Totalcar – Advice – Smart’s charger blows the fuse

Dear Electric Shepherd!

I have a problem charging a Smart fortwo EQ drive 2021, I would be very happy if you could help me. Charging worked fine for a few days.

The phenomenon has been happening for a few days now, that when I plug the car charger into the outlet, as soon as it starts to pick up power, it also blows the main fuse after 2-3 seconds.

I don’t know why the main fuse blows, the 10A charging adapter is after a 16A circuit breaker (it’s class C). The main circuit breaker is 40A! What do you think could be the problem in such a case?

Thank you very much in advance for your help. Zoli

Dear Zoli,

If you don’t mind, I shortened your question a bit by cutting out the unnecessary parts so that others don’t have to read everything.

According to my service experience, such a case is clearly an on-board charger error – and if my memories serve me correctly, this car type is equipped with the Chameleon charger from Renault Zoe, for which I strongly do not recommend single-phase charging! From the fault phenomenon, I dare to say for sure (after 50+ repairs) that the IGBT unit is short-circuited, the factory price of which at Renault is somewhere around 140,000 net. Of course, you won’t be able to pay for the entire repair with that amount, since the removal, repair, and testing of the on-board charger will result in a gross price between half a million and one million, depending on where you have your car repaired. (I don’t take it anymore, I switched to other types.)

The cause of the error is overvoltage: the Chameleon on-board charger is one of the most sensitive chargers on the market. I have had half a dozen cases when the T1+T2 “combined” coarse protection recommended by electricians was installed instead of the T3 fine protection recommended by me, and this was also not able to protect the life of the charger – it clearly reduced the damage, but the overvoltage was destroyed just the same. despite protection. So if the repair works, don’t listen to anyone and install a T3 class protection in front of your charging point. Whether they will talk about a T1, T2 or T1+T2 before that is up to you; according to a small part of the experts, the T3 can provide protection by itself (even in a kamikaze way, at the cost of its own life, which is still only HUF 8-24, not half a million), but the principle of “selective protection” was hammered into the head of the majority, according to which only together, the three of them provide sufficient protection – yes, this is perfectly true for a hospital intensive care unit, where a power failure due to a stray surge cannot be allowed. Well, do you have to install surge protection in a garage for about a million?

Finally, when you reach the electric clock cabinet, replace the class “C” slow circuit breaker with a class “B” fast circuit breaker. All eCar on-board chargers contain a soft starter, so they don’t have to be sluggish because they don’t have a power surge. However, the operation of the T3 class overvoltage protection is based on tripping the circuit breaker in the event of an overvoltage, so it does not matter how quickly it can do this.

Sincerely, Power Shepherd