EEVblog 1507 - Mida: A surprisingly good quality cheap EVSE - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: October 12, 2022, 11:08:09 pm
content: Teardown of the cheapest EVSE available in Australia, the 15A Mida Type 2 portable electric car charger.https://s.click.aliexpress.com/e/_DEYLWux

author: rhodges
author_rank: Frequent Contributor
timestamp: October 12, 2022, 11:58:59 pm
content: 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.

author: ssander
author_rank: Contributor
timestamp: October 13, 2022, 01:29:36 am
content: If those eye terminal connectors for the mains are loose, are they able to touch each other?

author: Circlotron
author_rank: Super Contributor
timestamp: October 13, 2022, 04:53:08 am
content: 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?

author: EEVblog
author_rank: Unknown
timestamp: October 13, 2022, 04:56:16 am
content: Quote from: Circlotron on October 13, 2022, 04:53:08 amPCB trace. It's approved and sold here. Don't know about the legalities of that.

author: gamalot
author_rank: Super Contributor
timestamp: October 13, 2022, 12:06:06 pm
content: I see Chinese characters for "国网电瑞" on PCBs, it should be a subsidiary of China State Grid.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 13, 2022, 06:52:38 pm
content: Quote from: Circlotron on October 13, 2022, 04:53:08 amI 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.

author: BrianHG
author_rank: Super Contributor
timestamp: October 13, 2022, 10:25:37 pm
content: 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.

author: EEVblog
author_rank: Unknown
timestamp: October 14, 2022, 07:39:36 am
content: Quote from: BrianHG on October 13, 2022, 10:25:37 pmIn this case the relay coils are 1.5W each. That's a lot inside a sealed case like this.

author: Wollvieh
author_rank: Contributor
timestamp: October 16, 2022, 01:43:19 am
content: Quote from: Circlotron on October 13, 2022, 04:53:08 amIn Germany the earth wires would have to be longer than the others, so they rip out as last.

author: VK3DRB
author_rank: Super Contributor
timestamp: November 16, 2022, 03:33:50 am
content: The unit does not have the RCM mark on it. It cannot be sold be legally sold in Australia.

author: KE5FX
author_rank: Super Contributor
timestamp: November 16, 2022, 04:36:58 am
content: Quote from: rhodges on October 12, 2022, 11:58:59 pmThey will have used what they could get.