On 2011-12-06, Peter (aka Bruce)
was almost, but not quite, entirely unlike tea:
> I got myself a weatherproof USB lead from
> <http://www.burnsmoto.com/usb-power-socket-weatherproof.php>
>
> Before I installed this I thought about it and got worried about the fact
> that USB is 5V and my motorcycle is 12V.
>
> So I got myself a voltage regulator like this
> <http://www.jaycar.com.au/productView...&keywords=7805
> &form=KEYWORD>
You didn't read the first sentence?
"Direct connect to 12 VDC system (Input voltage is DC 12V +/-4)"
It's got a builtin regulator.
> 12v in will be fused.
>
>
> Do I need a fuse on the 5v out?
Nope. It can't supply more than what the input would supply, which
would blow before anything catches fire. Can't say how well
engineered the stepdown regulator is though. I had one supplied with
my GPS, and I was using my GPS normally, and the bike was running
normally, and then spontaneously the regulator went "*pop*". The
chinese capacitor disease is spreading to transistors now too.
Actually, did you read any of it?
"Contains a built in automatic fuse that resets itself."
> Would you wire this up to permanant power or use a relay?
Depends. Do you want to be able to run and charge stuff while you're
sitting having a coffee? Will you unplug things when you leave your
bike locked up for days at a time?
I had all of my accessories wired up through a relay, until I realised
that I wanted to be able to use every single one of them with the bike
powered off, and they all take bugger all electricity, and I tend to
unplug them and take them inside when I get home.
> Will this setup drain the battery even if nothing is plugged in to the USB
> if on permanant power? Does the regulator drain power?
Not measurably, unless its real crap.
> How long would it take 5v 1 amp to drain a motorcycle battery if the bike
> is not running?
Depends on how good it is (shunt regulator vs switchmode). Say you
have a 20Ah battery, then it will either last 20 hours at 1amp output
(minus the fact that you want to be able to have enough left to start
the bike, so don't drain it past 5 or 10 Ah. Or if it's a switchmode
regulator, you might get up to 12/5*20=48 hours (or 12 to 24 hours if
you want to be able to actually use the bike again).
Now be warned - I spent 5 days or so in English and Scottish weather
with my USB socket to the side of the bike mostly out of the weather,
with the socket populated the whole time. It still corroded and broke
within 5 days. It may be weatherproof when not being used, but isn't
the point of one of these to use it?
--
TimC
>You seem to be implying here that one gets rich after gaining a PhD?
Of course one does. The other 99 out of a hundred get bitter.
-- Paula responding to TimC on ARK