[DeTomaso] Electrical questions--HELP!

Christopher Kimball chrisvkimball at msn.com
Mon Apr 30 01:41:19 EDT 2007


Thank you--that makes total sense to me now.

So, since I have a one-wire alternator, does it stand to reason, to keep 
from running large wires behind the dash to the ammeter (a crowded area) I 
could simply run a large cable directly from the alternator (piggy-backing 
on the "one wire" terminal) to the fan relays and stereo power amp?

Thanks again,

Chris


>From: Thomas Tornblom <Thomas.Tornblom at hax.se>
>To: Christopher Kimball <chrisvkimball at msn.com>
>CC: Thomas.Tornblom at hax.se, detomaso at realbig.com
>Subject: Re: [DeTomaso] Electrical questions--HELP!
>Date: Mon, 30 Apr 2007 05:25:24 +0200
>
>Christopher Kimball skrev:
>>This is amazing and seems counter-intuitive to me--when I hooked up the 
>>fan relays' main power, I purposely went directly to the positive terminal 
>>of the battery (as I did with the main stereo amplifier's power cable 
>>precisely so I would (I thought) avoid the car's electrical system 
>>completely.
>>
>>I took electronics in college a LONG time ago, and my memory is fuzzy 
>>these days, but if the fans are grounded directly to the frame (as they 
>>are now) and the power is going to the fan motors directly from the 
>>batery's positive terminal (which it is), how can the ammeter even be 
>>involved in the circuit?
>
>Because the power to all these things comes from the *alternator*, not the 
>battery, when the engine is running. The only way for the current to get 
>from the alternator to the consumers is through the ammeter, which will 
>indicate that current is flowing in the direction to the battery (== 
>charging).
>
>If you instead take the power on the alternator side of the ammeter, this 
>current is fed from the alternator to the consumer without having to go 
>through the meter, and the meter will not indicate that it is charging, 
>which is correct.
>
>It will also correctly indicate that the battery is draining if you run 
>these things when the engine is off, as the only way for the power to get 
>from the *battery* to the consumer is through the ammeter in the other 
>direction, and it will indicate a discharge.
>
>The only current that should flow through the meter is, as SOBill said, the 
>power going into or out of the battery.
>
>>
>>I'm not questioning that you are correct, I just need to understand what 
>>I'm missing!
>
>I hope the simple explanation above will help you do that :-)
>
>You are not alone in your thinking.
>
>>
>>Thanks
>>
>>Chris
>
>Cheers,
>Thomas
>
>>
>>
>>>From: SOBill at aol.com
>>>To: Thomas.Tornblom at hax.se, chrisvkimball at msn.com
>>>CC: detomaso at realbig.com
>>>Subject: Re: [DeTomaso] Electrical questions--HELP!
>>>Date: Sun, 29 Apr 2007 13:59:43 EDT
>>>
>>>
>>>
>>>Thomas is absolutely correct.
>>>
>>>The ammeter is intended to only show the current flowing into or  out of 
>>>the
>>>battery.
>>>
>>>If you connect a load on the battery side of ammeter, the  current coming
>>>from the alternator to supply that load will cause the ammeter to  
>>>erroneously
>>>indicate a charging current going into the battery.
>>>
>>>All loads in the car should be connected to the terminal of the  ammeter
>>>which comes from the alternator so that only charge or discharge  
>>>currents from
>>>the battery flow thru the ammeter.
>>>
>>>
>>>
>>>In a message dated 4/29/2007 2:00:02 AM Pacific Daylight Time,
>>>Thomas.Tornblom at hax.se writes:
>>>
>>>Do you  have any consumers connected directly to the battery instead of
>>>through  the cars wiring?
>>>
>>>The new fans perhaps?
>>>
>>>If so, then any current  these consumers are using will have to go
>>>through the ammeter and it will  indicate that it is charging the
>>>battery, when in fact the current goes to  the consumer instead of to the
>>>battery.
>>>
>>>
>>>
>>>
>>>
>>>SOBill  Taylor
>>>sobill at aol.com
>>>
>>>
>>>
>>>************************************** See what's free at 
>>>http://www.aol.com.
>>
>>
>>
>>!DSPAM:46351d8b290502457613276!
>>
>
>
>--
>Real life:   Thomas Törnblom             Email:  Thomas.Tornblom at Hax.SE
>Snail mail:  Banvallsvägen 14            Phone:    +46 18 444 33 21
>              S - 754 40 Uppsala, Sweden  Cellular: +46 70 261 1372
>                                          Fax:      +46 18 44 44 324
>





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