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AR15.COM
5/10/2015 4:00:07 PM EDT
I want to run a Yeasu FT8800 on 12v from a briefcase.   I believe the Yeasu runs 50 watts on VHF and  35 watts on UHF.  (It is adjustable).

If I use a Goal Zero Sherpa 50 watt battery (5200 mAh) with the Nomad 20 watt folding panels (about 1.3 ah) about how long will it last ?

If I use the Sherpa 100 watt battery (8800 mAh) with the Nomad 20 watt folding panels (about 1.3 ah) about how long will it last ?

The battery allows for use and charging at the same time.

What do you folks think ?  Good or bad ?
5/10/2015 7:14:09 PM EDT
[#1]
For info my area has many different 2 meter / 440 repeaters available to me and I can run on 10 watts of power pretty easy if that helps.  

I know there is an equation for it, I just don't know what it is.  

5/10/2015 7:21:11 PM EDT
[#2]
On receive, the panel would probably run it as long as you had sun light as the FT-8800 is pulling only about 1/2 amp (squelched).  Transmitting at high power it looks like it pulls 8.5 amps, not sure about 10w xmit power but if it is 20% of the high power draw  (for 50w xmit) that would be in the neighborhood of 1.7 amps, which you'd probably be able to do as desired pretty much as long as you had full sun.  Looks like you'd probably have multiple hours operation on low power even without significant panel contribution.

Nick
5/10/2015 10:20:35 PM EDT
[#3]
Quoted:
I want to run a Yeasu FT8800 on 12v from a briefcase.   I believe the Yeasu runs 50 watts on VHF and  35 watts on UHF.  (It is adjustable).

If I use a Goal Zero Sherpa 50 watt battery (5200 mAh) with the Nomad 20 watt folding panels (about 1.3 ah) about how long will it last ?

If I use the Sherpa 100 watt battery (8800 mAh) with the Nomad 20 watt folding panels (about 1.3 ah) about how long will it last ?

The battery allows for use and charging at the same time.

What do you folks think ?  Good or bad ?
View Quote


1)
what is the operating duty cycle, i.e. the TX:RX ratio?

said another way, on average of every 60 seconds, how many seconds are you transmitting?  6?  10?  30?

since the transmit current is so much higher than the receive current, the duty cycle makes a HUGE difference in battery life.  

you can see some sample calculations here:
https://www.ar15.com/forums/t_10_22/604477_Ham_Radio_101.html&page=1#i10323268
and here
http://losdos.dyndns.org/public/ham/RACES-box.html

ps
any complaints about the the images being broken in the Ham Radio 101, EMCOMM box, or any other thread on ARFCOM go here:
https://www.ar15.com/forums/t_1_2/1745939_Really_disliking_the_new_image_sizes.html&page=5#i53523076


2)
for the batteries you listed, what are those capacities referenced against?  20 hour discharge rate?

ar-jedi
5/10/2015 10:27:27 PM EDT
[#4]
Why bother with a heavy, power hungry mobile instead of an HT that's designed for battery power operation?
5/10/2015 10:54:26 PM EDT
[#5]
Quote History
Quoted:
Why bother with a heavy, power hungry mobile instead of an HT that's designed for battery power operation?
View Quote


I Have the HT's and the power to run them.   Same kind of set up.   I just wanted by FT8800 to have the same capability if possible.  
5/10/2015 10:55:00 PM EDT
[#6]
Quote History
Quoted:


1)
what is the operating duty cycle, i.e. the TX:RX ratio?

said another way, on average of every 60 seconds, how many seconds are you transmitting?  6?  10?  30?

since the transmit current is so much higher than the receive current, the duty cycle makes a HUGE difference in battery life.  

you can see some sample calculations here:
https://www.ar15.com/forums/t_10_22/604477_Ham_Radio_101.html&page=1#i10323268
and here
http://losdos.dyndns.org/public/ham/RACES-box.html

ps
any complaints about the the images being broken in the Ham Radio 101, EMCOMM box, or any other thread on ARFCOM go here:
https://www.ar15.com/forums/t_1_2/1745939_Really_disliking_the_new_image_sizes.html&page=5#i53523076


2)
for the batteries you listed, what are those capacities referenced against?  20 hour discharge rate?

ar-jedi
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
I want to run a Yeasu FT8800 on 12v from a briefcase.   I believe the Yeasu runs 50 watts on VHF and  35 watts on UHF.  (It is adjustable).

If I use a Goal Zero Sherpa 50 watt battery (5200 mAh) with the Nomad 20 watt folding panels (about 1.3 ah) about how long will it last ?

If I use the Sherpa 100 watt battery (8800 mAh) with the Nomad 20 watt folding panels (about 1.3 ah) about how long will it last ?

The battery allows for use and charging at the same time.

What do you folks think ?  Good or bad ?


1)
what is the operating duty cycle, i.e. the TX:RX ratio?

said another way, on average of every 60 seconds, how many seconds are you transmitting?  6?  10?  30?

since the transmit current is so much higher than the receive current, the duty cycle makes a HUGE difference in battery life.  

you can see some sample calculations here:
https://www.ar15.com/forums/t_10_22/604477_Ham_Radio_101.html&page=1#i10323268
and here
http://losdos.dyndns.org/public/ham/RACES-box.html

ps
any complaints about the the images being broken in the Ham Radio 101, EMCOMM box, or any other thread on ARFCOM go here:
https://www.ar15.com/forums/t_1_2/1745939_Really_disliking_the_new_image_sizes.html&page=5#i53523076


2)
for the batteries you listed, what are those capacities referenced against?  20 hour discharge rate?

ar-jedi


Thanks !