IMO, Fast charging is really only necessary for long trips.
Since L2 is more than enough to charge overnight, I'd rather see every parking space get a 30A 240V plug (which should be considerably cheaper than charging stations), with some shared metering to not overload the circuit, but also enough to fully charge all EVs overnight - essentially a single L2 charging station, that moderates load over a large number of plugs.
> I'd rather see every parking space get a 30A 240V plug
The whole crux of TFA is that this isn’t feasible to retrofit to existing apartment complexes:
> For many others, the parking spaces will be owned by the condo association or co-op, complicating the idea of giving each EV driver their own plug. Here, shared solutions make more sense, perhaps starting with one or two shared level 2 chargers as a pilot—often this won't even require extra work to the electrical panel. Costs are a little higher than for a home level 2 charger—between $7,500–$15,000 per charger, perhaps.
> But for larger developments, scaling up level 2 chargers can quickly become prohibitively expensive. Older buildings may well need their electrical infrastructure to be upgraded, and running copper wiring across parking lots starts to add up fast.
This battery-backed fast charger doesn't really help to charge the whole complex. How long does the battery last? What is the throughput?
Also, think of the trouble of trying to coordinate times and moving cars around. Everyone wants to charge in the morning, some people are smart enough to charge when get home. Nobody wants to get notification and go move their car in middle of dinner or breakfast.
I found a site with the cost, it is $58k for the battery-backed version. That pays for 5-10 level 2 chargers. Also, I'm not sure it changes the overall situation, cause either pay for wires, batteries, or time.
Once again the economic argument for retrofits is spelled out in TFA (I’ve now quoted 80% of it)
> Faced with the install costs for a dozen 2 chargers, a battery-buffered DC fast charger starts to look like an attractive alternative. These use an existing electrical feed to trickle-charge a lithium-ion battery pack that can then DC fast-charge an EV, rather than requiring hundreds of kilowatts. Instead of taking 6–10 hours to recharge with AC power, about 30 minutes is usually sufficient to return most EVs to 80 percent state of charge with a DC fast charger.
> A condo building in Miami, the Marina Palms, recently made just this decision after a boom in the number of residents with EVs created a need for more charging capacity than its six existing level 2 chargers could offer. It went with a ChargeBox from ADS-TEC Energy, which is capable of charging at up to 320 kW.
> "That was one of the biggest appeals, that we didn't have to work with the electrical infrastructure of our development or grow it or whatever, just to get this charger installed. I think we have 200 kW in the power grid on that side, and we're using 100 kW. The other way [with multiple level 2 chargers] we would be using a minimum of 140 kW, if not the whole thing, and then we have no buffer for something else we might be doing like—for instance a car lift or that type of thing," explained George Barriere, general manager for the Marina Palms.
> If the costs are comparable, there's another benefit to picking a DC fast charger in place of a bank of AC plugs—it takes up less room. "We didn't use anything from our inventory of parking, which is the biggest problem for condos—lack of parking. So, we would have to have 20 parking spaces for 20 level 2 chargers in order to service the same number of vehicles that we're doing with two parking spaces [with a single level 3 charger]," Barriere told me.
This is the most reasonable solution as far as I’m concerned. There are still challenges related to this he electrical service the building is provided. For example you may find the building doesn’t really have enough energy to provide every spot L2 charging.
Since L2 is more than enough to charge overnight, I'd rather see every parking space get a 30A 240V plug (which should be considerably cheaper than charging stations), with some shared metering to not overload the circuit, but also enough to fully charge all EVs overnight - essentially a single L2 charging station, that moderates load over a large number of plugs.