[ARC5] SCR274 field test

[Kenneth G. Gordon]

On 19 Jul 2015 at 0:28, J Mcvey via ARC5 wrote:

> I was hoping that I could run the dual rx/tx setup off of my  jeep battery, but
> it seems it needs a stiffer deep cycle type to keep up with the load in
> transmit.

No. You just need bigger wire and a better connection.

> The jeep battery sagged badly and for that matter so did the deep cycle
> battery (11v under full load),

I'll bet you're measuring that voltage at the dynamotor...

What is the voltage at the battery?

> but it was sufficient to keep things working. I
> think i'm missing something about the nature of dynamotors and batteries ...
> With the two transmitter filaments ( 4X 1625) @ 2a and the rx pulling about
> 2.5a, that's a constant 4.5a, add the dyno in stanby which bring the the total
> cw break-in receive mode 7.5a. The dyno says 9a @ 12V continuous duty for 440v @
> 200 ma .That should be a max of 16.5a a key down.

Yes, but that is after the dynamotor is already up to speed.

> So how can 16.5 amps draw a
> 130AH battery down to 11v from it's fully charged resting voltage of 12.6v ?

IR drop in the cables or connectors.

Use bigger wire and better connectors. I would suggest 3-ought welding 
cable.

Ken W7EKB