Can you make your own lithium batteries?

[Wabbit]

Have you asked around for free 18650s? Back in the day I would recycle bin about 3 laptop batteries a day. We had a guy pick up all the computer stuff we tossed. I had people call the shop asking for free\cheap stuff and they could take what they wanted from the recycle pile.

 

[XERTYX]

Not I lot of free batteries around here. Goodwill rarely even sells computers anymore. They have a contract with a recycling company and get like 10 cents a pound for all computers. Best buy and even some grocery stores have battery, phone, chargers, etc bins and have a similar contract.

 

[jonyjoe303]

Used 18650 are in the 2000 mah range or lower, rare to find them higher. The fake 18650 are usually brand new and rated 4000mah or higher. A true 18650 weighs about 43 grams, the fake ones are lighter then 40 grams. The mah of batteries is no big deal for a battery pack, you can use 1200 mah and 2600 mah batteries in the same pack, same with battery brand you can use sony with lg etc. As long as each parallel row of cells equals the same mah as all the other rows. To me the important thing is that they don't self discharge, that will cause balancing problems.

I always buy the used name brand 18650 that have been tested for mah, there is no guarantee they will be accurate, but the ones I tested are close to what is on the cell. No harm in getting an opus btc3100 and testing all cells for capacity, but it takes 2 to 4 hours to test each cell. It can take several days to test 100 cells, and thats running your testers round the clock, longer if you can only test several hours a day.

The 65ah battery cost me about 130 dollars in cells, 4 dollar bms, maybe 10 dollars for the battery holders, the bms connectors are about 1 dollar per connector, xt60 connectors (6 dollars for 10 pair), lcd meter 4 dollars, nickle strip less then 10 dollars, overvoltage protection relay 5 dollars, 12 volt dc receptacle 4 dollars. Total would be less then 200. I never drained all the way to zero. I only use as a backup to my house battery.

As far as charging lithium using solar, a regular lithium bms are incompatible for solar use, you can use if you have nothing else. The problem with the bms is they use solid state relays which leak voltage. When they shutoff to stop charging, the solar controller will try to keep charging causing voltage surges, these surges will destroy anything connected to the battery.  The only bms I recommend to charge with solar is the chargery bms8t, these use mechanical relays to shutoff charging.

If you going to use 4s li-ion on solar, your controller has to be capable of bulk charging above 16.8 volts, my mppt controller maxes out at 15.5 volts. Otherwise it will float charge very slowly. As an example my 3s li-ion pack (max voltage 12.6 volts) when connected to 240 watt panel/20 amp mppt, I had bulk setting set to 13.3 volts (lowest it will go) it charge at 4 amps, but when I change the bulk to 14.4 volts, I was charging at 15 amps. The more difference between the bulk voltage and battery voltage the more amps the battery will get. 




picture of exterior of a 27ah li-ion powerpack


largest li-ion pack I built 94 ah I used laptop cells from 1200mah to 2600 mah (total 156 cells). I used solder iron to build this one, all other packs I build with tab welder. In this pack to get it to fit in container, I had to build 2 battery packs and then connect them in parallel together. This was my workhorse until I builld my 220ah lifepo4 pack.

 

[vangotransit]

I use electric car parts company, good people and fair prices.
My latest pack was for me 500ah at 12 volts nominal
It is 5p 4s with a 200 Amp BMS system, highest load is 100 amps. I have 200 watts of solar with a mppt charger, a 60 amp Sterling battery to battery charger, and either a 10 amp shore power charger or a 100 amp shore power charger. I can also use a j1772 cable through the 100 amp charger and my work has free j1772 chargers and the boss is cool. I also have 6 amp balancer and near field effect current meter. I built and balanced the pack. It is 100 ah prismatic lifepo4 cells. I like having up to 10 hours of air conditioning

 

[Natgreen]

How much did that cost

 

[XERTYX]

I'm curious myself. But I know sterling battery to battery chargers are not cheap at all. And that's only 1 component. But those are supposed to be among the best of the best if not THE best.

 

[vangotransit]

I do electrical upfitting and micro grids semi-professionally(I also have a 9+5).
I install this for $7500 in most vehicles, the components are about $4800

 

[XERTYX]

That's outta my price range. Goodnight everybody.

 

[Mrcap]

About eBay sellers... make sure of what the sellers reputation is. It’s easy... how many sales and are the reviews favorable?

