Future of DIY LiFePO4 looks bleak…

toms

Photon Sorcerer
Joined
Jul 24, 2020
Messages
979
Sorry, didn't mean for you to type out your entire system, I was asking expressly about the battery itself. I should have been more clear on that. I plan on building one come spring, so plenty of time to order the parts. What's the difference between the 2 BMSs?

When i changed from Batrium to REC the REC was a better option for CANBUS comms with the Sunny Island which is required for AC coupling. I still use the original Batrium on another 12V system i have.

Armin from LiFeTech lithium is very experienced when it comes to the chemistry and construction of lithium cells. I have only ever worked with one other DIY install using his cells though.

I have mainly worked with Winston / CALB / Sinopoly cells, although in the last few years more people around me are using EVE / CATL etc (ali express specials)

When BYD B-Box first came out i thought it was great - a few years of experience has changed my mind.

I’m waiting now to see the longevity of the EVE style cells. The ones i see need more BMS intervention than the LiFeTech which often go more than a year without triggering the balance mechanism of the BMS. To me that’s not a good sign.
 
  • Like
Reactions: Dzl

RobertGreen

Solar Addict
Joined
Mar 15, 2021
Messages
302
My system is as follows:
Man, I really like those NH/NT fuse holder/disconnects! They look so handy, I wish I could find a convenient or affordable source for them in the USA.
I'm also reminded of how frustrating I found it when I learned that Victron wants to charge you an extra 30$ for the "wireguard" box to neatly enclose the bottom of their MPPT charge controllers.... It feels like I'm getting nickeled and dimed after paying $$$ for the unit already! I will probably try to 3d print one of my own just out of spite.
 

BlackWaterPark

Solar Enthusiast
Joined
Nov 26, 2021
Messages
42
I have mainly worked with Winston / CALB / Sinopoly cells, although in the last few years more people around me are using EVE / CATL etc (ali express specials)
You recommend one over the others here? Looks like lifetech is an Australian company, which I'm guessing one would have to get shipped from there? I poked around looking for stateside vendors but didn't turn up anything.
 

toms

Photon Sorcerer
Joined
Jul 24, 2020
Messages
979
You recommend one over the others here? Looks like lifetech is an Australian company, which I'm guessing one would have to get shipped from there? I poked around looking for stateside vendors but didn't turn up anything.

I would rank them Winston / Sinopoly / CALB. I haven’t used the CALB for a while now though.

I think you can only get LiFeTech directly from them - they are shipped from a production facility in Taiwan though, so might not be too hard to get.
 

Tony Scott

Solar Enthusiast
Joined
Feb 25, 2020
Messages
184
No, they don’t. The exact reason i DIY is because there are no commercial offerings available that match the quality of the components i use.
When I priced out building a rack exactly like the one for the EG4 battery it would cost about $150 more, In fact there is a YouTube video showing the same thing. Again shipping from all the sources is not included in the price.
 

Tony Scott

Solar Enthusiast
Joined
Feb 25, 2020
Messages
184
Man, I really like those NH/NT fuse holder/disconnects! They look so handy, I wish I could find a convenient or affordable source for them in the USA.
I'm also reminded of how frustrating I found it when I learned that Victron wants to charge you an extra 30$ for the "wireguard" box to neatly enclose the bottom of their MPPT charge controllers.... It feels like I'm getting nickeled and dimed after paying $$$ for the unit already! I will probably try to 3d print one of my own just out of spite.
That is what Victron does, which is why I did not use them. Good equipment, but expensive
 

HighTechLab

Small Business Owner
Joined
Sep 23, 2019
Messages
621
When I priced out building a rack exactly like the one for the EG4 battery it would cost about $150 more, In fact there is a YouTube video showing the same thing. Again shipping from all the sources is not included in the price.
Some rack-mount vendors in the near future are going to beat the price, quality, and availability of EG4, and will be giving away a free rack with the purchase of batteries.

It looks bleak to me.
 

