Using old laptop batteries to build homemade powerwalls

https://futurism.com/people-are-using-old-laptop-batteries-to-build-their-own-versions-of-teslas-powerwall/

by jonbaer • 8 years ago

313 197 8 years ago

Roritharr• 8 years ago

This seems like a great way to burn down your house and potentially injure firefighters coming to your rescue. Seriously this is quite a few leagues above normal DIY territory. Proceed with caution.

jpm_sd6• 8 years ago

yep. incredibly dangerous. UL would not be impressed. [I have worked in lithium-ion battery design and testing for >10yr]

ropeadopepope2• 8 years ago

Do you mind if I pick your brain about something? How feasible is it to homebrew a BMS for a Lithium-Cobalt battery pack that's relatively certain not to burn your house down? I know not going with a BMS at all is a huge nono. Lots of people in the e-bike community have found out the hard way how difficult it is to manage a battery pack without one.

aaroninsf• 8 years ago

My thought exactly.

Paging /r/osha

VectorLock2• 8 years ago

Mixed batteries of unknown provenance/capacity without balancing isn't something I'd want in my basement personally.

pmorici2• 8 years ago

If you watch the video it isn't quite what the headline suggests. The guy is collecting 18650 cells from old laptop batteries and using them with his own BMS to build a new battery. Not exactly mixing and matching rando used batteries.

nikodunk• 8 years ago

Caution, yes. But most things in hardware come with varying degrees of risk. If you make a chair it could collapse. Clothes? Toxins. Electric car? Explosive.

Is the upside of "living in the future and building what's missing" not worth it though if you're cautious with the risk?

matte_black• 8 years ago

It is absolutely not worth it. There’s nothing futuristic about this DIY project.

amluto2• 8 years ago

Unknown toxins in clothing is one thing. Building a device attached to your electrical wiring that likely violates the electrical code and puts firefighters as risk is something else entirely.

btian• 8 years ago

There is a risk/reward trade-off.

A lot of people build kit airplanes in their garage, but usually get the fuel system done by professionals.

It's not a everything or nothing game. You can still have fun and stay relatively safe.

ChuckMcM5• 8 years ago

Exactly right. It will catch on fire, it will burn down the house. I expect the insurance would not cover it (just like it doesn't cover fires caused by storing gas or propane in your garage)

I got a crash course on battery charging subtleties when building battle bots and there are many ways this can so south quickly, not the least of which is a battery in the middle of the pack developing dendrites and deciding its time to burn. The only way to prevent that is to have temperature sensors on every battery and a good enough model of the heat convection between the internal battery and the surface to recognize the temperature rise of a battery on its way to failing. Even with modern "battery monitor" chips like the ones Maxim and others sell there are corners in charge rate/temperature/battery that can get away from the algorithm before it recognizes a battery failure.

The reasons this is "easy" with flooded lead/acid batteries is that, when they fail, the lead doesn't then turn into a torch at 500 - 600 degrees F. So you have a chance to fix failures and move on.

fr0sty6• 8 years ago

I expect the insurance would not cover it.

I see this blanket assertion in lots of comment threads, but never with a citation.

(just like it doesn't cover fires caused by storing gas or propane in your garage)?

This is an assertion I have never seen before. It is extremely common to keep gas cans in the garage around here (IL, USA), where else would you keep them that is safer?

CPLX• 8 years ago

The idea the homeowners insurance doesn't cover the homeowner being negligent or stupid seems to betray a misunderstanding of what homeowners insurance is generally used for, namely protecting the mortgage lender from a catastrophic loss of the property's value.

maxerickson• 8 years ago

In many cases it will only burn down the dedicated battery shed.

PaulHoule6• 8 years ago

What is most likely to kill you in most fires is the smoke and that is definitely true about Lithium battery fires.

This what makes them so deadly on a plane: you cannot get away.

Assuming that your smoke detector reacts properly to that kind of smoke, you should put one near your battery array.

lostapathy• 8 years ago

(just like it doesn't cover fires caused by storing gas or propane in your garage)

What about the gas in your car or lawnmower?

