EEVblog 1507 - Mida: A surprisingly good quality cheap EVSE

[EEVblog]

Teardown of the cheapest EVSE available in Australia, the 15A Mida Type 2 portable electric car charger.

https://s.click.aliexpress.com/e/_DEYLWux

[rhodges]

For the brief image of the CPU, I think it was a STM32F030 with a lot of probably unneeded pins. I like STM32, but I think this could have been done with a cheaper STM8.

[ssander]

If those eye terminal connectors for the mains are loose, are they able to touch each other?

[Circlotron]

Didn't watch the whole video.
What joins the input ground to the output ground?
If it is a PCB track rather than a solid wire, is that legal in Australia?

[EEVblog]

Didn't watch the whole video.
What joins the input ground to the output ground?
If it is a PCB track rather than a solid wire, is that legal in Australia?

PCB trace. It's approved and sold here. Don't know about the legalities of that.

[gamalot]

I see Chinese characters for "国网电瑞" on PCBs, it should be a subsidiary of China State Grid.

[mikeselectricstuff]

Didn't watch the whole video.
What joins the input ground to the output ground?
If it is a PCB track rather than a solid wire, is that legal in Australia?

I would be surprised to see any standard dictate whether a conductor is carried by wire or PCB trace - more likely that it would specify a current-carrying capacity & leave it up to the manufacturer how to achieve it.

[BrianHG]

In this application, and even though I do use latching relays myself to save on system power, I think that they should have used normal relays which disconnect under loss of power.  The system did use a switching supply instead of a capacitor dropper, so it should have been a way to keep thermals of powering normal relays of that size under control in the sealed device.

I guess the other argument can be made if an MCU IO gets fried on or turned on by corrupted code, a connected relay would still immediately be turned on after connecting power.  Without the schematic, we cannot tell if there are any protections at the low level transistor relay driver level to prevent this which may actually be a plus if done right regardless of the MCU's state.

[EEVblog]

In this application, and even though I do use latching relays myself to save on system power, I think that they should have used normal relays which disconnect under loss of power. 

In this case the relay coils are 1.5W each. That's a lot inside a sealed case like this.

[Wollvieh]

What joins the input ground to the output ground?
If it is a PCB track rather than a solid wire, is that legal in Australia?

In Germany the earth wires would have to be longer than the others, so they rip out as last.

[VK3DRB]

The unit does not have the RCM mark on it. It cannot be sold be legally sold in Australia.

[KE5FX]

For the brief image of the CPU, I think it was a STM32F030 with a lot of probably unneeded pins. I like STM32, but I think this could have been done with a cheaper STM8.

They will have used what they could get.