Sizing up
How many amps do you actually need?
Three checks in order: what you drive, what your car accepts, and what your panel can feed. Whichever is smallest is your answer.
By Sawyer V. · Published September 8, 2026
How this page is funded: we earn a commission if you buy through our Amazon links, at no extra cost to you. It does not change what we recommend, and we say plainly when the honest answer is to buy nothing. Full disclosure.
There are three separate limits on how fast you can charge at home, and your actual charging speed is whichever of them is lowest. Work them out in this order and you will not overbuy.
Check 1: what do you actually drive?
Look at your odometer over a normal week and divide by seven. That is your daily average. Now work out how long it takes to replace it:
Replacing a typical day
40 miles driven / 3.5 mi/kWh = 11.4 kWh to replace
At 32 A (7.7 kW): 11.4 / 7.7 = about 1 hour 29 minutes
At 48 A (11.5 kW): 11.4 / 11.5 = about 1 hour
You are plugged in for ten hours either way.
If that is your driving, this check says 32 amps and everything above it is equivalent. If you drive 150 miles a day, the picture changes and you should size up.
Check 2: what does your car accept?
Your car's onboard charger converts AC from the wall into DC for the battery, and it has a fixed maximum. Common figures are 7.7 kW (32 A), 9.6 kW (40 A) and 11.5 kW (48 A). Some plug-in hybrids accept 3.3 kW or less.
Find yours in the owner's manual under charging or specifications. If your car accepts 7.7 kW, a 48-amp charger delivers exactly 7.7 kW to it. You can still buy the larger unit as headroom for a future car -- that is a real reason -- but be clear that is what you are buying.
Check 3: what can your panel feed?
Open the panel. Read the main breaker: 100, 150 or 200 amps. Count the free slots -- a charger needs two adjacent ones. Then work through a load calculation to see what is genuinely spare after your existing loads.
| Charger | Circuit | Panel implication |
|---|---|---|
| 32 A | 40 A | Fits most panels with spare slots |
| 40 A | 50 A | Comfortable on a healthy 150-200 A service |
| 48 A | 60 A | Needs genuine headroom; a full 100 A panel will struggle |
Take the smallest of the three
If your driving says 32, your car accepts 48 and your panel allows 40, buy a 40-amp charger and it will spend most nights loafing. If your driving says 48, your car accepts 48 and your panel allows 32, you have a panel problem rather than a charger problem -- read panel upgrades.
One charger per answer
Ranked for a first home charger. Every row jumps to the full write-up below.
| # | Product | Best for | Max output | Price |
|---|---|---|---|---|
| 1 | Grizzl-E ClassicHarsh weather and no app. J1772, 24 ft cable. | Harsh weather and no app | 40 A9.6 kW | Check price on Amazon#ad how we are funded |
| 2 | Emporia Level 2 EV Charger (Classic)A first charger, hardwired. J1772, 24 ft cable. | A first charger, hardwired | 48 A11.5 kW | Check price on Amazon#ad how we are funded |
| 3 | ChargePoint Home FlexHomes with an uncertain panel. J1772, 23 ft cable. | Homes with an uncertain panel | 50 A12 kW | Check price on Amazon#ad how we are funded |
The three units in detail
Matched to the three common outcomes of the checks above.
1. Harsh weather and no app
Grizzl-E Classic
United Chargers · J1772 · 40 A / 9.6 kW · 24 ft cable
A cast-aluminum box with no app, no account and no firmware to update. If you want a charger that behaves like an appliance, this is the one.
What is good
- Cast aluminum NEMA 4 / IP67 enclosure, built for outdoor mounting
- No app, no account, no network dependency
- Amperage is set with physical switches, not software
- Protections for over-current, over-voltage, ground fault and over-temperature
What is not
- 40 A ceiling, slower than the 48 A units if your panel can take more
- No scheduling, so off-peak charging has to be set in the car
- The cold-flexible 24 ft cable is only on the Extreme Edition
| Maximum output | 40 A / 9.6 kW at 240 V |
|---|---|
| Adjustable | 16, 24, 32 or 40 A |
| Connector | SAE J1772 |
| Cable | 24 ft on the Extreme Edition |
| Enclosure | Cast aluminum, NEMA 4 / IP67 |
| Certification | UL certified |
| Warranty | 3 years |
Skip this if: Skip it if you want scheduled charging or energy tracking in an app. The Classic deliberately has neither.
