JuiceBox

I don't know how many i3 owners use a JuiceBox EVSE, but because this EVSE and its firmware is owner-modifiable, I decided to start a thread that would allow i3 JuiceBox owners to discuss JuiceBox issues in own own forum. Unfortunately, there doesn't appear to be a forum anywhere dedicated to the JuiceBox, so JuiceBox threads in various EV forums have been started which isn't ideal. But I don't want to join the Leaf, Tesla, and various other EV forums just to discuss JuiceBox issues.

In response to http://www.mybmwi3.com/forum/viewtopic.php?p=18932#p18932:

Pentacat said:

I also have a JuiceBox that works great with my US BEV i3. I bought the pre-configured "base" unit via Amazon and used it for about three weeks with no issues. I decided that I really wanted to add the premium features so I ordered and installed the OLED screen, RF Remote control and the WiFi module. It's effectively a "premium" version now.

Click to expand...

Sounds like my JuiceBox except that I did not order the WiFi module because my JuiceBox is and will probably always be far outside of the range of my WiFi base station. My JuiceBox is in our apartment's parking garage which is a couple of floors below our apartment and ~180 feet away.

Pentacat said:

I would say that the JuiceBox is a great Level 2 charger in it's base configuration but the "premium" features really make it an amazing unit.

Click to expand...

I agree! As a retired Apple software engineer, I was attracted to JuiceBox's open source firmware written in C, so I also ordered the programming interface so that I could load new firmware as it's released and even customize the firmware for my own needs.

Pentacat said:

The added display makes it possible to see in real time the amperage draw, voltage and kwh rate that your car is charging at.

Click to expand...

Currently, the voltage is measured only once when the JuiceBox is first powered on; i.e., the voltage displayed isn't real-time, so it doesn't show any voltage sag that would likely occur at higher amperages. The voltage measured very shortly after power is turned on isn't very representative of the steady-state voltage, so this usually inaccurate voltage is used for kW and kWh calculations which are therefore not accurate. I have discussed this with Electric Motor Werks who agree that the voltage needs to be measured repeatedly as the current is. I would modify the firmware to do this, but there is a warning in the code that states that the voltage should only be measured once. I can't see why this should be, but I don't want to do anything that might harm the hardware or negatively affect the operation of the JuiceBox.

The measured current displayed might not be accurate, either, which, on my JuiceBox, is always 1-2 amps less than the set current. When a Tesla Model S was charging with my JuiceBox, the charging current displayed on the Model S's LCD agreed with my set current, not with my measured current. In the firmware header:

TODOs:
* [P0] calibrate current measurements in the lab

so current measurements might be improved in future firmware versions.

Pentacat said:

I might start a separate thread to start discussing the data that I'm now seeing from the JuiceBox's WiFi.

Click to expand...

Good idea! I've been disappointed that eMotorWerks hasn't hosted a forum where JuiceBox owners can discuss JuiceBox issues, modifications, etc. There are small JuiceBox threads in various EV forums, but I don't want to join the Leaf, Tesla, etc., forums just to post in JuiceBox threads.

Pentacat said:

Another thing, it looks like Electric Motor Works is either experiencing some parts shortages or they have decided to only sell completed units. The options to buy the "DIY" kit with self assembly (either the base or premium) seem to have disappeared in the last few weeks. It looks like some of the "premium" additional parts are no longer listed separately on their web page as well.

Click to expand...

I had noticed that kits were no longer being offered, but I hadn't noticed that premium parts were no longer listed. I know that Electric Motor Werks is trying to get UL approval for the JuiceBox which might not be available for a kit. Also, they're a very small company that might be having problems keeping up with orders, so they might have decided to reduce the number of things that they sell so that they can concentrate on assembled JuiceBox sales. I am happy that I was able to buy the kit version because assembling it helped me understand how it works and how I might modify it.

According to its manufacturer, Electric Motor Werks, a JuiceBox consumes about 10 w. of power while in standby mode. Some of this power is consumed by the OLED display which is always on. Some of this power is consumed by the CPU which executes the firmware continuously while in standby mode even though the firmware is doing nothing important. I would like to reduce this vampire drain considerably.

Turning off the display would be the most obvious first step. Not only would this reduce the vampire drain, but it would prevent display burn-in and other degradation that can occur when a display is always on with almost the same pixels illuminated continuously. The firmware could turn off the display after a certain inactivity period, but I don't know how it could be turned on again. I would think that the firmware could be put into a sleep mode from which it could be awakened by a hardware interrupt that would occur, for example, when the user pushes a button on the remote or plugs in the J1772 connector. Upon awakening, the firmware could turn on the display and resume firmware execution.

