Optional calculations

[eds]

when doing the optional calculations for a residence, would tesla charging receptacles, kilns, hot tub motors and heaters,electric patio heaters, and pool pump motors fall into the same area as my hot water heater , dishwasher, and dryer?

 

[Dennis Alwon]

What are you getting at. Do you mean do they get the same demand factor as the others. I would say yes except for the patio heater.

 

[eds]

Trying to decide if they fall into the heating and ac section of optional calculation or if they can be put into the add all the nameplate category. I imagine they belong in the heating category, just running thru my head about lumping them into the other area.

 

[Dennis Alwon]

Why would a charging unit be linked with the a/c or heating? Imo, it gets the demand at the end just like the other appliance then you add the heat/ac

 

[jaggedben]

My opinion, based on current code language:

tesla charging receptacles
No

kilns
Maybe

hot tub motors
No

and heaters,
Yes


electric patio heaters
Definitely yes.

, and pool pump motors
No.

As for whether the code should be updated, and whether you should account for those loads to cover yourself, those are different questions.

 

[caribconsult]

My opinion, based on current code language:

tesla charging receptacles
No

kilns
Maybe

hot tub motors
No

and heaters,
Yes


electric patio heaters
Definitely yes.

, and pool pump motors
No.

As for whether the code should be updated, and whether you should account for those loads to cover yourself, those are different questions.

In calculating load level, it's vital to remember that some fairly heavy loads, like a hot water heater, oven or anything that makes or removes heat by electricity, or a pool/water pump, air conditioners, or a big fridge with an icemaker, can switch their compressors or motors or heating elements on and off randomly and if several should occur at the same time, and you really have no control over that, you could easily be an either a 'high drain' situation with your battery, if that's what you are using, or even run it almost dead. The nominal load on the standard Powerwall is 5Kw, with surges of not more than 10 seconds to 7Kw, and it will provide some 13Kw/hours of juice. A good starting point is check your recent electric bill to see what your average daily Kw consumption is. Just divide the total # of Kw billed by 30 days or whatever your billing period is, and that will tell you how much juice your house uses in a day. On our single battery system, our daily consumption floats around 12Kwh per day, and with that, we can comfortably live off the PV production. We might be able to crank it up to 15-16Kwh per day but that might be the ceiling, unless we added more panels to provide more charging capacity. Or you might need more than one battery. Tesla will do a site survey for you, I believe. We've learned a lot about how to save electricity by having the Tesla system.