[HN Gopher] EV fast-charging comes to condos and apartments
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EV fast-charging comes to condos and apartments
Author : PaulHoule
Score : 24 points
Date : 2024-04-29 16:23 UTC (6 hours ago)
(HTM) web link (arstechnica.com)
(TXT) w3m dump (arstechnica.com)
| Rychard wrote:
| I wonder what the efficiency losses become in this configuration;
| using the grid to charge a battery to charge a vehicle.
|
| A quick google query says that efficiency of L2 residential EV
| chargers is somewhere in the neighborhood of 85%, and for DC-DC
| chargers the efficiency is in the order of 90%. I don't know
| nearly enough about this to state anything definitively, but it
| sounds like the efficiency losses start to accumulate pretty
| quickly.
|
| I wonder what the break-even point is in terms of cost compared
| to an average ICE vehicle.
|
| Apply a healthy dose of "Don't let perfect be the enemy of good
| enough" of course, but I am curious about the economics at play.
| Night_Thastus wrote:
| Considering ICE is less than 40% thermal efficiency of the
| fuel, I'd say it works out just fine.
|
| But fast charging in general should only be used when there's
| no voice - it's a lot harder on the battery. Better to slow
| charge overnight.
| travisb wrote:
| It sounds like you almost have enough numbers to calculate the
| ball-park efficiency.
|
| Grid -> condo battery ~85% (basically an L2 charger)
|
| Condo battery -> L3 charger let's say ~96%[0] because it's a
| high discharge rate
|
| L3 charger -> car ~90%
|
| It's simple math now: 0.85 * 0.96 * 0.90 = ~74% end-to-end
| efficiency.
|
| [0] https://www.researchgate.net/figure/Energy-efficiency-map-
| of...
| cogman10 wrote:
| With something like this, throwing in solar makes a lot of
| sense (IMO). There are already batteries involved so you could
| use solar as the primary recharge mechanism with the grid as a
| backup.
| lps41 wrote:
| A single apartment complex could almost certainly not cover
| enough space with solar panels in order to charge a battery
| to accommodate this.
| GenerWork wrote:
| I wonder how much the complex is charging for this, and whether
| people who have parking spots but don't have EVs also have to
| pay.
| turtlebits wrote:
| 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.
| gpapilion wrote:
| 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.
| cogman10 wrote:
| 1 L3 spot doing 150kW translates to ~15 L2 spots or ~100 L1
| spots.
|
| For the same power distribution, an apartment complex could
| easily do several L2 spots and L1 for everything else.
|
| With my 11 mile commute, L1 was almost viable (catching up on
| charge over the weekend).
|
| If both work and apartments had L1, that'd be enough for most
| people commuting.
| quickthrowman wrote:
| There are load management/load sharing products available for
| EV chargers today. Here's a white paper from Eaton: https://w
| ww.eaton.com/content/dam/eaton/products/emobility/e...
| h0l0cube wrote:
| > 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.
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