Open Source EVSEs- OpenEVSE vs. Juicebox

[chris1howell]

I have received many questions about differences between OpenEVSE and the EMW kickstarter campaign JuiceBox. It appears EMW has received the same questions as well. While a lot is still unknown about Juicebox as none of the source information is currently available some assumptions can be made base on the information provided in the campaign and features not mentioned.

While I support Open Source efforts and hope they succeed I do fear they are skipping critical safety features to save cost.

OpenEVSE was started on the premise of simplicity and safety, If it is required by NEC or SAE J1772 it was implemented.

Here is a quote from the Juicebox Kickstarter site on the comparison, it actually doesn't compare the two at all...

What is the difference between this and OpenEVSE?

Good question.

A couple of reasons for going with a completely different design:
1. We are reusing the platform that we have successfully worked with in our other products (e.g., our 12kW charging system, our motor control system, etc.)
2. We wanted it to be compatible with the existing Arduino shield ecosystem
3. We needed to optimize the design for manufacturability and would need to change the design substantially.
4. We needed more optionality in design in order to allow for $99 price point.

You can also expect a requisite level of support from EMW around the kits. Starting from the detailed manuals to EMW-moderated product forums. For example, check out our manual for the previous Open Source project - a 12kW EV charging system here: http://emotorwerks.com/VMcharger_V12P/EMW-12000_PFC-V12-Build_Notes.pdf" onclick="window.open(this.href);return false;.

Last updated: Tuesday Jul 9, 6:14pm EDT

The differences they list are actually similarities.

OpenEVSE is based on the Atmel 328p microprocessor the same as the Arduino Uno.

OpenEVSE is also compatible with Arduino shields, in fact you can build OpenEVSE as an Arduino shield https://code.google.com/p/open-evse/downloads/detail?name=OpenEVSE Arduino shield_th_v1.pdf&can=4&q=

It seems to reach a $99 price point they stripped critical safety features most notably GFCI. All OpenEVSE designs include GFCI.

So what are the differences:
All OpenEVSE sources are available schematics, board files, Bill of materials, documentation and they have been since October 2011 no source documentation is available at this time for Juicebox.
OpenEVSE started as the DIY EVSE weekend project in Febuary 2011, it is very stable and mature. Based on boards shipped and an estimate of those who built the DIY versions there are more than 500 OpenEVSE boards in the wild.
All OpenEVSE designs include GFCI (DIY series, Arduino shield, OpenEVSE plus)
OpenEVSE includes safety features like diode check, vent required state, stuck relay check, ground monitoring none of these are listed on the Juicebox site.
OpenEVSE is compatible with Wifi, Ethernet, Raspberry pi (wifi is a streach goal for Juicebox).
OpenEVSE supports any J1772 current from 6 - 80A. EMW is claiming 60A but it will be difficult/impossible for them to source quality 60A components and maintain a $99 price.

So what about the price?
None of the Kickstarter prices include the J1772 cable or AC cables, which is the most expensive part.

The Juicebox $109 kit is best compared to the OpenEVSE Arduino shield, the OpenEVSE shield does include GFCI while the Juice box basic does not.

Arduino Pro 5v Sparkfun $15
OpenEVSE Arduino shield board and components $25
40A Relay $13
GFCI coil $12
Enclosure and hardware $30
Total $95 (and you get GFCI)

The Juuicebox Premimum $219 adds GFCI and is comparable to the OpenEVSE Plus or the OpenEVSE DIY
OpenEVSE Plus $135
40A Relay $13
GFCI coil $12
Enclosure and hardware $30
Total $190 (and you get stuck relay detection, ground, diode check, etc.)

 

[valerun]

Hi Guys, EMW here.

Thanks Chris for a detailed comparison. Adding our few cents here:

1. Base units are designed to be pluggable, portable units. As such, they are assumed to be plugged into the GFI-protected outlets (as all garage outlets must be per latest code). Additional protection is redundant.

2. People do see certain benefit in having a one-stop shop for all the components they need to complete the builds - from the kits themselves to cables to wi-fi shields, etc.

3. Similarly, people do see certain benefit in the assembly service

4. Lastly, people do see certain benefit in the unique and attractive enclosure for the premium unit.

On the costs, I'll just say that there is a certain benefit in planning production at 1,000+ unit level.

Thanks again for your feedback.

