Who is still building DIY batteries

[Johneb]

I appreciate all of the replies. I'm still processing all of the info.
I would have no issue doing a DIY battery. I have tools and experience, so that's not a problem.

However I wonder about buying raw cells:

1. Are they actually quality cells and how do you know that? Even if you test them and they test good initially, how do you know they didn't shortcut something that will make them useless in 700 cycles?
2. Do the raw cells have a warranty? 18650batterystore.com offers a 1 year warranty on their cells apparently. So that's roughly 350 cycles.
3. Bare BMS units from what I have heard can be unreliable. Do they have a warranty that you could use? I've read quite a bit about failed raw BMS modules.
4. Packaged batteries generally come with a longer warranty. Redodo is at 5 years. Will they honor it?? Will 18650?? I don't know. The EG4 battery has a 5 year warranty. But shipping it back might be costly. 5 years x 365 =

I probably won't be buying more batteries or cells for a DIY battery until next year but I will be watching the prices. But I will likely need another 10-20 KWHR of capacity to get to where I want to be next year.

Dave

True A cells are available at a higher price. B cells from a reputable dealer work very well. I got my CATL cells from Docan and am very happy with them.

 

[Dave911]

I checked out Docan. I have heard that real CATL cells are supposed to be some of the best.
I filled out an order to see what would happen and I had selected ship from US warehouse and the shipping charges were pretty significant.
Like 1/3rd the cost of the cells. Is that similar to what you paid?

 

[upnorthandpersonal]

No politics. I removed the two previous posts. Stay on topic.

 

[JJJJ]

I have heard that real CATL cells are supposed to be some of the best.

I did get a batch of these a while back via "slow boat". They work well for what I need although I have not stress tested them with super high demands so I do not have any information on that.

My latest order is EVE cells. These tend to be more available to the average consumer and there are a ton of satisfied users.

I have not run a side by side so cannot comment on that.

 

[TimE]

I checked out Docan. I have heard that real CATL cells are supposed to be some of the best.
I filled out an order to see what would happen and I had selected ship from US warehouse and the shipping charges were pretty significant.
Like 1/3rd the cost of the cells. Is that similar to what you paid?

I also ordered purchased CATL cells from Docan, 6 months ago. shipping to Florida was free for me. $144 each for 280Ah x 8

 

[JJJJ]

My neighbor is finishing up a DIY build. He has a computerized milling machine and just put together a slick plexiglass case. The ultimate way of keeping an eye on things.

 

[Aak]

I have 4 redo do 24/100 ah wired 2s2p powering mylvx6048 for 9 weeks now no problems. Powers all my load at night will buy 4 more.

 

[Brucey]

Saw a real cheap 12V 280Ah pre built ecoworthy yesterday. $698 and then a $130 coupon bringing it down to $568....

Amazon.com

 

[Steve_S]

I have 4 redo do 24/100 ah wired 2s2p powering mylvx6048 for 9 weeks now no problems. Powers all my load at night will buy 4 more.

There is aVast Amount of experience here with regards to using 12V Batteries in Series to make up either 24 or 48 volt systems. The Vast Majority run into problems after a while of running that way and there are several extra factors at play with that arrangements. Ultimately it is a KLUDGE and that comes with consequences, like it ir not, it is just a fact. This is why we always suggest using Native Voltage Packs ie: 24V or 48V battery packs.

You know the old saying as we all do. An Ounce of Prevention is worth a Pound of Cure. This is extremely true for solar systems.

You do know, that you could disassemble the Redodo's and rebuild them into 8S IF the cells do not have Welded busbars... Not sure if Redodo does that or not... I think there may be teardown vids on YT.

 

[Aak]

Mechanic by trade if it works don't fix it

 

[ChrisG]

I’ve thought about DIY vs buy for a while now. Have built several 48v packs at this point more out of the coolness factor, yes I can do it, save some money, and have granular control.

What I didn’t take into account is my wife and her comfort with checking/fixing/replacing in the event I’m away, sick, in an accident, or dead.

I’ve since moved to easier ways to switch back to grid to completely bypass all inverter and battery if needed as well as knowing my next battery will be a fully assembled and warrantied units.

Keep your significant other in mind. There is always a chance they will have to live with the crazy shit we build.

 

[houseofancients]

I’ve thought about DIY vs buy for a while now. Have built several 48v packs at this point more out of the coolness factor, yes I can do it, save some money, and have granular control.

What I didn’t take into account is my wife and her comfort with checking/fixing/replacing in the event I’m away, sick, in an accident, or dead.

