PV Gap

Julia Said:

DC to DC converter in Solar Arrays?

We Answered:

They are used between the array and the batteries, so that the batteries get the maximum power possible. They are usually combined with a charge controller.

yes

MPPT? mean power something?

wikipedia:
A maximum power point tracker (or MPPT) is a high efficiency DC to DC converter that presents an optimal electrical load to a solar panel or array and produces a voltage suitable for the load. PV cells have a single operating point where the values of the current (I) and Voltage (V) of the cell result in a maximum power output. These values correspond to a particular resistance, which is equal to V/I as specified by Ohm's Law. A PV cell has an exponential relationship between current and voltage, and the maximum power point (MPP) occurs at the knee of the curve, where the resistance is equal to the negative of the differential resistance (V/I = -dV/dI). Maximum power point trackers utilize some type of control circuit or logic to search for this point and thus to allow the converter circuit to extract the maximum power available from a cell.

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Edward Said:

solar power help????

We Answered:

Good thought. But today's economics will not support you. It is going to be expensive. Putting it in the wood will make the panel less efficient. Then of course you require Batteries which will be charged by the solar panel in the morning to give you power to run your equipment in the night. The amount of power you get may not be enough to run what you want to run. Probably in another 4 to 5 years your dream may become true. For the moment you can have a solar water heater and this can at least give you decent amount of warm water for your use through out the day.

Roberto Said:

Solar power to run a television outside.?

We Answered:

Not a lot of information in the question regarding the power consumption of the television or the battery capacity but here are the formula needed.

power = current times voltage

If your television requires 100 watts at 12 volts then it needs to be supplied with 8 amps.

A battery will have a capacity such as 10 amp hours and a voltage such as 12 volts

This means the battery can supply 10 amps for one hour or 1 amp for 10 hours or 8 amps for 10/8 hours or 1.25 hours. You may be able to pull 275 amps out of the battery but for how long? If it is 27.5 amp hours the answer is 0.1 hours or 6 minutes, then it is flat.

How much power can a solar panel supply? It depends on the location and weather but there is a theoretical value based on the available power from the sun (250W per square metre) and 15% (typical) efficient solar panels. So consider a 1 square metre panel, it will provide 37.5 watts, and at 12 volts this will be 37.5/12 = 3.125 amps.

Hope you can work it out from this, if not post details of the television power requirements and the battery voltage and capacity. If you are using a converter to supply AC for a mains only television then details of that will also be required as it is not going to be very efficient.

Martin

Willie Said:

How can I power 15v or .08 amps in a remote loaction via solar panel.?

We Answered:

Solar panels generate dc voltage/current.
No conversion from ac-dc is required.
You can attach the solar panel to the battery.
Then attach the load across the battery.
Observe the + & - signs on the panel, battery & radio.
Ideally, you would use a lead-acid gell cell for the battery.
A house alarm backup battery or walkway lighting battery.

The biggest problem is the charging current from the solar array.

If there's no charge regulator, the battery will see a large charging current during daylight hours.

A gell cell can survive the heat generated by this as long as the solar panel is not large.

You have to "size" the solar panel for the maximum charging current you think you'll need to replace the energy that the radio used at night.

In your case it doesn't need to be large to recover a mere 80 milliamps per hour draw with no sunlight.

Never connect the radio to the solar panel in daylight without the battery connected (if no regulator). The solar panel will output a no load voltage of 20-21v. This could damage the radio. The battery will load the solar panel down enough to only show 12-14v.

Although I always prefer the more elegant approach of using a charge regulator between a solar array & the battery / load, I have done as the above & just hooked the battery & radio directly to the solar array & left them to run.

The batterys still last several months in the Nevada summer sun & winter cold.

Additionally, your radio probably has sufficient regulators inside to operate on 13.8 -18v. As the battery gets older, it may not load the solar cells down enough to limit the voltage to 14v. The light load voltage may well rise to 15-18v (direct sunlight) as the battery becomes aged.

Protecting your investment should include a cheap solar panel regulator. It will also disconnect the radio from the solar cell / battery in case of a low battery condition.

This helps protect the battery from going completely dead & putting a heavy load on the solar cells as they attempt to recharge the battery.

The regulator also disconnects the radio if the voltage to the radio climbs above a set threshold. This protects the radio if the battery shoud go bad or open fuse / circuit & fail to load down the solar panel output voltage enough.