Ammeter.

--
Jack "Rocket j Squirrel" Elliott
1984 Westfalia, auto trans,
Bend, Ore.

On 09/01/2015 10:33 AM, Rob wrote:
> How do you measure the draw?
>
> Rob
> vwrobb@gmail.com
> On Sep 1, 2015 9:39 AM, "Larry Alofs" <lalofs@gmail.com> wrote:
>
>> A lot of the speculation and contradictory "understanding" can be cleared
>> up for any given radio by actually measuring the current draw thru the
>> wires with the radio in various modes, on, off, high volume, low volume,
>> etc.
>>
>> Larry A.
>>
>>
>> On Tue, Sep 1, 2015 at 11:16 AM, Rocket J Squirrel <
>> camping.elliott@gmail.com> wrote:
>>
>>> This page also seems to indicate that the fatter wire (the constant-on
>>> wire) is the main source of power for the radio, and the skinnier wire
>>> (switched) is only used to wake the radio up.
>>>
>>> <
>>>
>> http://avic411.com/index.php?/topic/36319-which-wire-is-the-power-source-yellow-or-red/
>>>>
>>>
>>> "Without a doubt B+ (the yellow wire) is the main current carrying wire,
>>> but this is only up to a point, as you have seen due to the radio fuse
>>> not being more than about 10A typically on vehicles. Acc/ignition is
>>> just a turn-on signal. While it can be used at a lower current
>>> application, it is not typically meant for higher loads."
>>>
>>> --
>>> Jack "Rocket j Squirrel" Elliott
>>> 1984 Westfalia, auto trans,
>>> Bend, Ore.
>>>
>>> On 09/01/2015 07:57 AM, Jon VO wrote:
>>>
>>>> Well, my understanding is a bit different; the ignition switch controls
>>>> /switched/ power to the stereo, and is the source of the amplifier &
>>>> control power which is usually multiple amps for a high-powered stereo.
>>>> The other continuous power lead is supposed to draw only a few milliamps
>>>> to keep the memory charged and for control functions, and is powered all
>>>> the time. At least that is the way the stereos worked when the Vanagon
>>>> was current. If you want to reduce the current through the ignition
>>>> switch, you would need to add a relay, and I believe some newer vehicles
>>>> already do this.
>>>> Jon
>>>>
>>>> On 9/1/2015 8:45 AM, Rocket J Squirrel wrote:
>>>>
>>>>> The keying wire itself draws little current, it just provides a signal
>>>>> voltage to the unit to put it to sleep or wake it up. The designers
>>>>> assume that you don't want to draw a bunch of amperes through your
>>>>> ignition circuit, so it's the the always-on wire that is the main
>> source
>>>>> of power for the unit.
>>>>>
>>>>> How much current the unit itself draws from its always-on wire when
>>>>> asleep (standby) is a matter of design. But the key wire is not a
>>>>> significant current-drawer.
>>>>>
>>>>> What I'm saying is that you can put the unit into standby with the key
>>>>> wire and it can still be drawing hundreds of milliamperes through its
>>>>> always-on wire. That's the one you have to watch out for.
>>>>>
>>>>> --
>>>>> Jack "Rocket j Squirrel" Elliott
>>>>> 1984 Westfalia, auto trans,
>>>>> Bend, Ore.
>>>>>
>>>>> On 09/01/2015 07:30 AM, Jim Felder wrote:
>>>>>
>>>>>> I remember when you went through all that, about the same time I
>> bought
>>>>>> my radio. So, using the keyed hot wire will draw very little or no
>>>>>> current? I like the idea from a previous post that I could install a
>>>>>> switch to connect it to either circuit, aways hot and switched hot.
>>>>>>
>>>>>> Jim
>>>>>>
>>>>>> On Tue, Sep 1, 2015 at 9:26 AM Rocket J Squirrel
>>>>>> <camping.elliott@gmail.com <mailto:camping.elliott@gmail.com>> wrote:
>>>>>>
>>>>>>      Many car stereos/radios don't really turn off. They mute and the
>>>>>> front
>>>>>>      panel goes dark, the power amp sections shut down, and the
>>>>>> controls go
>>>>>>      to sleep, but they are still partially on and drawing current. I
>>>>>> guess
>>>>>>      the manufacturers assume that you drive your car frequently.
>>>>>>
>>>>>>      The current draw is through the main power wire, the other wire,
>>>>>>      frequently connected to the ignition switch, doesn't draw much
>>>>>> current
>>>>>>      at all -- it is used to signal the unit to wake up.
>>>>>>
>>>>>>      I had to search high and low to find a unit that actually powers
>>>>>> off --
>>>>>>      not only from the front panel power button, but from the remote,
>>>>>> too. So
>>>>>>      I could turn off the music when I get into bed rather than have
>>>>>> to lean
>>>>>>      up to the dash to shut things down.
>>>>>>
>>>>>>      --
>>>>>>      Jack "Rocket j Squirrel" Elliott
>>>>>>      1984 Westfalia, auto trans,
>>>>>>      Bend, Ore.
>>>>>>
>>>>>>      On 09/01/2015 06:08 AM, Jim Felder wrote:
>>>>>>       > About a month ago I wrote about having installed two pairs of
>> USB
>>>>>>      ports and
>>>>>>       > an LED voltage display in my Vanagon. The round double outlet
>> on
>>>>>>      the dash
>>>>>>       > took the place of my factory Eberspacher heater knob and the
>>>>>>       > outlet-and-voltmeter combination set neatly into what was the
>>>>>>      rear ashtray.
>>>>>>       >
>>>>>>       > That's when I noticed a drop in voltage that would flatten the
>>>>>>      battery
>>>>>>       > after a couple of days of being parked. Long story made very
>>>>>> short, I
>>>>>>       > discovered that it was my radio in standby mode that was
>>>>>> draining the
>>>>>>       > battery. I pulled the fuse to the radio on Saturday and this
>>>>>>      morning the
>>>>>>       > voltage is showing 12.9, exactly where it was when I pulled
>>>>>> the fuse.
>>>>>>       >
>>>>>>       > The reason that this was unknown to me all this time is that
>>>>>>      coincident
>>>>>>       > with the addition of the USB ports the Vanagon was, except for
>>>>>>      use of my
>>>>>>       > wife's Prius, my daily driver had been the Vanagon. When I got
>> a
>>>>>>      TDI Jetta
>>>>>>       > the Vanagon started sitting for days or a week at a time, and
>>>>>>      that's when
>>>>>>       > the problem showed up.
>>>>>>       >
>>>>>>       > I could wire the radio to the switched 12v circuit that no
>> doubt
>>>>>>      came with
>>>>>>       > it, but then I would have to have the key on to listen to
>>>>>> music while
>>>>>>       > camping. Is anyone using a switch on the circuit, and if so how
>>>>>>      was it done
>>>>>>       > and how does it work out for you?
>>>>>>       >
>>>>>>       > Jim
>>>>>>       >
>>>>>>
>>>>>>
>>>>
>>