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DIY Home EV Charger

jamesfotherby.com

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Re: DIY Home EV Charger

#61

Post by elihu »

KennyBlanken wrote: post #49
elihu wrote: post #30

Earlier quoted context omitted.

The terminology is kind of confusing, but usually the thing called a "charger" is the part that converts AC to DC at whatever voltage the pack requires. For level 1 and 2 charging, the charger is in the car. J1772 ports are basically just fancy 110v or 220v AC plugs with some extra signalling. DC charging tends to happen at much higher power levels, and that equipment is expensive so the AC-DC converter is kept outsi…

Not by the general public. The general public typically refers to the EVSE itself as a "level 2 charger." The general public does not know or care about the distinction and in the grand scheme of things, it doesn't matter.

And yet the technical people need accurate names to call things so they can communicate without ambiguity.

I think "charging station" is the least confusing term for the fixed infrastructure part. If regular people call those "chargers" in non-technical conversation, then I'm not going to lose sleep over it.

Re: DIY Home EV Charger

#62

Post by folmar »

rcxdude wrote: post #20
wannacboatmovie wrote: post #17

Earlier quoted context omitted.

Fairly certain most DIY electrical work is strictly verboten in the UK, where the author is located. I would think at a minimum you need approval from the council. Not too dissimilar to the permitting process in the US, but the UK is noticeably more safety-obsessed.

Well, there's a pretty large fraction which is still fine to do full DIY. (but not EV chargers) The next level basically either requires some certification or to get the council to inspect it, but plenty of people just ignore that.

It seems things are pretty lax in the UK. Here in Poland you need a qualification certificate to replace a broken socket and a supervisors' certificate to move it half a meter.

Re: DIY Home EV Charger

#63

Post by sitharus »

mindslight wrote: post #31
tw04 wrote: post #27

Earlier quoted context omitted.

>I'm disappointed at the anti-DIY sentiments here, it's this safety obsessed mentality that got us to where kids can't walk outside by themselves any longer. Just no? That analogy is EXTREMELY strained. From his own link: A word about safety. I’m not an electrician. I’m not allowed to make alterations to my consumer unit. I let my kids play outside all the time solo and with friends without supervision. On the flip s…

> would nullify my homeowners insurance What is up with this common refrain? One of the main functions of insurance is to indemnify you against your own negligence. Let's say you turn a small stovetop fire into a house fire by trying to put it out with water - the insurance company doesn't just get to stiff you because you were responsible for causing the problem. Are there actually prevalent and enforceable weasel c…

I don't live in the US (in New Zealand), but this made me check my policies. I'm no longer a home owner but I checked my policy from a couple of years ago, and I checked the contents insurance I currently have (which has indemnity for the rented property as well).

An intentional or reckless act wouldn't be insured if it directly causes a loss, but anything else is. There's no exclusion for doing things that are illegal other than illegal substance manufacturing, and I'm pretty sure I didn't miss anything because the whole policy is 12 pages, including the cover and table of contents.

Electricity regulations wise, it's legal for me to do anything that plugs in to a socket. If I owned and occupied the property it's legal to do anything that doesn't require moving or adding a fixed cable to the consumer unit. Adding new fixed cable runs required a licensed electrician to sign them off before energising. It's illegal to do DIY electrical work on a property if it's let to anyone other than family, unless it's certified by a licensed electrician.

Re: DIY Home EV Charger

#64

Post by thatfrenchguy »

eigenvalue wrote: post #9

More like a DIY arson investigation. You might not only burn down your house, but also get in trouble with the law and not receive compensation from your property insurance company. This is a horrendous idea. Just do basically anything else DIY besides high current/voltage electronics.

240v is not high voltage come on, in most European countries you don't need a permit / can DIY yourself electrical circuits and they're all 240v. It's hard to burn down your house with electricity, breakers are pretty good at what they do.

Re: DIY Home EV Charger

#65

Post by drivebycomment »

dreamcompiler wrote: post #26
eigenvalue wrote: post #9

More like a DIY arson investigation. You might not only burn down your house, but also get in trouble with the law and not receive compensation from your property insurance company. This is a horrendous idea. Just do basically anything else DIY besides high current/voltage electronics.

Page is hugged to death right now but I strongly disagree with parent. I'm an EE and I'm quite familiar with the National Electric Code. I build high current/voltage devices and I've wired two houses (both of which passed inspection). If you're trained, experienced, and generally know what you're doing there's nothing wrong with working on high power electronics.

To be honest, I think the guy learned more than most electrical contractors actually know or care to check when it comes to the EVSE. I certainly would object if he is selling this or installing on other people's houses, but this looks actually acceptable for now. The longevity is a big question, since usually there's no easy way to check / test that with a singleton bespoke design/build, and that's sometimes what distinguishes the one-off vs mass manufactured stuff, albeit in both directions. Sometimes a bespoke design misses some subtle design choice and it breaks down sooner, but sometimes you can do a lot more careful handcrafting and "simple" over-engineering with a bespoke singleton to make things last even longer than mass produced stuff. I think the mechanical and the environmental aspects - condensation, thermal expansion, etc - are probably the biggest question mark here.

Re: DIY Home EV Charger

#66

Post by mindslight »

reanimus wrote: post #46
mindslight wrote: post #31

Earlier quoted context omitted.

