JuiceBox Load Sharing

[solardudesf]

I realize most people probably get the Tesla wall connectors. We are planning on purchasing Teslas for both my wife and myself. We don’t want the Tesla wall connector since we don’t want to be locked into Tesla completely. We want to be able to get other brand EVs in the future.

After doing some research, it appears that the JuiceBox Pro 40 allows two boxes to load share on the same circuit. Does anyone here have experience with the JuiceBox load sharing feature? It sounds to me like the feature depends on network communication. What happens if the internet is down? Do the boxes just assume that they can use at most 1/2 the power? Any thoughts/experiences with this feature would be appreciated. Thanks!

 

[ewoodrick]

I understand your desire not to be locked into a single car. But, swapping out the EVSE is a pretty easy thing to do. Or even multiple 220V plugs with 2 UMCs.

It's just so much easier to push the button and not worry about the J-1772 adapter.

I've been through 3 EVs with my NEMA 14-50 plug.

 

[ajdelange]

"Network" can mean many things. In the Tesla HPWC's it's a hardwired network (CANbus?). I'd check the JuiceBox installation instructions to see whether it doesn't also work this way. If there are thin wires running between the boxes that implies that communication is through those rather than going out to the net.

 

[john85775]

Just get a TeslaTap and the HPWC works as a J1772 connected unit and no longer locked in.

 

[solardudesf]

"Network" can mean many things. In the Tesla HPWC's it's a hardwired network (CANbus?). I'd check the JuiceBox installation instructions to see whether it doesn't also work this way. If there are thin wires running between the boxes that implies that communication is through those rather than going out to the net.

it looks like the JuiceBox just communicates to the mothership via WiFi. If it cannot contact the mothership then for safety it assumes that the other car is being charged as well and reduces the charging speed. The Tesla method is definitely better (where the HPWC’s communicate directly), but looking to go with 14-50 solution and not use proprietary connector.

I do appreciate the other responses, but instead of telling me to get the Tesla connector, I would really appreciate responses from people who have experience with the JuiceBox. Thanks again!

 

[ajdelange]

The other guys are trying to help and I think you should carefully consider what they are saying. You are getting two Teslas and know that a pair of HPWCs can be reliably shared (hardwire interconnection) to charge a Tesla up to 80 amps or 72 amps (should you happen to acquire and older S or X) but most likely to be 48 A. You also know that there is an adapter which will allow most any J1772 car to charge from an HPWC at its (the car's) maximum rate.

OTOH there is the Juicebox which will charge any J1772 car including a Tesla but only up to 40 A. Again an adapter is required. So you are going to need a Tesla to J1772 adapter if you go with the HPWC and if you later buy a J1772 car. If you choose the Juice box you will need a J1772 to Tesla adapter which used to come with the car but will be limited to 40 A charging, The J1772 to Tesla adapter comes free (or used to come free with the car - I don't think they supply the full charging kit as they used to do as recently as last fall) but you will have to buy the Tesla to J1772 adapter. You can look up the costs of the HPWC and Juicebox.

I'd tell you all I knew about the Juice box if I knew anything. You seem to have found out what you basically wanted to know i.e. that the Juicebox fails safe. As no one seems to be forthcoming with additional details here I would look in forums dedicated to cars that actually use that technology. I'd also get a copy of the Juicebox installation manual.

 

[cray_guy]

I have this setup with two Juicebox Pro units set up on a load sharing group on a single 50Amp circuit. We use this between a Tesla Model S and a BMW i3. It does work, and it has a very nice web interface to control things and monitor usage from your phone or computer. One negative is that the cord is pretty bulky and it gets very stiff if you live in the north country and it gets cold. If I had a pair of Tesla cars, I'd probably opt for a pair of Tesla wall chargers with the hard-wired load balance feature. The thinner cord and the push to open feature would make it worth it. You can always sell them and get a J1772 if you change later.

 

[Turbojim]

I have this setup with two Juicebox Pro units set up on a load sharing group on a single 50Amp circuit. We use this between a Tesla Model S and a BMW i3. It does work, and it has a very nice web interface to control things and monitor usage from your phone or computer. One negative is that the cord is pretty bulky and it gets very stiff if you live in the north country and it gets cold. If I had a pair of Tesla cars, I'd probably opt for a pair of Tesla wall chargers with the hard-wired load balance feature. The thinner cord and the push to open feature would make it worth it. You can always sell them and get a J1772 if you change later.

Do you have the hardwired versions, or the plug-in style? I’m curious as to how they are wired together. I assume there would have to be a junction box where the two boxes would have to meet and then an inlet from the panel.
Thank you!

 

[dzmconstr]

I realize most people probably get the Tesla wall connectors. We are planning on purchasing Teslas for both my wife and myself. We don’t want the Tesla wall connector since we don’t want to be locked into Tesla completely. We want to be able to get other brand EVs in the future.

After doing some research, it appears that the JuiceBox Pro 40 allows two boxes to load share on the same circuit. Does anyone here have experience with the JuiceBox load sharing feature? It sounds to me like the feature depends on network communication. What happens if the internet is down? Do the boxes just assume that they can use at most 1/2 the power? Any thoughts/experiences with this feature would be appreciated. Thanks!

Why is this in X battery and charging not in "Supercharging & Charging Infrastructure"? I think you'll get a much wider audience there vs just one models charging sub-forum.
Dzm

 

[BP777]

Do you have the hardwired versions, or the plug-in style? I’m curious as to how they are wired together. I assume there would have to be a junction box where the two boxes would have to meet and then an inlet from the panel.
Thank you!