I plan to ask Electric Motor Werks about this. If you have any suggestions or ideas, please post them.

Mine is scheduled to be delivered this Monday 1/5/2015.
After delivery I have plans to mount a curb side extension for on street city charging.

I do not know if the signal sent from the EVSE is monitored by the car continuously, or if it takes a snapshot at the beginning of the cycle to determine what the power capacity of the unit is. If the voltage changed significantly over time and load, that would affect the overall current available and maybe disrupt the operations.

While the unit itself seems fine, the lack of a UL listing is a big red flag, and technically, could give you issues should it fail in some manner and cause damages to something. Your insurance could be impacted on the house and the vehicle. Slim chance, but it's still easily avoided with another unit. Before they stopped being around, I did enjoy building a lot of Heathkits, and am not intimidated by building something, the lack of UL certification made me choose something else.

alohart said:

I plan to ask Electric Motor Werks about this. If you have any suggestions or ideas, please post them.

Click to expand...

Here is the suggestion I sent to Electric Moto Werks:

I think you have a lot of potential, but the current approach is very hardware oriented and addresses the “hobbyist” market. EVs are going mainstream, the hobbyist market phase has ended. The UI of the “premium” JuiceBox looks like it was created in the 1990’s; it’s awful in 2015. It’s fine for hobbyists, but it won’t go mainstream. In 1990’s jargon, you need to “cross the chasm”. This is an unsolicited product management suggestion.

Discontinue the “Premium” version of the hardware, eliminate the kit offerings entirely and close your servers.

Put the control of all the “premium” features in software and provide access from mobile phone apps and/or a browser. This includes the ability to download charge history data (it could then be forwarded to a desktop/laptop for further analysis if desired). The cost of the wifi chip and a some non-volatile memory is the only real necessary hardware difference between “basic” and “premium” units offered today. The cost of those is negligible when compared with the cost of stocking parts and managing the builds of two different hardware units. Build one unit and get it UL approved. Customers who want the “premium” features can buy them at any time on your web site and you can then send a signal to the EVSE to enable the features purchased.

These changes in your approach to the business would have these benefits:

- reduce hardware engineering cost (it will just be a black box on the garage wall)
- reduce manufacturing cost (you can focus on minimizing the build cost of a single box)
- reduce parts, WIP and finished goods inventory cost
- you can offer a few variants on the basic unit, but the variations are just cables and connectors, the core box is identical
- eliminate the need and expense for maintaining your own servers to host customer data (even if they are hosted at Amazon or somewhere else) and the attendant privacy problems when it is eventually hacked. You will probably still need a firmware upgrade server, but it will not host any customer data, just the ability to push out updates. Hosting customer data (unless you’re planning to sell it) is a liability with no benefit to you or the customer.
- potential for various levels of “premium” product, each an incremental sale opportunity, for features that are not even envisioned today
- far superior UI on a mobile phone or web app when compared to the current premium product
- enables a lower “entry level” hardware product price and makes you price competitive with the “dumb” EVSE’s, while offering the ability to add features later. You could even price the entry level unit to undercut the pricing of the “dumb” EVSEs enabling you to buy market share knowing most customers will eventually buy more features (aka “razors and blades”) which are essentially pure profit.

The “smart” EVSE market is up for grabs and will be defined by reliable, easy to install hardware, and feature rich software.

I currently own a BWM i3 and since I’m remodeling my house I have only a 110v outlet in a rented condo from which to charge. This spring I’ll decide which EVSE to install in my “new” house. I hope that the JuiceBox will be a viable option.

alohart said:

Sounds like my JuiceBox except that I did not order the WiFi module because my JuiceBox is and will probably always be far outside of the range of my WiFi base station. My JuiceBox is in our apartment's parking garage which is a couple of floors below our apartment and ~180 feet away.

Click to expand...

The latest WiFi add-on includes an external antenna that appears to be a 6dbi model with an SMA connector. I had to drill a small hole in my JuiceBox to mount and connect it to the WiFi module. I'll have to find a way to measure the signal strength but my AP is about 100 ft away (minimal obstructions though, only residential drywall partitions) and connects with no issues.

