Solar Guppy
Red Cobra Guppy
There are now the same ECO Worthy painted ones on FleaBay ( DC house is ECO Worthy with Blue case ), the prices bounce around on both websites day by day so check both before a purchase
Future of DIY LiFePO4 looks bleak…
- Thread starter fafrd
- Start date
There are now the same ECO Worthy painted ones on FleaBay ( DC house is ECO Worthy with Blue case ), the prices bounce around on both websites day by day so check both before a purchase
ScrotusGobbleBottom
Solar Enthusiast
are they 15s or 16s?
ScrotusGobbleBottom
Solar Enthusiast
Never mind, i see they are 51.2 Yeah, im locked in at 15s
Solar Guppy
Red Cobra Guppy
They are fully accessible ( screws for cover ), so move one wire and they are 15S at this price point might still be the best low cost option. Also running in parallel with 15S and charging 15S voltages as is should still net likely net 90% of energy?
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ScrotusGobbleBottom
Solar Enthusiast
Hmmmm. That is a very interesting point. About 16s vs 15s and 90 percent.
Hedges
I See Electromagnetic Fields!
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You mean 16s in parallel with 15s? Maybe voltage a bit low for balancing. Consider setting charge voltage high enough and balance voltage low enough, but still above or well into knee of curve.
Can the extra cell be removed? I'd think leaving it disconnect to self drain forever might not be good. It could be used to power a gadget or boost to USB charger.
Can the extra cell be removed? I'd think leaving it disconnect to self drain forever might not be good. It could be used to power a gadget or boost to USB charger.
Solar Guppy
Red Cobra Guppy
The DC House / ECO-Worthy boxes are welded cells, someone posted and image. I'd leave it connected for the BMS to be happy
Sanwizard
Solar Wizard
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The ONE industry in life where everything gets faster, better, and cheaper over time is electronics.
Back in the early 90's, a one meg memory DIMM was hundreds of dollars. Now, 64GB Dimms are common and inexpensive. I bought the MPP LVX6048WP inverters on the waiting list from Watts247.com in 2021 for $2100 each shipped. Now they go for around $1100 directly from MPP's store US stock, and the hardware/firmware is better than the version I have.
The one buy I did make out on was when the Seplos Masons first came out. They were selling the Mason 135ah kits, which included the cells, for $1000 each. I bought 4 of them during that deal, and should have bought more.
ScrotusGobbleBottom
Solar Enthusiast
I totally understand your point. I remember buying my first ever CD burner computer drive in 98? perhaps. 1X speed at $350 and if you used the mouse more that a couple times it would ruin the disc. It was indeed terrible.
As far as the renogy batteries, I am a lot more salty about being locked in to 15s than the money lost. Renogy just has terrible software. DC HOME is a joke... They only give you 1 decimal point on the cell voltages. Just think about how clueless that is. 3.29 to 3.19 is a HUGE area in lifepo4 and Renogy gives you just 3.2 for 85% to 20%
One nice thing about DIY is you can use smaller capacity cells with oversized BMS for surge power handling of larger inverter. For example I am helping a friend of mine get started in offgrid solar with bare minimum cost by using LF105 cells with 250A BMS and Growatt 5000es. Battery, BMS, inverter and MPPT cost almost the same ($1636) as a single 100Ah rack battery.
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Overlooking the fact that grade B cells are more of a crapshoot (so it’s not an apples-to-apples comparison, the idea that you can build a DIY battery for under is a pipedream.There are sources for new, 'grade b' cells 280Ah from China for $50 or so if you buy 32 or so.
Even here in Europe you can get Envision cells for 69 Euro if you buy 16, and that's including VAT:
Even if I take your European 280Ah cells for 65 Euro as all-in price including shipping (which you did not state), that $74.52/896Wh or $0.083 /Wh.
Your $50 cell from China almost certainly does not include shipping, and even those cells alone (in quantity of 32 / 28.672kWh) cost $0.056/Wh.
Total up BMS, cables, housing and shipping and I’m pretty sure you’ll be over $0.014/Wh ($200.7 for a 14.336kWh 48V battery).
There is no question that having special requirements such as selecting components, repairability, extended temperature range, high current, etc… easily justifies DIY.
As does doing DIY just for the love of it (a hobby).
The future for those classes of DIYers does not look bleak at all (and in fact looks very bright).
The thread is directed at the majority of DIYers who build DIY because they believe it is much cheaper than buying OTS (~50% according to you and @midwestsolarnoob).
It’s for that vast class of penny-pinching LiFePO4 DIYers (historically) who do so primarily because of the savings that the future look bleak.
And I am not claiming that DIY is more expensive than OTS today.
I am merely pointing out that since I started the thread 2 years ago, the cost gap between OTS and DIY has been steadily shrinking and that irrefutable trend is almost certain to continue.
So even if there are still savings to be had by going DIY today, there will be less savings by going DIY a year from now and eventually DIY will be at parity and then more costly than OTS.
This exchange with you and @midwestsolarnoob has made me ready to claim that you cannot build a DIY battery for <50% of the lowest cost/Wh OTS offerings you can find on Amazon today (both including shipping).
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Again, DIY being less expensive for a LiFePO4 battery with special requirements is a no-brainer.
Looks like you’ve built 4 105Ah 4S / 12V batteries for $1636 minus the cost of the inverter.
