Hack charging off generator

[andrewket]

I lost utility power this morning at 5am, I presume caused by ice. I have a Cummins Onan whole house generator (20kVa) that is humming along. Just because I could, I plugged my model S into 120v. It's charging happily at 12A. Normally I use an HPWC but that is not wired off the generator. At the very least the battery pack will be warm before I leave the house in about two hours.

Andrew

 

[ACDriveMotor]

Charging at 108V. I would have thought that -10% was outside the charging envelope. Interesting.

 

[scaesare]

Any chance the generator can supply Level II charging voltage if you ever needed? A lot of tthe mobile units seem to have a 30A receptacle on them, not sure what your hardwired unit has in the way of auxiliary outlets on it, if any. Or if it's in close enough proximity that you could feasibly get the UMC connected to it.

 

[andrewket]

I could connect a 14-50 or even the HPWC to the generator. It has load shedding capabilities. It would make the wiring more complicated so I opted not to do it, with the logic that even if I lost power for several days I could use our ICE car. However when the X comes out we will be 100% EV. I will likely re-wire to put the HPWC on the generator, and keep the current down to 30-40A. With the load shedding capabilities of the generator I can do this and still meet code.

 

[scaesare]

Very cool.... when Dominion Power goes down for several days don't' be surprised if I knock at your door...

 

[Cottonwood]

I could connect a 14-50 or even the HPWC to the generator. It has load shedding capabilities. It would make the wiring more complicated so I opted not to do it, with the logic that even if I lost power for several days I could use our ICE car. However when the X comes out we will be 100% EV. I will likely re-wire to put the HPWC on the generator, and keep the current down to 30-40A. With the load shedding capabilities of the generator I can do this and still meet code.

With an MS and an MX, I would just put one or two 14-50's on the load shed side of the generator. If the power goes out, you can use the UMC's. If needed, you can charge both Tesla's at the same time with the current dialed back, etc. Keep your HPWC(s) in the main, non-protected panel and be able to charge fast when you want to.

 

[andrewket]

With an MS and an MX, I would just put one or two 14-50's on the load shed side of the generator. If the power goes out, you can use the UMC's. If needed, you can charge both Tesla's at the same time with the current dialed back, etc. Keep your HPWC(s) in the main, non-protected panel and be able to charge fast when you want to.

Yep, my thinking as well. I don't want to over engineer for the rare event. The outage yesterday was 7 hours long. A multi-day event where I want to leave the house will be really rare. In fact, I have a dryer outlet that is on the generator within 10ft of the garage. It might just be easier to use that.

 

[andrewket]

Very cool.... when Dominion Power goes down for several days don't' be surprised if I knock at your door...

Anytime. There are also the HPWCs at Tyson's. According to the supercharger map we're getting an SC around here too.

 

[Cottonwood]

Anytime. There are also the HPWCs at Tyson's. According to the supercharger map we're getting an SC around here too.

Besides, if Tesla puts in some of the cool battery packs to reduce demand charges at Supercharger locations, those packs will hopefully be backup power as well! :biggrin:

Tesla's Solar Power Storage Unit - Businessweek
SolarCity DemandLogic

 

[scaesare]

Anytime. There are also the HPWCs at Tyson's. According to the supercharger map we're getting an SC around here too.

Hehe yeah... I was joking more than anything else... but those are good backup plans.... provided the mall has power.

 

[N4HHE]

I lost utility power this morning at 5am, I presume caused by ice. I have a Cummins Onan whole house generator (20kVa) that is humming along. Just because I could, I plugged my model S into 120v. It's charging happily at 12A. Normally I use an HPWC but that is not wired off the generator. At the very least the battery pack will be warm before I leave the house in about two hours.

Andrew

Just for laughs, what MPG does your genset produce? How many miles of added range per gallon of gasoline?

I have a couple Honda EU2000i's for the toy hauler. Sometime after my Model S arrives I'll burn a gallon in one for practice and to see how many miles it adds.

