Why Did My Tesla Stop Charging at Night and Not Fully Charge?

Understanding the Issue: Reduced Charging Speed and Overheating

If you’ve noticed that your Tesla did not fully charge overnight and the Tesla app indicates that it’s only charging at half the usual rate, such as 16A instead of 32A, the likely culprit is overheating. This can be caused by several factors, including the Tesla NEMA adapter or the wall plug itself.

Potential Causes of Overheating

1. Tesla NEMA Adapter: The NEMA 14-50 adapter, commonly used for charging Teslas, is rated for 30A but often charges at 32A. This slight overcurrent can sometimes lead to overheating.

2. Wall Plug Quality: Using a low-quality wall plug can exacerbate the overheating issue. For instance, some users have reported issues with Leviton plugs. Overheating in these plugs can cause the charging current to be reduced as a safety measure.

3. Connection Issues: A plug that is not fully inserted or a loose connection can also cause the wall plug to heat up. This heat buildup triggers the safety mechanisms in the Tesla charging system to reduce the current to prevent damage or fire.

Troubleshooting Steps

1. Inspect for Overheating: Check if the wall outlet, plug, or adapter is unusually warm. Tesla’s manual advises that high temperatures detected by the Mobile Connector indicate the outlet used to charge is becoming too warm, causing charging to slow down or stop to protect the outlet​​​​.

2. Contact Tesla: Reach out to Tesla customer support. They can confirm whether the issue is due to overheating and identify if it’s caused by the adapter or the outlet. They may ask you to provide pictures of the affected components​​.

3. Use a Different Outlet: Temporarily switch to a different outlet, such as a NEMA 5-15, which charges at a lower rate and is less likely to overheat. This can help you maintain some level of charging while you address the issue .

4. Consult an Electrician: Have the electrician who installed the outlet inspect it. They can provide their opinion on whether the outlet needs to be replaced. If Tesla recommends a new outlet, consider getting a high-quality one like the Jowua NEMA 14-50 Weatherproof Power Outlet Box, which can be found here.

Safety Instructions from Tesla Manuals

According to Tesla’s owner manuals, several alerts related to high temperatures can occur:

• UMC_a007: Indicates that the Mobile Connector control box temperature is high. Ensure the Mobile Connector is not covered by anything and there is no heat source nearby ​​.
• UMC_a008: Alerts you when the wall plug temperature is high. Tesla recommends inspecting the outlet and wiring connections and possibly replacing the outlet if it is worn ​​.
• UMC_a009: When the charge handle temperature is high, check for debris or moisture in the charge port and handle .

For more detailed troubleshooting information and to understand the status lights and error messages from your Mobile Connector, refer to your Tesla’s owner’s manual or Tesla’s support page.

Useful Resource

For a detailed explanation and visual guide, you can watch the video by the creator Bearded Tesla on this topic: Watch Here.

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