Continuing DIY or give up DIY to buy already assembled battery?

[Rain@]

I bought 4pcs EVE280K from Tewaycell before, and now I want to build a 16S system. At that time, I made the 4S system out of temporary interest. In this DIY process, I did not feel the joy at all. I just feel tired.
And I saw on Tewaycell’s website that this model is no longer available in the European warehouse, but there is 15KWH of finished product in European stock.
So I'm very hesitant now.

 

[robby]

I spent hundreds of hours building my system during Covid and the thought of making my own packs was more work than I was willing to put in.
At todays prices it’s really becoming a question of how much free time do you have to save 30% on the battery bank.

 

[Rain@]

I spent hundreds of hours building my system during Covid and the thought of making my own packs was more work than I was willing to put in.
At todays prices it’s really becoming a question of how much free time do you have to save 30% on the battery bank.

Is your system also 16S? Or other systems?
I usually have time on weekends to make my DIY projects, but I'm very, very slow at making DIY projects by myself.

I am still learning DIY knowledge from forums, Youtube, ect. And I know that the DIY knowledge I learned online needs to be put into practice.

 

[50ShadesOfDirt]

I would consider your 4S experience as a test or experiment ... you've learned a lot of material to get to the point of 1st power from it. You can DIY again for the 16s, searching for the threads on this forum of folks (Steve_S, others) who have or continue to do it, and see if you get inspired for the next one.

But, at the very least, you now have a better understanding of what goes into a purchased battery, and can read the specs, watch the vids, and purchase more wisely.

I kinda/sorta did the same with a simple SOK 12v100ah battery, as this vendor constructs the battery in such a way that you can open it up and FRU (field-replaceable unit) any part of it. Replaced the vendor bms in it with something more interesting & communicative. Learned loads from it, without the joy of purchasing individual parts overseas, shipping/customs and other headaches, etc.

Moved on to researching more carefully any vendor of LiFePO4 batteries ... their websites, specs and warranties, their support capabilities, and more, including tear-down vids. When I buy a battery, it's from a company that did all the heavy lifting for me, and stands behind that battery. LiTime was one such company, replacing a problematic battery entirely on their dime.

The only thing I did wrong (with my initial SOK purchase) was: I didn't buy my SOK batteries through CurrentConnected; they seem to be a national dealer for the US. That would've been the absolute best and last thing to do right. I'll correct that if I buy into SOK's "server battery" line, where again, everything is FRU ...

I have SOK and LiTime (formerly AmpereTime) 12v batteries in various Ah capacities, up to 300Ah.

Hope this helps ...

 

[Zwy]

I bought 4pcs EVE280K from Tewaycell before, and now I want to build a 16S system. At that time, I made the 4S system out of temporary interest. In this DIY process, I did not feel the joy at all. I just feel tired.
And I saw on Tewaycell’s website that this model is no longer available in the European warehouse, but there is 15KWH of finished product in European stock.
So I'm very hesitant now.

If you're building a big bank, it makes more sense to go with DIY.

Luyuan currently offers a premade 280Ah battery with case and BMS for under $2000. Not much savings if you are only building one battery by the time one buys cells, a BMS and other materials.

 

[Sigunas]

If you can get used modules from EV's, DIY can save you a lot... For example 2020 and newer Hyunday modules go for as low as 100 EUR/kWh, when buying in small quantities. On the other hand, I would not bother with Tesla modules anymore.

 

[Nobodybusiness]

I bought 4pcs EVE280K from Tewaycell before, and now I want to build a 16S system. At that time, I made the 4S system out of temporary interest. In this DIY process, I did not feel the joy at all. I just feel tired.
And I saw on Tewaycell’s website that this model is no longer available in the European warehouse, but there is 15KWH of finished product in European stock.
So I'm very hesitant now.

Definitely a personal decision.

Personally built mine so I could understand how they work if any issues arose.

It is definitely tedious work but for me rewarding.

 

[Supervstech]

I like tinkering with stuff, learning from doing is my forte...
I also like stuff with a warranty, that will just work.

I have a mashup of both at my place.

 

[ScrotusGobbleBottom]

I diy so I dont get involved with a paper weight because 1 cell decided to kill his friends like that one unfortunate person here recently.

 

[Supervstech]

I diy so I dont get involved with a paper weight because 1 cell decided to kill his friends like that one unfortunate person here recently.