Where do you store your camping stove?

The insurance texts posted downthread don't actually seem that "damning" to me. They talk about chemicals etc in a blanket sense. If insurance companies were worried about the gas can for your lawn mower, they would come right out and say it.

It's not uncommon for cities and homes associations to prohibit sheds anyway. A gas can in the garage seems a lot less volatile than one sitting in the sun that looks like it's ready to burst.

2474• 8 years ago

Yes, obviously do not try this unless you have tremendous electrical engineering knowledge. However, I do give kudos in finding a DIY solution to reuse what would likely just become waste in some landfill.

blacksmith_tb• 8 years ago

I would hope most of the lithium in old 18650s is recycled? But maybe that's me being overly optimistic.

simple00• 8 years ago

Don't even think about building something like that yourself in your home. If one of the cells gets damaged it can set of a chain reaction which will burn down everything around it. A fire like this is quite hard to extinguish, similar to the teslas that burn down sometimes ( https://www.youtube.com/watch?v=vYKTTCNUV3o ). Using lithium iron phosphate batteries might be a safer alternative.

PaulHoule6• 8 years ago

If Tesla assumes liability for a PowerWall disaster than the $3500 price is a bargain.

JshWright• 8 years ago

As a firefighter, this is absolutely terrifying. We are not expecting this sort of hazard in a "routine" house fire.

rdl• 8 years ago

I see lots of people doing this in Puerto Rico, but mainly they are installing them in outbuildings, such that even a complete runaway fire will probably not really damage anything else. In that case, worth the risk I think.

saalweachter5• 8 years ago

Hell, I'm planning to buy a commercial solution, and I am still going to put it into an outbuilding. It's not an option for everyone, but when you start planning for failure, there's a lot of sense in not putting anything into your house itself that you don't have to.

vvanders9• 8 years ago

Yup, that's a fair risk mitigation.

Inside the house/garage? Hell no.

leggomylibro3• 8 years ago

18650 cells are great!

But be sure to protect them, and be aware that most commercial li-ion chargers and off-the-shelf protection circuits are designed to maximize short-term battery life. They'll charge to 4.2V, and many won't cut off until 2.5V.

Also know what to do if they short and catch fire; have an appropriate extinguisher and a plan for quickly getting failed cells outside and onto an inert surface like concrete.

If you want to make a 'powerwall' whose batteries could last you for a significant amount of time (e.g. decades), you'll also probably want to design your own charging and undervoltage protection circuits.

There's some good information here: http://batteryuniversity.com/learn/article/how_to_prolong_li...

amluto2• 8 years ago

Depending on chemistry, 18650 cells are quite dangerous. Tesla at least puts them in a metal box and will warn you when they’re about to catch fire.

leggomylibro3• 8 years ago

Well sure, something like a portable phone power bank is probably a better place to start than a battery for your house, but they're very useful things to learn about.

jpm_sd6• 8 years ago

re: Tesla - and they have individual fuses on every cell. And they have liquid cooling for every cell. And they have a rugged enclosure that has been designed to fail in a somewhat safe way while (briefly) containing the fire.

throwaway1X2• 8 years ago

have an appropriate extinguisher and a plan for quickly getting failed cells outside and onto an inert surface like concrete.

There are two problems:

a) There is no appropriate extinguisher when you have a thermal runaway on 20 kWh of chemical energy.

b) This isn't some shielded, extinguisher-nearby, one-time experiment, when you, for example, solder something off and then while yelling "see, I'm still alive!" run outside and throw it out. This is something that is intended to be running 24/7 at your home (and maybe mounted on wooden wall like the pictures in the link...). Unless you post guard duty shifts around the clock, there simply may be no person to perform the plan of getting failed cells onto concrete.

I see this as super-dangerous, especially when dealing with cells from many different vendors scavenged from thrown-out laptops.

leggomylibro3• 8 years ago

That's fair, and you'd definitely want to balance each cell and think hard about where to put it, but these batteries are popular for a reason; they're a potentially versatile and effective power source with charge density that is currently very hard to beat, and I'm happy to see people trying to make information about doing it safely more widely available.

