Fronius Wattpilot vs Tesla EV Chargers

Mark compares the Tesla Wall Connector and the Fronius Wattpilot EV chargers in this comprehensive video review. Key considerations include ergonomics, versatility, efficiency in utilizing solar surplus, and price. Mark also highlights the unique features and differences between the two chargers to help you make an informed decision for your electric vehicle charging needs.

Video Transcript

Whether you just bought an electric car or you’re thinking of buying an electric car, today I’m going to help you choose your EV charger. EV chargers are a big component in the electric vehicle experience, so it’s important that you select the one that’s right for you.

Now I’m comparing two of my favourite chargers the Tesla Wall Connector and the Fronius Wattpilot. Both of these charges will charge any electric vehicle on the Australian market. In fact, just because I never trust a spec sheet, I tested solar surplus charging of these chargers on my Tesla model 3 car and then I borrowed a BYD, and then a Kia electric car so I could test solar surplus charging on those cars.

Now, in this review will be looking at 4 big differences between the chargers:

  1. The first one is ergonomics and aesthetics – how nice it looks in your garage and how easy it is to use.
  2. And the second one is versatility. For example, how do these charges compare for use at work or in a public place?
  3. Now, the third point is the efficiency of charger when running on solar surplus. Now, I did heaps of testing around this point and I was surprised to find out that there is a clear winner.
  4. And the fourth point is, of course, price. For many people, price might just be the deciding factor, but these two chargers are wildly different in all four categories.

So, there is much to consider.

Let’s get into it. Let’s start off with ergonomics and aesthetics. This one is easy. Have a look. The Tesla Wall Connector is a work of art. It’s got this beautiful glass front that can even be swapped out for another colour to maybe match the colour of your car. It’s slimline and sleek, and it’s designed so that you can wrap the charge cable around it. I love the plug compared to any other charger that I’ve used. It’s so much more slimline and ergonomic. Now here is a small feature with a big impact for Tesla owners. Look at this. If I want to charge up my car, I press the button and it opens the cap. That’s pretty cool. Now this is just Tesla all over. I love it. If you own a Tesla, it may be hard to look past this charger, but hear me out. There are more things to consider first.

Let’s get into the Fronius Wattpilot. Full disclosure, I can be a little bit biased towards Fronius. I even won the Fronius Advocate Award last year. But as far as design goes, this was not their finest moment. Now, let’s have a look at it. It’s a plastic box with top cable entry, so you plug that into your power point. But that’s also the way that you would hardwire into your house. There’s nowhere to wrap your charging cable around it. But to be fair, the charging cable is intended to be taken with you. But if you’re primarily charging from home, you’ll probably end up leaving that cable dangling and it looks pretty cumbersome.

Although I do have to give Fronius points for this one. If you have a Fronius solar inverter and you connect your Wattpilot to the Fronius inverter app, you get a one-stop-shop for all your monitoring. I’ve got to admit, I find it very satisfying to see your solar production, your household usage and your EV charging all in the one place. However, monitoring isn’t the only cool feature of the Fronius Wattpilot.

Let’s talk about versatility. Now, let’s say you want to charge your EV at work, but the boss doesn’t want to install an EV charger. Well, use this little fella the Fronius Wattpilot Go… the plug-in version. You can just unplug it from home and take it to work. Now you will need a three-phase outlet to plug this into, and that’ll cost you around about $100 (AUD) or so plus installation. Okay. Imagine you’re installing the Fronius Wattpilot at a workplace or a share house where multiple people can use it. Well, first up, you can restrict the access to the use of the Fronius Wattpilot with a fob, and you can even see how much each person is using if you want to split the cost of electricity.

Now, second, if this charger is out in public, you won’t have to leave the cable dangling around, so it won’t get damaged or vandalised for that matter. Now, let’s move on to the Tesla. Despite what people think, you don’t need a Tesla car to charge with a Tesla Wall Connector. However, if you want to restrict who can use the Tesla Wall Connector, you can only limit it to certain Teslas to charge.

But then you won’t be able to use your Kia or your BYD so you’ll have to open it up to all cars if you want any other brand of car to use it. So, it’s a bit of a tough one, restrict it to some Teslas or open it to all EVs. Now let’s say you want to install multiple Tesla chargers at the workplace, but you don’t want to overload the power at your building when all EVs charge at once.

