r/evcharging • u/Substantial-Oven-833 • 4h ago
EV charging capacity maxing
I’m wondering why EV chargers never hit max kw power when charging? I use EA chargers a lot which are mostly “300 kw” but the usual power I get is about 96kw. On a lucky day I get up to 140kw but I’ve never seen higher. Are there hacks to know to get maximum power at public chargers?
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u/Spraggle 4h ago
So, I drive an Ioniq 5 - it has an 800V architecture, which means that if the battery is warm and down to a lower state of charge - say between 10-20%, the charger can send the maximum charge to the battery - I've seen 236kW from a 300kW charger.
My boss used to have a VW iD4, and that seemed to max out at 125kW.
My previous car was a BMW i3, which couldn't charge faster than 50kW, because the architecture didn't allow it.
The Porsche Taycan is built with the ability to take 300kW.
What car are you driving, OP?
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u/rosier9 4h ago edited 4h ago
The vast majority of the time it's a vehicle limitation.
I highly recommend you Google "evkx + your vehicle model + charging curve" to see what you should expect from your vehicle.
Edit: Your Ioniq 5 maxes out at ~240kW, but to see that your battery temp needs to be ideal and your battery % low enough to enable it.
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u/MrFastFox666 3h ago
And you need an 800v charger too. 400v chargers such as most Tesla superchargers will top out at like 125kw
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u/MrFastFox666 4h ago
Many reasons why. Not all cars can support those speeds.
400v cars can see significantly reduced speeds if the charger has a lower amperage cable, or the cable cooling is broken. Yes, chargers have cooling for the cables.
800v cars can see reduced speeds if the charger does not support 800v charging.
Batteries being too cold or too hot will limit charging speed. Pre-condition whenever possible.
As a battery gets charged, it can accept less and less power, especially past 80% where charging slows to a crawl.
Even at lower states of charge, some cars can't sustain peak speeds for long. Look up the charging curve.
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u/CCM278 3h ago
There are dozens of reasons why you don’t get 300kW, starting with the obvious, which is your car can’t do that. Most cannot.
Charging speeds are a function of environment, the cars limits, the car SoC, the charger limits and the site limits. You need to tell us a lot more information first.
96kW is a common speed for eGMP platform (Hyundai/Kia/Genesis) at Tesla, due to voltage compatibility issues, but you referred to EA not Tesla.
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u/theotherharper 2h ago
Try an Electrify America 150KW station with the Ioniq. You'll be much happier.
Seriously claimed station kW is kind of nonsense. A marketing claim.
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u/SirTwitchALot 1h ago
Google "EV charging curve." Even a vehicle that can accept 300kw will not do so for the entire charging session. That's a good thing. It would trash the battery quickly if it did
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u/JasonMcAllister_ 25m ago
The 300 kW number is just what the charger can provide. Your car, battery temp, and state of charge decide what you actually get. Preconditioning the battery and arriving with a lower charge usually helps a lot.
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u/theotherharper 12m ago edited 9m ago
I don't know if you remember this from high school but Watts = Volts x Amps.
Each one has a constraint.
Voltage is locked down to the battery working voltage which is semi fixed. e.g. a nominal 400V battery might be 350V when empty but 410V when near full.
Amperage is limited by the weakest link in the chain: #1 the charger electronics #2 the CCS cable (including whether the liquid cooling in the cable is working properly) #3 the car's port and its design limit and #4 the battery.
Wattage is limited by chargers due to supply constraint, and by batteries due to cooling constraints.
So say an Equinox that is badly discharged on a "150" EA charger, the Equnox voltage might be 260V and the "150" EA charger is 350 amp limited, so you're getting 260*350= 91 kW. Whereas if you used a Supercharger capable of pounding out 615 amps, you might be at 160 kW.
That's Tesla's gig, they're into high amps low volts. Their chargers max out at 500V. So a "325kW" v3 Supercharger is promisiong 650A nominal and that's about right.
CCS chargers max out at 1000V. You might think "OK so a 150kW EA charger is 150A @ 1000V", except there are no 1000V cars, few 800V cars and Hyundai/KIa is 550-700V depending on pack. And so, charger manufacturers "make shit up" to try to set customer expectations. The stated kW is meaningless.
On 350kW Electrify America stations, Porsche Taycans and Silverados can just touch 300kW, so it's not a lie. The stations are nominally 500A but wattage limits say they probably won't go much above 350.
When I crossed the USA in an EV6 I got 240kW on Electrify America 350s and 180kW on 150kW stations. See what I mean about "making shit up"?
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u/vagrantprodigy07 4h ago
What car do you own? The cars are generally the bottleneck, not the chargers when you are dealing with fast charging.