[Elecraft] Battery requirements for NPOTA activation withKX3/KXPA100

[Igor Sokolov]

I have experimented with LiFePo4 batteries feeding KX3/KXPA100 in contest 
environment where duty cycle is about 50% for TX. For SSB the current draw 
is a bit higher then for CW. 25Ah battery lasted 4 to 4.5 hour with 100 W in 
the beginning and dropping to 50-60W out in the end of the cycle. For SLA of 
the same capacity you will probably have  half of that time. With 2x 60W 
solar panels added to the mix I get between 6 to 8 hours in semi sunny 
weather. I have ended up with a pair of LiFePo4 25Ah each (about 2 Kg each) 
which allow full day of operation. Again if you use SLA instead of LiFePo4 
you will need at least 100 Ah.

73, Igor UA9CDC

----- Original Message ----- 
From: "Esquer Dave" <dave.esquer at gmail.com>
To: <elecraft at mailman.qth.net>
Sent: Wednesday, March 30, 2016 1:41 AM
Subject: [Elecraft] Battery requirements for NPOTA activation 
withKX3/KXPA100


> Hi folks,
> I know this has been asked and discussed before but I can’t seem to get a 
> handle on a clear-cut answer …
>
> I am going to do a SSB NPOTA (National Parks on the Air) activation with 
> my KX3/KXPA100/PX3 on battery power. It has been in the works for a while 
> with a special use permit required by the NPS.
>
> How much battery capacity do I need if I want to run full 100 watts? For 
> planning purposes, I am assuming a 6 hour activation with a (highly 
> optimistic I know) 60 QSOs per hour.
>
> The PX3 will be powered by a separate LiFePo 4.8 aH battery, it will do 
> just fine. My concern is the amount of draw I will need to last the 6 
> hours. With an inline (Hobby King) HK-010 Power Analyzer, I see a max 
> current (KX3/KXPA100 combo) of about 8 amps and about 80 watts during a 
> QSO. The QSOs varies between 50-80 watts on transmit.
>
> I also know that once I am spotted, I can drop the power down to maybe 
> 75-50 watts to save some battery juice.
>
> I have 2 12v-18aH SLA batteries at the ready, am I woefully underpowered? 
> If you have any real-world experience or tips, it is most valuable and 
> appreciated. You can contact me offline at dave dot esquer AT gmail as 
> well.
>
> Thanks,
> Dave, K6WDE
>
>
>
>
>
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