> would nullify my homeowners insurance What is up with this common refrain? One of the main functions of insurance is to indemnify you against your own negligence. Let's say you turn a small stovetop fire into a house fire by trying to put it out with water - the insurance company doesn't just get to stiff you because you were responsible for causing the problem. Are there actually prevalent and enforceable weasel c…

Homeowner's insurance assumes you're doing your due diligence to not do things that unnecessarily destroy your home. Negligence is specifically not covered when it's something that you should have reasonably been able to prevent. There's a difference between a panic-induced response that makes an accidental fire worse and you making the explicit decision to install something unsafe.

I see the distinction you're making with my specific example, but I'm aware of no such distinction for the policies I've had. Are you referencing any concrete laws or contractual terms?

Also then, a different example: You plug in a non-NRTL-tested appliance from Amazon, and it burns down your house. Clearly outside the bounds of what is prudent, but also something many people commonly do. You're telling me that insurance is set up to stiff all of them, and yet we're not seeing endless news articles about that happening?

Re: DIY Home EV Charger

#67

Post by shiroiuma »

sowbug wrote: post #41
Kirby64 wrote: post #22

Earlier quoted context omitted.

TBH I’m less concerned about dangerousness… but the costs listed are so much, whereas commercial EVSEs are so cheap. You can buy a 40A 240V capable EVSE for like $200-300. The OP says they bought the cable for $120… why not just have the rest of it for a small additional cost?

It is surprising to see this question on HN. We regularly see Show HN projects that cost tens of thousands of dollars in time (assuming a typical software engineering hourly rate), but that aren't all that innovative compared to existing options. And we love those projects. Why would DIY effort outside the software domain be any different?

I don't think this is a valid comparison. In DIY projects, your time is free: you don't count your engineering hourly rate as part of the cost of building the thing. The only cost is the actual costs incurred, which is mainly parts and materials.

So a Show HN project that's purely software effectively is worth $0, because the creator made it in their free time, instead of spending that time playing video games or watching TV or whatever. And a Show HN project with a lot of software running on a RasPi effectively costs only what the RasPi cost the author.

Here, people are complaining about the actual hardware cost to the creator, not the creator's time spent, which you're also ignoring.

Re: DIY Home EV Charger

#68

Post by amluto »

jacquesm wrote: post #55
sowbug wrote: post #43

Earlier quoted context omitted.

I've hired enough licensed, bonded, certified, well-recommended, well-reviewed professionals who completely botched the jobs* to agree wholeheartedly with your sentiment. You can't hire someone without thoroughly understanding what they're doing, and once you reach that level of understanding, you absolutely can make an intelligent decision whether to buy or build. At the point where my house burns down, I really don…

If only it was just the tradespeople. I've had an electrical inspector argue that I should route the ground from my windmilltower into the house and bond it to the distribution panel rather than to ground the windmilltower at the base of the tower . So in case of lightning strike (which is pretty much a given) that would invite that lightning into your home right at the distribution panel. People may be following 'th…

I don’t know the whole setup, but the inspector is likely right. When you have a feeder to an outbuilding (or external structure or piece of equipment or subpanel or basically anything else), you supply it with the intentionally current-carrying wires and the ground. (Ground may be called “equipment grounding conductor” or “protective earth” or perhaps something else in your jurisdiction. It’s a wire or the metallic conduit you used.)

And this is important for lots of reasons. If there is a fault from a hot wire to a grounded object, this (if done correctly) allows the upstream overcurrent protection to trip. And it minimizes the voltage rise of the object that gets energized. And it keeps the line-to-ground voltage within spec. And using a separate ground means that the voltage of “ground” doesn’t get pulled up by resistance in the neutral wire and that current doesn’t normally flow through “ground”.

You should, of course, also connect the ground wire to Earth, well, at the base of the structure. And possibly also install something to help conduct lightning currents from the non-ground conductors to ground in the event of a lightning strike.

Re: DIY Home EV Charger

#69

Post by sokoloff »

hristov wrote: post #50
jtagen wrote: post #28

Given what's in this, why are EVSEs so expensive? Given the quantities we see, the $150 range should be more than enough for a decent profit.

I see $200 evse’s on amazon nowadays. Only 32 amps tho. As to why they are so expensive one has to keep in mind these are inherently dangerous so they do not buy the cheapest parts, they have to go through a longish federal approval process and the companies probably have higher insurance costs.

Could you say more about or provide links to this “federal approval process”? It’s the first I’ve heard of it for at-home level 2 EVSE units.

Re: DIY Home EV Charger

#70

Post by sokoloff »

dylan604 wrote: post #60
jtagen wrote: post #45

Earlier quoted context omitted.

I'm not sure I buy this. If someone can hack this together for $40 HDMI cables are an option (albeit a terrible one). For EVSEs, there really isn't a reasonably-priced alternative on the market right now.

Most people aren't going to DIY something like this. Also, most people think that the price of a product should only be based on the price of its components, and possibly willing to accept a mark up on labor. However, the companies making a thing, whatever that thing might be, also has to make money to be able to pay the people that work for the company, the utility bills, and the rent. There's also the fact that the…

In engineering university, I learned the “retail needs to be 5x the BoM* cost” rule of thumb. For a very high value or very high units product, maybe you could shave that to 4x or slightly less, but there are a lot of hands between the designed part and the retail consumer and none of them want to work for free.

* BoM - Bill of Materials (“what stuff goes into this thing?”)

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