If I do any code modifications this would be where I would start. EVM's documentation is a little thin on the WiFi operation, they fail to mention that you can initiate a WPS request via the remote control/OLED display which makes the solder on WPS button included with the WiFi module redundant. I'm not sure why anyone would want to have to unscrew the casing every time they wanted to intiate WPS, especially considering the unit is powered on. That's all you can do regarding WiFi via the remote/OLED and it would be nice to at least get a connected SSID listing or some IP address details added to the information menu. I'm looking into some firmware mods to that end but I have a serious lack of free time at the moment.

alohart said:

I agree! As a retired Apple software engineer, I was attracted to JuiceBox's open source firmware written in C, so I also ordered the programming interface so that I could load new firmware as it's released and even customize the firmware for my own needs.

Click to expand...

I've got the FTDI interface and was able to add the WiFi code and do the upgrade to the latest firmware. Fairly straight forward but my coding skills are way rusty so that's as adventurous as I've gotten so far. I was considering buying another logic board from EVM for prototyping but instead I'm just going to by an Arduino Uno lab kit ans start hacking away with that first. I might try a Bluetooth FTDI interface like this: https://www.sparkfun.com/products/12576]

That way I connect to the JuiceBox via bluetooth from my MacBook and do firmware loads without having to crack open the case. Also having the FTDI connected to the JuiceBox board can cause some odd behavior since it fights with the off board power supply to power the Arduino CPU.

alohart said:

I had noticed that kits were no longer being offered, but I hadn't noticed that premium parts were no longer listed. I know that Electric Motor Werks is trying to get UL approval for the JuiceBox which might not be available for a kit. Also, they're a very small company that might be having problems keeping up with orders, so they might have decided to reduce the number of things that they sell so that they can concentrate on assembled JuiceBox sales. I am happy that I was able to buy the kit version because assembling it helped me understand how it works and how I might modify it.

Click to expand...

I think they are also a bit swamped by the PEV pilot program they are involved with, something like 500 pilot users can qualify to get a free or subsidized JuiceBox.

jadnashuanh said:

While the unit itself seems fine, the lack of a UL listing is a big red flag, and technically, could give you issues should it fail in some manner and cause damages to something. Your insurance could be impacted on the house and the vehicle. Slim chance, but it's still easily avoided with another unit. Before they stopped being around, I did enjoy building a lot of Heathkits, and am not intimidated by building something, the lack of UL certification made me choose something else.

Click to expand...

I also enjoyed building Heathkits, but were they UL-approved? I doubt that any kit could by UL-approved due to the possibility of the assembler making a dangerous mistake. Assuming that Heathkits were not UL-approved, you were apparently comfortable with Healthkits in your home but are not comfortable with a JuiceBox in your garage! My nice Heathkit quadraphonic receiver caught fire after an EMF pulse from a nearby lightning strike damaged a power transistor allowing too much current to flow to other parts of a circuit board. The electronics in my JuiceBox are enclosed in a waterproof cast aluminum case, so I'm less worried about a JuiceBox fire than I should have been about a Heathkit fire.

I'm willing to risk the potential JuiceBox liability in order to have a programmable, customizable, updatable EVSE, but I understand that not everyone is.

Boatguy said:

Put the control of all the “premium” features in software and provide access from mobile phone apps and/or a browser.

Click to expand...

If your suggestion is followed, I and many others whose EVSE's are not within WiFi range or who don't want to leave their EVSE's powered continuously would not be able to enjoy the premium features of the current JuiceBox. Your suggestions would be nice for those whose EVSE's are nodes on their WiFi networks, but such a design would be unnecessarily expensive for those of us whose EVSE's are out of range of our WiFi base stations (e.g., most apartment dwellers whose parking spaces are not adjacent to their apartments).

Maybe there should be two JuiceBox versions: a base version without a WiFi transceiver and a premium version with a WiFi transceiver. The premium version would be controlled by a mobile phone app or Web browser and wouldn't have an OLED display. The base version would include an OLED display and remote for control like current versions.

Different strokes for different folks…

Pentacat said:

I might try a Bluetooth FTDI interface like this: https://www.sparkfun.com/products/12576]

That way I connect to the JuiceBox via bluetooth from my MacBook and do firmware loads without having to crack open the case. Also having the FTDI connected to the JuiceBox board can cause some odd behavior since it fights with the off board power supply to power the Arduino CPU.

Click to expand...

