Will a Solar Specific Charger Save You Money?

The short answer is it’s often unlikely but it’s not always about the money so please read on.

To clarify a solar specific charger is a device that detects home solar input and can be set so an EVs charging amps will not be higher than the excess solar available, for instance if the sky becomes cloudy and solar input reduces so will the EVs charge input.

If you have a neighbour that loves calling your Tesla a “Coal burner” there’s no better way to shut down the claim than by charging 100% from solar power, a solar specific charger is a good way of achieving this. As your neighbour is already too thick to understand electric motor efficiency they won’t be wise enough to work out you’re not saving any money by charging via a sometimes expensive piece of equipment.

Perth is the sunniest capital city in Australia – Yep, even sunnier than Brisbane in the sunshine state. During daylight hours the sun shines on average two thirds of the time in the Perth area so installing a device that only allows solar to charge an EV is redundant for two thirds of the time.

Combined Installation and unit cost – This varies by a large margin so it’s best left to a case by case basis, what is important is to get an accurate dollar figure on the difference between a fully installed solar specific charger and a fully installed “dumb” (generic) unit that continues charging at the same amps. For instance if Tesla have provided you with a free Gen2 UMC that you plan to plug in to an existing 10/15amp wall socket your installation plus unit cost is zero dollars. If you’re considering a $750 Tesla destination charger (HPWC) with a $750 installation cost your total cost is $1500. Keep in mind $750 is an example as installation costs are wide ranging.

Now as an example if you get a quote of $2000 for the solar specific charger plus $750 installation the extra upfront cost to charge directly from solar is between $1250 and $2750.

How long will the payback on investment be?

Once you have a fixed and trustworthy quote and you also have a firm understanding on how many kilometres you plan to drive per day using home charging use the below chart to do some calculations. If you’re not sure about driving kilometres yet a good guide is this, the average passenger car travels 38kms per day in Australia.

I’ve factored in a unit cost of 30 cents from the grid and the 2023 feed in the tariff of 3 cents per unit, this provides a potential saving of 27 cents for every kWh of solar going direct to the car. Keep in mind that In Perth across a whole year the sun is shining 2/3s of the time anyway.

The decision to install a solar specific charger is up to you, just think through these questions:

  • Do you drive enough distance per day to justify it?
  • Do you plan to charge from home during the day on an almost daily basis?
  • Do you have enough excess solar?
  • And does the units warranty period match your expectations?

How to find Free Charging, some Hot Tips from a long term EV owner.

To be very clear if you purchased a $70k+ vehicle and saving money on refueling is the only focus you’ve missed the point, lower long term servicing and repair plus the far longer lifespan of a Tesla are just as important. Throw in the high safety rating and the additional storage a Tesla provides and ownership is a broad package.

Without doubt the best EV charging is at home, even 30 cents a unit grid power is at least half the price per distance driven than a similar size and performance petrol car. If you charge off peak, even cheaper. Those using home solar are reducing their fuel cost by up to a factor of 8. Best of all parking at home is safe, no door dings from lazy parking, no stray shopping trolleys, there’s big savings to be made from avoiding the panel beaters.

What about all those free Tesla destination chargers? These are not free, they’re complimentary, almost all Tesla destination chargers are owned by a local business that have installed them to support EV owners. The electricity is not paid for by Tesla, it’s paid for by the small business that would prefer you drop in and buy a product rather than you sitting in your car watching Netflix.

Is there an app that shows all the free chargers? I get asked this question often in public and the answer is “not specifically”, the best way to find them is to log on to Plugshare, find the busiest and always in use chargers in the metro area and its a sure bet they’re free.

So what is the best free charger in WA? The one at your home, it’s never ICED, it doesn’t require an app, you won’t get panel damage and best of all it’s free to use any time you like.

While on the subject of free, TOCWA have a free loan of charging cables and spare tyres for members, membership is $20 per year via this link.

Tesla Destination Charger Problem Solving

On occasions you’ll plug into a destination charger that doesn’t appear to work, a small number of these public chargers are becoming unreliable mostly due to the cable getting mistreated, to add some confusion the same charger will not work for one car and then work first time for the following car on the same day, the Williams Woolshed destination charger is a great example.

To make the Tesla experience a bit easier here are the steps to work through that will hopefully get a Tesla destination unit to charge:

If there’s no Green or Red light strip light on the front check that power is switched on at the meter box, some premises keep it switched off for various reason, this will be often noted on the Plugshare app.

If you’ve established that the unit is powered up but a Red light is showing check that the cable is not twisted or stretched in any form, also check the cable is not pulled out from the bottom of the charging unit, that is you can see each individual colored cable rather than the black insulation.

