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DIY LiFePO4 Cost Analysis - Almost February 2023 Edition

For comparison - RV build

16 280ah Li cells $2672 (Docan Houston stock Mar '22)
Overkil 16s 100a BMS $ 163
Job Site Box(dmgd) $ 115 https://www.amazon.com/gp/product/B001SF83F0/ref=ppx_yo_dt_b_asin_title_o09_s01?ie=UTF8&psc=1
Foam/thruhulls $ 90

6 230w panels $ 423 https://www.santansolar.com/product/used-sunpower-230-238w-solar-panel-lot-of-5/
Mounting Hrdwr $ 350 ( 3M 4950 with https://www.amazon.com/gp/product/B0B43VGFQZ/ref=ppx_yo_dt_b_asin_title_o00_s03?ie=UTF8&psc=1)

Sigineer M3048NC $ 900
Breakers/fuses/wire $200+-

Just shy of $5k .. payback = 2-3 years Vs gasoline in generators.
 
Probably wouldn't hurt to check every 2-3 years, also to see if any squirrels decided to stash acorns in the enclosure...
 
Interesting and useful thread, thanks @upnorthandpersonal. If you do this enough years you’ll then be able to chart the price trend which will be worthwhile too. Speaking of, I’m still waiting to see evidence of the EV battery price trend predicted in the below newspaper (Daily Mail) website clipping I saved from sept 2021.

I realise the price we pay as solar storage consumers isn’t necessarily reflective of the volume pricing to EV manufacturers, but it should at least be related. Probably our pricing owes something to how many ”spoiled” cells get offloaded into the grey market as well as demand for vehicles, so not just based on the manufacturing cost alone.

In 2020 there was a price dip due to covid of course, but beyond that is there any real sign of the forecast 58% reduction in lithium battery price by 2030, or the price equivalence with ICE cars by 2026? I can’t see it so far myself, but maybe I’m wrong!

1EF6C3D4-969F-472E-B6D6-D770EC598857.png
 
Keep in mind I did do something different this time compared to last year. Last year, I went with Docan cells, this time these are Luyuan cells that come with an EVE test report. In other words, this year it's grade A, last year was grade B (I don't like those terms, but it should make things clear).

If I do the calculation with Docan cells, I come to a total of about $2500 - which is less than last year. However, that's also in part because of the change in fuses and other stuff I didn't add this year. I should try to be more consistent perhaps...

As or EV prices, we'll see. One thing that will get the price lower is the increased competition. We've got some great EVs coming up here in Europe (and keep an eye on the Asian markets as well).
 
upnorthandpersonal said:
As or EV prices, we'll see. One thing that will get the price lower is the increased competition. We've got some great EVs coming up here in Europe (and keep an eye on the Asian markets as well).
Click to expand...
And of course Northvolt building a huge EV battery production plant up in Skellefteå, which should in years to come affect the prices for European produced BEVs, and possibly with spin-off benefits to us solar hobbyists.
 
upnorthandpersonal said:
This is a recalculation based on the situation today, of what I did last year.

Disclaimer: I mention vendors below and use them as an example and as reference. This should not be considered an endorsement of said vendors!

Let's start again with leveling the playing field. The EG4 is a 5kWh battery pack, and still pretty much the cheapest - I can find a price on Signature Solar for $1424 on sale right now. I know this is excluding shipping, but I'm assuming you're either picking it up or it's included.

The most common and popular cells available right now are arguably still the 304Ah EVE cells. So if we compare 3x the EG4 (15kWh) to 16x EVE 304 cells (15kWh) we're pretty much comparing apples to apples. At a cost of $4272 for the three EG4 systems we now have a price target to compare against.

For the cells, I'm using Luyuan as a reference this time. I asked for a quote for 16 cells, delivered to Finland. These go for $163 ('Grade A' with test report from EVE) per cell excluding shipping. As mentioned we need 16 and we include shipping, and this brings the cost to $2942. This includes the bus bars, etc.

I'm sticking to the JK BMS. The 200A with 2A balancing would set me back $208 with free shipping based on current prices at Hankzor.

Since class T fuses are still almost impossible to get, I'm going to go with BS88 fuses, 125LET Eaton Bussman. Conrad.com lists them at around $26. Just like last time, I'm adding a Schneider 250A 160V DC breaker at a cost of $110 at Signature Solar.

Adding this all together, we get to: $3286, so around $280 more expensive compared to last year. And of course, you have to add a housing of some kind.

You can once again decide for yourself if it's worth it for you or not.
Click to expand...
I kind of hedged my bets.

My initial batteries are DIY 280ah. 10 of them.
I dismantled 2 of them and keep them for spares so now 8.

However I didn’t want to ever be in a situation where I was without power so I bought some SOK from Current Connected.
He is offering 10 year warranty so I have the best of both worlds I guess.

The DIY is definitely cheaper but more labor intensive.
 
