I'm bumping this old thread, to report a precipitous decline in these DIN ISO 4165 (Hella) power connectors that now are ubiquitously made in China. Aside from the Hella and Bosch German versions that are sporadically available, the remainder of these products online now are complete junk. I completed the installation of an outlet provided by the latest incarnation of Powerlet. The socket itself is garbage, with an aluminum barrel (expect copious corrosion), and the connection to the positive pin is intermittent. Not only that, but the harness connections were not crimped properly--one of them spontaneously disconnected.
These connectors once were reliable and worked, but today the Chinese race to the bottom has ruined the whole deal, unless you manage to find the geniune German connectors and use proper wiring and components.
I do have a suggestion for a plug that works at least as well as these ISO 4165's. After this fiasco I have been using Neutrik Speakon connectors, specifically the NL2FX and NM2MP-XX, which have a more than adequate current rating at 12 VDC for this application. Their normal application is in professional audio systems. The Neutrik Speakon connectors are quick disconnect and self-latching, so that they cannot be inadvertently pulled out. They require a slightly larger hole than the Powerlet to install properly.