Comments
2lisimst t1_j7mbtlx wrote
If the 250 kWh battery is charged from a 120V, 15A circuit, it will still take about six days, assuming best-case efficiencies.
Lofteed t1_j7jtzkk wrote
how long does it take to fill a gas tank with a spoon ?
zakats t1_j7jjime wrote
A standard 108-120v north american outlet is very weak compared to just about everything else.
boganknowsbest t1_j7kant1 wrote
Even on a 240v he would only be charging at 2mi/h right?
stevey_frac t1_j7khymq wrote
The problem here is that a lot of the energy is going to keeping the battery warm enough to accept charge, because they're charging the battery outside, in the cold. Of the 1500 watts from the plug, less than 500 watts is actually going into the battery, with 1000 watts going to heat.
Move up to 3000 watts, and you're still throwing 1000 watts to heat, but 2000 watts will be going into the battery, and your charge time drops to like, 2.5 days instead of 10.
drweird t1_j7kshis wrote
Actually, assuming the Hummer is correct in its estimation, only 18.79% of the energy cannot be accounted for, and might be heat...?
Given 49pct charge on 250KWh battery, we have 122.5 KWh to charge. Standard 120v outlet has a max utilization of 1500W continuous, regulated by NEC, so the charger maxes out at that; this gives us 1.5KWh/h charging. IEEE has done studies EV chargers and found on average Level 1 charging is 83.8% efficient without heating present. This is not specific to this vehicle, so it's a rough number. Given 83.8% efficiency, our charging drops to 1.257KWh/h. At this rate, we have 122.5KWh / 1.257KWh/h, giving 97.45h. This is 4.06 days. Assuming that the video is roughly 1030AM on Sunday (he says Sunday morning) and we know the charge finish was projected as 1030AM Friday, we can roughly assume a 5 day charge period. 4.06 days being the optimal estimated charge period, and 5 being estimated gives us an estimate that is only 82.12% as fast as we expect. That gives us the unexplained 18.79% slower than expected charging.
I agree that in extreme cold Teslas and such will use heat to keep the batteries warm enough to charge, but at least if we trust the Hummer computer, it isn't cold enough to significantly heat the batteries, if at all. The unexplained slowness could be heating, or an incorrect estimate about the Hummers onboard inverter charging efficiency, or the Hummers ancillary charging equipment like cooling pumps pulling more power than the average car in the IEEE study. OR it could be as simple as the Hummer being wrong about 1030 on Friday.
My 2 cents
duckduckohno t1_j7lzlau wrote
Kinda. 240V outlets are capable of 30, 40, 50 Amps depending on what wiring/breaker was used.
A standard 120V outlet is 15 Amps.
For safety, you never use the full output of an outlet (-20%).
We can figure out the wasttage (power) by multiplying Volts x Amps
So on a normal outlet you have 120V x 15A x 0.8 = 1.5 kW
His battery is 250 kWh so it would take 7 days to recharge at normal outlet speed.
A 240V outlet on a 50 Amp circuit is capable of (240V x 50A x 0.8 =) 9.5 kW and could recharge his car fully in a little over a day.
zakats t1_j7kil43 wrote
Charging at 220/240 is more efficient and there won't be as great of a portion of the energy being used for battery conditioning, as pointed out in another comment, so it might be a fair bit faster.
110/120v charging is kind of a joke.
Rrdro t1_j7kmrsk wrote
Also assuming you are not driving enough to enjoy the battery each day you can probably keep it topped up with a slow charge alone
Honda_TypeR t1_j7jr28s wrote
While the speed of charging depends greatly on battery size, this is true of all level 1 chargers. Level 1 is something like 5 miles per hour of charging I think, so if you have a high mileage battery you're gonna be there for days (maybe 2-3 days for an average battery size).
If you want your vehicle to charge overnight you NEED to have a level 2 charger. That's like 6 times the speed of level 1.
If you want your vehicle to charge in an hour or two you need level 3 (but that's not something you will be installing in your home)
If you want an electric vehicle and want optimal charge speed you pretty much need to get a 240V AC outlet installed near your car bay. I could see how in the future this will be a common installation in garages of all new homes. We already do that in the dryer/washer rooms, since dryers always require very high voltage too. It's not something outlandish or out of the question to have installed. It costs maybe 2000 bucks to get a 240V line installed in your garage by an electrician. It's something to consider in the cost of gettin an EV. The level 2 chargers are like 300-1000 bucks on top of that.
iheartennui t1_j7ks60a wrote
what is even the point of going electric if you get something that has basically more carbon emissions than an ICE vehicle? the only actually sensible EV is an e-bike
[deleted] t1_j7kzhx7 wrote
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Zhuul t1_j7l2aq8 wrote
This has been disproven time and time again. Fuck outta here.
iheartennui t1_j7lg1kg wrote
what's disproven, that the hummer has a higher carbon footprint? got a source for that? it will really depend on your power source of course, most of which is generated by burning fossil fuels
Really, the idea of justifying this level of inefficient consumption blows my mind -- it has 250 kWh batteries! You can run a whole home pretty comfortably with just 10 kWh and a few solar panels. Why do you need to move 5 whole fucking tons of stuff just to get your ass from A to B when a bicycle would do?
Zhuul t1_j7lhwn1 wrote
I’m not sure you know what a kilowatt-hour is lol
hi9580 OP t1_j7n64lp wrote
Smoother/no shifting gears, quieter drive. Less air/water pollution in major cities, less lung issues. Less moving parts, less points of failure.
More efficient use of energy, electrical energy can be used directly instead of the chemical potential energy of fuel which needs to be transformed into heat/kinetic energy to be used. Any transformation wastes energy.
iheartennui t1_j7qndaa wrote
Most electrical energy consumed in the US is generated by burning fossil fuels. That energy had to be generated, transported, and then used to charge your battery, which has losses at each step. It also has to move a lot more mass in a typical EV than in their ICE counterpart, and especially in this Hummer.
So no, it's not really that efficient in terms of energy use -- a train or a bicycle and even a fossil fuel burning bus would be a lot better. And even compared to a normal car, unless you are installing your own solar panels to charge it, it isn't guaranteed to be less efficient in terms of carbon emissions, and with the Hummer it's been widely spoken of that they are far worse than even the ICE Hummer.
The only point you might have is air pollution, but the power stations are still burning that fuel and they are often doing so in or near cities. Car tires also produce toxic dust from friction with the roads and since EVs are heavier than other cars on average, they tend to produce more of this dust.
There's a marginal improvement in all of the EV business to what we were doing before, but there are still so many better options, like the e-bike. And if your choice is the hummer than you really can't claim any
rypher t1_j7jiy7f wrote
Thats in the snow. A good chunk of the energy is going to heat the batteries. Teslas have the same problem.