Re: FT-100D lowest usable voltage

I run my station on a large bank of 12 volt dry batteries typically 
designed for UPS applications.  But I installed a MFJ-4416C DC to DC 
battery voltage booster to feed my radios with the needed voltage for 
full RF output.  The booster will provide the required DC voltage to 
your radio up to about 14 volts, as the battery voltage drops down to 
the 25% SofC which is the 11.993 volt area (open circuit voltage).  FYI: 
most 12 volt wet cell batteries are totally discharged at 11.753 volts, 
(OCV).  Technically, that has been published as the "0 state of charge" 
at 70° f.  You should not try to use them lower than that or you could 
ruin them.

Most of todays12 volt DC operated100 watt radios will not operate 
properly with less than 13.6 to 14 volts under load.  That needs to 
include wire and connector losses in the DC wiring.  It should be 
measured at the radio DC connector, or more preferably on the PC board 
connections at the DC input.
Ray, W4BYG

On 9/23/2018 3:51 PM, Roy Ashkenaz roya-b4T0evRm615ZmPDBg+/6q1aTQe2KTcn/@public.gmane.org [FT100] wrote:
> I am running my FT-100D (with WSJT-X etc) off of some 12v batteries. It
> works fine for 1-2 hrs, until at some point, the radio and rig control
> starts to do weird stuff - seems to be due to low voltage being fed to
> the radio.
>
> Does anyone know from experience what the lowest voltage I should use to
> run my radio? Specs for the radio show 13.8v +- 10% (1.38v) = 12.42 but
> it seems like I've run below this voltage.
>
> I am in the process of building/buying a low voltage alarm for my
> batteries (built ones are just a few $$ on ebay) and want to set it to a
> reasonable value.
>
> Thanks, Roy K2RMA
>
>



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