And the extinguisher would be for things around where the batteries used to be, in a catastrophic failure.

smileysteve• 8 years ago

On A) a diyer could solve this the "nuclear" way by storing the batteries underground or submerged in a deep tank of fluid.

Of course, then you run into cooling and maintenance access issues.

MertsA4• 8 years ago

There is no appropriate extinguisher when you have a thermal runaway on 20 kWh of chemical energy.

Yes there is, it's called a hose. But you're right, that 20 kWh isn't just going to up and disappear. I think it's realistically possible to do this with a modicum of safety even for a hobbyist but it needs to be passively safe. It can't rely on cells being inherently balanced with respect to one another, it needs to have some serious thought about what to do with that 20 kWh if the worst occurs but that's not an insurmountable task. Sprinkler heads are cheap and even just a garden hose will put out 25 gallons a minute. A very slight risk of water damage can be acceptable IMHO, I wouldn't have trouble sleeping with something cobbled together sitting in my garage so long as I planned for the worst along the way when piecing it together.

saas_co_de2• 8 years ago

While there are some risks to building a powerwall if you don’t have the proper tools and resources

understatement of the century there. DIY electricity is risky. DIY li-ion at scale with used batteries is suicidal.

useful• 8 years ago

in middle school for a science project I converted non-rechargable batteries into rechargables. They all worked, they all held 80-90% of their original capacity.

They all leaked/exploded 6 months later while they were idle in flashlights and rc cars. The chemistry is different but that experience taught me to be more careful with 'outside spec' electronics.

908087• 8 years ago

Seems like a really stupid thing to DIY to save money, and a great way to burn your house down.

peterwwillis• 8 years ago

You can unplug from the electrical grid with one of these. If you don't have 5 grand to plunk down on a giant battery I'd say it's a pretty effective way to save money.

You don't have to keep it in your house. If you have a small section of land which would otherwise normally house a shed, you can build a fireproof enclosure outside to house the pack. If it burns down, your house doesn't. And if you're building it from scratch, you can include enough sensors for it to auto-shut down when an unsafe voltage or temperature is detected. (the linked video mentions all this)

When people build their own car, they're also taking their life in their hands. But if you learn the right way to do it, you won't blow yourself up.

PaulHoule6• 8 years ago

I recently bought an APC UPC to protect my DSL modem and phone when the power goes out. I have enough battery powered devices that I can be in communication as much as I need.

Those two devices draw about 8 watts, but the UPC I bought can run for only about 10 hours on that load. It could run a lot longer except that the inverter is scaled to handle a larger load so efficiency is bad. And why the hell is it converting AC to DC, then converting to AC, then converting it to DC in some awful wall-warts.

Since you don't run the inverter for really long times, there is a pressure to put in a cheap, inefficient inverter. However, if you took out the inefficiencies, you could afford to use lithium batteries and produce a much better product for this market. Hell, maybe the thing supplies power to the phone and modem through USB-C and it is just a super-powerbank.

Basically a "micro-powerwall". Safety issues still concern me but smaller scale reduces the odds.

haldean• 8 years ago

Something like this 50Ah battery pack?

https://www.amazon.com/Laptops-External-50000mAh-Portable-No...

Google around for external laptop batteries, they make some really big ones.

PaulHoule6• 8 years ago

That is close. The single 12V port packs enough amperage that I could wire the two devices in parallel. I'd still have to make cables to connect to the devices. (The phone in question is a cordless phone connected to a landline. It probably should take usb-c but it does not.)

bartvk• 8 years ago

Mike Gyver sells some interesting batteries: http://mikegyver.com/

VectorLock2• 8 years ago

You can buy 'super-powerbanks' for a few hundred dollars. Depending on the voltage and power requirement of the DSL modem you could probably run it, and your phone, right from there.

saalweachter5• 8 years ago

It's further down my list, but I am starting to investigate adding DC circuits to my house. Between solar and battery backups it would make sense to run as much as possible off of 12V DC.

arca_vorago• 8 years ago

I had the pleasure of working with one of the best electrical (motor) companies in the states, and decided to sit in on the journeyman electrician course (because sysadmins want to know everything), and I was surprised to find out that DC is what is used for the large high-power long distance transmission lines. I think there are probably quite a few applications where DC might be more appropriate than AC that haven't been realized yet.

jws4• 8 years ago

What I've learned powering an offgrid cabin…

Modern inverters and efficient walwarts (thank you EU) will be more efficient than 12v DC because of the power lost to the cables for anything but trivial loads.

