Portable 120/240 Autodetecting Charger $700

[jwallace3]

Once again, thanks for the feedback guys and gals. It's good to have a community of smart minds all over the country to share what they would like to see in the next generation of ESVE.

 

[jwallace3]

Just FYI for all the contributors to the conversation. Just got a call from a University of Louisville professor and his EE grad students. He is an engineer from GE who used to design motor controllers and control panel electronics for consumer products. He now is working with Grad students on ESVE smart grid integration. He was involved with parts of the ESVE product design discussions. He is one of my former professors and wants to discuss product application as well as smart grid integration. Things could get interesting in the coming months.

 

[smkettner]

I would still work on a basic evse to get something in the market. Smart grid stuff should not hold up a viable product. Plan to add it on later.

Who's benefit is the smart grid stuff? I think that benefits the electric company so the consumer might be less interested until the utility offers an incentive to use the technology. This is really selling to the utility and could be years away at best due to regulatory approvals etc.

 

[jwallace3]

I would still work on a basic evse to get something in the market. Smart grid stuff should not hold up a viable product. Plan to add it on later.

Who's benefit is the smart grid stuff? I think that benefits the electric company so the consumer might be less interested until the utility offers an incentive to use the technology. This is really selling to the utility and could be years away at best due to regulatory approvals etc.

Yes...Yes. We are going to continue with the simpler ESVE design. He will offer assistance with testing, design, etc. The smart grid integration is more of a "being a better consumer" item. I am a power systems guy so having mobile "loads" that have the demand of a house is a problem we've been worried about. If people start pulling 30-50 amps at any given location at any given time distribution fuses could shoot, transformers blow, brown out episodes, and the list goes on. So this is a problem from our professional standpoint that we want to take on during our working hours. I've heard presentation after presentation of how EVs will never take off because they will kill the power grid as it sets. This is a major problem that has to be addressed and he is already doing work with his grad students in this area. They have 14 GE chargers on campus that are integrated with the local AMI system studying charging patterns and trying to help shave peak load by automating the charging to postpone during those peak load times. This will be an ongoing thing to help develop a "friendly" product for the power grid. In the interim the simpler design will be the main focus.

Thanks for the input!

 

[TonyWilliams]

We are investigating our own portable "fast" charger as well. Wouldn't be the same rate as the one's on the road, but more in the 1-2 hour range using the chademo currently on vehicles like the LEAF, but I think we will wait until the J1772 for L3 is finalized before we jump fully into L3. Some preliminary work will be done in the mean time. At 2 hours it wouldn't be as hard on your battery and could be more affordable, but its all still up in the air at this point.

There's definitely a market for a 20-25kW portable DC charger that can work on 208 or 240 mono phase. Mine is not quite that portable, as it is capable of 50kW, and can take AC, DC, a combination of both, and virtually any voltage and phase you can dream up.

All you need are some big cables in the alley behind a big power user, and your sucking it down fast!!

 

[smkettner]

They have 14 GE chargers on campus that are integrated with the local AMI system studying charging patterns and trying to help shave peak load by automating the charging to postpone during those peak load times. This will be an ongoing thing to help develop a "friendly" product for the power grid. In the interim the simpler design will be the main focus.

Thanks for the input!

I think it would benefit all to consider slowing the charge as a stage 1 and postpone for a stage 2. I do believe the evse can change the amp signal on the fly while charging. I think I read it can be as low as 6 amps. Maybe lower?

The Levition 120 L1 evse has a button for 7a or 12a for example.

For commercial use it would might help to have 20 or more 30 amp evses on a single 100a feeder that could throttle back power to share the load if needed and not need a 600 amp feed.

 

[jwallace3]

It's going very well, my project has been open sourced as "OpenEVSE".

OpenEVSE is mature and fully supports the J1772 spec. It is currently in use by drivers of the LEAF, VOLT, i-MiEV and PiP.

OpenEVSE implements the pilot with diode check with a 1w DC-DC converter (MicropowerDirect D107E), 5V in and +12 and -12 out. A LF353 opamp is powered by -12/+12 and is controlled by the microprocessor. The Microprocesser reads the pilot to perform the diode check and read the state.

Source code and Schematics are at the OpenEVSE site... http://code.google.com/p/open-evse/

That's great Chris! I checked it out. We chose very similar and in many cases the same parts. I'm using the same optocouplers for 120/240 detection and ground path monitoring. I'm using a CR magnetics CT for GFI, but a cheaper model. Power supply is similar 89-259 AC input/12 out @3W. The one I'm using is a different manufacturer and runs about $14.00. Not sure what the one you are using is going for. And for my negative rail (which hasn't been implemented yet) we chose a charge pump IC which runs about $0.90. All in all very similar in design. Our GFI detection circuit is implemented completely different, but I do like your design. The students chose an Arduino as well just because the freescale MC9S12 series is very small and difficult to surface mount with our PCB equipment.

All in all I like the design. It's cool you open sourced it. Hope the progress continues.

 

[davewill]

... There are other 50 amp twist lock connectors that we could use to connect the RV style plug to the charger, but they are super high, so every other pigtail would be super high as well, just because of the plug cost on the ESVE end. At $100-$150 a pigtail that becomes cost prohibitive, but I do see you're point.

Thanks for the input. We will put this on the table and see if we can come up with a competitive option for this.

At the very least, I think you should consider being able to dial the power up when installed permanently. In that instance, the installer can connect it with either by hard-wiring or with a non-locking connector like a 6-50. That would put you as the price leader amongst the wall mount EVSE choices.

 

[srl99]

(OK, I have a REAL problem with SPX - because I have ZERO tolerance for electrical manufacturers who lie in their spec's.) - The SPX may "go to 11", but the actual max current is 24A. Further, it has some major compatibility issues, for example - won't charge a Honda Fit-EV at any current setting.

You price is competitive, but with plenty of competition for a very small market. The SPX has a selectable amp rating (up to 32 amps) and is portable... but with not so good reputation for build quality and durability.

You might want to check that one out for competition.