Can i use direct current directly from solar panels?

[muzaffar_ali99]

Hi i need to know can i use direct current from solar panels for my lighting or fans?

There are 3 kind of solar panels available in pakistan, 1. Chinese (Cheap) , German (Costly) and USA made also costly, don't know if their claim is right or not too.

I want to avoid battery.

PLease give suggestions.

THanks
Muzaffar Ali

[billvon]

Hi i need to know can i use direct current from solar panels for my lighting or fans?

For the most part, yes. Devices that have switchmode inputs will usually not work well due to their negative impedance characteristics. Simple LED lights, incandescents, and fans should all work as long as their voltage range is within the voltage limits of the panels. Needless to say their output will not be constant as sunlight changes.

[Sunny Solar]

Simple LED lights, incandescents, and fans should all work as long as their voltage range is within the voltage limits of the panels. cant see that would ever be possible.Say they are 12v system panels they have an output voltage up to 21v. No 12 v lamp or 12V LED is going to last more than a few seconds with that voltage.

[inetdog]

Simple LED lights, incandescents, and fans should all work as long as their voltage range is within the voltage limits of the panels. cant see that would ever be possible.Say they are 12v system panels they have an output voltage up to 21v. No 12 v lamp or 12V LED is going to last more than a few seconds with that voltage.

Although you do not want to use batteries if you can avoid it, you will still need to include some form of voltage regulator or DC-to-DC convertor which has a wide input voltage range and an output current capability which meets your needs.
I assume that the lights which you need during peak sunlight are for inside rooms which do not get direct light, or else for task-related lighting.
If the load goes temporarily beyond what the panels can produce, the convertor or regulator would have to just deliver what current and voltage it could rather than shut down.

[billvon]

[COLOR="#0000FF"]Say they are 12v system panels they have an output voltage up to 21v. No 12 v lamp or 12V LED is going to last more than a few seconds with that voltage.

Right; if your Vocmax were 21 volts you'd need a 24V LED; there are plenty of 24V devices out there.

However, I agree that you can't just hook up a "12V" panel to a "12V" device and have it work. "12V" panels typically produce 0-20 volts and "12V" devices typically can use 9-16 volts. You either have to be aware of the actual voltages and make sure the system works in that range or use a voltage regulator. They're pretty simple for low power devices; a 7812 IC will regulate to 12V and only needs two additional caps.

[COLOR="#0000FF"]I assume that the lights which you need during peak sunlight are for inside rooms which do not get direct light, or else for task-related lighting.

If that's the case a mirror or skylight is likely a much cheaper solution. Heliostats and fiber optics also work. They're more expensive but any system that transmits light is going to be much cheaper, easier, more efficient etc than a system that converts light to electricity then back. (We're talking 80% vs 6%.)

[Sunny Solar]

The reality is ,you really cant just connect solar panels to most devices. There are a few pumps that have been designed to run straight from panels but just about nothing else.
Lights of any type are going to drive you mad going bright then dim every time a cloud goes over the panel. 24v bulbs on 20v are going to be rather dim. Most 12V LED replacements wont last long on over 15v.
A small 12v lead acid battery and a 5a battery charger does not cost much and is going to improve dramatically the lights steady brightness and will improve the longevity of the lamps.

[muzaffar_ali99]

Ok thanks for the suggestions i will try to use dc to dc converter or some small battery.