Valery.

 

[wwhitney]

1. Base units are designed to be pluggable, portable units. As such, they are assumed to be plugged into the GFI-protected outlets (as all garage outlets must be per latest code). Additional protection is redundant.

I must disagree. The NEC requirement for GFCI protection on receptacles only applies to 125V, 15A and 20A receptacles. So you can not say the receptacle your JuiceBox will be plugged into is going to have GFCI protection.

If your JuiceBox does not incorporate GFCI protection, how do you propose to comply with NEC 625.22? It reads, to start, "Personnel Protection System. The electric vehicle supply equipment shall have a listed system of protection against electric shock of personnel."

Cheers, Wayne

 

[valerun]

Hi Guys, EMW here.

Thanks Chris for a detailed comparison. Adding our few cents here:

1. Base units are designed to be pluggable, portable units. As such, they are assumed to be plugged into the GFI-protected outlets (as all garage outlets must be per latest code). Additional protection is redundant.

2. People do see certain benefit in having a one-stop shop for all the components they need to complete the builds - from the kits themselves to cables to wi-fi shields, etc.

3. Similarly, people do see certain benefit in the assembly service

4. Lastly, people do see certain benefit in the unique and attractive enclosure for the premium unit.

On the costs, I'll just say that there is a certain benefit in planning production at 1,000+ unit level.

Thanks again for your feedback.

Valery.

Forgot #5. re Wi-Fi. JB will be compatible with WiFi just as open-evse is, even if we don't reach stretch goal. What we will do in stretch is build a service around it - with online profile / stats / login etc. getting hardware compatibility is 10-20% of the work there as you know.

 

[chris1howell]

Hi Guys, EMW here.

Thanks Chris for a detailed comparison. Adding our few cents here:

1. Base units are designed to be pluggable, portable units. As such, they are assumed to be plugged into the GFI-protected outlets (as all garage outlets must be per latest code). Additional protection is redundant.

2. People do see certain benefit in having a one-stop shop for all the components they need to complete the builds - from the kits themselves to cables to wi-fi shields, etc.

3. Similarly, people do see certain benefit in the assembly service

4. Lastly, people do see certain benefit in the unique and attractive enclosure for the premium unit.

On the costs, I'll just say that there is a certain benefit in planning production at 1,000+ unit level.

Thanks again for your feedback.

Valery.

I do also have to respectfully disagree, EVSEs are by their very nature safety devices and to strip out a core safety feature leaves you with a device that is more about circumvention of the standards than anything else.

There are several reasons EVSEs must have GFCI built in. Take a look at commercial offerings, every EVSE portable or hardwired includes GFCI, even the infamously horrible (and recalled) EV Charge America device incorporated GFCI.

You can't assume every outlet you encounter will have GFCI, especially in a portable plug unit. It has already been mentioned that your reference to mandatory GFCI only applies to 120v. My home was built in 2006 and none of the outlets in the garage have GFCI. I would also bet most of your supporters are wanting 240v charge stations as their vehicles came with a L1 unit so at 240v they will be without GFCI protection. If used with a plug (portable by definition) unit they could be vulnerable at 240v outdoors where the protection would be needed most. I would bet your supporters do not have the knowledge necessary to understand the risk they are accepting.

Also the sensitivity is different, standard residential GFCI is set to trip at a leakage current of 5ma, this is too sensitive for Electric vehicles the requirement for EV GFCI is 20ma. by depending on a outlet or breaker GFCI your customers may experience unreliable charging due to nuisance trips.

Please reconsider adding GFCI to the basic unit, you are welcome to use the OpenEVSE design. The circuit is simple but effective containing an Opamp and several resistors and capacitors. It will add less than $1, a single dollar to your cost. Even if you make the Current Transformer optional ($12) at least GFCI can be easily added.

I would also be careful if you plan to offer fully assembled units to the public. Your company could be taking on a ton of liability. With a commercial product of this nature independent safety certification (UL ETL etc) would be prudent.

 

[QueenBee]

Chris, thanks for taking the time to write up the concerns that I had with this. Maybe if they succeed in raising this money they'll consider giving everyone GFCI functionality.

It's too bad they aren't just building upon the OpenEVSE design.

 

[arnolddeleon]

FYI the Kickstarter was successful.

