Put the Fluke 75 on the 300 mAmp scale and it reads out directly in mill-amps up to the limit.
Inserted the Fluke meter into the SSPB ground connection; The SSPB draws 2.09 milli amps. That will last over 6 months on a 14 amp hour battery
Inserted the Fluke into the ground wire of the CF; The CF showed zero with 0.01 milli-amp resolution. Considering standard battery discharge rates that is effectively ZERO.
The CF is a MOSFET device and it would be only logical (if the designer even considered quiescent battery draw) to put all MOSFETs into an open (OFF) state when the IGN is off. This would be mega ohms of resistance to battery and so the only draw is mico amps of gate bias to MOSFETs which is what is bore out by the measurements. I see nothing; zero; nada.
A few more measurements:
My total battery draw with the SSPB (2.09 mA) is 2.55 mA so that figure that I have about 0.5 mA draw by the OEM Check Light brain box.
I also check the draw on my idiot light Battery sense wire which is hardwired to +12V through a 680 ohms resistor. When I installed this I used the inline resistor from the original battery to wire to +12V and did not bother to measure the drain. Since I had the meter out here is some data (for posterity).
680 ohms inline 1.61 mA
1K+680 ohms inline 1.4 mA
10K+680 ohms inline .59 mA
50K+680ohms inline .18 ohms
I checked and the idiot light was still functional (with key on) when I did the tests. So it looks like you can hook the idiot light right up to switched +12V ad suffer a draw of something less than 2 mAmp or hook it to a switched +12V and not worry about the +12V while running.
Mine is hooked to the switched output of the SSPB so no drain unless IGN is on and presumably I'm charging then.
I have a analog volt meter connected to the unswitched SSPB output connected through a switch with an LED to indicate it is on. Draws about 50 mAmps between the two of them.
Anybody done the equivalent on the SH-775 or care to do it? The SH-775 is an SCR type device. Looking at a typical 10amp SCR data sheet it needs 2 milliamps to not trigger so the quiescent loads are probably higher for the SH-775.
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