Future of DIY LiFePO4 looks bleak…

[FilterGuy]

Keep in mind also that most of these batteries are not available anywhere near this price point or at all outside the US - so they wouldn't even be an option to begin with.

Good point. Hopefully, it will change over time.

Do you happen to know why the markets have not opened up outside the US? Is it market forces or government rules or something else?

 

[toms]

I still stand by my DIY pack (already 11 years old and still going strong) ending up being cheaper per kwh over its lifespan than any commercially available battery.

Cheap up front doesn’t mean cheap overall - my experience in helping with a lot of systems is in fact the opposite is usually the case.

 

[curiouscarbon]

Sharing a little more.. DIY stays alive with me for two major incentive branches.

Hobby interest is one,
Personal repairability is another.

Ability to repair the device on site myself with basic parts and tools is probably more important than the passing hobby curiosity.

If this solar battery process involves transitioning my life needs onto a set of devices, I really really want to be able to autonomously recover from common failure modes independently by keeping tools and spare parts around.

Refrigerating medicine is a 24/7 need, which influences my design preferences.

All that said, if my interest in 100% uptime requirement were relaxed, premade batteries would be more interesting. Some like battleborn seem quite reliable, and I continue to use two of their 12V 100Ah regularly. One as solar fridge duty and one as portable power source.

For now it comes down to features still to me.

Programmable safety disconnect limits to user
Per cell voltage monitoring to user
Documented Wired Data Connection

When those features become available widely, I will probably rely on DIY a lot less.

 

[curiouscarbon]

Being able to walk away from a solar/battery system for a year or more and have confidence that it will operate provided solar input availability, is what I really want out of solar stuff.

Grid randomly goes down for a number of hours per year? Ok, but the sun only has tiny sunspots and provides more reliable energy each rotation. (for certain areas of earth)

I want to check on my solar system operation parameters easily within a moment, maybe multiple times a day. Or maybe once a week. Or less frequently.

Want to get to a point where checking is primarily out of academic interest rather than maintenance etc.

 

[Bleedingblue]

I built several of my 280ah packs when it was down to $75 a cell. With shipping and everything It was around 90 each. Counting the bms I had around 1600 in each 280AH pack. Prices went up and I bought 32 more of the 280AH cells at 100 each, shipping, bms etc brought cost to around 2000 a string.

Cost is still around that area

 

[upnorthandpersonal]

Do you happen to know why the markets have not opened up outside the US? Is it market forces or government rules or something else?

Here in Europe at least, most people don't have a need: the grid pretty much never goes down and electricity (was until recently) not very expensive (while unit prices are higher than in the States, households use around 3x less in comparison). Grid tied solar is by far the most popular option, and there are very few people 'off-grid'.
Maybe the situation will change, but at least up until now the market has been very small for home batteries.

 

[Skypower]

When you figure, your time, the risk of cell quality, the lack of UL certification, lack of long term warranty the simple logic is that a Big Battery or Eg4 makes more sense than a diy build.
Unfortunately, I may have done my last build unless the local cell prices( on US shores) come down. Just not willing to spin the lottery with off shore wait, hope & disappointment anymore. I may buy a few more JK’s to keep on hand because they are so cheap incase a server bms croaks.

 

[upnorthandpersonal]

Being able to walk away from a solar/battery system for a year or more and have confidence that it will operate provided solar input availability, is what I really want out of solar stuff.

Grid randomly goes down for a number of hours per year? Ok, but the sun only has tiny sunspots and provides more reliable energy each rotation. (for certain areas of earth)

I want to check on my solar system operation parameters easily within a moment, maybe multiple times a day. Or maybe once a week. Or less frequently.

Want to get to a point where checking is primarily out of academic interest rather than maintenance etc.

That's where I'm at - I rarely check on my system. It's now been in operation for almost three years without issues. I don't even check my state of charge all that often (maybe a bit more often in winter). It just sits there doing its thing while I spend my time on other things, like fishing

 

[offgriddave]

I went with signature solar 48v battery because of the warranty, but I really really really regret this. I'm worried they're going to screw me out of any warranty. The way that they behave is an indicator they're going to royally screw me in the future. I should have gone with my instinct.