They did end up adding a GFCI option to their base kit in the Kickstarter project (additional cost). Their online store for preorders only has two flavors, a base and deluxe version and both have GFCI functionality. I backed the project at the deluxe kit level so that was not an issue for me.

I was at Silicon Valley EAA meeting where Valery talked about the project. They confirmed that the components will meet or exceed the specs for charging at 15kW. They apparently ended making design changes like moving all the current carrying conductors from traces to big wires.

arnold

 

[TonyWilliams]

I'd like to thank Chris for sticking his neck out to get the GFCI issue addressed, when he could have just looked the other way.

Also, to Valery for accepting the critiques and implementing them (even if he didn't publically acknowledge or thank Chris).

 

[chris1howell]

I'd like to thank Chris for sticking his neck out to get the GFCI issue addressed, when he could have just looked the other way.

Also, to Valery for accepting the critiques and implementing them (even if he didn't publically acknowledge or thank Chris).

Thanks Tony. I am also happy they added GFCI. I looking forward to seeing their source material. I can't for the life of me figure out how they can include 60a relays and meet a $99 price point. I am hoping they are not making the same mistake as EV Charge America with SSRs which led to a mandatory NHTSA recall. 60a SSRs are very cheep on ebay but they are not safe for use in a EVSE.

 

[TonyWilliams]

I'd like to thank Chris for sticking his neck out to get the GFCI issue addressed, when he could have just looked the other way.

Also, to Valery for accepting the critiques and implementing them (even if he didn't publically acknowledge or thank Chris).

Thanks Tony. I am also happy they added GFCI. I looking forward to seeing their source material. I can't for the life of me figure out how they can include 60a relays and meet a $99 price point. I am hoping they are not making the same mistake as EV Charge America with SSRs which led to a mandatory NHTSA recall. 60a SSRs are very cheep on ebay but they are not safe for use in a EVSE.

The fact that this is not specified leads me to believe you are right. Perhaps they are too far into the project financially to back out (by increasing cost per unit with a proper relay).

 

[arnolddeleon]

I recall that Valery saying they went to a 80A relay in the final design. This was in response to question about UL certification (which he answered by saying all the components are UL listed). He indicated that some kind of certification would be possible in the future and they had tried to make design meet that goal, he cited a flameproof enclosure as one the things they did to make it more likely they would succeed in future certification.

The post Kickstarter but still preorder price is now $139 (w/ GFCI) for a base model kit, $239 assembled. The premium kit is $249, $349 assembled. They also indicated that price will go up once they start shipping. I don't think the BOM cost differences between the base and deluxe kit $110. I also suspect assembly cost is not really $100. This leads to my guess that the base kit is designed to sell close to the BOM cost or possibly be a loss leader and the margins come in the higher end products.

arnold

 

[chris1howell]

I recall that Valery saying they went to a 80A relay in the final design. This was in response to question about UL certification (which he answered by saying all the components are UL listed).
arnold

80a SSRs are found cheap on ebay also but they are still not safe for EVSE use. We will have to see a picture, schematic, BOM or something to know for sure. But there is very little information avaliable at this point. Surprisingly little for an "open source" project that is about to ship.

All the parts are UL listed? I understand they are using an Arduino micro board (or clone) as the microprocessor, that's not UL listed and the Dostar cable they are selling is also not listed. A much better quality 30a (UL listed cable) is avaliable though Leviton its $175 with free shipping and you can get 10% off with coupon code thankyou. So it is also less expensive than the Dostar cable listed on the EMW site for $149 plus ~$40 shipping...

 

[chris1howell]

I recall that Valery saying they went to a 80A relay in the final design. This was in response to question about UL certification (which he answered by saying all the components are UL listed).

arnold

Based on the latest Juicebox update, it does look like they found an inexpensive 80a (UL listed??) mechanical relay. kudos to the juicebox team.

As more information gets posted we can do better comparisons of the two Open Source EVSEs. The Juice box team has states a number of reasons the went with "a completely different design"

The juice box looks like a carbon copy of OpenEVSE +- a pin here or there... They could have easily matched pin functions to maintained compatibility between the two.