I’ve since moved to easier ways to switch back to grid to completely bypass all inverter and battery if needed as well as knowing my next battery will be a fully assembled and warrantied units.

Keep your significant other in mind. There is always a chance they will have to live with the crazy shit we build.

This is why :
1. The full system is documented, both in word and Visio drawing
2. Everything is properly labeled
3. ATS is in place and tested.
4. "Forced" the wife to follow a personalized " what if sh*t hits fan and hubby can't be reached" practical course of about 2 hours

Forced is of course relative, as since she has been the one taking care of the power bill the last 17 or so years, and she likes the once of the last years ( 0,- ) a lot better than before

 

[ChrisG]

This is why :
1. The full system is documented, both in word and Visio drawing
2. Everything is properly labeled
3. ATS is in place and tested.
4. "Forced" the wife to follow a personalized " what if sh*t hits fan and hubby can't be reached" practical course of about 2 hours

Forced is of course relative, as since she has been the one taking care of the power bill the last 17 or so years, and she likes the once of the last years ( 0,- ) a lot better than before

Completely agree and that is what I have done but she’s not going to dig into battery leads, connections , etc. She knows how to reboot system if needed and fully understands how to use the “Chris fucked up Double Throw” to get back to grid.

Just wanted to throw this out there for those considering building vs buying battery packs.

 

[JJJJ]

I’ve since moved to easier ways to switch back to grid to completely bypass all inverter and battery if needed as well as knowing my next battery will be a fully assembled and warrantied units.

Current system is UPS based with installed wiring system separate from the grid. Grid is readily available at all times but have the ability to run lighting and things such as a freezer as needed for a power outage since wiring and outlets are separate. Solar is planned for next year.

Also in the planning stages for automatic inverter shut off with bypass should the meter be pulled in case of a fire.

Currently designing a portable power station that can provide additional coverage inside or outside as needed.

There is lighting that runs all the time from this. This allows the batteries to cycle and charge as to maintain battery health.

 

[Steve_S]

My GF, Medical University Professor, not a techie and not comfy with electronics other than using them. She can do everything & anything needed with the solar system and understands it. I took the time to teach her and everything is documented, complete with graphics & logical drawings. It's not only electronic but there is a printed copy in the powerhouse. Everyone is capable of understanding it IF they just take the time and stop convincing themseves that they are too stupid oto learn it. Most often a Gentle Nudge of Encouragement is all that is needed.

 

[JJJJ]

Most often a Gentle Nudge of Encouragement is all that is needed.

Agreed. My wife is not a techie by nature but still manages to surprise me with the things she can do. For instance there are those who are overwhelmed by the process of canning. She learned this skill at an early age and is not afraid to pick up the Ball Canning book if needed for reference. I am also taking the time to share this with one of my sons who is very comfortable with technology.

I put together a binder with the product documentation printed out. In a power outage the internet might not be readily available and it is nice to have this as a back up.

 

[Steve_S]

Agreed. My wife is not a techie by nature but still manages to surprise me with the things she can do. For instance there are those who are overwhelmed by the process of canning. She learned this skill at an early age and is not afraid to pick up the Ball Canning book if needed for reference. I am also taking the time to share this with one of my sons who is very comfortable with technology.

I put together a binder with the product documentation printed out. In a power outage the internet might not be readily available and it is nice to have this as a back up.

Very Smart to NOT rely on Technology because it can go Poofdah... but in such events, other issues will take a Much Higher Priority.

 

[ChrisG]

Agreed. My wife is not a techie by nature but still manages to surprise me with the things she can do. For instance there are those who are overwhelmed by the process of canning. She learned this skill at an early age and is not afraid to pick up the Ball Canning book if needed for reference. I am also taking the time to share this with one of my sons who is very comfortable with technology.

I put together a binder with the product documentation printed out. In a power outage the internet might not be readily available and it is nice to have this as a back up.

But is your wife going to dig into a custom built battery pack, replace a cell, top balance a pack, and figure out what’s going on? Mine will not and has no interest into going to that level. She has the system use instructions, vendor/manufacturer name/ phone numbers, and etc.

Completely remove the system use topic and focus only on custom battery build vs buy.

 

[CoolWill]

But is your wife going to dig into a custom built battery pack, replace a cell, top balance a pack, and figure out what’s going on? Mine will not and has no interest into going to that level. She has the system use instructions, vendor/manufacturer name/ phone numbers, and etc.

Completely remove the system use topic and focus only on custom battery build vs buy.

