Featured Image courtesy of BatteryHookup.com. Thanks BH!
It’s cold outside – Time to find things to do Indoors
Did we mention that this Prototype Modular Home is going to be off-grid? Eventually, yes. Because we’ve pledged that the majority of it will be DIY-built this means the battery bank as well.
Battery Types and Sizes
18650’s – 18mm diameter by 65mm height (nobody knows what the last 0 is for) – most commonly used in e-bikes and e-vape/e-cigarettes, depending on the chemistries used; and yes, this form factor is even used in the Tesla Model S and Model X, to this day. We’ll be using used 18650’s for this prototype mostly because there’s just so many on the market and the prices are just too good to use something bigger…for now.
2170’s – 21mm diameter by 70mm height – the newest generation of cells used in Electric Vehicles due to their high energy density and thermal (heat) dissipation capabilities. Tesla Model 3 and Model Y’s use 2170s…for now.
Sourcing Batteries
Finding a good source of batteries is harder than it sounds. New cells can cost between $2.50 to $4.50 each. And that’s for the low capacity ones too, 2200mAh to 3000mAh. Luckily there are companies out there that sell used and “New-Old” stock that may be almost as good as new but have to be sold as used. Un-luckily, there’s lots of work to do to harvest these diamonds in the rough. If you’re patient and steadfast you’ll gather enough and save a ton in the process.
The picture above was the result of “shucking”, “harvesting”, and testing approximately 150, 2200mAh, 3.7v, used battery cells. There’s only 141 that weren’t just dead and only the ones on the far right (approx. 106) are worth keeping because they still have more than 80% of their life still left in them. Many of them were at 95% to 100% testing out at 2150mAh to 2250mAh as well. Here’s the best part though – we only paid approximately $0.45 to $0.50 per cell, before shipping. We estimate we’ll get between 70% to 80% of good usable cells out of each shipment for a per cell final cost of between $0.54 to $0.82 after shipping, depending on how many good ones we find per shipment.
Ah Shucks!
Did I mention we need around 1400 cells for the first set? More on that in a later post as well as how we test them. In the meantime, time to get “shucking”. We say shucking, because taking the battery packs apart is very reminiscent to those times, many years ago, when my family and I sat around the kitchen table shucking corn husks off the cobs, “snapping” green beans, and canning fruit…FOR HOURS ON END! And this task is no different. The metal and plastic parts are sharp too, so get a pair of good gloves, some needle-nosed pliers, wire-cutters, and a box of band-aids. We’ll try to upload a video on how we shuck packs like the following. In the meantime, here’s how they look at the different stages.
These are LG 2200mAh cells with most of the junk cleaned off but usually we wait to clean them better or just re-sleeve them with new shrink wrap AFTER we know they’re good enough to keep.
Learning About Batteries
The Lithium Ion battery industry is growing in leaps and bounds. Not all batteries are created equal and not all batteries are meant for all applications. The good news is there’s LOTS of resources out there in the form of websites and YouTube personalities who are playing in this arena as well, AND there are places you can purchase used or refurbished materials for small projects that won’t break your bank. We’ll share some of those in this and in future posts but we can’t quote EXACT pricing because like any other used market, prices fluctuate and supplies can peter out. That said, if you’re willing to put in the hard work, you can find some REALLY great deals like we did to begin working on your own “refurbished” power solution.
Over the coming months I’ll try to introduce you to my favorite sources of knowledge and experience and I strongly encourage you to consider donating to them if you find they helped you save time, money, sanity…or whatever. They’re trail-blazing ahead of us and have literally saved my wife and I YEARS of effort and kept us from making costly mistakes.
Battery Resellers
There are many companies who sell new and used batteries but few have good service AND good quality control. Only one is GREAT at both. BatteryHookup.com. They actually answer the phone and are willing to answer lots of dumb questions.
Battery Chemistries
First off, batteries made for cars, or e-bikes, or scooters aren’t necessarily good for portable or off-grid home storage. And vice versa. So do your homework and research what you need as well as the safety precautions you’ll NEED to take. We’ll go into greater detail on the different chemistries for different applications in a later post but suffice it to say, there’s lots to learn, so Buckle up Butter cup!
But seriously, safety first. We’ve all heard about the Li-Ion battery fires in cell phones and even in automobiles. Be safe and never do something with batteries of any kind without finding out how to handle them, charge them, discharge them, and store them. You should even go as far as making plans for how to fight a battery cell fire if one decides to go “critical” on you. I keep an extinguisher and metal ammo can close by and I never store my tested batteries at full charge. Which is what’s required for shipping them by the way.
Finally, for understanding Battery Chemistries there’s no one better than Jordan Giesige (Gee-suh-gee). Be prepared for a deep dive and a lot of details. His YouTube channel, The Limiting Factor, is one of my Top 10 channels to follow and support.
If you find his knowledge helpful consider showing him a little love by supporting his channel with a donation or by becoming a monthly donator at his Patreon site, https://www.patreon.com/thelimitingfactor/posts.
Thanks Jordan!
New vs Used Batteries
For people with experience shucking and repurposing used Li Ion batteries there are quite a few but no one does it better than Pete at his HBPowerwall YouTube Channel. Why? Because he shows you everything. His successes AND his mistakes. Check out his YouTube channel and watch all of his old ones up to recent months. He’s down-to-earth, very humble, and EXTREMELY funny too.
He’s shucked more batteries than anyone I know and his house down in Australia is 100% powered by Recycled 18650’s. His Patreon page can be found at https://www.patreon.com/hbpowerwall.
See y’all next month!
Thales of Miletus 