The problem is some squared math functions which come and bite you. Your 12V DC system will pull 10 times the current as a 120V AC system. That's going to mean bigger wire. But then the kicker comes in, each volt you drop means 10 times the energy loss because 11/12 is a lot worse than 119/120, so you'll have even bigger wire. My 24V system with the batteries in a shed has $900 of copper wire between there and the house.

Then consider that all your loads probably already have a voltage converter in them, either an AC-DC external converter or something internal. Most of them won't take 11-14VDC inputs with spikes on it, so you'll need DC-DC converters on them anyway, so you aren't saving the conversion losses on the device end.

In summary, with modern high efficiency inverters you will probably find that your dollar is better spent on solar panels and batteries than masses of copper wire. If I were starting in 2018 I would not have run the DC lines.

thesmok• 8 years ago

If you only need to backup power 12/24/48V devices, then you can skip the mains voltage inverter and use a battery-backed power supply. MeanWell comes to mind — they make these power supplies for security and telecom systems.

phil212• 8 years ago

The comments here are more evidence the "hacker" part of hacker news really no longer applies :)

In seriousness - of course putting this in your house is a a pretty risky and likely dumb idea. I absolutely have plans to do this though, just with a fire resistant (concrete block) "power shed" 50 yards away from my house.

Someone that can build a working DIY powerwall can cheaply build a cinder-block shack and run conduit back to the living quarters. If you can't afford to do that I'd say you can't afford to do the project at all.

ghostbrainalpha• 8 years ago

I love your comment, but do you mean 50 ft. or do you really mean yards?

Not many people have a yard the size of half a football field, and even if they did, it would probably put the danger close to a neighbors house.

So seriously, what would a reasonably safe distance be? Should this be avoided if you don't live in a really rural area with a giant property?

burger_moon• 8 years ago

You could build that in your garage with a concrete block or 3/8 steel box and a fire retardant system. Hell you could probably even just buy a sufficiently large gun safe if you didn't want to build something. Actually even a metal fire cabinet for storing acetone and such chemicals may be sufficient but if someone were interested would need to research this further of course.

phil212• 8 years ago

I just used 50 yards as an overly cautious example.

I haven't done enough research to feel comfortable giving a number, but it should be well under 50ft even.

You do make a good point that this won't be an option for everyone. If you live in a dense city without yards, I guess this is one fun project I'd take a pass on. If you live in a standard suburb you are probably okay at least in terms of space.

fpgaminer• 8 years ago

Your comment about a power shed reminded me of this neat youtube series where someone living off-grid built their own hydro-electric generator to supplement their solar: https://www.youtube.com/watch?v=MUNMjdmGIPI&list=PLEZ2hvCDKU...

thaumaturgy2• 8 years ago

"Hackers" historically developed such a depth of understanding of some system that it allowed them to modify and subvert the system to suit their needs. The people here who have built power systems for Battlebots and are familiar with the variability in specifications for 18650 cells and are saying that this isn't a good idea for reason X, Y, and Z, those people are the hackers.

The people that are saying, "a battery's a battery, I'll just put it in a shed" are dabblers. They don't understand the technology well enough to do it safely, so they just build it with the assumption that it's going to go FOOF someday.

FussyZeus2• 8 years ago

Well, the Powerwall, along with batteries, also has a ton of safety features that make it safe to install inside a home without worry.

One would argue even if you know exactly what you're doing, unless you're replicating those same safety features as well, you should put it in a shed anyway.

That said, totally agree with what you're saying.

rickbike• 8 years ago

"FOOF" is an interesting word choice. Have you heard of dioxygen difluoride, aka FOOF? If not, you may find this article interesting:

http://blogs.sciencemag.org/pipeline/archives/2010/02/23/thi...

