Can a faulty EVSE damage an OBC

[sandange]

Does any one know or have heard of any EVSE that has caused damage to a vehicles charging system/ Battery
is this even possible?

 

[FiddlerJohn]

Does any one know or have heard of any EVSE that has caused damage to a vehicles charging system/ Battery
is this even possible?

I have been studying the OBC/DC-DC converter. No. A bad EVSE should not be able to damage the main battery.

The outputs of all L1 and L2 EVSE and the inputs to the ON BOARD CHARGER have MOV high Voltage protection; however, the OBC and the DC-DC converter are the same box using the same components.

I can imagine using the MiEV 12 Volt battery to start an ICE car. Since the output of the OBC/DC-DC converter always connects to a battery (main or 12V), it doesn't need HV protection. If the output of the DC-DC converter is not protected from high Voltage, a jump started ICE starter motor high voltage kick back might be able to damage the output of the DC-DC converter which might be the same component that connects to the main battery when charging.

So I am guessing that disconnecting any high current, inductive 12V load could damage the DC-DC converter output which is the OBC output that connects to the main battery.

 

[PV1]

While highly unlikely, since an EVSE only switches wall power on/off, there is the possibility that there could be something wrong with the pilot signal that is damaging part of the charger.

Based on the diagrams we have of the charger, we theoretically could put 120 or 240 volts DC to it and it'll work since the first thing it does is rectify incoming power, but not enough is known to actually call that doable. If you haven't already, research having your electrical service checked for frequency, noise, and proper voltage. If the car is anything like solar panel inverter, having a frequency only a hertz off of either 50 or 60 is enough to shut it down.

 

[sandange]

Thanks for your input
As an average EV driver Not versed in electronics.
Putting fast charging DC aside

My layman's understanding is that The EVSE is a saftey switch ..

Once connected to the automobile it tells the OBC WHAT (120v/240v) current is available.
The OBC accepts the signal and directs the current to the proper circuitry 110 or 240
Finally the EVSE Then trips a switch to allow the power to flow through.

What if, or is it even possible that the EVSE tell the OBC the wrong Current is available
It tells the OBC that 120v is available but in fact it is 240v
Could this possibly happen & damage the OBC

Curious minds want to know

 

[FiddlerJohn]

... we theoretically could put 120 or 240 volts DC to it and it'll work since the first thing it does is rectify incoming power, but not enough is known to actually call that doable ...

I thought so too, so I modified an EVSE to output 100VDC to 300VDC. The handshake/pilot control signals worked, but when the fan came on and the car started charging, the EVSE displayed a fault and the car stopped charging. I tried this J1772 DC charging many times with different DC voltages, but it always faulted after starting to charge. Fortunately, nothing was damaged.

 

[Don]

My layman's understanding is that The EVSE is a saftey switch ..

Once connected to the automobile it tells the OBC WHAT (120v/240v) current is available.
The OBC accepts the signal and directs the current to the proper circuitry 110 or 240
Finally the EVSE Then trips a switch to allow the power to flow through.

What if, or is it even possible that the EVSE tell the OBC the wrong Current is available
It tells the OBC that 120v is available but in fact it is 240v
Could this possibly happen & damage the OBC

Curious minds want to know

First, you're saying 'current' when you mean 'voltage'. The EVSE does tell the car what 'current' (amperage) is available, but it doesn't report what voltage it is and it doesn't 'direct' anything 'to the proper circuitry 110 or 240'. The car doesn't care whether it's being supplied 120 or 240 and it all goes to the same place.

Our L1/L2 nomenclature is just to educate the user as to about how long charging will take and what sort of electrical support a particular EVSE will require because L2 charging requires different wiring than L1 charging uses. The car doesn't know beans about L1/L2 and it doesn't care - ANY voltage from about 90 to 275 VAC is accepted by the OBC, so there's no danger of the EVSE reporting the wrong voltage - All it reports is the amperage available so the OBC can adjust itself not to exceed that current so you don't trip a breaker

The J-1772 communication goes something like this:

J1772 signaling circuit

1.) Supply equipment (EVSE) signals presence of AC input power
2.) Vehicle detects plug via proximity circuit (thus the vehicle can prevent driving away while connected)
3.) Control pilot functions begin
4.) Supply equipment (EVSE) detects plug-in electric vehicle
5.) Supply equipment (EVSE) indicates to PEV readiness to supply energy
6.) PEV ventilation requirements are determined
7.) Supply equipment (EVSE) current capacity provided to PEV
8.) PEV adjusts so as to not exceed current limit reported by EVSE
9.) PEV commands energy flow
10.) Supply equipment (EVSE) closes relay to supply power

Don

 

[sandange]

Thank you Don
This has been very helpful to me in understanding the charging process.

