PV Gap

Jennie Said:

How can I make a sun tracker for a solar panel?

We Answered:

tbls101 has a good idea for the tracker, but let's take this one step farther. A clock motor large enough to move a solar panel, unless it is a very small one is going to be large, and expensive. Use the timer motor, as suggested, but attach a slotted disk to it, with a light source on one side, and a detector on the other side. As each slot comes up and allows light to pass through, this creates a one shot pulse which is used to cause a stepper motor to move 1 position to keep the panel aimed at the sun. At the end of the panel travel for the end of the day, a switch could be set to close, bypassing the step control to put the motor into full constant speed reverse, this causing the panel to swing back to the morning position. The whole affair gets it's start up call by means of a light detector, similar to those used to turn lights off at sun up. The control would, of course be set to turn the system on to track the sun during the day. While some digital control is going to be needed, the system would not need a "computer" to run it.

Byron Said:

How can I power a laptop whil camping?

We Answered:

First, get a car charger for your laptop so you can efficiently use a battery.

Next, get a marine deep discharge battery. They have them at Wal-Mart with 105 A-hr capacity for about $60 US, or a little bigger for quite a bit more. Deep discharging a typical car battery will kill it after just a few charges.

This should last for 40 or so hours of opertion for a typical laptop, much more for a low powered netbook. This should be enough for a short vacation. If you need more, you can charge from your car using cables, either from the battery or through the cigarette lighter or other wires (with the car running, of course).

If you don't have a vehicle, I would get a small generator <1kw for ~100 with a 12V charging circuit, and use that. Last choice would be a 50W or so solar panel if you use the laptop intermittently. Don't forget the solar panel requires an electronic box with a charge controller. Harbor freight has some for not too much money.

If you are charging it, a small digital multimeter can be used to determine charging current (put a small resistor, 1Ohm or less in series) by measuring the current across a resistor. Also, the voltage of 13.6V or so when the charger is taken off indicates full charge. Good luck!

Marion Said:

Solar Panel watts to volts?

We Answered:

forget it. you would need a truckload of those panels to power even a small tv.

Elsie Said:

Can I just leave the solar panel connected to the car battery?

We Answered:

Check the specifications on the regulator to make sure it will block current from flowing backwards from your battery. You do not want to discharge the battery at night time. You can also check this by placing a 100 ohm resistor in series with one of the leads to the battery and throw a towel over the solar panel and see if there is a DC voltage across the resistor. If not remove the resistor and reconnect the lead to the battery, your solar charger should work fine.

Make sure your solar panel and regulator are large enough recharge your battery during the day light hours. Estimate the watt-hours of use per day you expect from all of your equipment and then divide this number of watt-hours by say 8 hours of good sun light to come up with number of watts you need to size your system.