When buying 18650 cells buy the big 4 brands and you will be fine. Panasonic, LG, Samsung, Sony. When the batteries arrive test each cell and see if it meets the description it was sold under. It’s not that difficult. Check out EV West if you want to compare new prices on 18650 cells.

If you want to learn about building your own battery bank from some type of lithium cells google Jehu Garcia or go to his YouTube channel for tons of great DIY videos.

Will Prowse has a great book on Amazon all about diy solar and batteries that I like.

I am preparing my install of a 5.3kw Tesla model S battery module. It is made up of 444 Panasonic 18650s. It is likely to last 10,000 or more cycles at the slow discharge/charge rate I will be using it at in my RV compared to what it was designed for.

I mostly recommend using a Battleborn or some of the other drop in replacement options for lithium. Battleborn’s require nothing special as far as chargers or charge controllers and they are very difficult to damage. They come with a good quality BMS built in and have a ten year warranty. Waaaaayyy cheaper per amp hour compared to any flooded battery and a quarter of the weight. To get the same usable power you would need at least two flooded batteries of the same amp hour ratting.

My 5.3kw Tesla module only weighs 55 lbs.

Flooded/AGM and other lead acid type batteries should only be used if you are not prepared for the up front cost of lithium but as far as cost per ah it isn’t even close. Lithium is way cheaper.


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[IGBT]

A 31 pound battleborn battery is $949 on sale for 100 ah at 12.8V, or 1280watt-hr.   That is $0.74 a watt-hr and 43 watt-hr per pound.

A goal zero YETI 3000 is 66 pounds, $2250 on sale for 3075 watt-hr.  That is $0.73 a watt-hr and 47 watt-hr per pound.


Almost identical in price and weight.

The Battleborn has a longer life expectancy in cycles, although the Goal Zero uses the same cells that I have in my Torqeedo electric outboard 400 watt-hr battery which is 9 years old now and still is able to deliver 330+ watt-hr per use.  I think they way underestimate with their 500 cycle life...either they are thinking people will drain it to 0 every time or they must be accounting for use in high temperature areas.

The goal zero has a pure sine inverter and MPPT solar charge controller built in.  USB 2.0 and 3.0 ports too, although big whoop on those.

 

[geogentry]

@mrcap



Couldn't remember his name
Jehu Garcia is about the best on talking how to make batteries, test them, e.t.c.

I went and watched his channel after reading your post. Recent video on how to make a LifePO 12v battery. He has gotten way better at his videos.

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[Natgreen]

Was think about buying 40 of these and making 160ah battery.
HEADWAY 38120 HP 3.2V 8AH LIFEPO4 LITHIUM BATTERIES 25C 200A SUPER CELLS

Regular price$11.00

Good idea or nah?

 

[justawfulgamer]

I went on Facebook marketplace and sent a few messages to PC repair folks and bought 8 used laptop battery packs for $30. Even if most are good, I feel like it was a decent deal. Each pack holds 6 18650 batteries

Sent from my Redmi Note 6 Pro using Tapatalk

 

[jonyjoe303]

Thats a good deal on getting started. As long as the cells are in the 1200 mah range are higher they can go in a pack. Lower mah can also be use in a pack if you run out of cells but those are better in flashlights. All cells are good for something. Even the dead cells you can use them to practice soldering or tab welding. You might get lucky and find cells in the 2000mah range. The cells that self discharge are only good for flashlights.  

In the picture are some of the tools that I use, the opus btc3100 is the best tester for the li-ion 18650, I own 2 of them, I tested at least 300 cells with them, the best feature is it can charge/discharge 4 cells at a time at 1 amp, most testers discharge at 500ma. It also has a built in fan and can test lifepo4 cells,nimh cells. Its not cheap cost about 40 dollars but worth it. It comes with an ac adapter but the unit itself runs on 12 volts.

The hakko sidesnips (cost 7 dollars) will do quick work of removing the nickle strip that sticks to the end of the cells when you take them apart. Best tool for doing that, I struggle for years using needle nose. 

Somes cells if they read under 2 volts might not work on the opus, but another tester I own the foxnovo 4s is capable of reviving those, some of those cells when revived will still work good on flashlights for years of service. Its able to revive cells in the 1 volt range. It can also tests 18650, but only discharges at 500ma. Only works on 18650 li-ion and nimh. cost about 30 dollars

Thats how I started with a handful of cells, now building giant packs with hundreds of cells is no problem. 

