Save $500/day when you DIY your own batteries!!!

I made my own DIY battery and it saved me over $500 compared to the big brands. I wanted a 12 volt, LFP (lithium Iron Phosphate, LiFePO4) battery. There are several brands to choose from such as Battle Born, KiloVault, Victron, Renogy, and more. They are built solid and if you have the money to buy one, they are worth it. Seriously.

Battle Born Battery: This is a high-quality manufacturer. If you don't have the time, tools, or desire to build a battery yourself, then check out Battle Born. Use coupon code "DAVIDPOZ" for free shipping.

But, if you want more fun and the satisfaction of making things yourself, then you are like me. I want to DIY my own battery. Luckily, Battery Hookup recently started selling their own branded cells. These things are LiFePO4 cells, nominal 3.2 volts. They are 32700 (32650) cell size. I think this is the same size cell used to construct the big brands.

I ordered a case of cells, and an empty case to put them into, LOL. Then I set about the trial and error process of how to assemble them. I tried a few different orientations in the case before settling on a nice 20p4s. Then I had more trial and error making the bus bars, and nickel connections. It seems simple now, looking back.

Finally we did a capacity test and found these cells performed 15% better than expected! WOW! Awesome stuff.

Anything from Battery Hookup can be purchased using my coupon code "DAVIDPOZ" for 10% off.

-----------------------------------------------------------------
SPOT WELDER:
18650'ed Heat Shrink and Cell Holders
I have no affiliate with Keith, from 18650'ed. He sells accessories for builds. I purchased my K-weld spot welder from him, along with the Kapton tape, and nickel strip.
Case, Empty. I purchased mine through Aliexpress. However, you may be able to find it locally. Keith, from 18650'ed, sometimes has some empty cases in stock. I suggest checking with him first.
-------------------------------------------------------------------------
Amazon Affiliate Links:

“As an Amazon Associate I earn from qualifying purchases.”

Disclaimer:
My videos are in no way intended to be instructional "how-to" lessons. I am simply documenting my project for informational purposes. Property damage, personal injury, or death may result, even when following manufacturer's instructions. I cannot be held liable for such damage or injury. It is YOUR OBLIGATION to ensure that you are complying with any local and federal laws as well as code and permit requirements.

[ashylarry]

Just spent 40min watching a guy build a battery. Intriguing and fascinating. Learned a lot.

I’ll just buy one.

[george-broughton]

I'm sure you already know this but cells with built in battery protection circuits tend to be longer, even though they can be marked as 18650. Some of these circuits can add 5mm to the length and this may be why. If you rip the plastic wrapper off one, you might find one tacked onto the end of a cell.

[marsrover]

This is a somewhat unsafe battery. Timestamps to where build mistakes were made.

11:08 round your positive corners you madman. No fishpaper rings either. Sure it takes an extra $10 and 30min, but it's worth it for the peace of mind.

12:54, you folded a positive line over the negative casing of the battery. Meaning that thin pvc shrink the batteries are housed in is the only thing preventing a dead short. Put some fishpaper between them.

15:56 should be discharging from both "corners" it's fine I guess, but not ideal when you could have easily soldered the wires on each.

When charging to make perfect balance. Set power supply to slightly less than the balance current of the bms. (Usually 100mv) this allows the bms to burn off the high cells at the same rate of charging so no overvoltage cutoff will happen while balancing.

[brianvandy]

For increased cell life, you don't want to use 100% of the capacity. The peak and valley of the charge curve cause the most wear on the cells. So if you trim 5-10% off the top and bottom you get extended life. So if the cells will go as high as 3.65, trim that to 3.6 and if the bottom is 2.8, maybe bring that up to 2.9 or even 3.0v. You would still use 80-90% of the capacity, but you'd get another couple years of use out of those cells.

[pdufusc]

SON! probably the best presentation of any subject I have watched on u'tube! I've been to automotive and aircraft schools off and on over the 55 years in the mechanical field. I had only a couple of instructors that presented the info as concise as your did, and that's including speech delivery, clear! Thanks!