 

[Substrate]

What is weird is the amount of large-capacity single-cell offerings showing up on Amazon these days.

If you search for "lifepo4 cells", a bunch turn up and they aren't just solar garden lights or 26650's.

Not sure of the quality of course, but little things like ExpertPower selling 100ah singular cells (probably the same that they use in their boxes) - could also mean that they are already in their Calif warehouse, and might not be bloaty-bloat. Bus bars and hardware too.

Just saying - I haven't purchased any myself.

 

[billt1827]

Here in Europe at least, most people don't have a need: the grid pretty much never goes down and electricity (was until recently) not very expensive (while unit prices are higher than in the States, households use around 3x less in comparison). Grid tied solar is by far the most popular option, and there are very few people 'off-grid'.
Maybe the situation will change, but at least up until now the market has been very small for home batteries.

In the UK the situation is changing. My brother, who had no interest in PV, has had a system installed with batteries. No idea why he choose a system with batteries, but I must assume that installers are pushing them.

Also, I see a lot of enquiries about battery systems on self build groups. The eye watering cost of grid electricity here is pushing people to use as much of the power they generate as they can, rather than exporting it. Some people are using very cheap off peak rates to charge their batteries as well. (Not sure there's much value in that, but some people try and squeeze as much out of the system as they can.)

 

[sidpost]

In the UK the situation is changing. My brother, who had no interest in PV, has had a system installed with batteries. No idea why he choose a system with batteries, but I must assume that installers are pushing them.

Also, I see a lot of enquiries about battery systems on self build groups. The eye watering cost of grid electricity here is pushing people to use as much of the power they generate as they can, rather than exporting it. Some people are using very cheap off peak rates to charge their batteries as well. (Not sure there's much value in that, but some people try and squeeze as much out of the system as they can.)

Tesla, Generac, and others are starting to build 'powerwalls' which work well for this type of situation. You can charge during off-peak and then consume during peak usage rates. As you add solar panels, they can charge your 'powerwall' as well.

 

[Just John]

Tesla, Generac, and others are starting to build 'powerwalls' which work well for this type of situation. You can charge during off-peak and then consume during peak usage rates. As you add solar panels, they can charge your 'powerwall' as well.

Yes, to me the primary problem (besides cost) with most of these is the limited cycle life due to cell chemistry.
Pay attention and chose LFP chemistry, and load shifting is one way to help offset the cost. Depends of course on your rate structure, but if using a battery with only a 1000 cycle lifespan, not really recommended.

 

[sidpost]

Yes, to me the primary problem (besides cost) with most of these is the limited cycle life due to cell chemistry.
Pay attention and chose LFP chemistry, and load shifting is one way to help offset the cost. Depends of course on your rate structure, but if using a battery with only a 1000 cycle lifespan, not really recommended.

In my case, I have LiFePo4 batteries. If you charge them to ~95% vs. 98% and limit the discharge to 20% (from zero), you increase their "cycle life" significantly.

On my new Galaxy cellphone, I did the 85% charge limit and it seems to have made a significant difference after 12 months of ownership. I still have all of my battery life within a small margin of error.

On my flashlight batteries, I try to limit the charge to 0.5C which also makes a big difference in battery life. With 26650, 21700, and 18650 batteries that is pretty easy because most chargers max out at 2A.

 

[Just John]

In my case, I have LiFePo4 batteries. If you charge them to ~95% vs. 98% and limit the discharge to 20% (from zero), you increase their "cycle life" significantly.

On my new Galaxy cellphone, I did the 85% charge limit and it seems to have made a significant difference after 12 months of ownership. I still have all of my battery life within a small margin of error.

On my flashlight batteries, I try to limit the charge to 0.5C which also makes a big difference in battery life. With 26650, 21700, and 18650 batteries that is pretty easy because most chargers max out at 2A.