That would be nice! I suppose a menu item could be added that would allow one to turn Bluetooth on and off using the remote. I'm vampire-drain sensitive (>30¢/kWh electricity costs can do that), so I would not want WiFi and Bluetooth always on. Maybe a low-power sleep mode that would awaken with incoming WiFi network activity could be implemented.

I have seen another JuiceBox whose owner installed a USB port through the case wall so that it can be programmed without opening the case. However, this requires leaving the FTDI interface connected which apparently isn't ideal.

alohart said:

That would be nice! I suppose a menu item could be added that would allow one to turn Bluetooth on and off using the remote. I'm vampire-drain sensitive (>30¢/kWh electricity costs can do that), so I would not want WiFi and Bluetooth always on. Maybe a low-power sleep mode that would awaken with incoming WiFi network activity could be implemented.

I have seen another JuiceBox whose owner installed a USB port through the case wall so that it can be programmed without opening the case. However, this requires leaving the FTDI interface connected which apparently isn't ideal.

Click to expand...

30 cents per kWh, Wow! I guess living with -30 degree wind chills has SOME advantages.

You could wire a RF controlled 120V relay between the JuiceBox's "mains" relay and the internal power supply for the logic board. That's kind of an ugly solution but then the only vampire drain you would see would be whatever the idle draw of the mains relay and the added RF relay, that has to be less than claimed 10W of the JuiceBox. I found some relays like this for less than $20 with a claimed 300 foot range. In theory you could even leave the car connected and the JuiceBox should start up once you trigger the relay and it powers up.

According to other forums that I've visited it looks like 10W is pretty typical for an EVSE idle draw although the OpenEvse seems to have a much lower idle consumption of <3 Watts.

It looks like the EMW guys are extremely active on some forums and that's been the best way to get a sense of what's going on with them, in particular the MyRAV4EV forum seems to be very active. Otherwise they rely on Facebook for most updates which I hate but that seems to be the norm these days.

I just figured out that their Android app is available in a semi-open beta if you have a WiFi enable JuiceBox. Going to play with that tonight!

alohart said:

Boatguy said:

Put the control of all the “premium” features in software and provide access from mobile phone apps and/or a browser.

Click to expand...

If your suggestion is followed, I and many others whose EVSE's are not within WiFi range or who don't want to leave their EVSE's powered continuously would not be able to enjoy the premium features of the current JuiceBox. Your suggestions would be nice for those whose EVSE's are nodes on their WiFi networks, but such a design would be unnecessarily expensive for those of us whose EVSE's are out of range of our WiFi base stations (e.g., most apartment dwellers whose parking spaces are not adjacent to their apartments).

Maybe there should be two JuiceBox versions: a base version without a WiFi transceiver and a premium version with a WiFi transceiver. The premium version would be controlled by a mobile phone app or Web browser and wouldn't have an OLED display. The base version would include an OLED display and remote for control like current versions.

Different strokes for different folks…

Click to expand...

A wifi chip and supporting materials is very inexpensive ($5-$10) and definitely net less expensive than removing it and adding a display and mechanical UI to control the JB, or a wired interface like USB. In the situation you describe, the JB could establish a private network (my camera does this for example when I want to control it from my iPhone) and you could access/control premium features when you are within wifi range of the JB.

The JB needs a display and input device and the wifi/phone combination is probably the least expensive and highest quality solution. The issue you raise is really just about proximity to the JB when using the UI.

Boatguy said:

A wifi chip and supporting materials is very inexpensive ($5-$10) and definitely net less expensive than removing it and adding a display and mechanical UI to control the JB, or a wired interface like USB. In the situation you describe, the JB could establish a private network (my camera does this for example when I want to control it from my iPhone) and you could access/control premium features when you are within wifi range of the JB.

The JB needs a display and input device and the wifi/phone combination is probably the least expensive and highest quality solution. The issue you raise is really just about proximity to the JB when using the UI.

Click to expand...

The existing WiFi solution for the JuiceBox is a $49 upgrade. This module in commonly available for a little less than that but the EVM version does have a custom interface shield and includes the extra current sensor which probably justifies the extra cost. Most well built WiFi modules/shields for Arduino setups are at least $30 and some are much more, I doubt a decent one can be had in the $5-$10 range.

