantee that DIY parts are always available.

Yes, the safety / danger factor is another aspect I didn’t even bring up. That’s another reason that once the cost delta gets small enough, DIY will be limited to the hobbyist / enthusiast community only…

 

[Browneye]

I have no idea what a ‘GC2’ is…

That battery from Powerporter I linked to in the lead post just posted their manual. First of all, they have a relationship with GroWatt (and may even be an affiliate of GroWatt for all I know). So you can look at the delta between Victron and GroWatt in the inverter space to see what’s starting to happen now in the LiFePO4 OTS battery space.

These were posted by another poster: https://www.amazon.com/LiFePO4-Batt...rds=12v+LifePo4+battery&qid=1638487429&sr=8-3

2.3kWh @ $0.35/Wh doesn’t seem especially attractive in today’s market, especially since those Battery Evo offerings are almost certainly using substandard or even used cells…


Yes, as I said, substandard and/or used cells. Personally, I’d take a chance on one of those new batteries from Powerporter before I’d purchase anything from Battery Evo.

GC2 = golf cart 6V. Very common for RV's and trailers, in series, 210 to 240A flooded lead acid. I've replaced my pair twice in fifteen years. You used to be able to get them for about $90 each, now they are closer to $150. The TROJAN T-105 is like a legend. They sag like a mofo. LOL Plus you can only use half. So basically I'm going from a saggy 105A capacity to closer to 190A usable, with no sag.

The amazon packs linked are all too small. I guess you could get a bunch of them and build a bank.

Battery-Evo IS selling used cells. They do test them, but still. At least they're upfront about it - they call them 'recertified'. I called and asked them, 'Yes, they are used'. Evidently they come from commercial battery backup systems, and yes, he also said they expected to see even more of them become available as time goes on. The guy that founded Battery-Evo and BigBattery started out as a recycler - kind of his claim to fame. Also spent some time in prison for software pirating/fraud. They also sell new-cell packs as well, but they're a grand and up or thereabouts.

 

[HRTKD]

So I’m curious what limitations you’re placing on your battery use to achieve 15-year lifetime (5500 cycles @ 1 cycle per day).

I'm charging to 14.2 volts and not discharging below ~20%.

I have no expectation that these cells will last more than eight years. If they make it that long I'll be a happy camper. The lead acid batteries I've had in my RV never lasted more than about three years and that was with careful maintenance.

In theory, given that my batteries might see 100 full cycles a year (if that), they should last a very long time.

 

[fafrd]

GC2 = golf cart 6V. Very common for RV's and trailers, in series, 210 to 240A flooded lead acid. I've replaced my pair twice in fifteen years. You used to be able to get them for about $90 each, now they are closer to $150. The TROJAN T-105 is like a legend. They sag like a mofo. LOL Plus you can only use half. So basically I'm going from a saggy 105A capacity to closer to 190A usable, with no sag.

Got it - thanks.

The amazon packs linked are all too small. I guess you could get a bunch of them and build a bank.

They are just an example - a year ago, no such offerings were available on Amazon (indicating that Chinese resellers have now set up US operations with inventory).

Battery-Evo IS selling used cells. They do test them, but still. At least they're upfront about it - they call them 'recertified'. I called and asked them, 'Yes, they are used'. Evidently they come from commercial battery backup systems, and yes, he also said they expected to see even more of them become available as time goes on.

The fact that they do perform a capacity test on each recycled cell they sell gives them a big leg up on the Chinese resellers of factory rejects in my view…

The guy that founded Battery-Evo and BigBattery started out as a recycler - kind of his claim to fame. Also spent some time in prison for software pirating/fraud. They also sell new-cell packs as well, but they're a grand and up or thereabouts.

Didn’t know about the software pirating, but I’ve probably spent over three hours on the phone with him myself. I’ve always found him to be straightforward and he’s always explained clearly to me what cell types he was using to assemble his batteries and kits.

The bottom line is that EV cells are ‘used up’ once they have dropped to 80% of initial capacity, while those cells still represent significant value for other applications such as home powerwalls.

He saw that value proposition when the used EV cells first stated hitting the market and has run with it since then.

 

[toms]

Ah, OK. It’s a bit OT for this thread I’ve started, but I’m interested in your experience.

Looking at datasheets from manufacturers like EVE as well as papers like this: https://uwspace.uwaterloo.ca/bitstream/handle/10012/12177/Catton_John.pdf

It seems as though LiFePO4 cells can suffer significant capacity fade of as much as 3% per month (EVE’s datasheet) or ~4% per year (that paper) even if the battery is not being cycled.