You can limit the combined output of all these charges to a certain level so you don’t trip the power to the building. The same thing can be done with the Fronius Wattpilot. This will be a really handy feature as EVs become more and more common.

Okay, let’s move on to efficiency. And this is where it gets really interesting. The most cost-effective way to charge your car is to charge it with excess solar power – solar that would have otherwise have been sent back to the grid or power that would have otherwise been export limited.

Now, if you want the Fronius Wattpilot to charge with excess solar. You’ll need a Fronius solar inverter. The Fronius inverter then tells the Wattpilot how much excess solar power it is sending back to the grid and the EV charger then adjusts its charge rate. So, the excess solar is not sent back to the grid It’s sent to the car instead.

Now, the Tesla Wall Connector isn’t designed to charge and excess solar, but maybe this will be a feature in a future update. What you can do, however, is use this neat third-party app called Charge HQ. All you need to do is give the app the details of your Tesla car and permission to access your solar inverter monitoring. Now Charge HQ can communicate with several different solar inverter brands and different EV chargers.

However, here’s the downside of Charge HQ. It can’t communicate with the Tesla Wall Connector…  instead, it communicates with the Tesla car. Here’s a list of the Charge HQ compatible chargers and solar inverters as of today.

fronius vs tesla list

But how accurate is Charge HQ at controlling the Tesla Model 3 to charge, just using my excess solar? So let’s look at a mock-up of 1 day. Let’s say this is the curve of the excess solar that you might have. It will match your curve. Something like this. Pretty accurate.

wattpilot curve

Now first the Tesla charger can only ramp up at 3 amp intervals, or that’s 750 watts.

Compare that to the Wattpilot that can be adjusted to ramp up and down at 1 amp intervals when it’s charging at less than seven kilowatts. Now that makes the Tesla and the Charge HQ combination three times less accurate at following your production curve.

Now second Charge HQ can only communicate with the inverter every 2 minutes or so. Now that makes it four times less responsive than Fronius, which updates every 30 seconds or so.

And third Charge HQ is super conservative about switching off the Tesla Wall Connector. So let’s say a cloud comes over and you no longer have excess solar. It’ll take 6 minutes before that charging turns off, and then you’ll be drawing grid power. Now let’s say the charger finally turns off, but the cloud will disappear. It’ll take a further 12 minutes for it to turn back on. So that’s 18 minutes where your charger is not following your solar production.

Now, the Fronius charger on the other hand will respond to clouds within 30 seconds. That’s for turning on and off.

So that’s going to follow your excess solar production a whole lot more accurately.

wattpilot curve

Now, the reason that Charge HQ is so conservative at switching is not because they are concerned about the car battery. The car battery will look after itself. They don’t want to force the Tesla wall charger to switch on and off too often in case the relays inside the charger burn out.

The Fronius Wattpilot on the other hand, was designed to switch regularly, so you’ll have no issues there.

Okay, let’s talk about price. The Fronius Wattpilot will set you back somewhere in the vicinity of $3,000 (AUD) installed. The Tesla Wall Connector will cost you around about $2,300 (AUD) installed.

Now, obviously this depends a lot on how difficult the installation is, but in short, the Fronius Wattpilot will cost you around $700 (AUD) more than the Tesla charger.

Now, on top of that, while the Tesla comes with a hard wired cable, if you buy the Fronius Wattpilot, you’ll need to bring your own EV charger cable, which will set you back around about $200 when you buy it online. Saying that, it’s good to have a charge cable in your boot to use at a destination charger anyway should you need one. So maybe that doesn’t count so much.

Okay. So which charger am I going to use?

Well, I’m keeping the Tesla Wall Connector at home because it just looks so sleek and I do most of my charging at work and because I’ve got 17 kilowatts of solar at home, I’m not too concerned that it’s not super accurate at following my solar surplus.

Now over at my warehouse, we’ve got a few different brands of EVs charging all at once and we’re using a few different Fronius inverters as well. So, I’m going to use the Fronius Wattpilot over there.

But here at the office I’ve got multiple different brands of solar inverters and I want to charge of excess solar power. So, I’m going to need another option.

And that’s where Zappi comes in. It solves a few of the problems that both of these EV chargers have. My Zappi review will be coming out soon, you can subscribe to my YouTube channel to get notified.

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Mark Cavanagh

Mark is the Owner and Manager of MC Solar & Electrical. He’s an Electrician, accredited solar installer/designer and an electrical contractor.

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