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DIY Home EV Charger

jamesfotherby.com

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Re: DIY Home EV Charger

#41

Post by sowbug »

Kirby64 wrote: post #22
greenthrow wrote: post #8

This is such a bad DIY project because the costs of screwing up can be burning your house down. This is non-trivial amounts of power. If you spend the money fot an EV, buy something safe and have it professionally installed. Keep the DIY projects to something less dangerous.

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?

Re: DIY Home EV Charger

#42

Post by sib »

balls187 wrote: post #32
newZWhoDis wrote: post #25

Earlier quoted context omitted.

Some of us here are actually Engineers (Electrical). I’ve installed 3x 240V 60A EV chargers, was a cakewalk. I didn’t build my own in this case since I was going for an aesthetic match. Meanwhile you can enjoy paying some alcoholic $1000 for 30 minutes of work to: * pop out a hole on the back * Tap and install 2x screws into studs * pull 3 wires 6” through, wrap around the strain relief, strip/insert/torque * flip a…

First, it’s a bit more complicated than that—unless you went ahead and installed a 60A line without checking if your service(s) can handle the additional load. Advice like this is what gets people to screw up. Second, what’s the material difference between a 40A circuit and a 60A circuit? A few extra hours overnight to charge?

Well, there are times when you're not charging overnight (e.g., get home with low battery, realize you only have 3 hours before next outing) and you get 50% more charging done in the same time, without having to go out to a Supercharger / DCFC.

Or, as in our case, we have two EVs - speed is useful sometimes.

Re: DIY Home EV Charger

#43

Post by sowbug »

newZWhoDis wrote: post #25
wannacboatmovie wrote: post #13

Earlier quoted context omitted.

Software engineers have a tendency to overestimate their own abilities, the arrogance is often on full display here for all to see. Maybe we need a few to burn their own houses down to act as a deterrent and encourage others to stay in their lane.

Some of us here are actually Engineers (Electrical). I’ve installed 3x 240V 60A EV chargers, was a cakewalk. I didn’t build my own in this case since I was going for an aesthetic match. Meanwhile you can enjoy paying some alcoholic $1000 for 30 minutes of work to: * pop out a hole on the back * Tap and install 2x screws into studs * pull 3 wires 6” through, wrap around the strain relief, strip/insert/torque * flip a…

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't care about the credentials of the person who made the mistake. Rather, I personally make sure my house doesn't burn down.

* Solar panels installed facing North in the Northern Hemisphere; rapid-shutdown switch installed inside a home; supply side of 240v connection to backyard office has male prongs; fence built with non-pressure-treated wood contacting the soil. The list goes on, and these are only the errors I've discovered in 20+ years of being a homeowner.

Re: DIY Home EV Charger

#44

Post by beej71 »

Comfy-Tinwork wrote: post #35
dreamcompiler wrote: post #26

Earlier quoted context omitted.

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.

Suppose you aren't trained, experienced or generally know about working with high voltage systems, like the author?

Then you learn you some, like the author.

Re: DIY Home EV Charger

#45

Post by jtagen »

sowbug wrote: post #37
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.

Supply and demand. See also $40 HDMI cables at Best Buy.

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.

Re: DIY Home EV Charger

#46

Post by reanimus »

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…

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.

Re: DIY Home EV Charger

#47

Post by KennyBlanken »

myself248 wrote: post #3

Save you a click: It's an EVSE, not a charger. Looks very similar to OpenEVSE but he wrote his own code. Nice clean build. Not sure why the extra work instead of just downloading OpenEVSE.

Everyone calls them chargers. If you said "do you like the EVSE you have?" or "do you know where the nearest EVSE is?" most people would stare at you with a blank expression.

Re: DIY Home EV Charger

#48

Post by beej71 »

foobarian wrote: post #12

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. The box in that guy's build is outside and could probably burn to a crisp without hurting anything else. I suspect it would not hurt anything even inside a garage, other than making a lot of smoke and setting off smoke detectors.

I'm also a little disappointed. Yes it can go wrong, but it sounds like the author has learned a lot and listens to criticism. And clearly embodies the hacker spirit.

And I have a large number of items that either came with my house or I purchased legitimately that could absolutely burn it to the ground. It's all measured risk.

When I get an EV, I'll be adding a consumer grade charger to the house. And then I'll trust, with zero actual knowledge, that it won't burn down my house, or that my car won't.

Re: DIY Home EV Charger

#49

Post by KennyBlanken »

elihu wrote: post #30
timthorn wrote: post #4

Earlier quoted context omitted.

I'd have called an EVSE a charger - I might be naive but what's the distinction you're trying to make?

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.

Re: DIY Home EV Charger

#50

Post by hristov »

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.
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