She doesn't necessarily have to repair your DIY battery as long as it's a standard voltage. She can replace the whole pack. Unless you're an asshole like me and build the whole system for 32 volts?

 

[ChrisG]

She doesn't necessarily have to repair your DIY battery as long as it's a standard voltage. She can replace the whole pack. Unless you're an asshole like me and build the whole system for 32 volts?

That’s my point. Just replace DIY with purchased/warrantied over time if issues.

I’m not going to replace my existing DIY, just add rack batteries or other assembled product to the system going forward.

 

[houseofancients]

That’s my point. Just replace DIY with purchased/warrantied over time if issues.

I’m not going to replace my existing DIY, just add rack batteries or other assembled product to the system going forward.

Or..
As most you know , I use seplos diy kits and raw cells.
Best friends has been tagging along with my battery builds, and know where to order the cells and enclosures, and how to build them, and now uses them himself too
While I don't think my wife will ever build, my best friend does and will help should I ever become unable or unavailable to do so

 

[OffGridForGood]

Went the route of purchasing two factory built racks to get started in solar in 2021.
Since then I learned about DIY packs:
how to build them
how to source cells
options for BMS's
cell balancing
DC fuses
DC breakers

I have built four packs now, and all run perfectly, with very low cell voltage delta.
Three more packs planed, one every six months.
Cost per kWh is lower for DIY by a good margin.
Level of control and configuation is higher for DIY
Confidence to open up a pack and re-arrange cells if this ever became necessary is assured.

Future proofing:
We have all seen the change from 12v to 24v to 48v over the years in solar, higher voltages mean lower amperage for a given power output. Just look at EV's to see the trend to 800vDC.
The cells are expected to last 4000-6000 cycles, 10-16 years +plus. Who can say what the standards will be for ESS in sixteen years' time?
If the trend to higher voltages continues in solar inverters, we could see 96v (or higher) voltages become common in the furture - if so I am fully confident to re-arrange cells, add a new BMS and re-use all my DIY cells in whatever new voltage become the standard in the future.
I am equally confident to re-use the LiFePO4 cells in other applications if better battery technology comes to market during the life of these cells. A DIY pack of bolted cells is an easy modular unit to work with, compared with factory welded cells.

 

[Steve_S]

<<< Grins >>>
Some of us built our own Battery Cases/Boxes, some just have the cells bound together & sitting on "shelves", others use manufactured metal cases like "Seplos" offers or any number of others. The First TWO Options can really toss people for a loop, just the visual makes'em cringe, but for some, they think it's "cool".

Many now do offer assorted manufactured cases. Rack Mountables to Stackables to Roller Cabinet style. Some vendors are simply put, Ludicrous for their case kits, while others are not.

I built Plywood Boxes with Perspex clear tops, they look cool and are very neat BUT offputting to some (electrical inspector) who accepted it grudgingly... But thinking forward, I am redoing them all & adding another pack into my Bank and using these cases. (with a slight customization for my specs), shown below is similar to what I am bringing in.
These are nowhere near the cost of "seplos" retail cost. Sorry, I am getting these from the Manufacturer, not an open vendor. BUT with careful searching they can be found.

Any inspector, prospective buyer, or interested visitor/guest will see the stack of these and not think overly much about issues, complications etc.

 

[OffGridForGood]

Very nice - price point?

 

[houseofancients]

<<< Grins >>>
Some of us built our own Battery Cases/Boxes, some just have the cells bound together & sitting on "shelves", others use manufactured metal cases like "Seplos" offers or any number of others. The First TWO Options can really toss people for a loop, just the visual makes'em cringe, but for some, they think it's "cool".

Many now do offer assorted manufactured cases. Rack Mountables to Stackables to Roller Cabinet style. Some vendors are simply put, Ludicrous for their case kits, while others are not.

I built Plywood Boxes with Perspex clear tops, they look cool and are very neat BUT offputting to some (electrical inspector) who accepted it grudgingly... But thinking forward, I am redoing them all & adding another pack into my Bank and using these cases. (with a slight customization for my specs), shown below is similar to what I am bringing in.
View attachment 175060These are nowhere near the cost of "seplos" retail cost. Sorry, I am getting these from the Manufacturer, not an open vendor. BUT with careful searching they can be found.

Any inspector, prospective buyer, or interested visitor/guest will see the stack of these and not think overly much about issues, complications etc.

Not sure what you are paying for these, but a seplos case, inc BMS, busbars, fuse and everything one needs come down to about 420-435, that is inc shipping to my door

Most important here, the carry the required ce mark and certifications to pass insurance/electrical inspections.