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DIY Home EV Charger

jamesfotherby.com

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Re: DIY Home EV Charger

#171

Post by MostlyStable »

bigfudge wrote: post #125
myself248 wrote: post #116

Earlier quoted context omitted.

OpenEVSE can be a codebase or a kit. If you want to source all your own parts, or maybe reuse significant parts of a non-open EVSE and just drop the processor into it or whatever, then it can be very cheap indeed. If you buy their branded kit, then full price applies. When OpenEVSE was new, I built one on perfboard, actually a very compact modular stack of perfboards, one layer per subsystem. Handed it off to my soft…

What I don’t understand is what the motivation for manufacturers to not just install the open software is… are they trying to harvest charge time data or something? It seems like it would be easier to change any logos in software but leave the rest as is. Non tech buyers wouldn’t know or care… and nerds would buy it in droves. This goes for a lot of the low end network gear too. Are they really adding much value in s…

They must believe that there is, regardless of whether or not their _actually_ is. Manufacturers killing local control that is only used by extremely small numbers of their users is a pattern [0]. The only potential good reason I can think of is if the existence of these abilities allows users to get themselves into trouble when they don't fully know what they are doing, which could create a great deal of (expensive) support and so they decide to just remove the headache

[0]https://www.theverge.com/23949612/chamberlain-myq-smart-gara...

Re: DIY Home EV Charger

#172

Post by marcosdumay »

amluto wrote: post #167
marcosdumay wrote: post #159

Earlier quoted context omitted.

They conduct electricity. Thus if you have a leak from one conductor somewhere in your house (that without ground fault protection goes undetected almost every case) and gets a different one from a different wire, you now have a constant-on heater passing through God knows where, ready to start fires. A single leak also gives you a minor risk of electrocution. But the fire hazard is the important one.

This is possible with nonmetallic conduit, too, as well as with NM-B. At least metallic conduit has a decent chance of containing the resulting mess inside the conduit. The right solution is ground and arc fault protection, both of which are available, and one of which is increasingly required in the US.

You seem to be thinking about short circuits. That's not what my post is about. (Anyway, plastic conduits are quite capable of containing the mess.)

And yes, they are way less dangerous if you have ground fault protection. To the point that I'm not sure it's still important to ban them. But they don't have any upside either.

Re: DIY Home EV Charger

#173

Post by amluto »

marcosdumay wrote: post #172
amluto wrote: post #167

Earlier quoted context omitted.

This is possible with nonmetallic conduit, too, as well as with NM-B. At least metallic conduit has a decent chance of containing the resulting mess inside the conduit. The right solution is ground and arc fault protection, both of which are available, and one of which is increasingly required in the US.

You seem to be thinking about short circuits. That's not what my post is about. (Anyway, plastic conduits are quite capable of containing the mess.) And yes, they are way less dangerous if you have ground fault protection. To the point that I'm not sure it's still important to ban them. But they don't have any upside either.

I think metal conduits are most useful in more industrial-ish spaces where they're exposed -- they're quite resistant to getting banged up. Schedule 80 PVC works, too, but it's harder to work with than steel (at least for an electrician with the right tools).

Re: DIY Home EV Charger

#174

Post by BluePen7 »

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.

The Tesla official one is $230.

All you need then is a breaker, dryer outlet, and some thick gauge wire between the two.

Re: DIY Home EV Charger

#175

Post by repiret »

balls187 wrote: post #164
repiret wrote: post #106

Earlier quoted context omitted.

I know a few electricians, and none of them would agree with you. There's some things that can't be done safely on a live panel, but there are some things that can.

It's very hard to imagine any electrician advising a DIY homeowner to install a 240v line on a live panel. It's not difficult to do, which was GP's original point--though you need to take safety precautions (in addition to researching local code requirements).

My point is that electricians work in live panels all the time. (And the voltage of the circuit being installed does t matter. No matter what you install, the panel has 240V with approximately zero output impedance.

I don’t know what advice an electrician would give, but the advice I give is that if you don’t feel like you can safely install a new circuit on a live panel, you probably just shouldn’t install new circuits.

Re: DIY Home EV Charger

#176

Post by sokoloff »

StillBored wrote: post #163
sokoloff wrote: post #14

Earlier quoted context omitted.

He says he installed a 50A OCPD, which is the same overcurrent protection an electrician would install and used relays from TE Connectivity (a respected brand) rated at 125% of the current the EVSE advertises as available. Both of those decisions seem perfectly sane/safe to me.