So I’m curious what limitations you’re placing on your battery use to achieve 15-year lifetime (5500 cycles @ 1 cycle per day).

EVE’s latest cells will give you 6000 cycles to 80% capacity (if you clamp them at 300kgf and maintain them at 25C), but it’s not at all clear that they will maintain 80% capacity for more than 3.1 years even if not being cycled…

Sorry for dragging off topic, life of pack is the main reason i DIY though.

You could read theoretical studies, or go by manufacturers theoretical specs - or you could reach out to some of the thousands of people who have been using these cells for house batteries for a decade and look for a common theme.

My battery is 400ah@48V. It is limited to the voltage range of 50 - 55.5V. Max charge current is 100a, max discharge current is 200a. Max temp is 30°C. Maximum drawdown from 55.5V is 300ah.

Just last week i used the full 300ah without reaching 50V.

 

[Isaac-1]

...

I used to build computers too, now we buy Dell refurbs and fix them if they break. The high end stuff is still high end.

So that’s the humble viewpoint of a raw noob.

I used to do that too, until I realized about half the Dell refurbs out there until I realized about half the Dell refurbs out there come out of the box with some sort of flaky hard to find problem, that can often be traced back to a motherboard flaw.

 

[DLTooley]

It is already the case that OTS products are a better choice for the typical small user such as the RV market.

The best future value may well be in a lowered price for sub grade cells with fewer suckers purchasing.

 

[Browneye]

I used to do that too, until I realized about half the Dell refurbs out there until I realized about half the Dell refurbs out there come out of the box with some sort of flaky hard to find problem, that can often be traced back to a motherboard flaw.

I haven’t seen that since the blown capacitors on the old optiplexes. I have seen a few blown power supplies, but they’re cheap and easy to replace. Some of the latest SSD drives flake after a year or so.
I’m still in the process of upgrading the staff to win10 clients. Lol

 

[fafrd]

Sorry for dragging off topic, life of pack is the main reason i DIY though.

NP - interested to understand (more below).

You could read theoretical studies, or go by manufacturers theoretical specs - or you could reach out to some of the thousands of people who have been using these cells for house batteries for a decade and look for a common theme.

Real-world experience is far more valuable than any specs and/or test data. The fact that you and others have LiFePO4 batteries in actual use that have continued to deliver over 75% of initial rated capacity for over 10 years comforts me that the age-related capacity slump is far less of a concern than cell specifications or tests such as that paper I linked to would suggest.

My battery is 400ah@48V. It is limited to the voltage range of 50 - 55.5V. Max charge current is 100a, max discharge current is 200a. Max temp is 30°C. Maximum drawdown from 55.5V is 300ah.

Just last week i used the full 300ah without reaching 50V.

That’s great data and I’m happy to see that my usage parameters are even more conservative than yours at the moment.

How old is the battery and do you have any way to estimate the capacity slump you’ve had since your battery pack was new?

And back to your original motivation of going DIY for pack life, are you saying that purchasing an OTS battery made from similar cells and utilizing it within the same limits you’ve chosen (75% DOD, etc…), you don’t believe you’d get similar pack life?

I understand setting conservative usage limits to extend pack life.

I understand going DIY to save money.

But I don’t understand going DIY to extend pack life (beyond the extension you get by setting conservative usage limits).

 

[toms]

The OTS packs use inferior cells and BMS parameters that are not optimised for long life.

I think if an OTS manufacturer used high quality cells they would last a lot longer, but they wouldn’t sell any units - most people don’t consider the total cost/kwh, just the initial cost.

LiFeTech actually do make custom off the shelf batteries, and have an excellent reputation. Ironically the wealthy people that buy them end up with cheaper power.

 

[MrM1]

The OTS packs use inferior cells and BMS parameters that are not optimised for long life.

What bms optimized settings do u use for longer life?

 

[toms]

As listed in post # 34

 

[fafrd]

As listed in post # 34

Are those BMS settings or SCC / Inverter / shunt monitor settings?

How are you monitoring your battery SOC % and what are you doing to assure battery is never drained below the lower limit you have set?

 

[bgflyguy]

I wanted to go the pre built route for my latest purchase, but looking at 48v power walls or rack batteries it was still almost 100% more vs diy. And I over payed for my cells to maybe get a little better quality(luyuan).

BTW, eg4 etc prices are going up not down. The only prices I see dropping are the cheap 12v 100ah batts on Amazon.

Who knows a year from now? I would live to buy a pre built in my next upgrade.