Specifications above are the manufacturer’s published figures. Source: United Chargers, InsideEVs. We have not tested this unit — see how we pick.
2. A first charger, hardwired
Emporia Level 2 EV Charger (Classic)
Emporia · J1772 · 48 A / 11.5 kW · 24 ft cable
The safe default for a first home charger: 48 amps hardwired, a genuinely long cable, a NEMA 4 outdoor-rated case, and no subscription attached to the app.
What is good
- 48 A hardwired is the fastest tier most homes can realistically support
- 24 ft of cable reaches across a two-car garage without a fight
- NEMA Type 4 enclosure is rated for outdoor mounting
- Energy monitoring in the app with no subscription
What is not
- Drops to 40 A if you use the NEMA 14-50 plug rather than hardwiring
- The app is the only way to change the amperage setting
| Maximum output | 48 A / 11.5 kW at 240 V (hardwired) |
|---|---|
| Plug-in output | 40 A with the NEMA 14-50 plug |
| Connector | SAE J1772 |
| Cable | 24 ft |
| Enclosure | NEMA Type 4, indoor or outdoor |
| Certification | UL listed, Energy Star |
| Warranty | 3 years |
Skip this if: Skip it if you want a unit with no app or network connection at all. The Grizzl-E Classic is the simpler machine.
Specifications above are the manufacturer’s published figures. Source: Emporia Energy. We have not tested this unit — see how we pick.
3. Homes with an uncertain panel
ChargePoint Home Flex
ChargePoint · J1772 · 50 A / 12 kW · 23 ft cable
The most adjustable unit here. It can be set anywhere from 16 A to 50 A, which makes it the one to buy when you do not yet know what your panel will allow.
What is good
- Six selectable amperage settings from 16 A to 50 A
- Sold in both hardwired and NEMA 14-50 versions
- Rated for indoor or outdoor installation
- The app is mature and does not require a subscription
What is not
- 23 ft is a foot shorter than the longest cables in this group
- The 50 A setting needs a bigger circuit than most panels have spare
| Maximum output | 50 A / 12 kW at 240 V |
|---|---|
| Amperage settings | 16, 24, 32, 40, 48 or 50 A |
| Connector | SAE J1772 |
| Cable | 23 ft |
| Installation | Hardwired or NEMA 14-50 |
| Certification | UL listed, Energy Star |
| Warranty | 3 years |
Skip this if: Skip it if your circuit is already fixed and you just want the cheapest safe 40 A unit. You are paying for flexibility you will not use.
Specifications above are the manufacturer’s published figures. Source: ChargePoint, ChargePoint. We have not tested this unit — see how we pick.
FAQ
Questions people actually ask
How many amps should a home EV charger be?
Is 32 amps enough for an EV charger?
How do I find out what my car's onboard charger accepts?
What if my panel cannot support the charger I want?
Sources
Where these numbers come from
- NEC Article 625: EV charging equipment — WireRef
- Level 2 EV charger installation cost in 2026 — SimpleSwitchPublished service-upgrade cost range. Fetched 2026-09-08.
Read next
Related reading
- What size breaker and wire does an EV charger need?Breaker and wire size for every charger amperage, with the 125% rule worked through.
- Can your electrical panel take an EV charger?What a load calculation is, what goes into it, and how to get a rough answer yourself.
- 32 A vs 40 A vs 48 A: how many amps do you actually need?What each amperage tier delivers in miles per hour, and the circuit each one requires.
- Do you need a panel upgrade for an EV charger?When a panel upgrade is genuinely needed, what it costs, and the cheaper alternatives.