_ea1k2• 8 years ago

You've created quite the false choice there. You've completely left out the people who know that it is in idea for reasons, X, Y, and Z (and maybe some others too) but are doing in anyway with a full understanding of how to modify and subvert those risks.

You know, hacking with a depth of understanding. I think you are responding to a person like this.

amphibian872• 8 years ago

A battery is a battery, any lithium battery from a drill to a tesla is simply a 1.5 volt cylindrical cell stacked in series to produce the desired Voltage, then these stacks are connected in parallel or series again as needed (depends on application) to increase the load it can handle (Amperage).

The safety features you're so worried about are just fuses. And maybe some diodes if you're that worried. I can say that installing a bank on a piece of plywood on your garage wall is obviously stupid, but a simple opening of the NEC book will show the code for a battery bank, shall have clearance from a wall and rest on non-flammable/non-conductive material, usually in a nuclear power plant or a substation we would build a rack out of metal then install ABS plastic shields.

Source: I'm an industrial electrician and went through an IBEW apprenticeship,

metamet• 8 years ago

Since you mentioned Battlebots, I wanted to mention that when I was on Battlebots in 2002, the options for batteries were pretty damn slim.

The was one company making a good product called Battlepacks (for lightweight - super heavyweight classes). If you were doing anything in the smaller weight classes (antweights through the 30lbers), you were typically hijacking a lot of remote aviation resources.

The options available now are much better than they used to be.

tomxor• 8 years ago

They don't understand the technology well enough to do it safely, so they just build it with the assumption that it's going to go FOOF someday.

Accommodating for failure modes is not lack of understanding... most chemical batteries have some inherent combustive or explosive danger, lead acid can produce hydrogen explosions, LiPo can slow burn when the layers are punctured through expansion etc.

Failure in a car is one thing (make sure it doesn't happen violently so that it can be controlled and escape is possible), but in a house you just can't afford for it to happen at all, sticking it in a separate building is a very reasonable and simple precaution for such a large quantity of chemical batteries on one place.

It's bad enough when small laptop batteries burn up, and those have to pass safety test... imagine a few crates... in your house... under high load from having to power all of your appliances.

dopamean• 8 years ago

This definition of a hacker doesn't sit well with me. When I was a kid I hacked on things I didn't understand for a long time in order to get a better understanding. Was I not hacking? What I not a hacker then? I've never really put too much thought into it but always assumed I was.

lumberjack• 8 years ago

Personally I have no expertise on the matter, but there are also other hackers who have been doing this for ages. Go to EVTV.me, a community about home built EVs, for example. You'll find plenty of documented projects of recycling laptop cells for both EVs and home energy storage.

johnhenry• 8 years ago

From these comments, it seems like a "hacker" is either someone who understands the technology extremely well or not well at all... either way it's going to be fun ;) (and hopefully not too dangerous).

Piskvorrr2• 8 years ago

Eh. Of course "hacker" has some overlap with "danger", but that doesn't automatically mean "smart" - Radioactive Boy Scout was an essential hacker. (Now get those newfangled JavaScript contraptions off my lawn; kids these days, calling themselves hackers! waves stick)

stcredzero• 8 years ago

In seriousness - of course putting this in your house is a a pretty risky and likely dumb idea.

Would it be possible to design a minimal, modular metal rack to act as thermal isolation? I could picture a scheme with metal bent into a shallow Z shape with obtuse angles, which would direct the burning debris from a failed battery away from all the others.

saas_co_de2• 8 years ago

The comments here are more evidence the "hacker" part of hacker news really no longer applies :)

More like the same response that an article advising people to create their own crypto library would get. Except creating your own crypto library doesn't have the risk of killing your family, neighbors, and emergency responders.

Presenting this kind of project as a "hack" is really irresponsible given the very serious risk of death, severe physical injury and property damage involved.

tlarkworthy4• 8 years ago

No, Hacker Rule Zero, "don't be on fire"[1].

