[ARC5] SCR274 field test

[J Mcvey via ARC5]

Yes the startup current is huge, I was aware of that, but the drop is after it's already running in standby under transmit load. (the dyno runs continuously in CW mode). The startup inrush current will pop a 20A fuse, but not a 30.

I made the voltage measurements right at the battery terminals with key down. The power cable is about 6 feet of #12 AWG. The drop is nominal and there is no noticeable warmth, yet the transmitter can pull down the battery voltage quite dramatically. 


     On Saturday, July 18, 2015 10:04 PM, Roy Morgan <k1lky68 at gmail.com> wrote:
   

 
On Jul 18, 2015, at 8:28 PM, J Mcvey via ARC5 <arc5 at mailman.qth.net> wrote:

> ...how can 16.5 amps draw a 130AH battery down to 11v from it's fully charged resting voltage of 12.6v ? ( it recovers on key up)

Note well where you are measuring the voltage.  There may well be IR drop in the leads from your battery to the radio - if you are measuring the voltage at the radio, I’d bet on it.  And especially so if you are getting the radio supply voltage from somewhere other than the battery terminal itself.

If the wire to the radio does not come off the battery itself (and the connectors are bright and shiny inside) you’ll have voltage drop in the vehicle harness.

Roy]

Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958