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DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

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Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#131

Post by dreamcompiler »

KGIII wrote: post #89
digi_owl wrote: post #79

Earlier quoted context omitted.

Yeah i have read enough scary stories about people dealing with 18650 cells (effectively AA sized lithium batteries used in high powered flashlights etc), that trying to build a powerbank from used laptop batteries with enough capacity to handle domestic appliances is not something i would undertake.

I have a sneaky suspicion that their insurance isn't going to cover the fire this may cause. These are lithium batteries, with who knows what for quality control, being used by people with who knows what for education. This could be a tragedy in the making.

They're lithium-ion batteries, which contain very little elemental lithium and do not result in lithium fires (which are very difficult to put out). True lithium batteries (the kind that can cause lithium fires) are not rechargeable.

http://batteryuniversity.com/learn/article/safety_concerns_w...

[edited to add link]

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#132

Post by heartbreak »

shagie wrote: post #54
heartbreak wrote: post #48

Earlier quoted context omitted.

That’s not true for any of the United States. You can’t call yourself a Professional Engineer without being licensed, but anyone can call themselves an engineer. Train engineer, growth engineer, happiness engineer, and software engineer are all perfectly valid titles without a P.E. license.

Try calling yourself an engineer in Texas without proper licensure. http://www.mystatesman.com/news/state--regional-govt--politi... And the relevant court case: http://www.soah.texas.gov/pfdsearch/pfds/460/16/460-16-0550-...

To this day they still call themselves Tire Engineers, even through an acquisition last spring.

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#133

Post by dreamcompiler »

dom0 wrote: post #116
snarfy wrote: post #104

Earlier quoted context omitted.

How many watts are we dealing with here? What's the actual power output of a 1 second long direct short? I'm pretty sure if you shorted that 40-60 volts across a hotdog it would explode. Even if we disregard if that voltage can stop a heart (which it can, 50v is minimum), the amount of power you are dealing with is the amount of power that causes things to explode. I wouldn't go anywhere near a diy power bank without…

With batteries (and even small battery packs) there are two main safety issues: (1) chemical combustion (due to mechanical damage or stress or electrical stress i.e. over-charging) (2) Burns and fires caused by arcing. For (2) the exact configuration basically does not matter, because generally speaking all battery packs capable of storing a large amount of energy are also able to release a large amount of energy in…

>

    +  Charger  -
    |           |
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |-   Cell  -|
    |           |
    +   Sense   -
What is being sensed here and why is it wrong? If voltage is being sensed and the busses are fat chunks of copper, this seems entirely proper. What am I missing?

EDIT: Wait, I think I know. You also need independent current measurement at each cell to detect internal shorts. And probably a way to automatically isolate such cells.

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#134

Post by Reason077 »

fragmede wrote: post #42
Reason077 wrote: post #21

Earlier quoted context omitted.

Unrepairable black boxes? This isn't really true of Tesla. Sure, it would be nice if they could make service manuals and service parts more freely available, but the same could be said of all car manufacturers. There are guys on YouTube who have re-built entire Teslas from near-scratch using salvaged parts from multiple vehicles. Guys with no formal training and no previous experience with EVs. Tesla does not do anyt…

Going the salvage titled Model S route is, from the accounts I've seen (likely featuring the same videos from YouTube), is thoroughly unsupported by Tesla, to the point that Tesla will refuse to sell parts to people if Tesla knows they are trying to rebuild vehicles that have a salvage title. There's making parts "more freely available" and then there's "you can't have this from us, for any price". Fortunately the lu…

From what I've heard the Model 3 will be a bit different.

But certainly on the Model S, the battery is not that difficult to remove/replace - again, there's plenty of YouTubers who have done this.

You can even, in many cases, swap a higher capacity pack into older/lower-spec models if you're so inclined. There is no DRM or software checks that prevent this from working!

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#135

Post by Reason077 »

fragmede wrote: post #42
Reason077 wrote: post #21

Earlier quoted context omitted.

Unrepairable black boxes? This isn't really true of Tesla. Sure, it would be nice if they could make service manuals and service parts more freely available, but the same could be said of all car manufacturers. There are guys on YouTube who have re-built entire Teslas from near-scratch using salvaged parts from multiple vehicles. Guys with no formal training and no previous experience with EVs. Tesla does not do anyt…

Going the salvage titled Model S route is, from the accounts I've seen (likely featuring the same videos from YouTube), is thoroughly unsupported by Tesla, to the point that Tesla will refuse to sell parts to people if Tesla knows they are trying to rebuild vehicles that have a salvage title. There's making parts "more freely available" and then there's "you can't have this from us, for any price". Fortunately the lu…

"even if there's no office service manual available to amateurs."

