e-Manager not working with load-shared JuiceBox

[user 1815]

Sorry for the relatively long post...

I recently installed a second Enel X JuiceBox 40 in my garage on the same circuit as the first, with load sharing enabled so that both EVs will not draw too much current when both are plugged in. This seems to break the e-Manager settings.

When I plug in my e-Golf, it shows the yellow, timed charge light for a much longer time than usual (perhaps 30 seconds), then it immediately switches over to charging, even though the e-Manager settings should delay the charge until the next morning. Before the load sharing was implemented, everything worked fine.

I've tried rebooting the EVSEs and rebooting the infotainment system in my e-Golf (not sure that this reboots the e-Manager, though). These steps didn't help.

The load sharing feature starts charging at ~4 kW until it determines that the other EVSE is idle, then it ramps up to full capacity, which is limited to ~7 kW for the e-Golf. I am wondering, when initially plugged in and negotiating with the EVSE, if the e-Golf sees a very low charge capability and decides that it must start charging immediately to meet the e-Manager time setting?

Has anyone out there tried charging an e-Golf (using e-Manager) on a load-shared Enel X JuiceBox EVSE and faced similar issues?

We don't actually have the next EV, so I could turn off load sharing, but in the future I will want to use it, and it would be nice if e-Manager worked (although perhaps I can work around it using the Time-of-Use settings on the JuiceBox).

My next test will be if the environmental conditioning of e-Manager still works, even though the charging feature seems not to work, in the load-sharing EVSE configuration.

 

[user 1815]

Let me edit some numbers. The JuiceBox starts with 6 A or 1.44 kW, then ramps to its max 40 A or 9.6 kW ( however, the e-Golf limits this to 30 A, 7.2 kW) after checking that no other car is connected.

 

[user 1815]

I realize this is a rather specific topic and I'm taking a deep dive, but I think I may have the issue sorted. I carefully monitored the charging situation on my last charge. The car needed 9.4 kWh and e-Manager was asked to finish charging by a departure time of 7:00 am. On my load-sharing JuiceBox, the charging started at roughly 2:00 am and was finished by 5:00 am, two hours early. The charging period of 3 hours was consistent with a maximum charge rate of 13 amps, as was specified in e-Manager.

According to JuiceBox, the boxes default to 6 amps, starting there and ramping to 8 amps, and if no other car is connected, ramping to full charging rate (up to 40 amps for the JuiceBox 40). I believe that, upon plugging in, the e-Golf sees the possibility of an 8 amp maximum charge rate due to this ramping procedure. For the case here, it calculates that it will need about 5 hours to meet its final charge state, since 9.4 kWh/1.92 kW (8 amps at 240 volts) = 4.9 hours. It then sets the start time to 5 hours before the end time, namely to 2:00 am, which is what I observed.

In thinking this through, there is a general problem for load-sharing in that a second vehicle introduces an unknown about the possible maximum charge rate. This makes it impossible to precisely calculate a start time. However, the load-shared state will bring the charge rate to 50% of the JuiceBox maximum for each vehicle, so it would make more sense for the e-Manager to somehow learn from the JuiceBox 40 that the max charge rate is 20 amps, not the 8 amp rate it sees while the first JuiceBox negotiates with the other box. Using the 20 amp charge rate for its start time calculation would yield a better outcome.

Going forward, when my second EV arrives (I have a Nissan Ariya on order), I'll set a minimum charge level for each car to initiate immediate charging and use the time-of-use setting of the JuiceBox to delay the start of charging until midnight or so.

 

[miamor]

Moderator, can you move this thread into the proper place. It's a technical topic, Right?

I just started learning the Emanager to get the AC to turn on near departure time. Really useful. But this guy having two cars is also useful.