HighTechLab

Small Business Owner
Joined
Sep 23, 2019
Messages
621
My system is as follows:

Primary system:
32 cells 2p16s LiFeTech lithium 200ah
REC BMS / Gigavac contactors for main disconnect and DC PV disconnect
NT00 fuse/ disconnect
2x4 pole 300a busbars
Sunny Island 8.0H hybrid inverter
SunnyBoy SB1700 PV inverter
Outback Flexmax FM80 DC charger

Auxiliary system (high inductive loads)
32 cells 2p16s Sinopoly 100ah
Maxwell Supercapacitor
ZEVA BMS / Gigavac contactors for main and PV disconnect (REC precharge)
NH00 fuse/disconnect
2x4 pole 300a busbars
Victron Phoenix 48/5000 inverter
Victron 150/70 DC controller.
240V to 48V charger fed from Kubota J108 generator.

Auxiliary system feeds into generator input of Sunny Island.

System housed in a climate controlled enclosure constructed from 100mm coolroom panel.

As i have said, it isn’t as pretty as a rack mount or enclosed system, but it is more functional.

I don’t take many pictures, but i have some from when i was changing from batrium to REC.

The way the enclosure is setup makes taking photos of the entire setup difficult, there is essentially a sliding panel that seals the whole area.
Looks good, I love the REC BMS functionality, but boy do they cost a pretty penny!
 

toms

Photon Sorcerer
Joined
Jul 24, 2020
Messages
979
That’s the thing, that system has run for a decade now, still performing as new.

Only when it fails will i know how much it cost, but i have a couple of neighbours that are a lead acid battery set / and onto their second commercial set of LiFePO4’s over the same period.

Initial setup cost isn’t the same as per kwh cost over system lifespan.

I’m looking from the lifespan cost perspective.
 

offgriddave

Solar Enthusiast
Joined
Feb 14, 2020
Messages
179
My system is as follows:

Primary system:
32 cells 2p16s LiFeTech lithium 200ah

Tom,
On your battery system, how much did it cost?
.....

So folks my question is.

Can DIY build a:
- 100 amp 48v
- encased battery box (ok, lets make this optional but would be nice)
- BMS with either bluetooth or RS-485
- pre-charge resistor
- (edit) and some kind of LED or OLED Display
- Circuit breaker

For under $1500 + $200 shipping for a total of $1700?

Not including tools

Are you up to this challenge? Can you link to the part numbers, models, prices, availability?

Because I want to know if I should buy either 15kwh in another 3x EGLL or DIY...

Let's see what we can do! I'm even interested in a small bet, in $, directly or donated to a charity, if you can do it. Must have part #, price, availability. And can be delivered in 20-30 days.
 
Last edited:

offgriddave

Solar Enthusiast
Joined
Feb 14, 2020
Messages
179
When you say "100 amp", do you mean 100Ah at 48v, or a 100A charge/discharge rated system?
And then you say 15kwh?

Hi Robert,

100Ah, it was a typo. Please disregard. I can edit it.. but I guess I'll leave my mistake up for fun.

To clarify about the 15kwh: I have on order a single 5.1kwh EGLL. I am looking to in the future add an additional 15kwh. This would be a total of 20kwh when I am done. If somebody can convince me to DIY for 15kwh, I will do that. But the challenge is for 48v 100Ah. Let's keep this simple.

So the outcome will determine if I will purchase three additional EGLL or DIY. That's why I wanted specific parts, model, etc. So I can easily research and order it.

Does that make sense?
 

RobertGreen

Solar Addict
Joined
Mar 15, 2021
Messages
302
Hi Robert,

100Ah, it was a typo. Please disregard. I can edit it.. but I guess I'll leave my mistake up for fun.

To clarify about the 15kwh: I have on order a single 5.1kwh EGLL. I am looking to in the future add an additional 15kwh. This would be a total of 20kwh when I am done. If somebody can convince me to DIY for 15kwh, I will do that. But the challenge is for 48v 100Ah. Let's keep this simple.

So the outcome will determine if I will purchase three additional EGLL or DIY. That's why I wanted specific parts, model, etc. So I can easily research and order it.

Does that make sense?
Yes, I get it. But I will say that it appears to hit the sweet spot of cost effectiveness to use 280 or 302Ah cells as a 16s bank when you're DIYing.
If you made 3, 16s 100Ah batteries, you'd need 3 BMS instead of 1, 3 fuses/breakers instead of 1, the monitoring gets more complicated and expensive etc etc
edit: in other words, when for many people the largest advantage of the DIY route is the cost/kwh, then the larger cells are especially suited.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
10,681
The challenge is 100 Ah because that isn't the sweet spot for cells anymore.
You can do 280 Ah for lower price per Ah. Even more so with cost of BMS spread over higher capacity battery.

