[Elecraft] K1 -- VW Solar Panel -- Controller Help

[Don Brown]

Hi

I have tested my controller with a VW panel and a 2.8 amp hour battery. This 
setup WILL fully charge the battery and the controller will start cycling 
with the panel in full sun, but if the battery is discharged it may take 
several days to bring the battery up to full charge. The VW panels are very 
low power about 3 watts at best or about 180 mA. It would require over 14 
hours of full sun on the panel to charge a discharged 2.35 amp hour battery. 
If the panel is not perpendicular to the sun the output will be lower and 
would require even longer to charge the battery.

You may have a battery with a bad cell. You may want to try charging it with 
a battery charger designed for gel cells or connect it to a power supply set 
to 13.8-14.5 with a limiting resistor of about 5-10 ohms at 10 watts. If the 
terminal voltage of the battery will not come up to 13.8 or higher the 
battery is most likely bad.

You do not need a current limiting supply to test the controller. Any power 
supply with an output of 15 to 25 volts will work in place of the solar 
panel if you install a limiting resistor in series with the power supply of 
about 5-10 ohms and about 5-10 watts.

If you have any variable power supply that can be adjusted from 13.0 to 14.2 
volts you can follow the instructions supplied with my controller to check 
the operation of the controller. The current required for this test is only 
about 20 mA so any type of variable power supply should work.

If you still cannot get the controller to work send it back to me and I will 
test it for proper operation and repair or replace it if required

Thanks

Don Brown
KD5NDB

19132 Falls Creek Drive
Flint, Texas 75762




----- Original Message ----- 
From: "KEN" <CANNON213 at MSN.COM>
To: "elecraft" <elecraft at mailman.qth.net>
Sent: Sunday, November 05, 2006 9:42 AM
Subject: [Elecraft] K1 -- VW Solar Panel -- Controller Help


Hello folks,

Have a new 2.3SLA battery I'm trying to charge for the K1. Here the problem 
I'm having. The battery started out at about 9.6V and is now at 12.10V or so 
after charging for several days on and off.

The VW panel reads about 20V in full sun. When connected to Don Brown's low 
power controller, it drops to 12.75V (full sun). I have a few panels and 
tried them all....same results. Even paralleled two.

The controller will cut-off around 14.0V. Needless to say, this one will 
never make it to cut-off. I'm wondering if there is a problem with the 
controller. Don says the panel connection point at the controller should 
read about 15V.

I don't have a current limiting supply to test the controller the way the 
instruction sheet suggests.

Any thoughts appreciated,

Thanks....Ken...W2GIW
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