The last set of purchased batteries i bought came poorly balanced. They reached 100Ah, so i went with them, but the balance must be set really high, because they never did balance, and the imbalance killed every single battery.
They were global power batteries, cheap at the time with low temp disconnect, so i got em.

Fortunately, they were easy to open up and rebuild.
Several dead cells, but i had enough to get 4 working again...

Anybody want a few 100Ah dead cells?

 

[ScrotusGobbleBottom]

the imbalance killed every single battery

How can imbalance kill cells? If a cell isnt going past its HVC and LVC what difference could it make to the rest of the cells?
Or are you talking about a couple batteries that all had imbalance issues with them eventually?

 

[Supervstech]

How can imbalance kill cells? If a cell isnt going past its HVC and LVC what difference could it make to the rest of the cells?
Or are you talking about a couple batteries that all had imbalance issues with them eventually?

My guess is the imbalance allowed a few cells to sit at hvd, and stragglers didnt get charged, then eventually they took on less and less charge, and the disconnected bms, allowed the cells to co.pletely deplete until they would no longer take a charge...

Idk for sure, all i know is each battery had one dead cell, and one battery had 3 dead cells...

No clue how it happened.

But the seller of thw batteries wouldnt respond, so he must have had a lot of failed batteries.

 

[chrisski]

16s 280 ah is 13 kWh a Tesla power wall, or almost 3 of my 5.1 kWh fortress power flex 5.1 kWh

 

[ScrotusGobbleBottom]

16s 280 ah is 13 kWh a Tesla power wall, or almost 3 of my 5.1 kWh fortress power flex 5.1 kWh

Right! That is a lot of power for cheap. I dont understand why this is even a question. An hour of my time is certainly work $400.
Sig solar, 100AH 48v is $1398 5.1 kWh
DIY 16s Eve with BMS $1790 13 kWh

Its not even close!

 

[robby]

Right! That is a lot of power for cheap. I dont understand why this is even a question. An hour of my time is certainly work $400.
Sig solar, 100AH 48v is $1398 5.1 kWh
DIY 16s Eve with BMS $1790 13 kWh

Its not even close!

An hour is huge stretch but yes it can be a big savings if your up to it.
Even if you have lot of experience and all the tools it will take a several hours to get everything cut, drilled mounted, plus fabrication of brackets etc for fixation, then the wiring of the BMS, breaker, fuse holder, cutting cables and doing the crimping.

If you have very little experience and no tools it's going to be a whole different ballgame, a lot more time learning as you go plus added money to buy tools. Also there is the unknowns of dealing with the Cell Vendors and the lack of any warranty or support.
Another issue with 280A cells is that the Pack ends up weighting 300lbs!
You better have some strong friends to help you with this project.

DIY is a great cost savings solution for those that have the skills and time but in this case the Op made it clear that even building a 4S pack was not a great experience for him.

 

[ScrotusGobbleBottom]

several hours

Yeah, I admit you are right. But in my case, I didnt just wire up some batteries, I wired up an auxiliary solar circuit to nearly every room of my house. I loved it. Went in full fist.

I was mostly speaking of adding a 16s bank on a shelf to an existing bus bar and system. 1 hour. On a shelf.

 

[robby]

Yeah, I admit you are right. But in my case, I didnt just wire up some batteries, I wired up an auxiliary solar circuit to nearly every room of my house. I loved it. Went in full fist.

Nice!
I went all out on building the Electrical room for the equipment and mounting and wiring everything neatly. At the time I just could not see building batteries as an option. I do know that I would have probably saved $5K in the process but then the Job might have gotten stalled due to the extra weeks it might have added and my enthusiasms dying out.

 

[ScrotusGobbleBottom]

my enthusiasms dying out.

Yes, never let that happen!
Im still working on the neatly part. 8 months later

 

[Brett V]

I’m more comfortable with the reliability and safety of my DIY batteries. I recently commented in another post that commercially made batteries are getting better, and eventually the DIY battery will be a curiosity akin to owning a Heathkit radio that still functions. I’d draw a parallel to ham radio gear. My grandfather built his gear from scratch but today that’s unheard of. It’s just a matter of time.

 

[robby]

Yes, never let that happen!
Im still working on the neatly part. 8 months later

LOL, two years later and I still have that "One thing Left to do" to finish off my Electrical room.
It's actually pretty insane considering how much work I put in to not just finish building one cover panel.
I have to fabricate if myself but I always have a mental block when it comes to finishing that last 1% of any big project I build.