EVSE Failure

[archieb]

Last week I got in my i3 and found the battery not completely charged. Odd, but it didn't really bother me. That night when plugging in the light indicator suddenly went flashing red and an error message of "insufficient grid power" was displayed in the i3. Checked the EVSE, all green, no fault displayed. Tried the L1 charger, worked fine. Tried a local L2 charger, worked fine.

After finding no grid power issues in the wiring leading to the EVSE I turned off all power and proceeded to open the unit up. As soon as I got the cover off I could smell burnt something. The black wire from the main circuit board output to the J1772 cord was burned off at the female clip. This is a factory installed connection so its' failure was not an installation problem.

I've had this EVSE, Legrand 16amp, for 5 years. 3 years with our Volt and 2 years with the i3. Why after all this time it should fail is unknown. A electrician is coming out in a few days and as long as the male clip on the circuit board is not damaged the black wire will be re clipped and connected.

One thing I did note was that the wire gauge used is not heavy duty. While I can not say for certain, it looks like 14 gauge wire. Whatever it is, it looks like the minimum to meet code. This is an early EVSE and hopefully newer models have heavier duty wire used. I can't think of anything that could have prevented this, short of opening the unit every six months or so to make sure nothing looks overheated.

 

[gt1]

The electrician will be able to check the EVSE input, but it is unlikely he will have a desire or skills to fix the EVSE if needed. Do you hear a click from a contactor when you connect the EVSE to the car? Any smells?

 

[jadnashuanh]

A loose connection will generate heat, and more of it when carrying higher currents, and that can cause the wire to overheat. Much more likely it was a loose connection than a system fault. The EVSE is only a fancy on/off switch, but has an internal power supply and logic to take care of the interface signals and energize the power relay.

The electrical code dictates the wiring required EXTERNAL to the device for power, but it is the device manufacturer that determines the gauge wire for any internal connection, but it still needs to be UL approved. Often, the internal connections will end up smaller than those external because of how the leads are routed, the known length, and the acceptable losses and heat dissipation that will keep things working properly...IOW, smaller wires INSIDE the box often will work just fine, just not those going to it.

 

[TOEd]

I agree that wire size is likely not the issue. Bad connection with resulting heating/oxidation resulting in increased resistance is the more likely cause of failure. If you have a micrometer you can check wire size to determine gauge. Here is a link to a chart: http://www.powerstream.com/Wire_Size.htm Repair should result in many years of service. However, 16 amps is far less than the maximum of 32 amps that the i3 can draw. So if you want to decrease your charging time by nearly half you may wish to upgrade your EVSE. Charging rate tapers when charge is nearing 100% so extra current isn't helpful when battery is close to full.

 

[gt1]

Upgrading EVSE will most likely require replacing everything else- the wire, breaker, outlet (if used). It will be expensive, while even a 16A EVSE can charge the car overnight with a time to spare.

 

[archieb]

For gt1: Yes I can hear the contact clicking and all the indicator lights show green. As for smell, it smelled burnt upon opening and the area around the male clip on the circuit board was brown and discolored.

The wire (clip/connection) that failed is one of the wires that carries the full output of 16amps and is a continuous wire into the 25" cord and to the J1772 plug. With it melted off there is no 240V going to the i3. There is enough slack in this wire to allow for cutting off the damaged end and attaching a new female clip. The concern is whether the heat damaged the circuit board where the male clip attaches to the board. There is no additional troubleshooting involved for the electrician. The reason no fault is displayed on the EVSE is that power is going in correctly and the response from the i3 when plugged in is correct. The problem is there is no output from the EVSE due to the disconnected wire.

As for upgrading, when I had the EVSE installed 5 years ago I planned for a future upgrade. I had the electrician install wire that could handle a 40 amp load, even with the current circuit only being a 20 amp. That additional cost, while not minimal, would save me money in the future and give me peace of mind that the wiring could handle high current loads. I added a new panel box in the garage and have separate circuits and breakers for both 120V (with heavy duty single outlet) and 240V (hard wired).

Being on time of day rates, the 16 amp EVSE works very well for us. If all that is needed is a new clip that would be much cheaper than a whole new EVSE.

 

[archieb]

All is well. Electrician came out yesterday afternoon, inspected the damaged connection/wire, cut off damaged wire and installed a new clip. I reassembled everything and yesterday evening plugged unit into the i3. Blue light came on and charger functioned properly. i3 was fully charged this morning.

Electrician gave a possible cause for the failure. If the wire crimped to the female clip and/or the female clip itself was not a tight, secure fit the connection would generate heat. Initially the amount of heat might have been minimal, but over time this heating (expansion) and cooling would have weaken the connection. As the connection weaken more heat (more expansion) would have gone on until the heat was sufficient to weaken then melt the wire at the base of the female clip. Because the Legrand 16 amp EVSE is a large wall mounted unit, there was sufficient area that there was no outward sign of the heat being built up internally. Electrician also confirmed wiring is correct for this application; 12 gauge.

Best part was he did this repair for no charge. Disassembly before his visit and then reassembly myself after made this a 5 minute service call.

Archie

 

[gt1]

You got off easy. Connection related problems are probably the most common EVSE failures. In the worst case, it all could end in fire. One of the features I like in my OpenEVSE unit, is that includes a temperature sensor, that will shut down the circuit if insides of the EVSE will get too hot.