TinyEVSE - $50 240V/30A L2 Charger

I made my own charger using a very basic MicroProcessor.

It's about 10 components and a very small 1sq" PCB board that uses the same PB-TR92 relay as many others. It all fits in a small aluminum inclosure with a 12v power supply. I've been using it to charge my Volt at home for a year now. The components to build the charger equipement is well under $50. The J1772 handle/cord are typically an additional $100.

Here's the site

Is there any interest in me making this open source or building it? $150 total with cords and NEMA plug.

-Bruce

I noticed you have no safety features whatsoever, and the failure mode for Triacs is ON. Also, if you do a 30A capable EVSE, you're going to have to dispense with at a minimum of 60 watts of heat from those Triacs, probably more like 120 watts, that's non-trivial!

-Phil

Ingineer said:

I noticed you have no safety features whatsoever, and the failure mode for Triacs is ON. Also, if you do a 30A capable EVSE, you're going to have to dispense with at a minimum of 60 watts of heat from those Triacs, probably more like 120 watts, that's non-trivial!

-Phil

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I haven't done SSR/TRIAC yet. The one I've been using is an enclosed mechanical relay. Obviously needs analysis and testing. It's still a work in progress. Just gauging interest.

A proper power triac will handle that no prob, but the through holes will not at all. they use a full sized spade pin and will have a solid metal heat spreader that the junction is bonded to for heavy heaat disipation.

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage. Sure it's $140 more than your idea but it's actually complete and safe.

QueenBee said:

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage. Sure it's $140 more than your idea but it's actually complete and safe.

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My other L2 charger is an OpenEVSE. It can be improved.

bruceme said:

QueenBee said:

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage. Sure it's $140 more than your idea but it's actually complete and safe.

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My other L2 charger is an OpenEVSE. It can be improved.

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After reviewing your proposal, your dismissal of the competence of OPENevse seems odd to me.

Why don't you spell out the misgivings you find in OPENevse, instead of taking a pot shot at it?

I'll get my popcorn.

I built the prototype J1772 compatible Level-2 (120 or 240v up to 30A) for $77.54 total! This same methodology could yield a commercially viable system for $40-50.

Great, simpler; sure how?
Uses the simplest controller, DigiSpark
Does only charging; doesn't check for wildly unusual conditions (stuck relay, GFI, power.
small electronic parts list; two transistors, 5 resistors and a diode
Built the J1772 Socket, commercial units come at "non-standard" cost ($130+)
Use commercially available electric parts (conduit, boxes, cord, etc)

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While you may think those conditions are "wildly unusual" you need them in a commercial (or just non-experimental) product. A lot of street lights are actually maintained/owned by the power company themselves, and they certainly would not cut required safety features for cost.

bruceme said:

QueenBee said:

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage. Sure it's $140 more than your idea but it's actually complete and safe.

Click to expand...

My other L2 charger is an OpenEVSE. It can be improved.

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Perhaps you should start with an offering that is an improvement not one that is a step above a cord and plug. Your premise is low cost and size but you have not made a proper EVSE. Once your development stage reaches an Open EVSE level it will no longer be as small as you propose or as cost effective. At this point you have not yet shown anything better and if you are intending to skip the use of relays you already have a non-starter.

Asking if there is interest on something primitive seems a bit silly, perhaps you should wait until you have a unit that is better, smaller, as safe, costs less and offers the same or better feature set. On the other hand if you are asking if anyone is interested in an unsafe cheap EVSE kit then you may get some answers.

PS- It is not a charger, that is in the car.

QueenBee said:

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage.

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That's not actually how open source works..
It would be like saying "I hope there isn't any interest in Nginx because we already have Apache."

More projects actually tend to help all the projects, as long as they are open.

If his project takes off great.
If not (or even if it does), maybe ideas from it will work into Open EVSE (or a fork of it for a smaller format EVSE).
Who knows?
But open source isn't afraid of competition, it encourages it.. ;-)

desiv

I would suggest making it open source and you will likely find a lot of interest with suggestions for improvement and hopefully contributions from others here. This forum, at least in the early days, has supported these efforts. In fact, OpenEVSE was born as a weekend project by Chris Howell. He is a great guy who has been known to be encouraging of new open source efforts but will, of course, insist on proper safety.

eHelmholtz said:

I would suggest making it open source and you will likely find a lot of interest with suggestions for improvement and hopefully contributions from others here. This forum, at least in the early days, has supported these efforts. In fact, OpenEVSE was born as a weekend project by Chris Howell. He is a great guy who has been known to be encouraging of new open source efforts but will, of course, insist on proper safety.

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I couldn't have said it better myself...

