EV Charger Load Management (EVEMS) vs Panel Upgrade: How to Decide in a 100A or 125A Home
- akaielectricltd
- Dec 13, 2025
- 5 min read
This 2025 homeowner guide explains how EV load management works in real houses and when you should consider a panel or service upgrade. It includes a clear comparison of EV Energy Management Systems, a worked example using optional time-of-day pricing, and direct next steps for safe permits and inspections.
Quick answer:
EV load management lets a Level 2 charger share available capacity with your home so you can often charge on a 100A or 125A service without upgrading the panel.
A panel or service upgrade makes sense when your existing demand is already high, you want faster simultaneous charging, or you plan to add other large loads like a heat pump or hot tub.
Optional time-of-day pricing can offset slower shared charging by making overnight kWh cheaper. Shift charging to 11 p.m. to 7 a.m. for predictable savings.
Start with a load calculation. It shows whether EVEMS will work on your service and what breaker size and settings are safe.
At-a-glance: EVEMS vs panel upgrade for 100A and 125A homes
Option | What it is | Typical scope | Pros | Cons | Best fit |
EVEMS (load management) | A monitored controller or smart charger network that limits EV current when your home load is high | Current sensor on service or feeder, controller or compatible charger, settings and labels, commissioning | Lower upfront cost, faster to permit, avoids immediate upgrade, good with overnight charging and time-of-day pricing | Charging can slow during cooking or HVAC peaks, needs commissioning and occasional verification | Most 100A or 125A homes that charge overnight and want to avoid an upgrade now |
Panel upgrade | Replace or add a panel to increase spaces and bus rating | New panelboard, feeders, labeling, potential meter work | Stable charging speed, more circuits, easier future additions | Higher cost and downtime, utility coordination possible | Homes with crowded or aging panels or plans for more large loads |
Service upgrade | Increase main service size with utility coordination | New service conductors, main switch, meter base, possible trenching | Maximum headroom for EVs, heat pump, hot tub, future loads | Longest schedule and highest cost, requires utility and inspections | Large households, two EVs charging at higher power, or heavy electrification plans |
Worked example: 100A home using EVEMS and time-of-day
Assume a 100A, 240 V service with a typical evening load of 3 kW and overnight base load of 1.5 kW. You install a 32 A Level 2 charger set to 7.7 kW.
With EVEMS, the charger automatically reduces current during dinner or HVAC spikes so total demand does not exceed your safe limit.
You schedule the car to charge from 11 p.m. to 7 a.m. The optional time-of-day plan discounts overnight kWh by 5 cents and adds a 5 cent surcharge from 4 p.m. to 9 p.m.
Savings example with overnight charging only:
200 kWh per month to the EV at night saves about $10 per month from the 5 cent discount.
300 kWh per month saves about $15 per month.
If you sometimes plug in during 4 p.m. to 9 p.m., each on-peak kWh adds 5 cents, which can reduce the net savings.
These are illustrative numbers. Your actual settings and savings depend on your home’s demand calculation, breaker size, and charging habits.
Who qualifies in 2025
Most detached homes with 100A or 125A service can support Level 2 charging with EVEMS if the load calculation confirms spare capacity.
Homes with very high baseline loads or multiple large appliances running together may need a panel or service upgrade to meet charging speed goals.
All installations require a permit and inspection in the applicable jurisdiction.
Dates, deadlines, and coordination tips
Time-of-day pricing windows are fixed. Overnight runs 11 p.m. to 7 a.m. and on-peak runs 4 p.m. to 9 p.m. Use your vehicle app or charger app to schedule within the overnight window.
Label the charger setting and EVEMS limit on your panel schedule so future changes do not exceed your calculated demand.
Keep commissioning records with your permit documents for inspections and insurance.
Stacking and special cases
If you plan to add a heat pump, hot tub, or a second EV within 12 to 24 months, consider a panel upgrade now or at least design EVEMS with headroom.
In suites or laneway homes, EVEMS can prioritize dwelling loads. The charger pauses or reduces current temporarily if the home approaches its demand limit.
Networked chargers can coordinate load sharing across two vehicles so both finish by morning within your limit.
How to proceed in 3 steps
For homeowners
Book a load calculation to see if EVEMS will fit your charger on 100A or 125A.
Load Calculations and Capacity Assessments
Decide on EVEMS vs panel upgrade based on your results and charging goals.
Service and Panel Upgrades
Install a dedicated Level 2 circuit, set your charger’s max amps, and enable overnight scheduling.
For two-EV households
Use EVEMS or charger load-sharing to split current between vehicles.
Stagger departure times or charge one car to 80 percent nightly and the other to 100 percent a few nights per week.
If overnight windows are still tight, plan a panel or service upgrade.
Frequently asked questions
Is EVEMS accepted by code in BC
Yes. Technical Safety BC’s EVSE and EVEMS bulletin explains acceptance, labeling, and load calculation requirements.
Will EVEMS make charging too slow
Most charging happens while you sleep. EVEMS reduces current only when your home load is high. With time-of-day pricing, overnight charging can be cheaper even at reduced current.
Can I install a 40 A charger on 100A service without upgrading
Often yes when EVEMS is used and the calculation confirms capacity. The charger’s maximum current must be set and labeled to match the permitted design.
When is a panel upgrade the better choice
If your panel is full, equipment is aging, or you plan to add several large loads soon, a panel upgrade gives stable charging rates and room to grow.
Make it easy with Akai Electric
We design and commission EV load management so your charger fits safely on a 100A or 125A service. When it is time to upgrade, we handle panel and service upgrades, permits, and inspections across the Lower Mainland.
Get a same-week assessment
Load Calculations and Capacity Assessments
Plan a future-proof upgrade
Service and Panel Upgrades
Install a reliable Level 2 charger
Sources:
Topic or claim | Official source |
Time-of-day pricing windows and amounts: 11 p.m. to 7 a.m. discount of 5 cents per kWh and 4 p.m. to 9 p.m. surcharge of 5 cents per kWh | |
Optional flat rate can be combined with time-of-day pricing for additional savings | |
EV power management device overview and rebate for single-family homes | |
EVSE and EVEMS acceptance, labeling, and load calculation requirements in BC |
Comments