All it reports is the amperage available so the OBC can adjust itself not to exceed that current so you don't trip a breaker

Is it possible the EVES reports the wrong amperage resulting in damage to the OBC?

 

[PV1]

No. Public charging stations usually report 32 amps available, but the car can only use 16 at the most. If the voltage of the pilot signal is too high, that can damage the logic board. Remember, it's frequency of the pilot that determines amperage pulled by the car.

If something is up with the pilot that it reports an amperage too low, the car won't charge.

Hopefully Mitsubishi comes back with what was wrong with the charger.

 

[siai47]

Yes it can (at least alleged). I had a Nissan LEAF a while back and used a GE Wattstation as my EVSE. At that time there were failures of the onboard charger that Nissan said were caused by the Wattstation. A diode within the charger was failing. All kinds of warnings were issued, GE studied the problem, threads we started on the LEAF fourms, all kinds of causes presented, etc. In the end, more and more failures started showing up that included other EVSE's. Finally, Nissan made a firmware change to the timing and way the handshake and start up of the EVSE occurred which seemed to stop the problem. Never got a good answer as to why this particular diode was failing, but the problem went away. So, I guess, the EVSE can damage the onboard charger if enough underlying issues exist.

 

[Don]

If more than one brand of EVSE was involved in the Leaf's problems, it would seem to indicate that the problem was probably with the car and not the EVSE's - The fact that Nissan made a change and the problem mysteriously went away would further bolster that argument. And then the fact that those same EVSE's were being used by other brands of EV's without any problems would pretty much prove it . . . . at least to me

It should not be possible for any EVSE to harm any car or the circuit the EVSE is plugged into - That's why the J1772 protocol was developed. You just can't afford to have even one instance with this 'new' technology where a car was damaged or someone's house was burned down while charging an EV. The average person with little knowledge of electricity already erroneously thinks it's more dangerous than gasoline so even a really unusual problem would get all kinds of negative attention. Recall that when a couple of Teslas ran over something on the road and caught fire all kinds of people were screaming about them being unsafe, never mind the fact that during the same period of time probably 50 or 100 gas powered cars went up in flames and those didn't even make the news. I think it didn't help any that the 787 Dreamliners were experiencing battery problems at about the same time

If for some reason the EVSE reported an incorrect charge current to the car, it shouldn't hurt anything on the car. If the reported amperage was too low, the car would charge at that lower value. If somehow the EVSE reported a higher amperage than the circuit it was plugged into could support, you would probably trip the circuit breaker supplying power to the EVSE and charging would cease. Neither case should harm anything on the car

Don

 

[FiddlerJohn]

Yes it can (at least alleged). I had a Nissan LEAF a while back and used a GE Wattstation as my EVSE. At that time there were failures of the onboard charger that Nissan said were caused by the Wattstation. A diode within the charger was failing.

Thanks for reminding me. So siai47 says "Yes it can." That's the answer. I use a early GE Wattstation and studied but forgotten your LEAF forum post.

 

[sandange]

I had an extensive discussion with Mark at EVSE Upgrade and his conclusion is that ...
No the EVSE was not capable of damaging the OBC.

All charging stations Including Public stations go through the same protocol.

There was once the problem with The Wattsstation case as mentioned above that was resolved.

I spoke to him about having My new 2014 OEM 2 stage L1 EVSE Upgraded.

Mark informed me that Mitsu has changed EVSE suppliers and he would need some one with a 2014 Miev to drop by at their location in Berkley Ca to evaluated doing an Upgrade .


I am putting this request out here

Do we have any forum members with a
2014 Miev in the Berkley Ca area willing to drop by..
Please contact Mark at
http://evseupgrade.com/?main_page=contact_us

EVSE Upgrade
1037 Murray St.
Berkeley, CA 94710-2814
(509)651-8000
Fax: (509)651-1717

So he can make an evaluation for an upgrade for our 2014 OEM portable EVSE

Thanks Sandy

 

[jray3]

So I am guessing that disconnecting any high current, inductive 12V load could damage the DC-DC converter output which is the OBC output that connects to the main battery.

INteresting, as I've used my MiEV to jump start a big diesel several times. I had a hobbyist-grade DC-DC (old DCP brand) on Karmann Eclectric fail due to voltage sag on the main battery pack- I'm told that the DC-DC would try to operate in reverse and over-amp trying to prop up the traction pack from 12V! Installing a diode may have prevented it, but I was told it would not be a financially viable repair.