They do actually make the manuals available to anyone, just for a hefty fee if you're not Tesla-certified:

https://service.teslamotors.com

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#136

Post by sctb »

kwiens wrote: post #52

The original story is far better researched and more technical. Can we change the link to that instead of this repost? https://motherboard.vice.com/en_us/article/kzz7zm/diy-powerw...

Thanks! A moderator updated the link from https://futurism.com/people-are-using-old-laptop-batteries-t... a while ago.

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#137

Post by cucuuc »

dreamcompiler wrote: post #133
dom0 wrote: post #116

Earlier quoted context omitted.

With batteries (and even small battery packs) there are two main safety issues: (1) chemical combustion (due to mechanical damage or stress or electrical stress i.e. over-charging) (2) Burns and fires caused by arcing. For (2) the exact configuration basically does not matter, because generally speaking all battery packs capable of storing a large amount of energy are also able to release a large amount of energy in…

> + Charger - | | |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| | | + Sense - What is being sensed here and why is it wrong? If voltage is being sensed and the busses are fat chunks of copper, this seems entirely proper. What am I missing? EDIT: Wait, I think I know. You also need independent current measurement at each cell to detect internal shorts. An…

Short detection Technically it depends on the cell chemistry and how they fail.

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#138

Post by throwaway76543 »

funkaster wrote: post #130
bb611 wrote: post #127

Earlier quoted context omitted.

The batteries being talked about are 18650s, which is mentioned pretty clearly in the article and apparent from every single picture of batteries in it. This makes sense, because the vast majority of laptops sold across the world use a set of 18650s as their batteries. These are also the form factor of batteries being used in current Tesla powerwalls (though I believe they will also switch to the 21700 form factor as…

> In short, you're overestimating the risks and underestimating the level of safety attainable with these products. No. When it comes to things that might produce fire inside your house, there is no such thing as overestimation. You cannot be over protective when it comes to fire safety. Source: I was a firefighter for +7 years.

"You cannot be over protective when it comes to fire safety."

Ridiculous. There are obvious examples of overestimation of risk, why not prohibit electricity in homes entirely for example? Should I get rid of my kitchen stove?

This kind of absolute rhetoric is banal, obviously absurd, and is not helping anyone.

Effective safety measures involve accurately quantifying and balancing risk.

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#139

Post by andlier »

dreamcompiler wrote: post #133
dom0 wrote: post #116

Earlier quoted context omitted.

With batteries (and even small battery packs) there are two main safety issues: (1) chemical combustion (due to mechanical damage or stress or electrical stress i.e. over-charging) (2) Burns and fires caused by arcing. For (2) the exact configuration basically does not matter, because generally speaking all battery packs capable of storing a large amount of energy are also able to release a large amount of energy in…

> + Charger - | | |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| |- Cell -| | | + Sense - What is being sensed here and why is it wrong? If voltage is being sensed and the busses are fat chunks of copper, this seems entirely proper. What am I missing? EDIT: Wait, I think I know. You also need independent current measurement at each cell to detect internal shorts. An…

If each cell is connected to the bus bars with fuse wire (like in the Tesla battery pack for instance) this connection diagram seems valid. Same way it is connected in the car/powerwall packs that tesla makes at least.

Re: DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes

#140

Post by cucuuc »

SwellJoe wrote: post #115
z3t4 wrote: post #80

Earlier quoted context omitted.

Imagine the bad PR you would get when your product kills your customers.

I can go to Home Depot or Lowe's, right now, and walk out with a breaker box, conduit, a bag of breakers, a couple hundred pounds of copper, and install my own household 220V/150A electric service. Local codes or the electric company may require an electrician to sign off on my work before I grid tie, but the companies who make the stuff aren't going to refuse to sell to me. Nobody seems to think me killing myself by…

Unless you're an EE and an expert in power supplies, this is way more dangerous than splicing some copper wires and following some building codes.

Which ppl manage to f. up all the time anyway (missing ground, neutral and live swapped, splices used in lieu of a longer length of cable, improper gauge, poor cabling technique)

This community takes it as a given that "email is too hard" for an amateur to do right. Then how is wiring a house considered easy when the electrical code books are thick as bricks?

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