Ebay MC34063 based USB car PSU

I bought this on ebay for £1.17 including postage, but it was worse than my low expectations.

Here’s what I said to the seller:

I have just tested this item and found it does not work.

It is meant to supply 5V at up to 1A. In reality, it outputs 4.6V with no load, and this falls rapidly to 4.3V at 0.1A and only 2.4V at 0.8A. This is not sufficient to charge USB devices, which is what the product is intended for.

Furthermore, this is not just a faulty unit but an inadequate design. The MC34063 dc-dc converter IC used can supply a maximum of 750mA in the configuration used, so it is impossible for the supply to give 1A. The specifications given are wrong.

The product also lacks a fuse. This is a basic safety precaution and without it the charger could cause a fire.

This product is dangerous and does not meet its specification. You should stop selling it.

Please refund.