Tesla Power needs

[art]

looked through some previous threads but, here I am.

We're planning on using a tesla charger to provide battery backup a traffic signal (load is ~3 amps) during the Public Safety Power Shutoff (PSPS) in California . Tesla has not been helpful. They won't provide much technical information unless where at the point of ordering the unit. the idea is to run the signal on utility power and when there's an outage switch to the charger as a power source. the input to the charger will be utility or solar power.

I found the installation manual online but still have some things to confirm or deny:

Assuming this will work, the maximum charging current in the specs, will be 80 A (thinking this is on 120 V, with the actual current being dependent on the charger.)

On one web page (not the manual) it says peak power is 7 kW, which, at 120 V and a continuous load is around 79 Amps - so, an 80 A breaker. At 240 V, it's half of that so a 40 A breaker.

It says to use a 100 A breaker for fastest charging. However, don't think I can go lower anyway, because it's in the manufacturer's instructions.

Your time and comments are much appreciated.

 

[LarryFine]

Any chance you can give us a better idea of what you're doing? Perhaps a drawing?

What's being charged and used, and where is the DC becoming AC?

 

[Sierrasparky]

Why would you use such a device for this. Tesla chargers are meant for charging cars. The charger needs to communicate with the car if you are speaking of the tesla wall connector. I would think you are violating the listing of the product.

 

[hillbilly1]

Not really getting what your doing, most EV charging stations, except for the level 3 are 120 or 208/240 volt ac output. They do not put out DC. Or are you talking about the charger built into the car? If so, I think it would be too high of dc voltage to be usable.

 

[Sierrasparky]

Not really getting what your doing, most EV charging stations, except for the level 3 are 120 or 208/240 volt ac output. They do not put out DC. Or are you talking about the charger built into the car? If so, I think it would be too high of dc voltage to be usable.

The tesla wall connector is a different animal for level 2 charging , it has some smarts in it. It allows for switching to high amp charge to 80 amps.

 

[hillbilly1]

The tesla wall connector is a different animal for level 2 charging , it has some smarts in it. It allows for switching to high amp charge to 80 amps.

But output is still A/C? The onboard charger decides rate from communications with the wall charger and converts to DC?

 

[Sierrasparky]

But output is still A/C? The onboard charger decides rate from communications with the wall charger and converts to DC?

Actually I think it is still a/c. The Tesla " wall connector " still uses the onboard charger , There is some communication probably carrier signal that lets the car know what the max charge rate on the Wall Connector setting. There are DIP switches in the unit you set to the circuit size run. Currently the max level 2 charge rate of a tesla is 42 amp I think .

 

[texie]

The OP is a more than a little all over the place but my best guess is he is actually referring to a Tesla Power Wall to use as backup power.

 

[tom baker]

There are UPS systems designed for traffic signals. If you need more run time then more batteries are used. This would be a system that is tested and compatable for traffic signals. If interested check with a city/state traffic signal department for a company contact.

 

[LarryFine]

Is the OP expecting to have a Tesla car parked at each stoplight controller, powering each one? Wouldn't portable generators be cheaper and more practicable?

 

[hbiss]

Yeah, I think he's wanting to suck power from the Tesla batteries to power an intersection when CA shuts down power to keep from starting wildfires.

Neither one makes any sense.

-Hal

 

[Sean.Day72]

Use an inverter/battery charger and automatic transfer switch. I did this to provide backup power for tunnel lights when the use of a generator wasn’t practical


Sent from my iPhone using Tapatalk

 

[hillbilly1]

The OP is a more than a little all over the place but my best guess is he is actually referring to a Tesla Power Wall to use as backup power.

That makes more sense, probably not practical, but as others have said, manufactures already make UPS units for that application.

 

[art]

Sorry. I am referring to the Powerwall. Another engineer has one at home and thought it would work to backup a traffic signal in case of a planned outage. It would be fed from utility power and a solar array with 120 V output going to the controller cabinet. We already use battery back-up but it only provides power for around 8 hrs. We're aiming at 3 days.

 

[LarryFine]

We're aiming at 3 days.

What's a Tesla's AH capacity?

 

[Todd0x1]

3 days at ~ 3 amps is around 25kwh. You would need two powerwalls. Plus you will have other issues in that the powerwall is designed for 120/240 input, and when utility comes back on and the powerwall wants to recharge its going to draw alot of current.

Me, I would set the TCC up with a generator inlet, get a little towable diesel generator, and call it a day.

If you are insistent on using batteries get one of these https://www.cotek.com.tw/product/High-Frequency-Pure-Sine-Wave-Inverter-Charger-SC1200/ and ~1900ah of AGM battery. Could maybe cram it all into an empty traffic signal control cabinet. Or as others have mentioned there are probably application specific devices made for the traffic signal equipment industry.

 

[Sierrasparky]

Sorry. I am referring to the Powerwall. Another engineer has one at home and thought it would work to backup a traffic signal in case of a planned outage. It would be fed from utility power and a solar array with 120 V output going to the controller cabinet. We already use battery back-up but it only provides power for around 8 hrs. We're aiming at 3 days.

now you tell us.

 

[tom baker]

Another option is a fuel cell. These can be powered by a hydrogen rich fuel, and produce DC power. If you used LEDs, then you could run them on 12 VDC and avoid the conversion from AC - DC - AC which is very inefficient This one uses a cartridge for fuel. https://www.imarineusa.com/Efoy151-...MI9r3TyYOH5wIVkKDsCh1d-Q0nEAQYAyABEgIMePD_BwE

DOE page on fuel cells https://www.energy.gov/eere/fuelcells/fuel-cell-systems

 

[Open Neutral]

I've always thought the Prius solution would make sense. Buy them for pool cars for the city.
When the blackout hits, give the building inspector time off and put her car at the control box.

Generators need maintenance and BIG chains to keep from disappearing.
You'd want some software tweak to the car such that with that key it would start as needed but would not go into gear, period.

On long blackouts, have a fuel truck go around topping them off.

 

[ggunn]

Why would you use such a device for this. Tesla chargers are meant for charging cars. The charger needs to communicate with the car if you are speaking of the tesla wall connector. I would think you are violating the listing of the product.

He means a Powerwall, I'll wager.

EDIT: Sorry, I posted that before reading the rest of the thread.