Buy or build.

[Torben J]

I was considering building a 3.5 kWh solar generator in a Craftsman toolbox.
Looks like I can get a similar pre-built one here.
Any thoughts?
Buy or build?

630.0US $ 40% OFF|24v 100ah 120ah 150ah Lifepo4 Battery 24v Lifepo4 100ah 120ah 150ah Battery 24v Lithium Iron Phosphate Battery With 10a Charger - Battery Packs - AliExpress

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[Supervstech]

What were you going to power with your diy box? If you were going to include solar charge controller, and an inverter, yours would be a solar generator. The prebuilt box you linked is just a usb charge bank on steroids. It includes a wall charger, but diy can be much more robust than that unit.

 

[Bob B]

I was considering building a 3.5 kWh solar generator in a Craftsman toolbox.
Looks like I can get a similar pre-built one here.
Any thoughts?
Buy or build?

This is a lithium battery with (LiCoMnNiO2) chemistry ..... It is not LiFeP04. I don't know anything about this chemistry but some of them are a lot less safe than the LiFeP04.

I would do some research about this chemistry.

 

[Torben J]

I appreciate everyone's feedback. I have decided to build my own. Point taken I'm going with LiFeP04.

I have selected a Dewalt tough system for my project box.

DEWALT TOUGHSYSTEM 22 in. Medium Tool Box DWST08203H - The Home Depot

DEWALT has taken its Guaranteed Tough philosophy of power tools and expanded it to storage. The DEWALT TOUGHSYSTEM Medium Tool Box (DWST08203) is ideal for use on the job site, made with a durable, 4 mm thick, structural foam box wall that provides robust structure to the standalone unit. An...

www.homedepot.com

Considering the following batteries. They are LiFeP04 and assembled. NEW CASE OF 4 BATTERY HOOKUP 3.2V 100ah MODULES

NEW CASE OF 4 BATTERY HOOKUP 3.2V 100ah MODULES

Shipping only available to the United States and Canada. Shipping out of the country requires these to be shipped via freight. For a quote email us at sales@batteryhookup.com. No compression needed since these are cylindrical cells which means these are the easiest batteries to assemble, all you...

batteryhookup.com

I know I can get cheaper ones from China with delivery at the end of May. Don't want to wait that long for this project.
Get it now for $0.24 a Wh or from China $0.12 a Wh. I will build a larger one later. These boxes are stackable so easy to expand.

If someone knows a cheaper source in the US, let me know.

 

[Torben J]

4pcs/lot LiitoKala 3.2V 200Ah lifepo4 Battery 12V 200ah $458.​

$0.18 per Wh
Definitely a better price for a US seller. No reviews though.

4pcs/lot LiitoKala 3.2V 200Ah lifepo4 Battery 12V 200ah Battery Suitable for Solar Energy Long Life 3500 Cycles EUUS Tax Free : Health & Household

Buy 4pcs/lot LiitoKala 3.2V 200Ah lifepo4 Battery 12V 200ah Battery Suitable for Solar Energy Long Life 3500 Cycles EUUS Tax Free: 12V - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[Forbisher]

Considering the following batteries. They are LiFeP04 and assembled. NEW CASE OF 4 BATTERY HOOKUP 3.2V 100ah MODULES

NEW CASE OF 4 BATTERY HOOKUP 3.2V 100ah MODULES

Shipping only available to the United States and Canada. Shipping out of the country requires these to be shipped via freight. For a quote email us at sales@batteryhookup.com. No compression needed since these are cylindrical cells which means these are the easiest batteries to assemble, all you...

batteryhookup.com

THESE ARE OVER 2000 CYCLE RATED CYLINDRICAL CELL MODULES. COMPARE THESE TO POPULAR 12V 100ah BATTERIES ON THE MARKET AND YOU CAN BUILD ONE WITH THESE FOR 50-70% LESS COST. WE HAD OUR CELLS ASSEMBLED INTO 20P 100ah MODULES BY A TOP QUALITY AND POPULAR COMPANY. OUR CELLS ARE NOT CHEAP, OFF-BRAND CELLS. THEY WILL LAST A VERY LONG TIME. THEY ARE NOT GRADE B OR REJECTS, THESE ARE THE REAL DEAL.

WE HAD THEM MANUFACTURED BY A VERY POPULAR MANUFACTURER THAT MAKES CELLS FOR A COMPANY THAT CHARGES $950 FOR A 12V 100AH BATTERY.

Hmmh are they saying these are Battle Born cells?
Battle Born has four 30P battery modules so 120 cells total.

 

[Positronium]

Since I have a spot welder, I would build my own pack with the K2 Energy LFP26650E-3800-21 cells for almost a $100 less. K2 Energy cells are high quality. K2 Energy and A123 (now known as LithiumWerks) are among best manufacturers of 26650s.

Full Case of 120 K2 26650 3800mah Lifepo4 Cells

Just $1.90 per cell when you buy a full case! These cells are brand new in the original case. You get 120 of them for just $228. These are genuine K2 3800mah lifepo4 26650 cells. These cells are overstock and this is a liquidation sale. These are not grade B, rejects, or used cells being...

batteryhookup.com

 

[Supervstech]

Since I have a spot welder, I would build my own pack with the K2 Energy LFP26650E-3800-21 cells for almost a $100 less. K2 Energy cells are high quality. K2 Energy and A123 (now known as LithiumWerks) are among best manufacturers of 26650s.

Full Case of 120 K2 26650 3800mah Lifepo4 Cells

Just $1.90 per cell when you buy a full case! These cells are brand new in the original case. You get 120 of them for just $228. These are genuine K2 3800mah lifepo4 26650 cells. These cells are overstock and this is a liquidation sale. These are not grade B, rejects, or used cells being...

batteryhookup.com

Those are less expensive, but would require more cells per pack to equal 100Ah

 

[Positronium]

4pcs/lot LiitoKala 3.2V 200Ah lifepo4 Battery 12V 200ah $458.​

$0.18 per Wh
Definitely a better price for a US seller. No reviews though.

4pcs/lot LiitoKala 3.2V 200Ah lifepo4 Battery 12V 200ah Battery Suitable for Solar Energy Long Life 3500 Cycles EUUS Tax Free : Health & Household

Buy 4pcs/lot LiitoKala 3.2V 200Ah lifepo4 Battery 12V 200ah Battery Suitable for Solar Energy Long Life 3500 Cycles EUUS Tax Free: 12V - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

I had terrible experience with LiitoKala cylindrical cells they listed and labeled as 7000mAh. When I tested them the highest had a capacity of 5700mAh. I wouldn't trust the capacity they claim.

 

[Torben J]

Positronium
Thanks for the warning,

 

[Torben J]

Those are less expensive, but would require more cells per pack to equal 100Ah

Welding my own will be for my second project.
Want to start with something easier.
Just getting started. Going for a portable box.

A power all would be nice, then would definitely weld.

 

[Positronium]

Those are less expensive, but would require more cells per pack to equal 100Ah

True but that case is enough for 4s30p 114Ah battery. More cells is not necessarily a minus because 100A would be carried by 30 parallel pure nickel strips for average current of 3.33A per strip.

For 20p 32700 battery pack the current is an average of 5A per strip. A 10mm x .15mm pure nickel strip can handle around 6A. For 32700 20p battery pack I would recommend doubling up the series links so there is a larger margin for peak current.

Welding my own will be for my second project.
Want to start with something easier.
Just getting started. Going for a portable box.

A power all would be nice, then would definitely weld.

That is good. Stick with K2 Energy 26650, A123 26650, or the batteryhookup 32700s. The cheaper cells are notorious for overstating capacity.