Ingineer
Well-known member
Thanks for posting this!bowthom said:All that being said, here is my experience,
As some of you may remember my Leaf had a charger failure May 14th of this year. During the diagnosis period there was much conjecture about possible causes and as you would expect Nissan was looking for it to be something other that the Leaf's fault. The whole episode culminated with a pair of Japanese engineers accompanied by a Nissan Technical Service Manager coming to my house to test my blink. The NTSM acted very concerned that I had used a Rev 1 modified EVSE. I assured them that I only used it AFTER the blink would no longer charge my car and the charger (diode) had already failed. He wanted to test it but I had sent it out for Rev 2 modification when my Leaf went to the dealer (they kept my Leaf 3 weeks before this meeting took place). So there was much concern that the modified EVSE was a contributing factor and I had to repeatedly state the timeline to make it very clear it was not in anyway related. I had another meeting with the same NTSM at Wilsonville Nissan 9/22 and he again asked me about the mini EVSE and the fact that I had been TIG welding that day. I assured him again, the car was being driven up in Washington at the time of failure and was not related to welding or the mini EVSE in anyway. He told me the engineers had not found a cause for the failure although they suspect a lightning strike was the cause of the one in Tennessee. No proof though.
My conclusion: They play their cards very close to the chest. The NTSM's mission is damage control and to be the translator. No matter what, they will not admit any liability on Nissan's part nor give out any technical info. They never once said outright that I should not use the Rev 2 EVSE or blamed it for the failure.
What these tour people may be circulating is all the rumor mill FUD churned up in the wake of my and 2 other Leaf's charger failures. Isn't it just like the internet, the good info gets buried under weight of FUD being circulated.
My $.02
ON EDIT: My rev 2 mini EVSE works perfectly.
Here's what I can tell you: The on-board charger used in the LEAF is made for Nissan by Nihicon. It's using high-power IGBT's (Insulated Gate Bi-polar Transistors) as the main power handling device. These high-power semiconductors, like all, have a certain "Yeild Rate" from the factory. This means some will never leave the factory, some will be derated and sold as lesser units, and some make it out certified "good", but fail later. These are then used in other manufacturer's products. The Engineering team that builds these, if they are concerned about reliability, is very conservative in their design and allows a wide safety margin so these devices will last a long time in their product. However, a certain amount never pass their quality control, even though the original manufacturer passed them. That's because some fail "in the field". This is why all products have warranties, so it can catch these near "still born" products. This is a normal reality for almost all consumer products, and even more so with complex products like automobiles which are subjected to extremes in daily use.
Given that the EVSE is simply passing power through to the car, unless by some almost unthinkable scenario, it was severely damaged (think shooting at it with a clip of 9mm rounds) I doubt there's any statistically significant way it could ever damage the car. (on board charger module, pack, etc).
Now I can see their concern if you were using a welder, especially TIG, or something like a Plasma Torch, as these are severely noisy, both by emitting EMI/RFI, but they also use large peaks of power intermittently, which can cause severe power disturbance. Many residential power systems cannot adequate to handle this, and if you add 2 large 240v power systems on one heavily configured residential system, especially if it's older, bad things™ are going to happen at some point!!!
But even if you don't meet any of those risk factors, you could still just be one of the few unlucky people out of thousands of LEAFs, who happen to have a power semiconductor fail somewhere in one of the complex systems. This is what the warranty is for, and by repairing the car under warranty, they legally accept responsibility for it and fix it on their dime. You can bet your bottom dollar if they could somehow show it wasn't their fault, they would! If the failures hit a certain percentage, that appears to statistically be higher than they should be, they will revise the design and possibly switch suppliers. Something will be changed so the anomaly will be fixed, and Nissan is being really careful about this stuff, because they have a lot riding on the LEAF, and this program cannot to get bunch of "bad reliability" messages.
-Phil