Using the reference I just posted, you could have bought those 4 batteries OTS from Amazon for $680 ($170 each).
So unless you got your BMSs for under $50 and your cells for under $40 each (shipped), your batteries were not less expensive than lowest-cost OTS (again, overlooking that your DIY batteries are 250A and the OTS batteries on Amazon for $170 were only 100A).
Would be interesting to know what you spent on the batteries alone as an end-of-2023 datapoint for DIY ~100Ah 4S / 12V.
Cells cost $40ea for 2020 date code unused cells from batteryhookup. Shipping was $6/cell for $736 total. BMS was $150 if I recall. Right now 18650 store has 2023 date code LF105 cells for $45 + ship.
Chances are those OTS batteries are being sold at below cost to move old inventory. It seems that there would be no profit margin at those prices since LFP battery cost from manufacturers is at $100/kWh this year which makes LF105 cost $33.6 / cell to source.
I wouldn’t consider any Amazon purchased budget battery any better than an 18650 store B cell
From what I’m finding, there is little to no saving building your own. Only advantages are maybe you get to pick “grade A” vs. ESS cells and a particular BMS of your choosing. Also, you don’t have to lift a 300lbs battery! ?
Tulex
Solar Wizard
I've got just over $9K into three 304ah batteries with "grade A" cells and a bms that will communicate with my inverter. I don't see how I could do that buying premade batteries. That's over $13K in Signature Solar batteries to do the same. And if I made them today, it would be even less.
At one time DIY was the only path available and members scrambled to find a reliable source. It was common to hear terms such as top balancing and capacity testing. With the advent of active balancing things have changes a bit for most. Conversations about capacity testing while present is not as common as it once was.
This is an emerging market. I can't imagine moving around a 16s battery case with 300-500 amp capacities. I wonder if the day is coming where several modules are connected, sharing a common BMS and other resources? In the meantime, DIY lets me build a battery as large as I like in place without any special equipment.
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FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The point is that pre-made batteries are getting cheap enough that they become an option for people that would not have considered them before. I could still make batteries out of cells and save a few bucks, but I would rather spend my time elsewhere.
ksmithaz1
Solar / EV Junkie
Make sure you don't get integrated serial/parallel ports on the motherboard. If it blows up you'll need to replace the motherboard to fix it. That new VIA chipset is really something, and make sure your 9600 baud modem is not using a rockwell chipset, AT&T's is much better.
The problem is, as a general rule, technology improvements keep pushing the costs down and quality up along with the increased integration. More power to all these guys playing with lithium cells and BMS's, but I would rather pay a little more and get a fully integrated solution. I used to build PC's, now I just wish INTEL would stop re-inventing every part it makes when it comes out with an "upgrade". I just picked up an N100 based 10" laptop, it is EXACTLY the footprint and performance improvement I want as an upgrade to the 11" N4100 I have/adored, which I dropped, and glued the case back together, and the battery is done, and ... I run Debian, so in order to use this thing, I have to run a backport kernel that bleeds on the edge to get Wifi and sound, and Bluetooth requires a Cauldron, a slow fire, and Wolvesbane with some incantations to make it work. I wish someone made an AMD version of one of these things, it just works.
I'm pretty good with a soldering iron and/or a crimp tool. I can get 16 cells and a 100A BMC with 20 leads, could custom build a rack to hold it all and bolt it all up. Create a wiring harness, tie it all up nice and neat. I've done similar with computers, I actually folded up a custom cabinet at one point in the distant past. DIY batteries are even worse than a computer though. It's not like there are a few thousand choices for a cabinet, I've seen a handful, and the ones I've seen are really expensive. My problem is I don't want my batteries in a wooden box or random metal shelf or in a generic cabinet. Thus, by the time I get all the components and the rack cabinets and cable and a rack and bus bars and ... I've maybe saved $1000 on an $8000 expenditure, and I have this custom creation, which is fine as long as I'm around if something isn't right with it at some point.
I'm waiting for Aluminum ION if they can get it mass-produced
!
ksmithaz1
Solar / EV Junkie
Just some ramblings . . .
RUiXU has a 30KWH rack under $8000. "Assembly" involves sliding the rack mount boxes into the rack and attaching the cables. 3x300AHx???v? 51.2? that would be 900AH or 9 rackmount units, roughly $12K.
18650 is selling 304's for 120 * 48 = $5760 + 800shipping = 6560. Coupla 3 BMS's 8x24 200A * $200 = 600 + 6560 = 7160. Build a couple of wood trays to hold each string, some 1/0 cable a bus bar, no more than $500, call it $7500 even with the stuff we forgot. A coupla days to build the racks and wire it all up. Saves about $4500. Significant for sure.
So If you want to spiff up your DIY with equipment racks, they are going to run you $500 ea, so that's $1000 for 2. Now I need a battery cabinet for the rack those run another $500 ea but they come with a BMS so $1500 - 600 about $900 more so 2100 brings the difference down to ~ 2500. Still cheaper, just more hassle. Those 16x300ah (280) battery boxes are going to need a lift to get in the cabinet.
If you have lot's of room and don't mind a roll-your-own cabinet design, you can definitely save coin fully DIY. To the point of the article , that gap is narrowing. I expect a 600AH rack to hit ~ $5K within a year or so. That would likely make the gap $7500 racked vs $5000 DIY. There is a lot of downward pressure on battery cost.
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