[ARC5] adventures in battery ops

[Bill Cromwell]

Hi J,

The first thing is I actually said I use them portable which is 
different from 'mobile'. If I was going to use them mobile I would have 
to consider rewiring the heater strings for 12 volt operation. Or, as 
some owners have done, replace the tubes with some that run 6 volts on 
the heaters which will be happy with 12 volts applied to the original 
series-parallel heater wiring. There is not a direct 6 volt replacement 
for at least the 12K8 - I think that's the one - but it's still a viable 
option that has been used successfully.

For battery operation on picnic and camp tables the 24 volt string draws 
half the current with twice the battery and no mods (reversible or not) 
required. It lasts twice as long (and not times four). My charger deals 
with the entire series battery pack in situ. I am not restricted to a 
'12 volt charger'. Two fewer reasons to change the wiring.

Yes..the sheet metal needs to be grounded. Any time I hear extra racket 
the first thing I look for is that ground connection being 
loose/missing. That ground connection does nothing at all to keep 
conducted crud from the power line out of the cans. Brute force 
filtering in the power supply helps with that. Or batteries.

Of course, taking a cute plastic box of ICs and transistors to the 
picnic table would be ever so much easier but it's not nearly as *kool*.


73,

Bill KU8H


On 04/07/2015 09:17 AM, J Mcvey wrote:
> I have a question about the original premise of this thread.
> You mentioned  that you are using the radios in mobile mode, so why 
> not operate them on the car battery?
>
> There is a very non-destructive method for putting all the filaments 
> in parallel which is just a matter of moving a few connections.
> At present, I am using a 12 volt dynamotor, but I am going to  build a 
> replacement 12v SMPS supply to fit onto the dynamotor plug.
> I found that the noise in these radios is dramatically reduced if the 
> receiver rack is grounded to the frame of the vehicle with a short 
> strap. The noise is probably dynamotor hash, so I am curious how much 
> less noise and current demand will come from a properly bypassed SMPS.
>
>