chris1howell
Well-known member
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...
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.)
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.)