Once the above steps are done locate the Red reset button on the side of the unit, using your thumb press it in and hold until all lights go off and wait until the Red/Orange light on the front turns Green, this will take between 5 and 30 seconds, if all goes to plan the Green light will start moving and the car will charge. If it doesn’t work the first time give it another go, also try unplugging and plugging back in before attempting a third reset, once again make sure the cable is not unduly stressed. If the charging doesn’t start after 4 resets the chances of it working at all on your car are very low.

If you do get charging started don’t rush off, hang around for a minute until the cars charging at full amps, if the unit has a fault it is likely to trip off within the first minute, if it does trip off it’s best to no longer attempt charging and report the issue. If you have no other choice and desperately need to charge try dropping the amps down via the cars touchscreen, keep in mind this is an absolute last resort. As an extra precaution if you walk away from the car to visit the shops or cafe check the phone app after 15 minutes, it’s very likely charging is still okay but there’s no harm making sure.

Using Tesla destination chargers (HPWC)

A Tesla destination charger is also known as a High power wall connector (HPWC), it has two variations, the rarely seen 40amp single phase that was issued to owners and venues up until late 2015 and the most common and more versatile  32amp three phase (22kw) that can also be connected to a single phase circuit. Technically the HPWC it’s not actually a charger but better described as a smart device that provides safe AC electricity to the vehicle’ s onboard charger, the charging power is limited by both the electricity feed to the HPWC and also the capacity of the onboard charger, a vehicle with an 11kw onboard charger connected to a 22kw HPWC will only charge at a maximum of 11kw, the same vehicle connected to a 6kw limited HPWC will only charge at a maximum of 6kw.

Although a Tesla HPWC is restricted to a maximum of 22kw (32amp three phase) they still have two advantages over DC charging, firstly AC charge points are multiple times cheaper to install per kw of power available compared to DC chargers. Secondly AC charging speeds may be slower but are very consistent and predictable right up to a battery state of charge (SOC) above 97%, DC chargers on the other hand have a large variance in charging speed depending on battery SOC, this can be confusing for new EV owners.

Publicly available HPWCs are provided by Tesla but on the vast majority of occasions owned by the property it’s connected to, prior to late 2017 the installation fee was covered by Tesla, since that time almost all installations have been paid for by the buildings owners, in regional areas this can cost upwards of $1500 per unit, this is a significant cost for EV’s that may or may be few and far between over the next couple of years.

Although most publicly available Tesla HPWCs are referred to as free to use they are better seen as being complimentary for customers. In other words a shopping centre that’s installed a charge point is expecting the EV owner to be a paying customer even if you only buy a drink, no one is monitoring purchases but any drivers taking electricity without supporting the location is an unwelcome member of the EV community that will spoil it for other owners in that area. If the local council has installed a charge point they’re not expecting you to sit in your car, they’re expecting you to get out and boost the local economy (keep in mind, there are ratepayers less than happy with their local council installing charge points), anyone seen sitting in a EV getting free electricity is sure to get a negative mention at the next council meeting.

Tesla HPWCs in regional motels and service stops are very much “not free”, the owner, management or staff will likely see you drive in from the main highway. Some charge a per kWh cost others charge on a time basis, those that don’t charge for the electricity have a high expectation you’ll stay overnight or buy lunch, at this stage electricity is still expensive in regional areas, if they don’t see a business case to continue providing a charge point it will soon get disconnected. In every occasion when using a regional Tesla HPWC always thank the owner/manager, it goes a long way.

A few tips:

  • Don’t trust the Tesla touchscreen maps to display the correct power rating of the HPWC, cross reference the location with reliable comments on Plugshare. Often newly installed units have not been adjusted up from the factory setting of 6kw, if you’re the first visitor to that location it’s always a possibility.  A few Tesla owners have been know to open the HPWC and increase the setting, personally I wouldn’t do that, firstly it’s not my property and secondly there could be a very good reason it’s at that setting. Best to mention it to the owner who will call out the electrician.
  • If the HPWC is not displaying a Green light it’s very likely switched off at the meter box, often in regional areas management will do this so EV owners make the effort to go in a say hello. Even if the HPWC is switched on its always good policy to ask permission before plugging in the car, it only takes a minute and provides goodwill for future EV owners.
  • If the HPWC is switched on but fails to charge it may need a reset, unplug from car, press and hold red “Reset” button on left side of HPWC until the light on the front of the unit goes out, let go of red button and wait until light goes back to normal (about a minute), then attempt to charge, this may take two attempts.
  • The biggest tip I can give you is ALWAYS BE CHARGING, if you are in a country area don’t bypass a HPWC that you know is working for one that hasn’t been used in a while.