Is there something you’d like us to discuss? An issue we can help you better understand?
Send us your ideas for future blog topics here.


Jun 9, 2017, 16:29 PM by Amy Choi

A Site Assessment Is First

After you've placed your $500 deposit, a MPOWER Certified Installer will contact you to book a site assessment.  A site assessment typically lasts 1.5 to 2 hours.  

Here are ways you can help expedite the process: 

1.  Provide 1 year's worth of utility bills ( your electricity provider can usually help provide these), 
2.  Pictures of your main electrical panel (to see how large a system or electrical service you have),
3.  Picture of the space you want to install Powerwall.

What will the Certified Installer Do?

  1. Electrical systems are up to code - our electricians cannot start work if the wiring is not up to code; they could be liable if anything happens even if they didn't do the work
  2. Wall space - you need a minimum (HxW) 1.52m x 2.13m or 5'x7' of wall space to hang the Powerwall and the additional electrical equipment.  If not, then a Plan B will be devised.  Read more about Essential Load Backup and Whole Home Backup below.  
  3. Electrical loads - the Certified Installer will measure the electrical loads in your home.  Read below for more details.
  4. Moving in equipment - the Certified Installer will look at how they will need to move all 122 kg/ 269 lbs of Powerwall plus the additional electrical equipment into the area where it will be installed.  Stairs, tight corners, etc. all play a factor.  If things can't be installed together like the picture above, a suitable arrangement will be made.

Whole Home Backup

Why Do We Measure Electrical Loads?

Measuring your electrical loads is the same as understanding how much energy your home and lifestyle require.  This helps us determine how many Powerwalls you need.  Ideally, if you have your energy bills for the past year, MPOWER can determine what your maximum consumption is and can get to that number quicker.  Your maximum consumption will provide you with the number of Powerwalls needed to fully backup your home or "Whole Home Backup".  This means should the grid go out, you would be able to maintain your lifestyle for a desired amount of time - the more Powerwalls, the longer the time.

What are electrical loads?  Powerwall needs to work with all things electrical in your home from appliances, devices, lights, etc.  The technical term for all these items is 'electrical loads'.  

Let me try this analogy.  
1980s stereo system

I'm dating myself but i think back to the stereo system my parents had when we were kids.  We had one that played vinyl records (the big 33-1/3 and the smaller 45s), 8-tracks, cassettes and had AM/FM radio.  Stay with me.  All these different musical 'formats' could be played off one 'box'.  When installed, Powerwall will be the 'box' that will supply electricity for all the electrical loads connected to it.  Just like the stereo box supplied electricity to play the different musical formats.

We need to know how much electricity to send to each electrical load.  If the energy needed exceeds the capacity of Powerwall, it will shut off.

Peak and Continuous Power

One Powerwall 2 stores 13.5 kWh of energy.  It can discharge a peak of 7 kW and a continuous of 5 kW of power.  What does this mean?  It means that when Powerwall starts sending energy out to the loads, the maximum at peak or the 'inrush' (or when the load is turned on) is 7 kW.  We add all the power that these loads need and it can't be more than 7 kW when they turn on.  If it is more than 7 kW then you will need more Powerwalls or you will need to reduce the number of loads so that it is below 7 kW when they are turned on.  Remember, Powerwall will shut off if the loads exceed the peak.  The analogy to peak or inrush is the deep, comfy couch.  When you sit in one, it takes an upsurge of energy when you need to get up; so do some of your electrical loads when they turn on.

The 5 kW of continuous power means that after the load is turned on, what is the amount of power needed to keep these loads running.  Again, if they consume more than 5 kW all at once, then you need to consider another Powerwall or reducing the loads connected to Powerwall.

How Do We Measure Electrical Loads?

The Certified Installer will likely use a Clamp-On Meter.  It is attached to your main electrical panel and the various electrical loads you want backed up by Powerwall will be turned on.  The meter measures how much energy the load uses when it is turned on (inrush) and the energy required to keep it running.

Whole Home Backup

If you would like to maintain your regular lifestyle when the grid goes out, ask the Certified Installer to calculate how many Powerwalls you need for Whole Home Backup.  You will also need to provide your utility bills for the past year so we understand what is your peak consumption and your off-peak consumption.  We need to know how much energy you consume when your home is at its busiest.

Essential Load Backup

If you choose to have specific loads in your home backed up, then a little more work is required.  For backup power, we ask you to provide the electrical loads you absolutely need in an emergency when the electricity goes out.

We normally suggest the loads below and normally one Powerwall 2 can back these up for 12-24 hours.  The timing is uncertain until our Certified Installer comes in and measures the amount of energy these items consume in your home (we all use different brands, types, age and condition/ upkeep of electrical loads).

1.  Lights - so you can walk safely through your home.  This can be isolated to a main area of the home where your family gathers.
2.  WiFi - so you can stay connected and know what's happening.
3.  Refrigerator - so your food doesn't go bad if it lasts longer than a few hours
4.  Fan for gas furnace - we live in Canada and need heat in the winter; the assumption is the natural gas that powers your furnace is still available.  The fan is to ensure the heat produced is moved throughout your home.  Electrical heat consumes a lot of energy as your bill will attest if this is how you heat your home.  If you live in an area where electric heat is used, a different conversation will be had with the Certified Installer.
5.  Key electrical outlet(s) - one or two so you can plug in miscellaneous items that need charging like your mobile phone or a TV to watch the news.

During a site assessment, our Certified Installer will work with you to understand what your needs are and conduct a Load Assessment to understand how much energy these electrical loads consume.

Next up, Engineering Approval.

Plugged In

Find out how MPOWER Energy Solutions, featuring the Tesla Powerwall, is delivering on our customers’ green energy goals.



Learn more about key green energy issues and sustainability in our whitepapers.


Can't find what you're looking for?