This is a three part article
One of the things I’ve been meaning to do for a while is to wean as much electricity usage away from Herman’s main battery and onto the leisure battery as possible. I can never fully relax when I’m running electricals off the main battery at night, for fear of hearing that dreaded tired groan from the starting motor in the morning, when I try to turn the engine over –especially when I’m in the middle of nowhere.
So, the latest idea in my long list of crazy schemes was to build a powerboard with several USB sockets for wiring into the leisure battery circuit. This would allow me to charge various USB devices for hours on end, without worrying about depleting the main battery.
Look, I know that in theory my 85Ah starter battery will charge a 2A phone or tablet for 170 hours, so is extremely unlikely to be depeleted by a few hours charging overnight. But allow me my irrational fears, won’t you!
Anyway, I ordered a hlaf dozen each of 12V to 5V Voltage Converters, 220 µF Capacitors and USB Sockets from Farnell’s a week or two ago and, having finished all my recent wonky furniture building and panelling tasks of the past several days, it was finally time to embark on this mission.
First job was to solder lengths of wire to the voltage converters.
Looking at the voltage regulator from the front, as in the above photo the pins are [L to R] 1:Input, 2:Earth, 3:Output. The capacitor is wired between the Earth pin  and the Output pin  and helps mitigate against voltage spikes and thus lessens the likelihood of you frying your precious USB gadgets. The short leg on the capacitor is the Earth, by the way.
At this point in the procedings I realised that ideally I could do with a third colour of wire, so I could tell at a glance which lead was 12V in and which was 5V out. But I only had red and black, so I improvised by putting a wee collar of blue heat shrink on the output wires, for easy visual identification.
Once I’d got one voltage converter wired, it was time to test it and make sure my grasp of basic electronics hadn’t let me down. So I attached the input to my DC Power Supply and the output to my circuit tester and fired it up. I took the input up to about 14V just to make sure nothing untoward would happen with a bit of voltage spiking. The voltage converters I bought are supposedly good for anywhere between 7V and 17V as input voltage, so they were fine. Nice to test these things though, before plugging something valuable into one.
With ‘Prototype 1’ passing with flying colours it was a case of ‘Rinse and Repeat’ as I soldered up the rest of my stash.
Finally, I slathered each one in a blob of glue from my hot glue gun, just to make sure the wee buggers wouldn’t get any smart ideas about coming undone, once my back was turned.
And thus ended the first stage of Operation Powerboard.
This is a three part article