Just take your time taking the packs apart, I see some people use dremel tools but you never ever want to puncture a lithium battery, best just to work slowly. Avoid shorting out cells as you take them apart, if you see sparks try a different method. 



foxnovo 4s

 

[Natgreen]

Why are you guys more keen on the 18650. I haven't heard anyone in this thread mention the 38120 or the prismatic ones.

 

[RoadStar66]

You could try. But you might as well just douse the inside of your RV with gasoline and throw in a lit match. Same result.

 

[justawfulgamer]

You could try. But you might as well just douse the inside of your RV with gasoline and throw in a lit match. Same result.

So, free heat too?

Sent from my Redmi Note 6 Pro using Tapatalk

 

[XERTYX]

Are prismatic ones inherently more dangerous? Will prowse has an affiliate link to prismatic cell diy kits on his site. He has YouTube videos explaining in depth how to configure them.

 

[Gypsy Freedom]

Was think about buying 40 of these and making 160ah battery.
HEADWAY 38120 HP 3.2V 8AH LIFEPO4 LITHIUM BATTERIES 25C 200A SUPER CELLS

Regular price$11.00

Good idea or nah?

your math is off a touch. these cells are 8 ah each and only 3.2 volts. so you need 4 in series (4s) to make a 12v battery bank. with 40 cells you would wire 10 cells in parallel, do that 4 times and then wire those 4 parallel banks in series to get a 12v battery. that would only give you 80 amp hours at 12 volt. at $11 each you have $440 just in cells. is there shipping? how heavy duty of a bms do you need. if you only run small loads then a smaller cheaper bms would work. but if you want to run a larger inverter then you battery management system would get more expensive. those particular batteries are very high output, i believe they are rated for like 200 amp output. with 8 in parallel you could draw 1600 amps without hurting the batteries. kinda over kill in an RV type application. great in electric car

when i look at a project like this and try to decide if it is worth it from a $$ stand point, not a learning hobby view. i compare the price of commercially available equivalents. there are a couple very high quality respected brands that are selling 100 ah LiFePo4 batteries with 100 amp discharge BMS all built ready to drop in with a good warranty for under $1000 so about $10 per amp hour. the cells you mention (if i did my math right) would put you at $5.50 per amp hour for bare cells. about $50 (or about $0.50 per amp hour) gets you a 100 amp separate port BMS from china on aliexpress then you have the odds and ends like making buss bars wire and connectors to put it all together by the time you put it all together and put it in some box/package to protect it while in use you will probably be around $7 per amp hour. that also put $0 value on your time involved.  could be a cool project with a high quality battery at the end, but cheap and easy is not how i would describe it. only you can decide if it is a good idea. you have to include the benefit of fun and learning. but for me, strictly money, giving up a warranty from a reputable company and a new product, i would need more than a 30% savings. 

Posted by Natgreen - Yesterday, 02:15 PM

Why are you guys more keen on the 18650. I haven't heard anyone in this thread mention the 38120 or the prismatic ones. [\quote]

most if not all the comments in this thread referring to 18650 cells are incorrectly using that term to refer to lithium ion chemistry cells/batteries that era available cheap on the internet used/salvaged/surplus. 18650 is only a size/form factor. you can get lifepo4. lithium ion and even lithium titinate cells in that same size. the reason so many folks are miss using the terms is because there are so many sources online for used/salvage 18650 lithium ion cells for really cheap prices that are coming out of laptops or modems or some other recycled electronics. and they just dont know or dont care to use the proper terminology. the 38120 cells you listed are lifepo4 used/salvaged/surplus and are a totally different battery type, with different voltages and characteristics. so are most of the prismatic cells. the lifepo4 chemistry is a much safer and long lasting chemistry than any of the lithium ion chemistries. but there has not been a large availability of used/salvage/surplus lifepo4 cells at cheap prices so they are not as popular in the hobby lets build a battery group.

the premium and new lithium ion cells are more energy dense than lifepo4 so you can get more amp hours for less weight. the trade off is more dangerous (or more damaging when something goes wrong) and shorter life

 

[Natgreen]

Thanks for the input. I realized i should have said 80 instead of 160 but it was too late to edit it. But you are correct. I have been researching this and have come up with the same conclusion as you. I still haven't decided of I want to build one or just bite down and buy battleborn