OpenEVSE is not perfect, but from day 1 our primary focus has been on safety. We went throigh 4 major revisions before the schematics were released to the public. I do support and encourage all open source efforts but required safety features can not be left out to save a buck or two.

I did not participare in SAE, UL and NEC standards but they are there for a reason. Each safety feature layers on top of the other to make the J1772 EVSE safe for the average person to use daily.

TonyWilliams said:

bruceme said:

QueenBee said:

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage. Sure it's $140 more than your idea but it's actually complete and safe.

Click to expand...

My other L2 charger is an OpenEVSE. It can be improved.

Click to expand...

After reviewing your proposal, your dismissal of the competence of OPENevse seems odd to me.

Why don't you spell out the misgivings you find in OPENevse, instead of taking a pot shot at it?

I'll get my popcorn.

Click to expand...

To be fair everything can be improved. It's clear though nothing about this EVSE is an improvement.

desiv said:

QueenBee said:

I hope there isn't any interest as there already exists an open source EVSE which has all the safety features included and is well past the under initial development stage.

Click to expand...

That's not actually how open source works..
It would be like saying "I hope there isn't any interest in Nginx because we already have Apache."

More projects actually tend to help all the projects, as long as they are open.

If his project takes off great.
If not (or even if it does), maybe ideas from it will work into Open EVSE (or a fork of it for a smaller format EVSE).
Who knows?
But open source isn't afraid of competition, it encourages it.. ;-)

desiv

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Certainly and there are a couple forks of OpenEVSE. Seems like the energy would be better spent improving OpenEVSE than reinventing the wheel but ending up with a square wheel.

QueenBee said:

Seems like the energy would be better spent improving OpenEVSE than reinventing the wheel but ending up with a square wheel.

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Assuming that the only possible result of reinventing the wheel would be a square shaped wheel, then probably. ;-)

Then again, a square shaped wheel moves nicely along a repeating V shaped road.

It's some of the outside-of-the-box thinking that makes open source great.
IMHO

desiv

desiv said:

QueenBee said:

Seems like the energy would be better spent improving OpenEVSE than reinventing the wheel but ending up with a square wheel.

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Then again, a square shaped wheel moves nicely along a repeating V shaped road.

desiv

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Wouldn't the road need to be more like a series of inverted catenaries in order for a square wheel to move smoothly? ;-)

Actually, and at the risk of going too far afield, I don't think there is a road shape (V or "in-v catenary") that would allow a square wheel to move smoothly (meaning the center of the square moves with constant speed and with no undulation). Does anyone think or know differently?

QueenBee said:

It's clear though nothing about this EVSE is an improvement.

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Is an e-Bike an improvement over a LEAF? It's much less safe, true, but it's also smaller, lighter, and cheaper. I think there's room in the market for a product like this, but I would still prefer the ability to plug in my car in the rain without fearing for my life. I'll pay extra for safety.

kubel said:

QueenBee said:

It's clear though nothing about this EVSE is an improvement.

Click to expand...

Is an e-Bike an improvement over a LEAF? It's much less safe, true, but it's also smaller, lighter, and cheaper. I think there's room in the market for a product like this, but I would still prefer the ability to plug in my car in the rain without fearing for my life. I'll pay extra for safety.

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No, it's a completely different mode of transportation. I really hope there isn't room in the market for products like this because electricity kills people and there just isn't a good reason to leave out basic safety features.

I feel like I am missing something. Is it me or is the OpenEVSE pretty dang tiny and light already? If I wanted to make a smaller, lighter, unsafe, and cheaper EVSE I'd take the OpenEVSE and remove all the safety features, and then shrink the circuit board. Bam! It's still not clear to me why I would want to do that.

But if I wanted to make a safe smaller EVSE I'd probably focus on shrinking the enclosure. I think all the OpenEVSEs I have seen have enclosures that allow large conductors and lots of room to work in. Something rectangular like the OP seems to indicate they used but I imagine their EVSE actually just lives in a shoe box. Then use smaller incoming and J1772 cordset wire gauges. Obviously would leave out the fuses and MOVs. I suspect a smaller GFCI Current transformer could be found. If it was only going to be used on 120 volt then could probably get away with only one relay. Spend some time optimizing the wire paths and the circuit board layout to minimize the space taken up by wires running around the enclosure. Obviously no LCD.

I'd love to see a $50 EVSE. But how could that be possible when J1772A cords are at least $100?

Bob

mbender said:

Wouldn't the road need to be more like a series of inverted catenaries in order for a square wheel to move smoothly? ;-)

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Precisely. See, e.g., http://mathmidway.org/math-midway-activities-pedal.php" onclick="window.open(this.href);return false;

Cheers, Wayne