Are you an EE with a specialty in power electronics? Cause that seems insane to me, inductive loads will cause a voltage spike (flyback) when disconnected, which will exceed that easily. That is why there is generally a reverse diode across the contacts, which I didn't see in the diagram. Granted the article notes it appears to be largely a resistive load, but I would want data sheets on the car/charging requirements…

No, but I'm a mechanical engineer who's taken a subset of my uni's EE curriculum, done a fair amount of hobby electronics, read a lot about the SAE J1772 charging standard that applies here, and disassembled two commercial EVSEs (all in contemplation of building my own EVSE, which I haven't pulled the trigger on yet).

It turns out that the engineers who designed J1772 thought a fair amount about how to handle the connect/disconnect concerns that you raise (via the pilot signals and proximity microswitch) and they didn't just leave it to EVSE designers to YOLO it.

> I would want data sheets on the car/charging requirements, not measurements, to ensure this is true 100% of the time

The "datasheet" that you want is the J1772 standard. There are many free summaries of it, including https://openev.freshdesk.com/support/solutions/articles/6000... Scroll all the way to the bottom and read the section on "Proximity" to understand how the relays are not disconnected while large currents are flowing.

Re: DIY Home EV Charger

#177

Post by rockooooo »

jesterson wrote: post #112
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…

> I’m not an electrician. I’m not allowed to make alterations to my consumer unit. It's funny how we reach a society where you need government as a babysitter and tell what you can do and whatnot. > Would I mess around with attaching something at 240v that I made from scratch that could burn my house down and kill my family It's also funny how those people readily plug in any consumer device they buy on amazon, which…

> It's funny how we reach a society where you need government as a babysitter and tell what you can do and whatnot.

every code regulation is written is blood. the inconvenience is designed to prevent people burning their house down or worse.

Re: DIY Home EV Charger

#178

Post by nsteel »

gambiting wrote: post #147
nsteel wrote: post #144

Earlier quoted context omitted.

I used a granny charger for the first 3 weeks after getting my EV. I don't use the car that much but even so, the painfully slow charging made it a hassle. And also remember, if you want access to cheap electricity, you need to use a "real" EVSE. This DIY one can't provide access to that either.

>>And also remember, if you want access to cheap electricity, you need to use a "real" EVSE. Why? I was on Octopus Go for a long time, I'd just set the in-car timer to charge between 00:30 and 04:30, worked fine even with a 3-pin charger. It won't work with Intelligent Octopus, but it's by no means the only way to get cheap electricity. Not that it matters anyway, I kept a detailed log of our usage for months and con…

You are right, sorry. I forgot there's the non-intelligent version. Although you can't put in much in just 4 (I think?) hours with a granny on Go.

Intelligent Go is saving me a lot. But the peak rate where I am (I believe it varies by region) is only a few pence more than the cap. And I'm trying to use washing machine etc only off-peak where possible. My bill is now less compared to before I had the EV.

Re: DIY Home EV Charger

#179

Post by Comfy-Tinwork »

beej71 wrote: post #44
Comfy-Tinwork wrote: post #35

Earlier quoted context omitted.

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.

Same way I learned to drive actually, behind the wheel of an 18 wheeler going down the freeway in the snow.

Re: DIY Home EV Charger

#180

Post by jseutter »

Symbiote wrote: post #135
dbrgn wrote: post #132

Earlier quoted context omitted.

I talked to the electrician about using a CEE16 connector to charge the car. He said that this should only be done if you don't load it near its max (16A) for long periods of time. He's seen multiple CEE16 connectors that deformed condsiderably after a year of use with regular charging sessions at 16A. If you load it to 10-12A, it should be fine.

I have servers and UPSs and so on connected with these sockets, drawing a high current 24/7. Just like every datacentre in Europe, UK included. They are only very rarely unplugged though. Is it a case of using a high quality socket which costs 2-3 times as much?

Not the person you're asking, but it might also be where it is installed. The connector I looked up online is rated to +40C, and being located in direct sunlight on a hot day could derate the connector compared to a temperature controlled environment. Add in some dirt or corrosion in the connector and it will generate more heat. Like you said about buying a high quality connector, something with more margin in terms of current will help prevent problems from developing.

The electrician may have been referring to the 16 amp connector specifically being too close to the charging current.

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