 

[fafrd]

I wanted to go the pre built route for my latest purchase, but looking at 48v power walls or rack batteries it was still almost 100% more vs diy. And I over payed for my cells to maybe get a little better quality(luyuan).

BTW, eg4 etc prices are going up not down. The only prices I see dropping are the cheap 12v 100ah batts on Amazon.

Who knows a year from now? I would live to buy a pre built in my next upgrade.

I’m waiting for one of our members to try one of these: https://diysolarforum.com/threads/t...hich-use-catl-battery-cell.32066/#post-394021

 

[toms]

Are those BMS settings or SCC / Inverter / shunt monitor settings?

How are you monitoring your battery SOC % and what are you doing to assure battery is never drained below the lower limit you have set?

The voltage / temp / charge rates are all controlled by the REC BMS.

The SOC cut off is controlled by a Victron BMV. (this was a left over from my original system configuration - not required any more as LVD of 50V would be sufficient protection)

 

[fafrd]

The voltage / temp / charge rates are all controlled by the REC BMS.

The SOC cut off is controlled by a Victron BMV. (this was a left over from my original system configuration - not required any more as LVD of 50V would be sufficient protection)

Hadn’t heard of a BMS controlling charge current before (other than disconnecting when it passes a maximum).

I get voltage / temp and charge rate control from my SCC - BMS just offers cell-level protection for LVD and HVD (which are not programmable in my case).

 

[curiouscarbon]

Yes, i have seen many issues with both of those offerings. I wouldn’t use or recommend either of them.

I don’t know what cells SimpliPhi use, judging by voltage sag i’d say they are high quality. The SimpliPhi BMS has been the issue.

interesting! considered them in the past but Astronomical Price and No Data Link nailed that coffin real tight.

Only people that have never seen a well put together off-grid system would choose the SimpliPhi.

lol, damn, burn

i don’t disagree though, it so darn expensive and they aren’t keen on user having all the performance data last time checked a year or more ago. before i knew anything about how these systems worked, their batteries seemed like a perfect solution. wonder what it is about their BMS that doesn’t quite operate properly.

for maximum flexibility, data access, safety assurance, i’m doing DIY. it’s taking a long time. but the knowledge gained makes me feel great having a better understanding of what goes into a “safe, high performance, long lasting” battery. turns out it’s rather complicated! haha

 

[curiouscarbon]

Hadn’t heard of a BMS controlling charge current before (other than disconnecting when it passes a maximum).

I get voltage / temp and charge rate control from my SCC - BMS just offers cell-level protection for LVD and HVD (which are not programmable in my case).

some BMS make decisions like “given immediate conditions temperature each cell voltage etc, what is the maximum allowed charge rate?” and send this over CANBUS link to a separate device. most DIY aren’t using this from what i’ve seen around.

so in this sense, the BMS is commanding it, and a separate device actually controls/actualizes the limit

hope this helps

 

[Zwy]

I read thru all this thread while in the waiting room at the doctor today. Let's look at Sig Solar 48V 100Ah, it is $1749 plus shipping.

I'm currently building 2 48V batteries with 32 280Ah cells. Cost was $120 per cell from Amy with shipping, I bought 40 cells in August, 32 for the 48V banks and building 2 12V banks for my boat trolling motor and other uses. I decided to use Batrium for the 2 48V packs, cost was just under $1200 with the CORE, 2 K9 expansion boards, the fuse holders, 500a shunt, and extra long com extension cables ($10 bucks each, a bargain).

I'll have $5040 so far, figure another $150 for compression fixture, misc items which is quite generous. I'll have $5200 in the 2 batteries., 560 Ah. These are going into a used Hoffman electrical cabinet I paid $200 bucks for.

For Sig Solar to equal that I'll need 5.6 of their batteries. $1749 x 6 = $10,494 plus shipping plus you need the rack to hold them $499 https://shop.signaturesolar.us/products/6-bay-battery-rack

Let's go to this 13.2 Kw battery that Will tested the 10 Kw version. https://www.electriccarpartscompany...4-lithium-battery-solar-energy-storage-system

$5212 x 2 = $10,424 but hey, you get free shipping for the extra $5,224.

So, is the future of DIY LiFePo4 really bleak?

 

[curiouscarbon]

the price difference between feature equivalent builds may lessen

data ports are not as common as i like.

i strongly dislike OTS batteries with no data port

or even a way to check the individual cell voltage manually

there are some features that are desirable for a few, but not enough for an OTS integration. that’s one reason i come to this forum