Date: Fri, 13 Nov 2009 17:18:26 -0800
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Little problem with trickle charger
In-Reply-To: <4d1b79350911131705r5a148277ya154d3dee7a187a8@mail.gmail.com>
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Okay, in all seriousness and with due respect.
One needs to cut the circuit someplace and insert an ammeter.
The cable on the end of your charger, the one that has the cigar lighter
plug on the end of it, has two conductors in it -- like a lamp cord (often
called "zip" cord). The thing to do is to cut one of the two wires and
bridge the cut with the ammeter. Like this (this might require a monospace
font):
THE WIRE
------------------------ (conductor #1)
PLUG CHARGER
----- +(ammeter)- ------ (conductor #2)
With a digital ammeter, it doesn't matter which way its plus and minus are
oriented -- it will display current either as positive or negative, just
take the absolute value. An analog meter could end up being driven
negative so you just reverse its plus and minus (red and black) leads to
obtain a reading.
I hope this helps.
--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR
On 11/13/2009 5:05 PM Jim Felder wrote:
> Put the ammeter where exactly? No smart-alecking needed beyond this point.
>
> Thanks, grand-dad (we've obviously never met if you use the term
> "youngster," unless you are about 100! : )
>
> Jim
>
> On Fri, Nov 13, 2009 at 6:51 PM, Rocket J Squirrel
> <camping.elliott@gmail.com> wrote:
>> Welp, mighty good questions, ya got there, youngster.
>>
>> The answers are, of course, "it depends."
>>
>> Without knowing the design of the charger, a fellow can't easily know how
>> much current it parasites off the battery when unpowered. Now, one would
>> think, one would /hope/ that the designer said to hisself, "self, I'd best
>> make sure that my customers' batteries are not discharged if there is a
>> power outage at his or her house."
>>
>> But one never knows, does one?
>>
>> Use an ammeter.
>>
>> A diode would take away 0.5 to 0.6V from the charge voltage, which is pretty
>> significant when considering how much voltage a battery needs in order to be
>> fully charged. 12.6V is full charge. 12.0V ain't.
>>
>> --
>> Mike "Rocket J Squirrel" Elliott
>> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
>> 74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
>> Bend, OR
>> KG6RCR
>>
>>
>>
>> On 11/13/2009 4:35 PM Jim Felder wrote:
>>
>>> About a month ago, I mated a trickle charger with a cig lighter plug
>>> so I could plug up the westy electrical socket to a power source, plug
>>> the trickle charger in to the interior 110v socket, and plug the cig
>>> lighter plug into the receptacle on the bulkhead under the seat. No
>>> muss, no fuss, but not quite permanently wired in. That turned out to
>>> be a good thing, as I noticed on a recent camping trip that even with
>>> the charger unplugged from the interior 110 receptacle, the LED light
>>> on the charger glowed when the setup was plugged into the cig lighter
>>> socket. That means that the battery was feeding the charger.
>>>
>>> Is there any significant current loss going backward through the
>>> charger? Is it just running the LED, or is it running down my battery?
>>> I presume the proper diode in the proper place would stop this. Can
>>> anyone describe what I should to do modify?
>>>
>>> Jim
>>>
>
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