Last edited:
Sverige said:
And of course Northvolt building a huge EV battery production plant up in Skellefteå, which should in years to come affect the prices for European produced BEVs, and possibly with spin-off benefits to us solar hobbyists.
Click to expand...

Same with FREYR building one in the area here in Finland. They'll be focusing on LiFePO4 (in Finnish) cathode material; they aim for 60 000 tons per year. Another company that is in the planning stages in the same area is an anode material factory (in Finnish).
 
upnorthandpersonal said:
Same with FREYR building one in the area here in Finland. They'll be focusing on LiFePO4 (in Finnish) cathode material; they aim for 60 000 tons per year. Another company that is in the planning stages in the same area is an anode material factory (in Finnish).
Click to expand...
while i certainly like all these factories and initiatives, it remains to be seen how of those products will actually become available to the consumer (diy) market.
from what i have been reading , car man. already claimed 100% of future products of those
 
upnorthandpersonal said:
Same with FREYR building one in the area here in Finland. They'll be focusing on LiFePO4 (in Finnish) cathode material; they aim for 60 000 tons per year. Another company that is in the planning stages in the same area is an anode material factory (in Finnish).
Click to expand...
Interesting, I didn’t know Finland was also strong in this business, but I suppose the level of automation which goes into battery building these days means the higher labour costs in these Nordic countries are not prohibitive. Good to see our economies positioning themselves well for these growth industries.
 
Sverige said:
Interesting, I didn’t know Finland was also strong in this business, but I suppose the level of automation which goes into battery building these days means the higher labour costs in these Nordic countries are not prohibitive. Good to see our economies positioning themselves well for these growth industries.
Click to expand...

Also plenty of renewable energy so to speak to run these factories, skilled people, and sources of raw material:

Keliber aims for lithium hydroxide production - Finnish Minerals Group

Keliber is one of our portfolio companies, focused on mining and battery chemicals. The company aims to accelerate the electrification of transport and smart storage of energy.
www.mineralsgroup.fi www.mineralsgroup.fi

The Vaasa region here is Energy Central in Finland so to speak, with lots of supporting and customer industries like ABB, Wärtsilä, Danfoss, etc. all located here.
 
houseofancients said:
while i certainly like all these factories and initiatives, it remains to be seen how of those products will actually become available to the consumer (diy) market.
from what i have been reading , car man. already claimed 100% of future products of those
Click to expand...

If they get the cost of EV down, and tech such as V2L takes off, a car can become essentially an extension to a DIY effort. I'm waiting for a decent EV with V2L and an LFP battery to become available, since it will then just become an extension to my home battery while at the same time will allow me to help maximize the use of my energy production. Cheaper EVs will likely also mean that the second life storage for DIY will become more easily available at lower costs and more options.
 
upnorthandpersonal said:
And of course, you have to add a housing of some kind.
Click to expand...
This is not an insignificant consideration. For the same quality of housing it won't be cheap, plus adding terminals and other fixtures. And the extra tools required.

Size, weight and form factor also matters.

I can lug individual 5 kWh batteries and they will fit inside my existing cabinet space. I can't however lug a single DIY 15 kWh battery, it would need to be built in situ and I don't think I could do that.
 
upnorthandpersonal said:
If they get the cost of EV down, and tech such as V2L takes off, a car can become essentially an extension to a DIY effort. I'm waiting for a decent EV with V2L and an LFP battery to become available, since it will then just become an extension to my home battery while at the same time will allow me to help maximize the use of my energy production. Cheaper EVs will likely also mean that the second life storage for DIY will become more easily available at lower costs and more options.
Click to expand...
V2L is typically not bidirectional. It's a source of (limited) AC power supplied by the EV's inbuilt inverter. Like having an oversized portable power station. Most EVs with V2L use a separate plug to connect loads to but you can't charge the EV through it.

A bidirectional charger is required for V2H / V2G scenarios which do treat the EV battery as part of the home (or grid's) energy supply and demand system, and an EV which has been designed to work with bidirectional charging. Way more expensive. Here bidirectional chargers are about the same cost as just buying a professionally installed home battery system, so there is little incentive to buy one.

I was looking at the specs for the BYD Atto 3 which comes with V2L. Here it comes with a 3.6 kW in-built 230 V AC power supply via an included plug in power adapter. Other EVs like the Hyundai Ionic and others are coming with V2L.

Bidirectional charging however is a big jump up from V2L.
 
wattmatters said:
This is not an insignificant consideration. For the same quality of housing it won't be cheap, plus adding terminals and other fixtures. And the extra tools required.

Size, weight and form factor also matters.

I can lug individual 5 kWh batteries and they will fit inside my existing cabinet space. I can't however lug a single DIY 15 kWh battery, it would need to be built in situ and I don't think I could do that.
Click to expand...

