DIY LiFePO4 Cost Analysis - Almost February 2023 Edition

[Bluedog225]

V2L?

Edit-vehicle-to-load (V2L)

 

[wattmatters]

And of course, you have to add a housing of some kind.

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.

 

[wattmatters]

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.

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.

 

[upnorthandpersonal]

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.

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.

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.

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.

 

[TorC]

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]

I just wanted to add a (looks like) good source for battery boxes/cases for the DIY:

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 0 more Products.

cneel.en.alibaba.com

 

[Danke]

I just wanted to add a (looks like) good source for battery boxes/cases for the DIY:

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 0 more Products.

cneel.en.alibaba.com

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]

I just wanted to add a (looks like) good source for battery boxes/cases for the DIY:

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 0 more Products.

cneel.en.alibaba.com

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).

Battery box/case, Battery box/case direct from Shenzhen Luyuan Technology Co., Ltd. in CN

Battery box/case from Shenzhen Luyuan Technology Co., Ltd.. Search High Quality Battery box/case Manufacturing and Exporting supplier on 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.

 

[Symbioquine]

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?

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.

 

[Checkthisout]

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.

 

[svetz]

Have you posted anywhere an update on how the system is doing (e.g., battery capacity) after it's first year?

 

[eranjo]

Some newbie question as I'm trying decode the language that is all new to me Trying to avoid newcomer mistakes and order my first cells + accessories from sellers that this community has already confirmed to be reputable.

For the cells, I'm using Luyuan as a reference this time. I asked for a quote for 16 cells, delivered to Finland.

Are you referring to this seller from Alibaba?

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.

Is Hankzor this BMS seller in Aliexpress?

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.

Is this the fuse you are talking about?

ps.
Thank you for all the ideas on this forum to get me started on my battery journey!

 

[upnorthandpersonal]

Are you referring to this seller from Alibaba?

Yes.

Is Hankzor this BMS seller in Aliexpress?

Yes.

Is this the fuse you are talking about?

Yep

Edit: ja tervetuloa foorumille! Always good to have more people from Finland here.

 

[Steve_S]

Luyuan is a Known Good Vendor. They sell everything you need including the JKBMS (Cheaper than Hankzor too btw).
Shipping from China costs "per box + weight" and if you buy from one vendor they can package bits & pieces into one box and save you money on S&H and other things... every box has a minimum cost regardless, so if you can buy most everything from one place, you can save money. BTW Luyuan doesn't screw around with warranty issues and such (like so many others).

NOTE: I just received notifications from 3 suppliers advising of significant retail price drops for cells. To get a current & accurate pricing, open Chat/Messenger session on Alibaba / AliExpress with the vendrs to get that until things are updated.

 

[houseofancients]

Luyuan is a Known Good Vendor. They sell everything you need including the JKBMS (Cheaper than Hankzor too btw).
Shipping from China costs "per box + weight" and if you buy from one vendor they can package bits & pieces into one box and save you money on S&H and other things... every box has a minimum cost regardless, so if you can buy most everything from one place, you can save money. BTW Luyuan doesn't screw around with warranty issues and such (like so many others).

NOTE: I just received notifications from 3 suppliers advising of significant retail price drops for cells. To get a current & accurate pricing, open Chat/Messenger session on Alibaba / AliExpress with the vendrs to get that until things are updated.

could you share those prices and suppliers steve ?
bout to order more ( already have a quote) , and seller is pushing a bit , i think i know why now

 

[MrM1]

could you share those prices and suppliers steve ?
bout to order more ( already have a quote) , and seller is pushing a bit , i think i know why now

I'm seeing $223.19 per cell for an order of 16 cells of the EVE 304s from Luyuan shipped to USA ... I must be missing something.

 

[houseofancients]

I'm seeing $223.19 per cell for an order of 16 cells of the EVE 304s from Luyuan shipped to USA ... I must be missing something.

well i got a pricing of 114/cell for lf304 ( b grade) , that is ex shipping.
total for 16 cells and ddp shipping is around 2160

 

[MrM1]

well i got a pricing of 114/cell for lf304 ( b grade) , that is ex shipping.
total for 16 cells and ddp shipping is around 2160

Well sure ... for B Grade. You know those gradings !! I'm looking for AAA+ Certified EV Jet Fuel grade myself. ? (not a bad price BTW)

 

[MrM1]

Yeah from Luyaun ... the 1 x 16 cell 304 grade A order method is WAY more expensive than the 4 x 4 cell 304 grade A order method on their Alibaba page.

 

[Checkthisout]

Well sure ... for B Grade. You know those gradings !! I'm looking for AAA+ Certified EV Jet Fuel grade myself. ? (not a bad price BTW)

Offhand, Looks like 18650 is the way to go?