[ARC5] SCR274 field test

[Chris Bowne]

As others have also commented your vehicle battery is sick.   Should not drop voltage like you describe on key down.

Re the FT 450 dropping the voltage,my FT 100 was very sensitive to input voltage apparently a design issue - would chirp badly on CW in a mobile setup unless it was seeing near 13.8 volts with the battery on charge. I had low resistance power cables to it also right off the battery.

Sent from my iPhone

> On Jul 19, 2015, at 12:22, J Mcvey via ARC5 <arc5 at mailman.qth.net> wrote:
> 
> I was trying to avoid needing to run the engine while operating for only a few hours at a clip.
> I also was not aware (since I never did the experiment) that the battery will drop as low as 8 or 9 while cranking the engine, so maybe 11 volts at the battery isn't so bad after all.
> As far as I know, lead/acid batteries can also be "quick checked" by their no load "resting voltage" several hours after charging. It should be at least 12.6V.The deep cycle was pulled fresh off of my trickle charger. In rx mode and tx dyno running, it reads 12.6v. When keying the transmitter it sagged to 11v . The Jeep had been sitting for about a week and a half , so it's resting voltage was 12.2v which indicates a partial discharge state. 
> Both are the "sealed" type with no access to the cells.
> 
> Some here are saying that it's the "light" cable., but that series resistance would only be a problem in wire heat loss and a drop at the dyno end, not at the battery! A resistive cable would actually DECREASE the current draw.
> 
> Yes the power cable should be beefier, but sometimes i have to work with what I have laying around.Doing the the math at 30 amps for my 6 foot length, considering 12 ft total.#12 is about 1.58 ohms. 12 ft is 19 X 10^-3 ohms. Even at 30 amps the drop is  only 560 millivolts. Under actual operating conditions, it will be much less.
> Now that think about it, my 100W ft 450 will drop the battery voltage in tx as well. I guess the load resistance starts to rival the internal battery resistance, but I don't think it got to 11V, though. maybe 11.6 or so... I need to revisit this...