I did add the enclosure to the previous calculation. The reason I leave it off is because it's different for everyone. Mine was built out of scrap wood and cost me nothing, there are vendors that will have a case for around $100 (Luyuan for example), and yet others are more expensive.
I'm actually going to redo my enclosures this spring so it's more shelf-like; won't cost more than $100 either.

Of course, form factor is a thing and you're right that DIY packs of this size can't be lugged around easily.

wattmatters said:
V2L is typically not bidirectional. It's a source of (limited) AC power supplied by the EV's inbuilt inverter. Like having an oversized portable power station. Most EVs with V2L use a separate plug to connect loads to but you can't charge the EV through it.
Click to expand...

Yep, I know. I want to use the inverter output the charge my home battery when needed, and charge the vehicle though its charge port for the other way around. Like you said V2H/V2G are more complex, expensive, and I don't see them work in an off-grid situation.
 
DIY packs can't be lugged around easily, but they can be designed to fit more spaces. I have mine as 16x1 strings on double 2x4 shelves. If I need to fix something, all I have to do is loosen the compression rods, slide the front one out, and I can slide any cell I need to out. No reason to ever try to move the whole pack at once.

Depending on the internal cell layout of the server racks batteries, I'm not sure I could have fit the server rack batteries into the same cabinet I used without putting some cells in a wrong orientation. No space to spare for a server rack, either.
 
Just John said:
I just wanted to add a (looks like) good source for battery boxes/cases for the DIY:

cneel.en.alibaba.com

Shenzhen Eel Battery Co., Ltd. - LiFePO4 Battery Cell, LiFePO4 Battery Pack

Shenzhen Eel Battery Co., Ltd., Experts in Manufacturing and Exporting LiFePO4 Battery Cell, LiFePO4 Battery Pack and 334 more Products.
cneel.en.alibaba.com cneel.en.alibaba.com
Click to expand...
Labor being relatively cheap in Asia (especially considering assembly line process), why are DIY and kits so much cheaper than their finished rack battery product?
 
Just John said:
I just wanted to add a (looks like) good source for battery boxes/cases for the DIY:

cneel.en.alibaba.com

Shenzhen Eel Battery Co., Ltd. - LiFePO4 Battery Cell, LiFePO4 Battery Pack

Shenzhen Eel Battery Co., Ltd., Experts in Manufacturing and Exporting LiFePO4 Battery Cell, LiFePO4 Battery Pack and 334 more Products.
cneel.en.alibaba.com cneel.en.alibaba.com
Click to expand...

I've also found a cheaper source willing to customize (as in you could get it with a JK BMS rather than a Seplos BMS).

Products list direct from CN

Main products Lifepo4 battery, LTO battery and 142 more Products from Shenzhen Luyuan Technology Co., Ltd. on Alibaba.com
szluyuan.en.alibaba.com szluyuan.en.alibaba.com

I've tried one of their cases for the 105AH EVE cells and a JBD BMS and was quite happy with the fit and finish, as well as the price.
 
Danke said:
Labor being relatively cheap in Asia (especially considering assembly line process), why are DIY and kits so much cheaper than their finished rack battery product?
Click to expand...

Presumably, because it's the price point the market will bear for the convenience of a ready-made mid/high-end battery - and there's not enough competition for that segment of the market to drive the price down further. Especially since DIY and budget batteries erode the size of that market segment.

Batteries are heavy and generally have hazmat shipping/facilities considerations so being a middle-man probably incurs a fair bit of overhead.

Finally, it takes a long time to validate the true quality and life-expectancy of a battery so you'd need to be really committed to having a long term business to make it worthwhile it to overcome the initial distrust as a new entrant to the non-budget market - and if you try and sell close to (or below) cost initially to compensate, folks will assume you're just another budget battery brand with B (or worse) grade cells.
 
My recent build.

24V 304 AH cells from 18650 battery store.

1) Cells $1185.01
2) BMS $148.00
3) 2 group 27 trays. $20.00
4) Terminals $16.00
5) Balancer (might not be necessary) $50.00

Other stuff (steel, conduit, all-thread I had laying around so add in that stuff however you want)

Total $1416.96

Nominal WH 7782 or .18 Cents per WH.

As tested so far to 85% DOD 7168 WH or 20 cents WH

An EG4 24V server rack battery $1450.00 + 300 shipping + tax $1890.00 for 5120wh nominal or 4382wh to 85% DOD.

DIY as tested to 85% DOD = 20 cents per WH

EG4 24 Volt delivered 85% DOD = 43 cents per WH.

Nameplate rating DIY = 18 cents WH

Nameplate rating EG4 = 37 cents per WH.

There are obvious benefits to the server rack batteries. The packaging being the most obvious. Good form factor and nice looking. Built-in pre-charge circuit. Fire resistant case fully enclosing the cells. Fused and generally what appears to be an easy to use BMS that will talk to lots of different stuff and decent customer support.

Shipping goes down the more you order. The server rack batteries cost more but are still an excellent value and worth the price, I think.
 
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