[paulshain]

One of the best vids on you tube. No over explanations, no poxy music in the background, well done.

[realitytv]

Its people like you that make youtube a great place. I know people come to youtube for different reasons, some purely entertainment, some news, I do sometimes for those reasons also. My biggest reason for coming to youtube and spending countless hours on it, is to learn from people like you, it has allowed me and millions of people around the world to watch great videos like this to learn new things that otherwise we would be clueless about. Thx for the video and clear explanations and I wish u the best in 2021!

[glentaybow]

Awesome thing to build your own battery David! Amazing what you have learned about all this stuff because you were not afraid to try. Your kids are also watching and learning. They'll be awesome as well. You and your wife are great parents.

[johnpatrickmatthewsmusic]

I did not know that my wire stripper had screw cutters in it. Thanks for that info @26:25. Also at the end he shows cost, but it would cost me another $1000 for all the tools he uses...lol

[staym]

Thank you David, alot people make comments that just rediculous and waste of time to say, instead of being appreciative of knowledge you share and time given to share with others. So thank you.

[williamhustonrn]

Good project bud, that's not a bad value for the battery with knowing what's inside. I recently bought a premade lithium battery from amazon that was suppose to be a drop in replacement for my motorcycle, received it and it felt very heavy for a lithium battery, pulled it apart to find it was made up of used 18650 cells with 4 different model cells in use inside and had no internal bms at all, just lots of snot covering everything to keep everything glued together.

[DavidSmith-dmew]

I'm liking these cells and the battery box... if you did 80 cells in the box and you did a 48v battery 16s5p you could make a nice 25ah battery for your 48 volt inverter. All you need is a 16s bms.

[darkkevind]

10:57 You needn't have put the kapton tape, nor the insulating fish paper on those ends of the cells as you're folding them together, which means actually, if they touch, that's going to be better for your series joins as the nickel will be touching each other from the negative of one cell to the positive of the other (in series).... as long as the pack it taped tightly together, you don't need all that insulation and kapton tape.
You should probably have some circular/ring positive cell protectors on those cells though, to make it safer.
Also, where you fold over that nickel from the positive side, you've got nothing preventing that nickel, after time and with vibrations, rubbing away at the cell's thin plastic shrink wrap and having a direct short from the + of that cell to the - !! Dangerous!

[DeXoDeD]

Solid Build!!

Only critique I have is at @12:52. When you bend your busbar back, it's now in a place where it can rub on the can. Since the can is negative, if you use this battery in a mobile application, you have created a fire risk when the bar rubs through the cell's original insulation. Some of the battery paper, maybe 2 layers, would help that a lot.

[wrenchstallion]

Mind blown I had to immediately check my wire strippers and have the same screw cutting feature I had no clue existed. Thanks for that tip!!!

[engineer]

Greetings from Russia David! I would advise you to charge the battery with a balanced charger, bypassing bms, and entrust the board only with a protective shutdown. I do not trust balancing to these boards (my personal humble opinion), and balancing is not needed every time if the cells are new and from the same batch. Good luck with your projects!

[stalthyone]

The 5 extra millimeters of size on you LiPo batteries is from the protection circuitry, you can see it as that extra wafer size on the positive anode.

[justanotherguy]

You know honestly I don’t remember the last time I have watched a 30min+ video but man I have really enjoyed yours
I don’t own a solar panel, I don’t know the first thing about electricity or batteries but I have really enjoyed it
Keep it up 👍🏼
Love from Syria 🇸🇾

[thestate]

Thanks for taking the time to video this project. New subscriber thumbs up. Cheers

[robertallen]

I can't believe I forgot about this diy favorite of mine from way back with the salvage car hybrid battery buid for the garage/house power bank. Or the test and trial of finding the right power inverter the solar panels and solar water heater system that was built. Man, now finding the latest Lytham 14 volt clean diy .. nice! Ty Dave p.