Slow Charging

Ohme chargers use AC power and can deliver up to 7.68 kW (32 amps) on a single phase supply. This is the fastest rate the charger can provide, depending on your electrical installation and charger type.

When using its smart features, the charger may slow the charge at times as part of its dynamic charging feature. This helps manage demand on the energy grid and can reduce strain on your car battery.

If you choose Max Charge, the charger will aim for the highest speed your vehicle can take, based on your electrical supply, charger type, and the vehicle profile you selected in the Ohme app.

If you notice that Ohme is charging slower than expected on Max Charge, here are some things to check to help troubleshoot and resolve this issue.

Vehicle’s AC Charging Speed

Your vehicle may charge at a lower speed than your Ohme charger can provide.

For example, some plug in hybrid vehicles and smaller battery EVs can only accept up to 3.7 kW on AC charging. If this is the case, your Ohme will not be able to charge any faster than 3.7 kW, even if the charger itself is capable of 7.68 kW.

It is also important to note that AC and DC charging speeds are different. Your vehicle may support much higher speeds on DC rapid chargers, but still have a lower maximum speed for AC charging at home.

You can check your vehicle’s maximum AC charging speed:

• In your vehicle handbook
• Online using trusted EV specification websites such as EV Database
• By contacting your dealership or garage

If your vehicle’s maximum AC charging speed is lower than your charger’s top rate, make sure the correct vehicle is selected on the My EV page in the Ohme app.

Our vehicle list includes the maximum AC charging speed for each model. If your exact model is not listed, or the specification does not look correct, you can create a custom vehicle. This helps Ohme calculate accurate charging times based on your car’s real maximum speed.

Incorrect car profile in the Ohme App

Each vehicle profile in the Ohme app includes technical details such as its maximum AC charging speed. Ohme uses this information to calculate charging times and create accurate schedules.

If the wrong vehicle is selected, the charger may limit the charging speed based on the profile shown in the app.

It is important to check that the correct vehicle is selected on the My EV page, and that the listed Max AC Charging speed matches your vehicle.

To check this:

1. Open the Ohme app and tap Settings
2. Select My EVs
3. Check the Max AC charging speed is correct

Please note: You cannot remove a vehicle while it is set as the primary EV. If you have selected the wrong vehicle, you must first add the correct one, switch to it on the charging screen, and then remove the original vehicle.

If your exact model is not listed, you can create a custom vehicle profile to ensure the charging speed and time estimates are accurate.

Charger set to a lower maximum speed

In some cases, your installer may limit the maximum charging speed of your Ohme for safety reasons.

For example, if your property has a looped electricity supply, the installer may set the charger to a lower limit, such as 16 amps, in line with guidance from your local Distribution Network Operator.

If your charger has been set to a lower limit, it will not charge above that level.
To learn more about looped supplies and why you may be asked to contact your DNO, please see our help centre article: What is a DNO and why might we ask you to contact them?

You can check the maximum charge current in the Ohme app:

1. Open Settings
2. Tap My Charger
3. Select Advanced Settings
4. Scroll to Charger configuration and view the Max Charge Current

If you believe the limit has been set too low, contact your original installer. They can confirm whether it is safe to increase the limit and, if appropriate, update it remotely.

Load Balancing

Ohme chargers include a feature called Load Balancing, which helps prevent your home’s electrical supply from being overloaded.

During installation, a small device called a CT clamp will be fitted to your main electricity cable. This measures how much electricity your home is using in real time.

Your installer will also set a Load Limit. This is the maximum total current your home can safely use at one time. Depending on your property, this could be 60A, 80A or 100A.

When load balancing is active, the charger will automatically adjust its charging speed if your household electricity use gets close to the set limit.

For example, if the load limit is 60A and your charger is using 32A, turning on other appliances may increase your total usage. If the combined demand approaches 60A, the charger will temporarily reduce its speed to keep your home within safe limits.

You can check whether Load Balancing is enabled in the Ohme app:

1. Go to Settings
2. Tap My Charger
3. Select Advanced Settings

Here you can view the Load Balancing and see how much electricity the CT clamp is currently measuring.

Load Balancing helps ensure your home does not exceed its safe electrical limit.

If charging slows down due to Load Balancing, this is a normal safety feature. The charger will automatically increase its speed again once enough capacity is available.

If you believe the Load Limit is set too low, or you would like to discuss turning Load Balancing off, contact your original installer. They can confirm whether changes are safe and adjust the settings remotely if appropriate.

CT Clamp

Load Balancing requires a device called a CT clamp. This is a small black clip fitted by your installer to one of the main incoming electricity supply cables, usually near your electricity meter.

If Load Balancing is enabled but the charger is not receiving readings from the CT clamp, Ohme will reduce its charging speed as a safety precaution. In most cases, charging will be limited to 16A (around 3.7 to 3.8 kW).

This can happen if:

• A CT clamp has not been fitted but Load Balancing has been enabled
• The CT clamp has been fitted incorrectly, for example on the wrong cable or not connected properly
• The CT clamp is faulty

How to check the CT clamp reading

You can check whether the CT clamp is sending readings in the Ohme app:

1. Go to Settings
2. Tap My Charger
3. Select Advanced Settings

During a Max Charge, check the CT Clamp Reading. The value should increase when your home is using electricity. If it stays at zero or does not change, there may be an issue.

What to do next

If you suspect a CT clamp issue is causing slow charging, contact your original installer. They can confirm whether Load Balancing is required for your installation and check that the clamp is fitted and working correctly.

If the issue continues after these checks, please contact our Customer Care team. To help us investigate, include:

• A photo of the charger and surrounding cables
• A photo of the main electricity meter and supply cables
• A photo of the dedicated breaker switch
• A photo of the CT clamp, if fitted

Clear images will help us diagnose the issue more quickly.