[1] https://wiki.london.hackspace.org.uk/view/Rules

matthewwiese3• 8 years ago

Those read more akin to safety rules with "hacker" tacked on for theme.

yardie• 8 years ago

In any hacking group there has always been a large contingent who criticize using the worst case scenario. It's pretty par for the course when engaged in any critical thinking.

If I had the space and need to build a powerwall. I probably wouldn't do it with a bunch of 18650s. Calb and Winston cells make a lot more sense.

jotm• 8 years ago

It's quite sad, "don't do this, don't do that, never use the stairs 'cause you can die and insurance won't pay". What's the word for "non-hackers"... "normies"?

While Li-Ion is a different beast, I used to play with car batteries and UPSes, a simple setup could run some lights, fridge, the phones and computers for over a day. It took some time before I wisened up and made a separate metal box for everything. Until then, ran it all from the closed balcony.

WJW• 8 years ago

"Muggles"? :)

bb882• 8 years ago

Someone that can build a working DIY powerwall can cheaply build a cinder-block shack and run conduit back to the living quarters

The real issue here is to prevent thermal runaway.

I would go further, and add a thermal cutoff switch to turn off the battery charging if it's too warm outside (We've had summer days here at 115F.) Then maybe a fire suppression system of some sort.

semi-extrinsic• 8 years ago

Fire supression should be pretty easy in this configuration. Get a 55 gallon drum of deionised water, put it on top of you battery shack, feed a plastic hose from the bottom of the tank into the shed and seal the hose with a plastic that melts at, say, 150 F.

moron4hire• 8 years ago

I touched a six volt battery to the back of my neck and got told by HN I was going to fry my brain. Grossly overestimating risk is a minor league sport around here. Why do you think most of these people haven't actually started their own company or left their supposedly soul-sucking corporate jobs, yet?

elago4• 8 years ago

As a counterpoint to the hysteria expressed in most of these comments, a few years ago I was watching a youtube series by "Rinoa Super Genius" where a similar project was undertaken to create an e-bike battery from disassembled laptop batteries.

The videos are done by an interested amateur with basically a pocket knife and a large soldering iron. I'd highly recommend it if you want practical and confidence building knowledge on the actual behavior and safety of batteries, rather than this comment section which is filled with outrage and "experts" referencing their credentials and years of experience.

I'm an experimenter not an entrepreneur so I'll never claim I can produce battery packs in my basement safe enough to sell to grandma, but I've had no problem ripping apart broken electronics, charging old cells with a DIY dc power supply, and using cells in all kinds of 'dangerous' manners.

Personally I think chance of injury is far higher with dozens of other technologies used every day by non professionals: chainsaws, cars, and many other types of motorized or heavy equipment.

vvanders9• 8 years ago

chainsaws, cars, and many other types of motorized or heavy equipment

You know what a bunch of those have in common? A ton of effing safety measures.

Chainsaw chaps, ROPS, etc all exist exactly because those things are so dangerous. The power density of an e-bike is at least one if not more orders of magnitude less than a 40kWh bank of batteries.

He also has the potential to not only burn down his house but kill a lineman working on the line if the power ever goes out.

elago4• 8 years ago

All the table saws I've ever used have been super dangerous. Car crashes are a leading cause of death for young people. I could go on, these sorts of things can't be made safe while still being useful. Beyond a point, it's up to the user to understand the danger, learn behavior that minimizes risk, and pay attention when using the tool.

With all of those things, like batteries, it's not good to assume the general public can use them, so they shouldn't be as common as elevators, shopping carts, and other ubiquitous tools/machines. But it's very dis-empowering to claim only elites can use these tools.

Your final comment regarding lineman safety is completely decoupled from DIY battery pack with re-used cells. That would be a failure of the inverter in a grid-tied system. You could have an unsafe grid-tied inverter with a 100% functional battery pack with every certification in the universe and backfeed the utility lines, or I could connect a faulty battery to a proper grid-tied inverter and it would not cause the utility lines to be energized by my house when the utility shuts off the power upstream.

