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Re: Battery recommendation...with external amp

Jack Purdum
 

Marco:

I don't know how "portable" you need to be, but I've used a 10W panel with my Forty-9er and it worked well. I was given a 7AH motorcycle battery, so that's what I used. I don't use it a lot, but when I have, it worked fine. As I recall, the panel is about 17"x10" and weighed about 3.5lbs. I also used a cheap ($10) solar panel charge regulator with the setup. I kept all of the electronics and battery in a toolbox. (I had an Arduino controlled stepper motor that adjusted the panel throughout the day so it always faced the sun. You can see it in the Arduino Projects for Amateur Radio book.)

Jerry's suggestion for a different battery makes sense and may be cheaper in the long run.

Jack, W8TEE


From: M Garza <mgarza896@...>
To: [email protected]
Sent: Sunday, January 22, 2017 10:38 PM
Subject: Re: [BITX20] Battery recommendation...with external amp

Jerry,
WOW.? Completely off grid.? Nice.
I guess I need to investigate better batteries (NI-MH maybe?) and solar/wind power.? I live near the coast, in S. Texas.? Plenty of sun and wind. ?

Marco - KG5PRT


On Jan 22, 2017 9:28 PM, "Jerry Gaffke via Groups.Io" <jgaffke=[email protected]> wrote:
That battery should have 12v*7AH = 84 Watt-Hours of power in it.? Will take at least 84/1.5 = 56 hours of full sunlight perpendicular to the panel to recharge the battery.? Assuming the rig is 6 Watts at 50% efficiency (so draws 12 Watts), could run the rig for 84/12 = 7 hours of continuous transmitting, perhaps 10 times that for just receive.? Could deal with your 30 Watt amp as well, for a while.
A starting battery like that is built for occasional high current draw for a few seconds.? They are not built to be repeatedly discharged.? So the lead plates are more of a lead foam, for maximum surface area, and disintegrate after the battery is discharged a few times.? Avoid discharging below 11v or so, and always charge it back up as soon as possible to avoid sulfation. The motorcycle battery will get you started but will wear out with use.? There are deep-cycle lead acid batteries built to be discharged 1000 times, that is not one of them.? A lithium-ion battery pack might be a better choice long term. ? I doubt that panel will be worth the bother, though when the sun is out it should at least keep up with the Bitx40 receive current draw.
All near and dear to my heart.? We're fully off grid, running from an 18 KWh deep cycle lead acid battery bank in the basement and 4400 Watts of solar panels out in the yard.
Jerry, KE7ER
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