Questions And Answers

OP-Amp Problem as of 11/05/06 Op Amp is our sticking point at this juncture.

We have had success in getting reading but the recurring problem is getting a stable consistent reading.

10.04.06 Gilad found that adding a capacitor to the circuit helped stabilize the output. However, it slowly falls when the device is turn off.

Gilad is going to revisit it with another student 10.05.06

10.03.06 Megan purchase several Current rings for us to work with. She also scanned and distributed pages on amps from the inventor’s book.

• Op Amp tutorial
• Megan's op Amp Flickr

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Problem as of 10/14/06

Both Jenna and Barbara (batteries) are not charging from the solar panel. We are getting between 15 to 19V in daylight from the solar panel leads coming from the roof. These leads connect to the SunSaver-10 Controller, which is in charge of regulating the power flow into the battery. When we connect the battery leads to the specified place on the controller, the measured voltage going into the battery is 0.4V. This happens with both batteries. When we unplugged the solar panel leads, and plugged a DC power supply into the SunSaver-10 controller, the incoming voltage (from the power supply) matched the outgoing voltage (to the battery). Finally the battery started charging. The amperage going into the battery started out at 0.08A (with 19V) and climbed with time (20 minutes after, current drawn from the battery was 0.13A... and rising).

why is the Solar Panel not charging the battery?

• We need to get the specs for the Solar Panel, and find out how much amperage is produced by the panel.

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What we've figured out already:

1. The SunSaver controller is working properly. When fed with over 12V, it slightly regulates the voltage going into the battery.
2. Both batteries are responding to DC power supplies => the batteries are charging.
3. Solar panels are giving an output of 15-19V during the day.

What we don't know yet:

1. How much time (on average) does it take to charge the battery? Using the AC charger which came with the battery, it takes 15 Hours to fully charge the battery, at 12V DC and 5A. But we need to figure out the time it takes to charge using Solar Power from the rooftop panel.
2. Whats the amperage flow into the battery?
3. How long will the battery be able to supply power to the room (battery supplies: 115V, 60Hz and 1500W)?
4. Whats the internal resistance of the battery?