Additionally, you can use a home storage battery without a grid-tie inverter at all.

johnatwork• 8 years ago

I think the main issues it that it's always "on" and sourced with an unknown usage history. And it seems like it's placed in a location where if things were to go wrong, without proper mitigation, it could cause serious harm.

The chance of injury is probably higher with Chainsaws and cars as you say, but they are not in constant use, and usually have safeguards in place by a regulatory board.

wkearney992• 8 years ago

This is the important point. A whole lot of things are dangerous when you're using them. But when you're not they're largely safe. Various saws, tools, cans of gasoline, propane, butane, etc. They're all unlikely to be used on a 'set and forget' kind of basis.

Whereas a battery bank is VERY likely to be used that way. Set it up and get on with other activities, likely including leaving the building entirely. Meanwhile the unsupervised device has an exponentially greater risk of become unstable and causing tremendous damage.

It seems like a clever idea but how much risk it poses is debatable. One would hope anyone attempting to do this is going to be dissuaded from pursuing it on a grand scale because of the various problems they're going to have along the way. But some 'mad scientist' types are never going to be dissuaded. With luck the rest of us will at least get an entertaining video clip of their disaster. Hopefully without anyone else suffering from the ignorance.

ryanwaggoner• 8 years ago

"In contrast to what all the expert statisticians here have to say, I watched a guy on Youtube play Russian roulette and he was fine. I've played these kinds of "dangerous" games myself and it's always been fine. Ignore the experts, what could go wrong?"

There are all kinds of dangerous things in the world, and many can injure or kill you if you don't treat them carefully. I don't understand the callous disregard for safety concerns, nor the attacks on people with expertise and credentials in these areas, all in favor of some random guy you saw on Youtube who happened to survive and your own limited experience.

elago4• 8 years ago

If that's your interpretation then we fundamentally disagree.

"Random guy on Youtube" happened to be an intelligent and capable human being who learned all the relevant techniques and principles from available information without paying for "credentials".

Go watch the technique used for testing, evaluating, sorting, and re-using batteries used and tell me specifically what is unsafe rather than trying to spread fear because there's no college degree/certification/other form of economic gate keeping.

I'm not attacking people with credentials, only the type of people who vaguely threaten people not to twist 120VAC wires together in a wirenut unless they understand Maxwell's Equations.

solarkraft2• 8 years ago

This isn't news. People have been doing this before the Powerwall has come out (except jehu has started branding them this way after it did). Newer Li-on batteries aren't all that dangerous, especially the round cells. Even when overcharged absurdly they don't combust nowadays.

solarkraft2• 8 years ago

The real downside is that according to my calculation, at least from German E-bay, DIYing gets about the same price per capacity without all the added technology and convenience of buying from someone.

MertsA4• 8 years ago

It's not much cheaper but you can get good deals on 18650 cells. It's not unheard of to find deals on genuine cells for as low as $1 a cell.

https://www.youtube.com/watch?v=Hpv4G6HY2Rs

Then there's the option of buying lightly used battery packs like a single module from a Tesla.

https://www.ebay.com/itm/Tesla-Smart-Lithium-Ion-Battery-186...

That's $690 for 3kWh that is all assembled, tested, cooling is taken care of, BMS included, individually fused cells as well as a 100A fuse on the entire pack. That's not too shabby, slap an inverter and a charger on that pack and you've got yourself a somewhat decent diy powerwall for like $1100 bucks.

ngvrnd• 8 years ago

There will be fires.

muthdra• 8 years ago

I'm personally using old laptop fan and hard drive motors to build my own version of Tesla's Roadster.

test6554• 8 years ago

Dont forget to use the wifi adapter to ward off evil spirits

tsumnia• 8 years ago

To at least satisfy all of the "fire" comments, what if you designed a Powerwall with many interchangeable batteries? Like a street light, instead of having a massive bulb that is expensive to repair/replace, hundreds of tiny little lights that are cheap and the repair/replace of a single failed unit is not as detrimental.

