Tesla Cybertruck: The Future?
- Thread starter erstwild
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D
Deleted member 9101
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For a stage 2 charger it might even require an upgrade to the electrical service. 40 amps at 240v is quite a bit of juice. If they have all electric appliances, it might cause problems at times.
Stage 3 will require all kinds of new wiring....lol.
shade
Well-known member
I haven't paid attention to the Powerwall. Does Tesla have a scheme in place to allow charging a Powerwall at relatively low power over time, with the Powerwall used as a source to charge an EV? That could be a workaround for improving charge times when high output circuits aren't available.
That shouldn't be a problem as that is what a solar+powerwall setup does. But I'm quite certain you won't get 300 Amps at 480 volts from it. That takes specialised hardware and batteries that can take it.
shade
Well-known member
I'm not talking about solar charging a Powerwall, although that could certainly help.
I was thinking about using a Powerwall to charge at say 15A/120V over many hours while the EV was off doing whatever, and then dumping the Powerwall's charge into the EV along with that same 15A output from the mains when the EV returns home. If Tesla was clever, I think that would be a way to get more of their EVs into homes with a minimum of fuss, as well as sell more Powerwalls.
I know you were talking about that. But with a charger you can provide DC (from the 120v AC) at the voltage the batteries will accept. Rereading my post, I admit that wasn't as clear as it could have been.
shade
Well-known member
I'm not following.
Charging a Powerwall on a low amp circuit over many hours, and using it to fast charge an EV doesn't seem to have much to do with what I know about using shore power with a boat's house bank.
Okay, I will go a little overboard, but keep in mind that most batteries (if not all) are able to discharge faster than being charged. Just as you wanted.
The following numbers are made up, but they relate to one another exactly like the following. I have to say that I make the assumption that the powerwall accepts 48v as that seems like a good voltage widely used. It could be 12v, but there is no way it is because it would mean horrendously thick gauge cables and much bigger voltage drops (as a percentage).
Anyway, you get a charger to convert the 120v 10Amps AC (from the wall) to DC at 48V, which means the cables will now carry 25Amps at 48v.
This is then fed into the battery bank however big a powerwall is.
For getting it out, and depending on how much draw the powerwall batteries can be discharged, you either use an inverter to get to AC, or a DC-DC converter/stepup transformer to go to DC (I don't know if Tesla uses DC charging, but I think they do) at least on the level 3.
Anyway, when you have converted it to, say, 240 volts, it's a question of how much you can pull from the battery bank. 240 volts @ 100 Amps is pulling 500A from the 48V battery banks (ie. before being converted). So, if it has enough amp hours, it can charge the car at a rate (500A / charge rate 25A) which comes out at it being able to discharge at 20 times the amperage of the charging.
A "house bank" (I think I need to explain this too) in a normal boat is mostly 12V or 24V. It is used for "House loads" - that is, it is not used for starting an engine. For people with shore power, they can keep their 12/24 volt house bank charged either by solar, the alternator, or by plugging in to shore (dock). It's the same principle here. It's just a matter of getting the right type (AC/DC) and the voltage right, the rest is about keeping the cables thick enough to cope with whatever amperage.
I hope I managed to explain this so it's somewhat understandable?
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Boatbuilder79
Well-known member
Just from watching the news at night it seems like Having at least 1 electric vehicle and a way to charge it if the grid goes down is a really good idea to me.
D
Deleted member 9101
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The problem with that is time. If you use a generator, it will take a day or more, unless its a large one.
We had a problem during Hurricane Irma with EVs running out of power while people were evacuating. They were stuck on the side of the HW with no way to recharge and had to wait hours for a tow truck. Most were fully charged when they left home, but sitting in 100° heat and having to run the A/C on high with no opportunity for the brakes to help recharge the batteries killed them.
Tesla updated the cars remotely to give them more range by allowing them to run the batteries down further than normal since it was an emergency.
shade
Well-known member
If it's the shelter-in-place kind of emergency, maybe so. Having a natural gas fueled generator & solar charging options could serve you well.
If it's the get-out-of-here-NOW! kind of emergency, maybe not.
Mike W.
Well-known member
That's spelled America..
Hehe, he is Swedish. Here in Scandinavia we spell it "Amerika". But yeah.
In fact, it should be "parts of North America" to be specific. Or "parts of the Americas" - "parts of the Northern Americas"?
Just having some fun. He's a fellow Scandiwegian, he, he.
Boatbuilder79
Well-known member
I am not saying it’s a good idea to only have an ev and I would not want to use one to run from a hurricane.
I remember when the plantation pipeline sprang a leak that took a few days to fix and gas got tight on the whole east coast.
I remember when a hurricane shut down the Louisiana refineries for a few days and there were gas lines in atlanta and gas was $5 a gallon on Peachtree street.
It’s not so much of a doomsday prepper idiot scenario as a disruption in the gas supply where you still gotta get to work so you can pay your bills.
Think about what would happen if things get out of control with Iran.
The Permian only has so much to give and the shale boom that we have been riding high on is gonna peter out eventually too.
I remember when the plantation pipeline sprang a leak that took a few days to fix and gas got tight on the whole east coast.
I remember when a hurricane shut down the Louisiana refineries for a few days and there were gas lines in atlanta and gas was $5 a gallon on Peachtree street.
It’s not so much of a doomsday prepper idiot scenario as a disruption in the gas supply where you still gotta get to work so you can pay your bills.
Think about what would happen if things get out of control with Iran.
The Permian only has so much to give and the shale boom that we have been riding high on is gonna peter out eventually too.