Microprocessor
Juicebox
Atmel 328p-au via Arduino Pro Micro Module
OpenEVSE
Atmel 328p-au integrated in board design

Juicebox Wifi
Wifi RV171 WiFi module
OpenEVSE
Wifi RV171 WiFi module - tutorial found here http://code.google.com/p/open-evse/wiki/OpenEVSE_WiFi

Pin usage

Juicebox
D0 -RX for Wifi
OpenEVSE
D0 - RX for Wifi (FTDI pinout)
*hardware defined uart

D1 -TX for Wifi
OpenEVSE
D1 - TX for Wifi (FTDI pinout)
*hardware defined uart

Juicebox GFCI
D3 INT1
OpenEVSE GFCI
D2 INT0

Juicebox Relay
D5
OpenEVSE
D8

Juicebox Pilot
D9 (Timer 3)
OpenEVSE
D10 (Timer 3)

Juicebox Pilot read
A0
OpenEVSE
A1

Juicebox RTC
A4 and A5 i2c
OpenEVSE
A4 and A5 i2c

 

[chris1howell]

It's too bad they aren't just building upon the OpenEVSE design.

Yeah I agree, the juice box is almost a carbon copy. It would have been nice if they contributed to the already established community.

There is no reason they could not have based Juicebox on OpenEVSE. The OpenEVSE licenses allows commercial use with attribution.

Software License GNU GPLv3 http://www.gnu.org/licenses/gpl.html
Hardware and documentation Creative Commons v3 BY-SA http://creativecommons.org/licenses/by-sa/3.0/

I am not sure what license EMW Juice box will use. Their other "Open Source" product the 12kw Charger does not seem to actually be "open source" at all. The model is source is available only with purchase and only if it is not for commercial use. I hope Juicebox product is different or they are just using "Open Source" as a marketing term...

Open Source as defined by the Open Source Initiative has guidelines based Debian Free Software Guidelines which are:
1.Free redistribution.
2.Inclusion of source code.
3.Allowing for modifications and derived works.
4.Integrity of the author's source code (as a compromise).
5.No discrimination against persons or groups.
6.No discrimination against fields of endeavor, like commercial use.
7.The license needs to apply to all to whom the program is redistributed.

from their website:

open-source (for non-commercial use only)

If you have bought a kit from us, you will be provided a special link to access all the technical information on the charger & kits. Contact us at [email protected] email address is being protected from spambots. You need JavaScript enabled to view it. if you have not received this documentation with your package

 

[valerun]

It's too bad they aren't just building upon the OpenEVSE design.

Yeah I agree, the juice box is almost a carbon copy. It would have been nice if they contributed to the already established community.

There is no reason they could not have based Juicebox on OpenEVSE. The OpenEVSE licenses allows commercial use with attribution.

Software License GNU GPLv3 http://www.gnu.org/licenses/gpl.html
Hardware and documentation Creative Commons v3 BY-SA http://creativecommons.org/licenses/by-sa/3.0/

I am not sure what license EMW Juice box will use. Their other "Open Source" product the 12kw Charger does not seem to actually be "open source" at all. The model is source is available only with purchase and only if it is not for commercial use. I hope Juicebox product is different or they are just using "Open Source" as a marketing term...

Open Source as defined by the Open Source Initiative has guidelines based Debian Free Software Guidelines which are:
1.Free redistribution.
2.Inclusion of source code.
3.Allowing for modifications and derived works.
4.Integrity of the author's source code (as a compromise).
5.No discrimination against persons or groups.
6.No discrimination against fields of endeavor, like commercial use.
7.The license needs to apply to all to whom the program is redistributed.

from their website:

open-source (for non-commercial use only)

If you have bought a kit from us, you will be provided a special link to access all the technical information on the charger & kits. Contact us at [email protected] email address is being protected from spambots. You need JavaScript enabled to view it. if you have not received this documentation with your package

Good points, Chris.

We are moving all our open source projects into GPL license domain. JuiceBox will be the same, as well.

We are going to start posting the files next week.

Technically, we probably could have forked from the Open-EVSE. But a part of why we didn't was that we are planning to have a number of [potentially] closed-source derivatives for commercial use once we get this thing certified and start going after commercial networks. Just makes it easier that way.

In retrospect, we should probably have thought a bit more about pin compatibility, yes.

In fact, we'd be thrilled if we can get Open-EVSE working on our hardware at some point. This way the community could benefit from the amount of energy we've put into the component sourcing, enclosure design, etc. Perhaps we should chat about this once we put this project on production rails (which should be later this month).

Thanks,
Valery