Could the home battery then be formed in a similar manner to this article, without the scary "fire" danger?

aphextron2• 8 years ago

That's how a power wall works. They are made up of thousands of 18650 cells. The problem is charge balancing. When you have a pack with thousands of different cells from different origins with different internal resistances, keeping the charges balanced becomes a really tricky thing to do.

lev99• 8 years ago

People aren't making hacked versions of Tesla's powerwall. Tesla is making cooperate versions of preexisting diy power storage solutions.

rmason• 8 years ago

There's a startup incubator West of Lansing, Michigan in the little town of Grand Ledge called The Fledge http://grandledgefledge.com/ It's really a cross between a makerspace and an incubator.

I toured there and among the projects I saw was someone who had made a Tesla Powerwall from laptop batteries. Another was a solar array on a trailer which they explained could be shuttled between your house as well as a cottage up North.

Course building a project is less than half the journey to successfully commercializing it however it was inspiring to see what people were creating.

godelski• 8 years ago

Jehu Garcia [1] does a bunch of youtube videos on old batteries and different DIY powerwall designs. I'd say to always double check his work, because I've seen some stuff that looked a little dangerous, but for the most part what I've seen is good.

[1] https://www.youtube.com/channel/UCcMfCkN1juSa49DJFYltOTw

dalbasal2• 8 years ago

This is a tangent^: How many people dump a laptop with a usable battery. My experience has always been that the battery is first to fail/suck.

^to the main point, this is a cool project. go DIYers. try not to get killed

Obi_Juan_Kenobi• 8 years ago

Typically what happens is only some proportion of the cells are bad, but that makes the whole battery unusable. Scavenging these batteries requires testing each cell individually to find which are suitable for reuse.

dalbasal2• 8 years ago

Cheers.

danielvf• 8 years ago

Once I volunteered at a large tech non-profit. Between projects, I took over an unused desk in the sysadmin team cave. After lunch one day, I heard a loud noise. I went to the cave door - it looked out over a large cubicle farm.

There were now a dozen fires burning over a forty foot diameter, along with little bits of smoldering cubicle wall.

Someone had apparently removed the battery from a laptop, plugged it into a bench power supply, and then gone off to lunch. It exploded in their absence. It gave me an instant respect for li-ion batteries, plus a small concern every time I fly in a small metal tube full of a couple hundred laptop and phone batteries.

But several hundred used laptop batteries, with no balancing, in my garage, mounted on wood. NO FREAKING WAY EVER.

olivermarks2• 8 years ago

My paranoid side wonders if this is more clever marketing/pr by or for Tesla. Why headline this 'powerwall' rather than 'home battery packs' or 'rechargeable lithium-ion battery home energy storage'?

'Powerwall' is like a prelaunch version of 'Hoover' for vacuum cleaners, a brand name used to describe a generic. People have been experimenting with capturing energy from solar panels for years. We know it is fraught with risks.

Powerwalls are really expensive, barely launched and not a proven household name with reputation like Hoover. Is this ultimately a 'better choose safety and choose the known brand' gambit?

drb91• 8 years ago

Eh, a powerwall is a well defined product with well-defined uses. “Home battery pack” is nearly meaningless—are you talking about a UPS unit, or something that backs your home power, or is it something that feeds back into the grid?

Not saying you’re wrong, but I think the name is undeniably useful at quickly describing a set of functionality. This could also be a case of poor evangelism on behalf of people who care/competitors.

olivermarks2• 8 years ago

https://www.fool.com/investing/2018/03/04/energy-storage-war...

deft• 8 years ago

To people coming into this thread, let me sum it up "don't do this it's dangerous let tesla handle it"

dmix• 8 years ago

TIL you can get 18650 batteries from old laptops, which is something I use in my mechanical vape..

https://www.youtube.com/watch?v=6GpvOvw5oEc

droidist2• 8 years ago

Yeah true I use these for vaping, although regulated mod not mechanical mod.

wglb• 8 years ago

If I were to do this, I would go the old-school lead-acid deep-discharge marine battery route. They are safe enough to put in the basement or garage. How to do this is well understood and doable by hackers.

Lithium batteries are pretty scary. For example, https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_... is pretty frightening.

Using old laptop batteries to build homemade powerwalls

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