We've seen 100 Ah read-made batteries still on the market, probably due to the appeal of "drop-in" replacement. And price-point.
 

upnorthandpersonal

Administrator
Staff member
Moderator
Joined
Dec 25, 2019
Messages
3,018
Location
63 degrees North, Finland
So folks my question is.

Can DIY build a:
- 100 amp 48v
- encased battery box (ok, lets make this optional but would be nice)
- BMS with either bluetooth or RS-485
- pre-charge resistor
- (edit) and some kind of LED or OLED Display
- Circuit breaker

For under $1500 + $200 shipping for a total of $1700?

Not including tools

Are you up to this challenge? Can you link to the part numbers, models, prices, availability?

Because I want to know if I should buy either 15kwh in another 3x EGLL or DIY...

Let's see what we can do! I'm even interested in a small bet, in $, directly or donated to a charity, if you can do it. Must have part #, price, availability. And can be delivered in 20-30 days.

Let's assume we want to create a 15kWh 48V battery, since I don't have current pricing on smaller cells.

1) Cells:
- I'm using this post as a reference for cells in the US. One 280Ah = $147 delivered from Texas.
- To get around 15kWh at 48V, we need 16 of these, so $2352.
2) BMS with Bluetooth and RS485 and I'll take the 200A version: $215 shipped. Should make it in 30 days
3) Precharge resistor and push button: $50 or so including shipping, don't know - round it up to $100, get a few of them.
4) BMS display - get it together with the BMS, $25
5) Breaker, let's go big. 250A version, $142, and I think they have free shipping.

Total: $2834

Since this is 3x your original battery capacity, divide this by three and you get $944, including shipping, per 5kWh. Note that this isn't even the cheapest one you could build, you probably get the cells slightly cheaper as well since you'd buy 16 instead of 4 in the original post.

I'll leave the box up to you. Some plywood would do, or whatever you want.
 
  • Like
Reactions: Dzl

Dzl

Perpetual Newbie & Unofficial Forum Librarian
Staff member
Moderator
Joined
Dec 10, 2019
Messages
5,078
Why would you constrain yourself to 100Ah 48V when you would need three of them to meet your needs? I get it if you are going the pre-built route, but one of the greatest advantages of DIY is you can design for your needs and not be constrained to off the shelf options. You are putting the DIY side at a disadvantage if its needlessly constrained to the same limitations as OTS options.

If you need 15kWh the goal should be 15kWh rather than specifically 3 x 5kWh, unless there is some particular reason you actually prefer it that way for your situation. One thing you haven't specified is the max current you are designing for, this will impact BMS selection.

The 20-30 day time limit will make it add some cost and constraints but shouldn't be unmanageable. To be fair though, note that an EG4 has a 28-42 day lead time at this time, so the EG4 would not pass your 20-30 day requirement at this time.

Cells:
16 * 304Ah cells (15.6kWh) = $2530 from Docan Power (link)

BMS (lots of options, here are a few:)
1 * 100A Heltec BMS w/ BT = $90 from Aliexpress (link)
1 * 100A JBD BMS w/ BT = $165 from Overkill Solar (link)
1 * 200A JBD BMS w/ BT = $140 from Docan Power (link)
1 * 200A Heltec BMS w/ BT = $180 from Aliexpress (link)
Many higher end options as well (and a few slightly cheaper options too)

Display
JBD BMS that have RS485 can add a $25 display if BT isn't enough (link)


OCP
1 * 200A Class T Fuse and Holder = $57 (link)
OR
1 * Outback High Amp, High AIC Breaker = $87 (link)

Switch
Manual Pre-charge = ~$50 (based on this design/parts list)

Enclosure
DIY cost varies.
 

Bluedog225

Texas
Joined
Nov 18, 2019
Messages
978
Good stuff! Seems like there ought to be a thread dedicated to diy alternatives to the rack batteries with components listed.
 
Top