So anyone know if it’s feasible to DIY a supercharger at home? From what I gather, you need an AC to DC converter, a load manager, a battery power source like a power wall, and an adapter for the Tesla. I’m thinking it can be used sporadically after charging up an energy storage device and then dumping the electricity from storage to the Tesla.
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DIY Supercharger
- Thread starter Whtrbt7
- Start date
Yes if your name is Larry Ellison and you own a private compound (much of an island) in Hawaii.
What is the benefit of such a device? Between all of the components and the smarts to make it all work, you're looking at a substantial amount of money. A Tesla Wall Connector ($400) on a 60 amp circuit will completely charge the car in about six hours.
It's gonna be tough.
A quick glance at the Powerwall 2 shows it can provide 5.8kW continuous ... until it runs out in about 2.5 hours.
The Tesla Wall Connector provides about approximately 11.5 kW (48 amps at 240v) continously, until the car is charged. That's about 15% per hour.
A V3 Supercharger provides up to 250 kW. I might be off, but to match this rate would require about 43 Powerwalls, give or take 5 or so?
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Ah good point. It’s just a curiosity to see if one can be DIYed. So most likely, I would have to find a way to store more energy and then dump it at 250kW. I figure since the vehicle is about 75kWh, you just need to store about that much or about 100kWh of energy to dump it into the vehicle. The main thing would be to have the battery dumps at a rate of 250kW so it would supercharge. It would be easier to get a high amperage source and then convert from AC to DC to supercharge. The usage case would be when you just need a quick bump of energy in a short amount of time vs the 6 hour charge from a level 2 wall connector. From what I understand of the process, it’s not great for the battery to always be supercharged since it’s feeding DC directly to the battery which I think wears down the number of total charge cycles. If you could keep a separate battery at home and then dump it into the vehicle when you want, it would serve as an alternate quick charging method in case you needed it.
davewill
Active Member
It wouldn't have to be 250kW to be useful. This is not exactly DIY, but is something more feasible for a home solution:
Delta Wallbox 25kW DCFC 25kW - Dual Port
This level 3 DCFC (DC fast charger) comes with dual SAECombo and CHAdeMO connectors and is the perfect low-cost solution for high-powered fast charging. The Delta Wallbox delivers 25kW of power, starting at less than half of the price of competitors' units.
www.evchargesolutions.com
fiehlsport
Tire Guy
Yep, you can get a Delta or ABB CCS fast charger that utilize a 125A breaker on a 240V household circuit. They're wildly expensive (thousands) but are just about the fastest charger you can install at your home.
As fast and expensive as they are, that's still only 30kW. We're still not near "Supercharger" charge rates.
But back to the real world, I'm pretty darned happy with my Wall Connector and 48 amps @ 240v.
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fiehlsport
Tire Guy
I'd call it Defective Supercharger charging rates.
And they're only around 24-25kW, since they only pull 80% of 125A. (100A) The wiring alone would be very expensive.
If I had a huge family with a lot of EVs, money no object, and everybody did ridesharing, this might make sense for home. (Hard to think of a use-case that makes sense...)
fiehlsport
Tire Guy
So yes, I was thinking of doing this without 3 phase power from the line and using AC to DC to charge battery cells and then use a DC battery dump directly into the vehicle with a manager in between. This way, whenever I’m not charging the vehicle, it can charge the batteries using single phase power and store it for a DC charge. After thinking about this more, it would only make sense if I was to run the house using these batteries and even more efficient if I used solar panels to charge the batteries. That way, I don’t lose 20% from AC to DC conversion since solar is DC to DC batteries. I do have access to 3 phase power since I’m close to a major road but 3 phase power is extremely expensive and the setup would also be a pain.
A DC fast charger isn't exactly what you are imagining. It's a variable voltage DC supply. If you are starting with DC, you are doing a conversion that is essentially DC-AC-DC. Everything that makes for an efficient DC-DC converter e.g. synchronous rectification, resonant magnetics, etc. applies to separate DC-AC inverter and AC charger sections.
Note that the on-board AC charger is far more efficient than you are imagining. An 80% efficient charger would be throwing off hideous amounts of heat. The Tesla on-board charger is estimated to be over 95% efficient, perhaps over 98% at the peak. Naive measurements that claim lower efficiency (often in the low 90s) are not compensating for the fixed power usage of the modules that are active while charging.
This is also known as the arduino paradox.
You can build anything yourself, but it won’t be cheaper or easier than what’s already available off the shelf.
You can build anything yourself, but it won’t be cheaper or easier than what’s already available off the shelf.
How far from home is your closest Supercharger? That’s exactly what it’s for. ….
I really can’t think of a scenario where you’d arrive at home with such a low state of charge and the need for immediate long distance driving, that couldn't have been offset with strategic supercharging in the rare event such might happen.
Tesla wall connector charges really fast and you’d don’t have to “wait (charge) 6 hours” to drive again after every time you get home. What people need to do is plug in EVERY time they get home.
I’ve put 20K miles on our ModelY in 8 months. We drive a lot. We travel in it often. In and back out at all states of charge. impromptu excursions to north ga mountains. Range anxiety is NEVER an issue. We only supercharge when vacationing,
I’ve never thought I needed DC direct at home.
Are you really gonna drive 250 miles nonstop at highway speed, get home and immediately need to drive 250 miles again?
If so electric might not be a good choice.
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Putting aside the technical challenges of the "supercharger" for a minute, getting enough solar to provide 100kW of power daily, year round, would be 10s of thousands (likely 40k+), and getting enough battery storage to dump that solar into would likely also be "10s of thousands".
If you dump the solar requirement, then you have the cost of that much power from the utility.
Even if the technical hurdle of making something that charges at anything close to supercharger rates is overcome, there is virtually zero chance of ever even breaking even on it... even at CA or Hawaii electricity rates, and certainly never at what google says are average electricity rates in georgia (the location under your name).
So, I am guessing this is basically just a thought experiment.
Yeah, I’m a bit of a tinkerer so it’s more about the journey than the destination. It’s not about the cost but rather if it’s possible to DIY one. I’ve done lots of Arduino projects before and they all end up being more expensive than off the shelf. I’m just looking to get a deeper understanding of the technology involved.
Lol, you’re going to crack up when you hear this. I’m 2 miles from a Supercharger. It’s not really about range anxiety because I know a supercharger is always close by. Glad to know another fellow GA Tesla owner. It’s just to see if I can build a DC charger to get energy from solar or off-peak grid stored and then dumped. Normally for longer trips, I’ll drive about 750 miles but it’s not round trip. I also kind of do it cannonball style. The superchargers will force me to wait and charge, hence getting some rest in between.
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