@cray_guy I also am curious to the answer to this question. How did you have an electrician wire the split to share the circuit?

 

[quitepossibly]

@cray_guy I also am curious to the answer to this question. How did you have an electrician wire the split to share the circuit?

The Juicebox in load sharing configurations are wired like how the Tesla Gen 2 HPWC are wired, there needs to be a junction box that splits the circuit between the two Juicebox units. But instead of having a separate communication wire between the units, the Juicebox requires connection to internet and the JuiceNet site actually controls the load sharing configuration.

When the setup is working correctly, each Juicebox is allocated 7 amps. If you plug in your Juicebox into your Tesla, it will check if the other Juicebox is in use and start charging at 7 amps. If the other Juicebox is not in use, it will ramp up to full charging rate.

If you plug in another car into the another Juicebox in the load sharing group, then that Juicebox will check into the JuiceNet cloud and reduce the charging current of the first Juicebox by 7 amps and then the start charging at 7 amps. Then it will ramp up again and ramp down the first Juicebox until both units each have half of the circuit capacity.

While Enel X has some documentation about the load sharing setup on their website, I feel like it is a bit out of date. Their documentation says each car starts at 6 amps, and in talking with their customer service, they said it was raised to 7 amps because some cars don't work correctly at 6 amps.

If you have two cars that are charging and one car finishes charging, then the Juicebox allocates 7 amps to the car that has finished charging and the reminder of the circuit capacity to the car that is still charging.

I currently have this setup, but I am not sure if I would recommend it right now.

The Juicebox firmware and the JuiceNet system seem to be buggy. I don't know if it is a recent problem, or if it has always been this way, but I've run into several issues. I don't think most people have these issues since most people don't have the load sharing groups set up.

I found that if I set TOU charging on the Juicebox, but decided I wanted to override that schedule, it would override the load sharing current limits as well. This is a fire hazard. If you accidentally stop charging in the app and then swipe back to start charging, you would run into the same issue.

Also a few days ago, Enel X changed their load sharing algorithm and then my two cars would not draw more than 7 amps, instead of sharing the capacity of the circuit. I reported this bug and the previous one to Enel X and it looks like they fixed this problem for now; I don't know if they fixed the load sharing override bug.

But now, both of my Juicebox units won't connect to Wifi. I had a Wifi outage at my house and when it came back online, neither Juicebox would connect to it. On top of that, neither Juicebox would enter Wifi setup mode either, so I couldn't change the Wifi network either.

And neither of my Juicebox units will allow any cars to charge. The documentation says that if communication is lost, the units should charge at 6 amps. At least with the current firmware, that doesn't appear to be the case. I've reached out to Enel X technical support and they have been helpful with troubleshooting, but it looks like the units need to be swapped out.

Since I am still in the return period, I am going to try to return them. When the setup is working, it works pretty well. But in one week, I've run into several bugs that need to be fixed, and I don't want to be their QA department for something as essential as vehicle charging.

 

[herrerom]

I have a Tesla Gen2 charger on a dedicated 80 amp circuit, but I had the electrician go ahead and put in the junction box in order to put in a 2nd charger. HOWEVER, my 2nd EV is an Audi Q5 plug-in, so I want to get a Juicebox 48 or a Chargepoint+ flex. Can I combine these on that same circuit or do I need to run a new dedicated circuit?

 

[Mako11]

load sharing only works between same brand chargers that support the feature

 

[mxnym]

load sharing only works between same brand chargers that support the feature

This is true, but a single circuit can at least theoretically serve multiple devices if their combined usage doesn't exceed the circuit's rating. The devices would simply need to have their maximum outputs configured appropriately. The downside is if you could use more power on a single charger than what said appropriate configuration allows, you won't be able to get it due to the lack of a load-sharing feature. IOW, consult an electrician and consider your situation.

 

[Rocky_H]

I have a Tesla Gen2 charger on a dedicated 80 amp circuit, but I had the electrician go ahead and put in the junction box in order to put in a 2nd charger. HOWEVER, my 2nd EV is an Audi Q5 plug-in, so I want to get a Juicebox 48 or a Chargepoint+ flex. Can I combine these on that same circuit or do I need to run a new dedicated circuit?

Well, neither of those really. You don't need to RUN a new dedicated circuit, but they can't actually share. What you would do is just divide that 80A circuit into two dedicated circuits.

 

[DCGOO]

I have a Tesla Gen2 charger on a dedicated 80 amp circuit, but I had the electrician go ahead and put in the junction box in order to put in a 2nd charger. HOWEVER, my 2nd EV is an Audi Q5 plug-in, so I want to get a Juicebox 48 or a Chargepoint+ flex. Can I combine these on that same circuit or do I need to run a new dedicated circuit?

You could combine the loads. The Tesla can be configured to start at a specific time, and the maximum current can also be reduced. Can you do similar things with the Audi? If you fumble, worst case is the breaker will trip.

 

[Rocky_H]

You could combine the loads. The Tesla can be configured to start at a specific time, and the maximum current can also be reduced. Can you do similar things with the Audi? If you fumble, worst case is the breaker will trip.

That is a code violation for sure. NEC doesn't allow EVSEs to be shared on the same circuit without actual power sharing communication between them restricting their currents.