In order to function in the manner of something like an IP based camera then the JuiceBox WiFi module would have to be able to negotiate an ad-hoc connection with other wireless devices (smartphone, laptop, etc.) or run in a "Soft" AP mode basically emulating a standard WAP. The wifi module chosen by EVM can only run in traditional client mode OR in ad-hoc and cannot do these simultaneously. That would make the data collection and web statistics that EVM provides from their servers impossible since the wifi module would not be connecting to a WAP as a client with access to the Internet. There is nothing preventing someone from writing a completely custom firmware using the existing JuiceBox with wifi (base or premium) that can perform exactly like you lay out in your post but you would lose out on some of the utility EVM provides with their existing solution.

Now, I've been testing the beta of the EVM Android application tonight and it has promise but it's pretty basic right now. You can set the amperage limit of your charging, see the rate of charge and setup a charging schedule. These are all features you can currently access using the add-on screen/rf remote and they are much easier to access using the smartphone app. According to their Facebook page EVM are going to add more features in the near future including the ability to remotely turn off the JuiceBox, which would be great. However, it looks like most of the new features they are working on will require the latest revision of their PCB (v8.10, which as only been shipping since 11/14) and possibly a new Wifi module they are working on from a company called ACKme. That will be great when you are at home but if you want to take your JuiceBox on the road you still have to deal with trying to connect to existing wifi hotspots in order for the JuiceBox to be accessible. That's still hard to do without the screen/rf remote interface unless you are comfortable with opening your JuiceBox up while it's connected to the mains power in order to push the WPS button to sync with a hotspot. Or you could drill the case and install an external WPS button.

Bottom line is that the current wifi solution is incomplete but should improve.

For folks who DON'T want all the complexity and features, the upcoming "JAMP JR" is a stone simple 40 charging solution.

No wifi
No programming
No building

Just a high quality, lightweight 40 amp cord at 25 feet long, and a NEMA 14-50 plug.

Available March 2015.

TonyWilliams said:

For folks who DON'T want all the complexity and features, the upcoming "JAMP JR" is a stone simple 40 charging solution.

No wifi
No programming
No building

Just a high quality, lightweight 40 amp cord at 25 feet long, and a NEMA 14-50 plug.

Available March 2015.

Click to expand...

I would say the base pre-configured base JuiceBox is stone simple right out of the box and matches those features. Unless your going to offer this at a reasonable discount to the existing Base JuiceBox price point ($499 assembled) then I'm not sure where the value is in buying something that has no upgrade path. Or if it's going to be UL listed for the same price as a JuiceBox that might matter to some buyers.

Don't get me wrong, I'm glad to see choices and options. If nothing else it will help to drive down the prices across the board.

hey was wondering if anyone else get the GFI error upon plugging in their juice box. it happens nearly 50% of the time for me....

ddarvish said:

hey was wondering if anyone else get the GFI error upon plugging in their juice box. it happens nearly 50% of the time for me....

Click to expand...

I know this was an issue with earlier board revisions and earlier firmwares. I have not had any GFI issues but mine is the latest board running the latest firmware.

You could send EMW an email and see if they have a suggestion. The only fix (aside from newer firmware) that I'm aware of is to make sure that the output wires are run as straight as possible as they pass through the current sensor. My preassembled JuiceBox had some silicone between the wires and the current sensor to keep the wires "locked" into position as they passed through.

Hi all,

I'm getting a 40A JuiceBox Classic today. My electrician had installed a 40A breaker and 4AWG wiring (up to 40A). He said this setup would work for up to 30A chargers. He's worried that the JuiceBox might draw 40A and cause wiring overload.

My understanding is that the i3 can only draw a max of 32A (after the onboard limits have been fixed by the dealer: http://insideevs.com/bmw-to-finally-replace-i3-onboard-charger-to-restore-promised-7-4-kw-charging-rate).

So I think the set up should be fine but wanted to see what folks think or if anyone has done measurements when using the 40A JuiceBox with their i3.

Thanks in advance!

JuiceBox just came in and it looks like it's defaulted to 30A, which makes my electrician's question a non-issue.

Still I'm wondering if the car will take more than 32A if you change the JuiceBox setting higher, 'specially since it's got the onboard combo charger.

It might fry the onboard charger though: http://insideevs.com/bmw-to-finally-replace-i3-onboard-charger-to-restore-promised-7-4-kw-charging-rate/

If the juicebox is a properly designed EVSE it will communicate with the car's charger and negotiate the maximum current that the car will accept. You can crank up the max amperage on the juicebox but it should still only supply what the car asks for.

If it doesn't behave like that, then it's a disaster waiting to happen.