NHTSA Investigates Defective Charger That Started A Nissan LEAF Garage Fire

APR 20 2014 BY JAY COLE 28

An August complaint about an overheating/fire incident involving a Nissan LEAF and a Bosch charging station has now turned into an open investigation by the National Highway Traffic Safety Administration into the EVSE.

The Cadillac ELR EVSE Is Actually A Re-Branded Bosch Power Xpress

The Cadillac ELR EVSE Is Actually A Re-Branded Bosch Power Xpress Unit

The cause of the fire has been determined to have originated with the charging unit, and as such the NHTSA is opening an investigation into 50 Bosch Power Xpress 240V charging units.

The original complaint stated that the Nissan LEAF (MY2013) “began to emit smoke around the vicinity of the vehicle/charger interface when charging at a private residence.”

It goes on to detail that after about an hour and a half of charging the overheating was first observed.

“The overheating condition can cause damage to the vehicle and charger rendering both inoperable. Charging vehicles are typically left unattended and there is a risk of fire that could affect the vehicle and its surrounding environment.”

The 2013 LEAF had less than 10,000 miles driven in total and was just five months old.

The complaint further states that “The connection had gotten hot enough to melt the plastic and create smoke indicating a fire. Nissan has determined by pictures that the car was not to blame for the incident. They are blaming the charging station for the failure. They have denied any warranty coverage. The burden of the bill has been placed with the customer.”

Besides their own brand, Bosch also repurposes their EVSEs as OEM stations for other brands and vehicles, such as the Cadillac ELR (story and video on the Caddy’s Bosch EVSE can be found here).  There has been no word however on if the investigation might include these units as well at some point.

The Detroit News asked for a comment from both Bosch and Nissan, but nether had responding before going to press late Saturday. Specs on the Bosch Power Xpress EVSE units can be found in PDF form here.

Bosch Investigation

Bosch Investigation Document

Bosch Investigation Document

Bosch Investigation Document


Detroit News, hat tip to Mart!

Categories: Cadillac, Charging


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28 Comments on "NHTSA Investigates Defective Charger That Started A Nissan LEAF Garage Fire"

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I have an early model of this EVSE (SPX, Oct 2011). It has the same Rema handle that bedeviled Blink, and they appear to still use that handle, presumably with completed crimps. No signs of trouble on my 16 amp I-MiEV, but Bosch did not respond to my handle question when I sent the EVSE in for a firmware upgrade.

I’m surprised that EVs can’t detect when overcharging and heating is occurring.
Perhaps the engineering is more difficult than is obvious.
Its all very well to blame the charger, but it is preferable for fail safes to be used, and cut offs to be at more than one level, just as a house has multiple fuses in its electrics.

EV’s can detect overheating, but apparently not all actually do. Honda released an update to their Fit EV that allows the car to charge at a reduced rate if excess heat is detected at the charge port (it previously would terminate the charging session).

Nissan’s original equipment EVSE does monitor outlet temp and shuts down the charge if it exceeds a safe value. This unit (like the original Tesla model S units) must not.

Misleading title. It has little to do with the LEAF and everything to do with the Bosch evse. The title should reflect that.


An EVSE is not a charger. The charger is in the car.

The “vehicle/charger interface” should be called the plug, or handle.

Anyone charging at 30A for the first time at home should moniter the plug for a while to be safe.

Also +1 on heat sensors.

Sounds like they need to start putting temperature sensors in the J1772 handles too.

I disagree that the handle should have a sensor. The EVSE should be a low cost item, but the car should protect itself from poorly made low cost items.

So, Nissan Leafs will continue to suck full load from a questionable burning connection? Interesting…

I think Tesla solved this one already…

Ah, Tesla only made a change after burning down someone’s garage and then after only getting negative press about their smug attitude about the whole incident.

Heat sensors in the handles would be a very good safety feature worthy of being mandated.

Regardless of defective crimps in new handles like the case above, old handles will inevitably end up with contact wear, bent pins, corrosion, all of which could lead to overheating and potential fires as they age.

There are bound to be more connector related overheating problems in the future.

These stores are more fuel for the fire (pun intended) increasing the case for contactless charging. With no parts to wear out, they are probably safer.

That is a very good point in favour of wireless charging.

Dr. Kenneth Noisewater

As long as they’re engineered to be strong enough to be run over repeatedly, or parked on.

For public infrastructure they are probably going to be buried.

The Tesla Model S chargers will reduce current load when it senses some sort of change in the voltage. It’s not clear how they do this as it’s hard to distinguish heating induced changes from changes due to normal loads. There have been some reports of false triggering. I think it’s unlikely a charger would detect 100% of all overhead problems just by monitoring the voltage.

Tesla also recently shipped a plug adapter (for the NEMA 14-50 connector) that is thermally fused. I think this is a good solution. Every point of mechanical contact should be thermally fused in EVSE systems. Normal wear and tear IS going to be a issue in the future.

I would like to see thermal sensing tape used on connectors. There is a type that indicates the highest temperature achieved (and stays that way). It could be as simple as a tag that changes color when the unit reaches a temperature above normal operating range. If it’s set to below a dangerous level, it might catch a failing unit before it causes a fire.

While it is not that simple to describe. Any fault as a signature, as for example in Canada, might be USA to, all new installation of plug outlet in sleeping room has to be connected to an arc fault breaker that trip when there is a fault with a similar behavior signature as the incident related here.
In short, yes, it can be monitored.


Newer EVSE have better fault detection. The new Aerovironment TurboCord has heat sensors.

In the handle?

Those heat sensors are at the electrical outlet, not in the charge coupler (handle). At least according to their TurboCord manual.

Weren’t all these connectors tested and agreed upon by SAE?

I’m going to play the Devils Advocate here and if the manufacturers worked within the guidelines of the connector standard set forth by the SAE, why would it be the manufacturers fault?

SAE does not set standards for product entropy… Only new equipment.

Too bad they can’t do an OTA update like Tesla did with this issue (or one similar). Another victory for Tesla, especially if they have to recall to make a fix.

I, too am a 2013 Leaf owner < 10,000 miles. I had an unnerving event that could have resulted in smoke and flames from the same area of the car. This happened after a 100+ mile day of driving in freezing weather, having fast charged twice. Once home, I plugged into the EVSE, it was made by Lear, but brand doesn't matter. I immediately heard the sound of a heavy relay buzzing from under the right side front of the hood. I looked up at the Leafs blue light indicators, and saw no activity. My next action was to un-plug. Lucky for me after reading this post! I waited and thought about it a moment, and decided to give it another go. It worked fine. Nevertheless, I was back to the dealer that next day. They found nothing out of the ordinary, and quizzed me about the EVSE unit I'm using. So here's my takeaway, We have new technology, operating in the harshest environment. As end users, be alert to abnormalities and have it checked out. Nissan, I understand takes failures with the Leaf very seriously. I have read where they will send out a team of engineers on an… Read more »

The Germans Bosched the design of EVSE.

This is why my EVSE is rated at double the rate Volt can use. A 30amp charger running at 30amps continuous is just asking for trouble.

Why does the title for this story contain the word fire? There was no fire. There was smoke and melted plastic. No doubt it’s a serious issue, but there was no fire.

This isn’t a flaw with the J1772 standard. I trust the unit is UL tested to make sure it doesn’t have this sort of problem, at least with the unit(s) tested.

This is a problem with quality control in the manufacture of the connector (assuming Nissan’s assessment is correct, which seems likely given Jay D’s comments).