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Price per watt hour-diy versus 48V rack battery

Bluedog225

Texas
Joined
Nov 18, 2019
Messages
2,826
Edit-watt hours not amp hours

I’ve been digging around and thinking about diy or buying a rack battery like the EG4.

Here what I’m seeing. The representative “rack” battery is the EG4 at about $1500. Shipping and taxes not included.

The DIY option are cells from Shenzen Luyuan Tech, 4pcs EVE 304AH LiFePO4 (LFP) 3.2V Cells Battery (Fully Matched&Batched)--Genuine Grade A. Shipping and taxes not included.

EG4 type-$1500 for 4800 watt hours (wh)
= 31.25 cents per wh

DIY-16*$137 each=$2,192 + BMS (overkill at about $175 all in) + $100 (capacity tester and power supply)=$2,467 for 14,592 wh
=17 cents per wh

I’d appreciate any input on firming this up. Did I miss anything?

I’m thinking of picking up 32 (or 34) cells in Houston.
 
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FYI - Wh (watt-hours), not Ah (amp-hours)

The EG4 is 48V (51.2V) 100Ah which is 5120Wh (not Ah). At $1,500 that is $0.29/Wh
The 16 3.2V 304Ah EVE cells would be 15,564.8Wh (not Ah). At $2,467 that is $0.16/Wh

DIY gives 3x the battery at less than twice the price.

Don't forget the EG4 is ready out of the box. The DIY needs lots of effort. Save time or save money.
 
A more accurate comparison would be EG4 100 amp hour versus DIY 100 amp hour.
EG4 =5120 wh $1499 +tax and shipping
DIY = 5120 wh CALB 100ah $56*16= $896 + 155 for BMS + 100 extras +50 circuit breaker =1201. + lugs, crimper, wire, time, anxiety...

EG4 $0.29 per wh.
DIY $0.23 per wh.

Do you just want a battery or do you want a hobby?

Edit Was writing same time as rmaddy
 
I kept good records - my 81kwh 18650 (second hand cells) battery bank cost $245/kwh = $0.245/wh. This includes *everything* from Batrium to solder to installation to tax credit. LifePo4 has come down / more-available that ever before.
 
A more accurate comparison would be EG4 100 amp hour versus DIY 100 amp hour.

Is it? I wouldn’t think so if one wants more watt hours.
 
DIY = 5120 wh CALB 100ah $56*16= $896 + 155 for BMS + 100 extras +50 circuit breaker =1201. + lugs, crimper, wire, time, anxiety...

EG4 $0.29 per wh.
DIY $0.23 per wh.

Do you just want a battery or do you want a hobby?
Back to my earlier question.
If I were only looking for a part for a system, I'd probably go for these newish rack prebuilts. They're very nice.
But...
I spent my formative years in the USAF doing DC electronics but have been away from it for many years. This became for me an opportunity to relearn and re-explore. Hobbyist. Building a 6kw, 30kwh system. I'm into the design and engineering and assembly and testing.
That's not for everyone. People have different tolerance to minutae.
Good luck with your decision.
 
I looked around for a fairer comparison battery.

The Fortress Power eVault is 18.5 kWh. It comes in at 72.5 cents per wh.
 
Edit-watt hours not amp hours

I’ve been digging around and thinking about diy or buying a rack battery like the EG4.

Here what I’m seeing. The representative “rack” battery is the EG4 at about $1500. Shipping and taxes not included.

The DIY option are cells from Shenzen Luyuan Tech, 4pcs EVE 304AH LiFePO4 (LFP) 3.2V Cells Battery (Fully Matched&Batched)--Genuine Grade A. Shipping and taxes not included.

EG4 type-$1500 for 4800 watt hours (wh)
= 31.25 cents per wh

DIY-16*$137 each=$2,192 + BMS (overkill at about $175 all in) + $100 (capacity tester and power supply)=$2,467 for 14,592 wh
=17 cents per wh

I’d appreciate any input on firming this up. Did I miss anything?

I’m thinking of picking up 32 (or 34) cells in Houston.
I have been going through the same thought process. Really like the look and ease of use with the rack batteries. However, when needing lots of storage, I keep coming back to DIY. Especially as I am looking at needing the possibility of needing to triple my storage capacity.
 
I've built 3 fairly large batteries recently, each have 16 cells of EVE 304 ah cells, making 24 volts at 600 amp hours (approximaely), or about 15 kWh each. The cost for each was about $2400 for the cells and $120 for the BMS, a little over $2500 each. The EG4 is about $1500 for about 5 kWh, 3 of them would be about $4500 to match my DIY battery at $2500, watt hour for watt hour.

If you have the money and don't want to build, they're a great option. I enjoy the bulding process and since I wanted 45 kWh of storage the saving added up, EG4 would have been $13,500 versus $7500 homebrew.. It's nice to have the choice whichever way you go.
 
Do you need / want UL cert or listed? OTC batteries are fine and convenient, but without UL cert / list you'll spend a good bit less on diy. (especially for larger banks).

I personally would not buy an OTC/OTS battery unless it was UL listed.
 
Please allow me to further complicate the matter.

4 of these is $1320 shipped :

https://www.amazon.com/dp/B08FMTRYPT

A bit over 25 cents per Wh.

Add some busbars or jumpers to series them up and it’s almost out of the box ready ?.

Although I love my EG4 and my DIY batteries it’s another option.
I'm looking at doing this very thing.
I'm getting mixed advice on whether or not putting 4 of these in series would be an issue.

Can actually get 4 of them for only $1200 including shipping.
 
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Please allow me to further complicate the matter.

4 of these is $1320 shipped :

https://www.amazon.com/dp/B08FMTRYPT

A bit over 25 cents per Wh.

Add some busbars or jumpers to series them up and it’s almost out of the box ready ?.

Although I love my EG4 and my DIY batteries it’s another option.
I will be wary of a manufacturer that refers to a LifePo4 battery as 'deep cycle'
 
I looked around for a fairer comparison battery.

The Fortress Power eVault is 18.5 kWh. It comes in at 72.5 cents per wh.
Fairer comparison with what?

You can make a larger capacity battery with multiple EG4 (or similar) batteries in parallel at the same $/kWh cost.

Then price your own DIY set up including cells, battery housing, bus bars, BMS, circuit protection (breaker, fuses), smart shunt, cables, lugs, bus bars, pre-charge set up, specialist tools, cell chargers, test equipment....

Latter provides opportunities for saving money and specifying exactly what you want in a system but the former is pretty close to idiot proof.
 
I'm looking at doing this very thing.
I'm getting mixed advice on whether or not putting for of these in series would be an issue.

Can actually get for of them for only $1200 including shipping.
Putting 4 in series is not the best since they independently have their own BMSs / won't be kept in balance without non-standard means. That's why people do 16s lifepo4 with BMS on the 16 cells instead of trying to put 4 x stand-alone 4s in series. There may be some more-expensive 12v that has communication with others you put in series so they can maintain balance among themselves but that's not the norm (cheaper) solution.
 
I looked around for a fairer comparison battery.

The Fortress Power eVault is 18.5 kWh. It comes in at 72.5 cents per wh.
Yes and the eVault is pretty much in line price wise with all of the Tier one brands. Most of them are 70+ Cents per Wh.
Your paying for a premium Factory New Grade A cells, build quality and Support not to mention a true 10 year warranty. Luckily we have choices so people can pick what suits their needs and Budget.
 
No one looking at or talking about the Silicate Chemistry batteries at watts247 ?
What is not to like about them ?
 
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