Dual charger useful when away from home?

[Rocky_H]

I recommend getting Dual Chargers if you can afford it, they are useful now and they will only become more useful in the future as more higher amperage destination chargers become available.

Well, I find it the opposite. There were two trips I took early on when we had the car when there were no Superchargers in this part of the country where there was an 80A HPWC available that I used at 40A, and it was really slow. Now that the Superchargers are here, those trips are easy, and I don’t see a need for dual chargers in the future.

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Heading east from Bend, its 318 miles to the Supercharger in Boise, ID. There's an older Tesla branded J1772 charging station behind the Harney County Chamber of Commerce in Burns. It runs at 208v, 70 amps. Over Christmas we used it to springboard us to Boise, charging for 2 hours in the evening while we ate dinner, then spent the night in a nearby motel plugged into a 120v wall plug (mainly to keep the battery warm), and then plugged it in for another 2 hours in the morning while we got ready and ate breakfast.

I live in Boise, and I’ve looked at that route to/from Bend. Since I don’t have dual chargers, that high amp charger in Burns wouldn’t benefit me anyway, but the route I figured out was this. Instead of going through Burns and Ontario, it looks like you can go all the way through John Day to Baker City to the Supercharger (if you have an 85), and then easily get to Boise. It is about 40 miles farther, but there’s no slow charging.

 

[AWDtsla]

I have requested that plugshare allow filtering as you suggest. When I called they indicated that they did not see a need for it. Perhaps more people calling and making this request is in order.

I requested it. Seemed more positive "we're working on it"

 

[Scotty]

I started a thread last year about "Why I ordered my MS with the 2nd charger". I don't know if the OP on this thread found it, but it still has some relevant info, even though the 2nd charger is no longer available as a factory ibstalled option before initial delivery.

Quite a bit on that, and this thread. I usually use SpC when traveling, but being able to charge at up to 80 Amps is a big adavantage. Also, when charging at more than 40 A, and below 80 A, the dual chargers split the charging work between them. A single charger at 40 A would be more stressed than each charger charging at 35 A each and yet charging the MS at 70 A.

After 15 months, and 55,000 miles, if I was ordering a new MS, I would still have the 2nd charger installed, after delivery. Even if not currently using the full capability, it's good to have options.

 

[Rocky_H]

Also, when charging at more than 40 A, and below 80 A, the dual chargers split the charging work between them. A single charger at 40 A would be more stressed than each charger charging at 35 A each and yet charging the MS at 70 A.

I don’t know if I can find the reference for it, but I have heard that the dual chargers do not split the current half and half between them. It’s more of a “spillover” of anything over 40 going to the second charger. So with 52 amps or something, you would have 40 and 12.

 

[linkster]

with 52 amps or something, you would have 40 and 12.

Nope.

Cottonwood "edumacated" :scared: us years ago on this.

 

[Cottonwood]

Nope.

Cottonwood "edumacated" :scared: us years ago on this.

Correct! I've watched it many times in multiple Model S's. The split is 50-50 for anything over 40 Amps.

 

[Rocky_H]

Correct! I've watched it many times in multiple Model S's. The split is 50-50 for anything over 40 Amps.

Oh, OK—learned something new. You said you’ve “watched” this. How do you see it? Does Visible Tesla get a reading on how much each charger is using?

 

[Cottonwood]

Oh, OK—learned something new. You said you’ve “watched” this. How do you see it? Does Visible Tesla get a reading on how much each charger is using?

Just watch the charge start with the displays in the car. You will see the current ramp up to half the total, pause as the slave charger comes on line, then the current continues to ramp up as the slave takes the second half of the load.

 

[Cottonwood]

I thought of another reason to get dual chargers. If the Tesla engineers did a reasonable thing, then the waste heat from charging will help heat the batteries in the winter. Use 80 Amps and let the charge session finish just before you depart and you will have less of a regen limit.

Here is the coolant loop diagram from a maintenance screen:

View attachment 108066

We believe that the valve on the left can go to "series" mode from "parallel" mode to put the inverter/motor into the loop and help heat the battery. Note that this also puts the liquid cooling of the AC chargers in a place where their waste heat can help heat the batteries. If we assume 90% AC to DC conversion, that is almost 1 kW waste heat 40 Amp charging and almost 2 kW waste heat from 80 Amp charging to heat the batteries. This is a good reason to have your charging finish just before departure on cold days and also a good reason for dual chargers and 80 Amp charging at home if you live in a cold climate.