 

[Enadler]

Generally power outages are usually localized, in that case it would be much more efficient to find a local charging station or plug in at a friends rather than charging off a generator.

 

[William13]

The superchargers at malls will be back on line well before many residences. That is my backup plan.

 

[Only Trons]

Andrewket;

I too am in Northern Virginia and we lost power Monday for over five hours --- likely due to ice conditions. We also have a Cummins Onan 20 kW generator. Because of the existing household electrical distribution, the electrician found it easier to simply wire the generator to the two main panels in the house (requires two disconnects and two transfer switches though). The likelihood that that we would have an excessive load in that configuration is minimal but the generator would shed the load if necessary. The 14-50 in the garage is wired through one of the main panels. So we get L2 charging to the car from the generator. I tested it once the generator was installed and it works perfectly. During the test, I increased the charge level to Maximum to ensure the car would pull maximum amperage. Note: we use UMC and the 14-50; we do not have HPWC. When we lost power on Monday, the car was already charged, so it didn't need any extra juice from the generator. In fact, the generator had very little load on it (we have natural gas heating and water heater).

 

[andrewket]

Just for laughs, what MPG does your genset produce? How many miles of added range per gallon of gasoline?

I have a couple Honda EU2000i's for the toy hauler. Sometime after my Model S arrives I'll burn a gallon in one for practice and to see how many miles it adds.

From what I've read, portable generators such as the EU2000 can't regulate the voltage well enough for the MS to charge. The MS stops with an error.

 

[andrewket]

Andrewket;

I too am in Northern Virginia and we lost power Monday for over five hours --- likely due to ice conditions. We also have a Cummins Onan 20 kW generator. Because of the existing household electrical distribution, the electrician found it easier to simply wire the generator to the two main panels in the house (requires two disconnects and two transfer switches though). The likelihood that that we would have an excessive load in that configuration is minimal but the generator would shed the load if necessary. The 14-50 in the garage is wired through one of the main panels. So we get L2 charging to the car from the generator. I tested it once the generator was installed and it works perfectly. During the test, I increased the charge level to Maximum to ensure the car would pull maximum amperage. Note: we use UMC and the 14-50; we do not have HPWC. When we lost power on Monday, the car was already charged, so it didn't need any extra juice from the generator. In fact, the generator had very little load on it (we have natural gas heating and water heater).

I too have two main panels, but only one transfer switch. One panel is on the generator and the other utility only. It's interesting that your electrician was willing/able to wire both your panels to the generator with two ATS's. Mine was not willing to do that. Similar to you, I have excess capacity and could easily have powered both panels. I ended up moving tons of circuits between the panels to get the circuits I wanted onto the generator. This includes all of the large appliances, minus the HPWC. The HPWC is fed from a sub panel off the main utility only panel. I should get the name of your electrician.

You do know that only two circuits work with the load shedding capability, right? You have to wire those circuits through a separate relay. The idea is to put your two largest loads on these circuits. Most people out their AC/heat pumps on them.
A

 

[Only Trons]

Yes; understand all. We didn't want to go to the trouble/expense of moving bunches of circuits to have one panel on the generator and the other on utility only. We used Holt Electric in Maryland based upon a recommendation from a local remodeler who has done work at my home. I don't think you would find them to be the cheapest but their work was good. Our major electrical consumers are two electric wall ovens; two AC units; electric dryer; and the Tesla. In the winter, the AC units are not in use. The two ovens are rarely used at the same time except for a special occasion when preparing a meal for a large group. So it is fairly simple for me to manually turn off something to manage the load if necessary.

 

[N4HHE]

From what I've read, portable generators such as the EU2000 can't regulate the voltage well enough for the MS to charge. The MS stops with an error.

My delivery is scheduled for next Thursday. Sometime when I quit driving it everywhere I'll stop and hook up the Honda. I don't believe there will be a problem as illumination by generator power is even and without flicker. There is a drop when a sudden load is applied with the generator in ECO mode. ECO mode adjusts the throttle according to demand.