Cell phone batteries are a different chemistry, 80 percent is the recommended top charge for longevity. With LFP, good luck hitting that 95% mark, really until you hit 98% the voltage is not a good indicator of state of charge.

 

[sidpost]

From ~95% to 100%, the voltage measurement differences are pretty small as you are way past the knee of the voltage/charge curve. At least that is what we see with our battery tests and our our batteries. My bank is ~35Kwh and a friends primary bank is ~60Kwh

Flashlight and RC batteries can be a bit of mess because chemistries and battery quality varies so much but, 4.1V works a lot better than 4.2V for me. Of course in a ~$4 battery I generally don't stress much over battery life in an easily replaced battery. Heck, that is less than a Starbucks coffee and barely more that bottle of soda at random store or the same as most bottled cold coffees commonly sold ready to drink cases.

 

[Just John]

From ~95% to 100%, the voltage measurement differences are pretty small as you are way past the knee of the voltage/charge curve. At least that is what we see with our battery tests and our our batteries. My bank is ~35Kwh and a friends primary bank is ~60Kwh

I find the last 5% has the most voltage change. What chemistry are you talking about?

 

[Ahjwinth]

In Ireland and Belgium there is no money paid back to the producers of Solar energy. In Ireland everyone that installs solar panels also installs battery’s to store the self produced power instead of sending it to the grid for free and later buying it back. As I understand from my colleagues most of them have a 10kwh storage so they can balance the solar and self consumption during the day. In Belgium it is the same story.
I’m from the Netherlands and same thing is coming. currently we can balance out on the yearly invoice the self produced power and used over the full year. From 2025 this rule will be changed and it is reduced in steps until 2030. Therefore it is becoming attractive to put in a ESS. The majority of the price in the Netherlands is taxes so were currently paying between 0.50 and 0.70 cents a KWH (USD/Euro=Close to 1).
This is driving me to put in a ESS and battery’s are ordered and the Victron Multiplus is already waiting installation. So I’m ahead and ready for 2025.

 

[Goboatingnow]

I don’t see this as “ bleak “. None build lead acid from individual cells. LFP is no different.

We will have to wait to see major mainstreams like Bosch , Varya, exide enter the market will quality product. It will happen in time.

In specialist areas like boats emerging standards some which have legal standing will end diy anyway and force specialist drop in batteries anyway

Amateurs should in Dangerous diy. LFp and associated systems can be dangerous I see this as a good step.

 

[Goboatingnow]

In Ireland and Belgium there is no money paid back to the producers of Solar energy. In Ireland everyone that installs solar panels also installs battery’s to store the self produced power instead of sending it to the grid for free and later buying it back. As I understand from my colleagues most of them have a 10kwh storage so they can balance the solar and self consumption during the day. In Belgium it is the same story.
I’m from the Netherlands and same thing is coming. currently we can balance out on the yearly invoice the self produced power and used over the full year. From 2025 this rule will be changed and it is reduced in steps until 2030. Therefore it is becoming attractive to put in a ESS. The majority of the price in the Netherlands is taxes so were currently paying between 0.50 and 0.70 cents a KWH (USD/Euro=Close to 1).
This is driving me to put in a ESS and battery’s are ordered and the Victron Multiplus is already waiting installation. So I’m ahead and ready for 2025.

In Ireland due to forthcoming EU directive all retail electricity suppliers are now offering feed in tarriffs. No doubt Belgium will fall in line also.

This then can be usefully compared to battery based time shifting and in fact in a lot of case removes the need and cost of batteries.

Currently I’m paying €0.13 KWh night rate and €0.22 day rate. Typically feed in tariffs ate €0.15 to 0.18 from recent published data.

I dont know yet if I can retain night and feed in , I suspect feed in is only on the day tariff.

Hence there’s a computation but I think a bigger array and FIT removes the need to have any batteries. I see no justification for batteries anyway , as the grid is available 24/7 and they add a lot of money to the install cost and have a unknown life cycle.