Glad you like it
I've tested many supplies and I will be publishing a review on them shortly. I've basically made an adjustable load so I can test any power source from 0.5A to 10A and I've got a dozen or so power sources to review. As a sneak-peek, for an in car power source I can't recommend highly enough the:
- 45W 9A Hunda 5-Port
https://www.amazon.co.uk/gp/product/B01 ... UTF8&psc=1
- TeckNet 4 Port PowerDash D2 9.6A/48W Rapid Travel USB Car Charger
https://www.amazon.co.uk/gp/product/B00 ... UTF8&psc=1
They are both excellent. Good voltage output of 5.1v with a light load and they do not drop below 5.0v when supplying a full 2.5A on a single port. I've loaded them up to 9A (across the ports) and the lack of voltage drop was remarkable. (Surprisingly, for mains use, the official Raspberry Pi 2.5A PSU does not perform that well, dropping below 4.7v at full load! - more to come once I publish my results)
Another tip - don't skimp on the power lead. I was very surprised with my test results, but a 2m long good quality USB lead had hardly any negative effect on the supply voltage/current. I had bought some cheap leads of eBay that are only 15cm long thinking they would be better (shorter lead = less voltage drop), but once the load goes over 0.8A, the voltage drop was horrendous. I wonder how people have a good PSU, but then suffer power issues because they use an inferior cable!
Yet another tip - I also back power the Pi as the Raspberry Pi does introduce a voltage drop between it's supply and USB ports. Back powering helped immensely when powering power hungry USB devices.
As for the graceful shutdown in the car..... I'm on that to
I have one made up and it's working lovely. I've designed a simple detection circuit which after 5 seconds sends a signal to the GPIO header on the Pi. A script then commences a graceful shutdown. In the interim super capacitors supply the Pi for up to 3 minutes to allow time for the Pi to do what it must. Doesn't cost much at all to assemble and the more capacitors you add the longer it will power the Pi - but I figure it just needs to be long enough to safely shut down. Once I'm done testing, I'll write and publish a guide on how to build one.
Good luck with your own installation. Cheers! Dusterz