You do realize that high current charging is inefficient (heat dissipated in the battery goes up 4x if you double the current ("miles/hr"), and the A/C has to work harder) and, in theory, is not a good idea for battery longevity?
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You do realize that high current charging is inefficient (heat dissipated in the battery goes up 4x if you double the current ("miles/hr"), and the A/C has to work harder) and, in theory, is not a good idea for battery longevity?
There's actually evidence that high amp AC charging is more efficient and not as hard on the cells. There are a lot of fixed losses in the charging electronics that are not related to the amperage, at least not in a linear fashion. These types of losses are more closely related to time so they waste more heat the longer the car is charging. At low current the cooling system ends up working for a longer period of time even if not as high. 80 amps is still very slow for these large batteries. Very little internal heat is generated. The resistance does not go up at higher amps. In the winter months you actually want to generate more heat so the battery heater does not have to waste as much energy.
The argument has also been made by at least one battery scientist that 72 and 80A charging is better for the life of the cells than slower charging. This is because the cells spend less time at their maximum voltage. Many of the recommendations for treating cell phone batteries don't apply to our cars.
dk10438
Member
Idk but 17 kw doesn’t seem like a lot to me, 0.2c?
AC is working harder? Call me a skeptic.
AC doesn't work at all when I used to charge at 80A. 4x of nearly 0 is still nearly 0.
It's just out of stock... That happens...
When they have the Email me when this item is restocked. Means just that... The 8 foot looks available.
eprosenx
Active Member
The max onboard charge rate of any currently sold Tesla is 48 amps, so that is where the 11.5kw is coming from I think. All the Wall Connectors (except for the corded one) are capable of 80a charge rates as far as I know.
I have a dual charger Model S, and there were quite a few sold before...
Many destination chargers still run at 80A...
eprosenx
Active Member
Yeah, all the current published specs say ‘48’ for the cars even though there are tons of 72 and 80 amp capable cars out there. The past does not exist to Tesla.
My.X has a 72 and both my HPWCs are set to 80 (well, one is, and the other is set to slave/secondary).
Nor the future... It is hard for me to imagine that the Tesla truck will only have a 48 amp charger onboard. It will inherently be much hungrier per mile so if they want decent recharge times my hunch is that it will have a faster charger (maye even 80 amps?)
Note that NO wall connector is a charger. It just feeds power to the charger in the car. It does have a maximum power/current capacity, which is what it's stating, but you should understand what it really does/is capable of.
And cell phones don't have on-board cooling (and cooling management) systems that the cars (well, at least Teslas, lol) do.
EVSteve
110% Solar Powered
Seriously? I missed this change. Yet another reason not to buy a new S. My home HPWC is one of the first gen units at 100A. My current car can use most of it (2017 100D) but honestly why pay extra for a wall connector at this point? I remember when we could pull 19.2kW. I could come home from work, grab a shower and such. The car would be back to full by the time I was ready to go. Now I’d have to go to the supercharger. Plus when I’m there it’s be beyond the taper wasting more time with more stress on the battery. Dumb.
Your ‘100’ is really an 80. The 100 was the circuit it was made for and they are all derated to 80%. As I said, every HPWC/TWC can do 80 amps to the car on a 100 amp circuit (max continuous load 80%).
If the car can’t use it, that’s another issue. My X, like your car, can use most of it (72) when we need/want to.
HPWCs are still good choices for permanent installation when you want a long cord, and to share one circuit between two or more units.
Load balancing. One can daisy-chain the wall connectors and have up to 4 cars charging at the same time.
EVSteve
110% Solar Powered
I’d like to see a residential installation with 4 daisy chained HPWC lol. IMO some homes will install at most two with the vast majority installing one and a 14-50 outlet for the less used car.
Dropping the car down limits it’s ability to fully utilize some destination chargers. Tesla was all about their destination charging network of hotels, inns, and such. Do they really save that much in production cost not offering the 17.5kW onboard?
I can't recall if @MorrisonHiker has 3 or 4 HPWC in their garage... I think it is only three, but they really should add a fourth outside for guests to charge at.
EVSteve
110% Solar Powered
It’s a 100A capacity. NEC code requires derating to 80% of maximum if the circuit is expected to be used more than 3 hours hence the 80A maximum output but the designed spec is 100A to be code compliant. It’s capable of 100 but not allowed by code. The kW number is then influenced by available voltage.
What sucks is because they’re limiting the amperage unless it’s getting the full 240v the car won’t reach the listed 17.2kW charge rate. I suspect those with the current option package will have similar limits respective of the voltage at their home. Point being one of the advantages Tesla has was being able to recover quickly at home if desired. 11.5kW with less voltage than optimal turns into less. Getting close to the charge rate of a Nissan Leaf at 7.2kW.
Currently only 3 load-balanced wall connectors but we have room for a 4th. Typically we don't charge all four cars at once so we can just move the cable from one of the other cars over to the 4th car when necessary.I can't recall if @MorrisonHiker has 3 or 4 HPWC in their garage... I think it is only three, but they really should add a fourth outside for guests to charge at.
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