Powered shed, but don't use much power...

[416freeze]

Hi There. About to purchase a Renogy 50w kit + 12v deep cycle, + 1000w inverter. This will be used on my shed to power: Lights + radio for a couple hours a day, and to charge mobile devices if we ever lost house power (rarely happens).

My question is, since I will obviously have much more power than I need daily (which I want for emergencies), where does the excess power go daily? How is excess power managed? Can I have something hooked up to this system that deals with the excess power (lights that come on automatically)?

Thank you.

[SunEagle]

Hi There. About to purchase a Renogy 50w kit + 12v deep cycle, + 1000w inverter. This will be used on my shed to power: Lights + radio for a couple hours a day, and to charge mobile devices if we ever lost house power (rarely happens).

My question is, since I will obviously have much more power than I need daily (which I want for emergencies), where does the excess power go daily? How is excess power managed? Can I have something hooked up to this system that deals with the excess power (lights that come on automatically)?

Thank you.

Welcome to Solar Panel Talk

First off a 50 watt panel will produce maybe 200 watt hours max a day during the summer. Not sure how you figure you will have "excess power" from that. Especially with that 1000 watt inverter which will probably use about 100 watts every hour it is on.

Before you purchase a that 50watt kit go read the Sticky posts in the off grid section on sizing the battery for an off grid system. Read, ask questions, research and then if you still want purchase your equipment.

What you are doing is similar to Fire, aim, ready.

[Sunking]

A 50 watt panel with PWM controller can only support a 12 volt 35 AH battery the size of a motorcycle battery. A 12 volt 35 AH battery can only support a 50 watt INVERTER.

Take notes Panel Wattage roughly = Inverter Wattage

[416freeze]

Appreciate the response. Clearly i need to read up more on all this. But your comment here answers my inverter question... and actually reduces the cost Of the system if its only 50w inverter and not 1000 That i need.

QUOTE=Sunking;144628]A 50 watt panel with PWM controller can only support a 12 volt 35 AH battery the size of a motorcycle battery. A 12 volt 35 AH battery can only support a 50 watt INVERTER.

Take notes Panel Wattage roughly = Inverter Wattage[/QUOTE]

[Sunking]

Inverter size depends on maximum connected load running. If maximum load is 50 watts then you want a 75 to 100 watt inverter.

Inverter size determines minimum battery size. This is due to the current the Inverter will demand from the battery at full power. If the battery is too small, the voltage will sag causing the inverter to trip off line from under voltage.

Batteries like Inverters require minimum charge current requirements in order to prevent the battery from stratifying (heavier acid sinking to the bottom floating the water on top). The charge current has to be high enough to cause the electrolyte to gas (bubble that stir the pot). Minimum charge rate is C/12. Morale to the story as a general rule is Inverter should be no larger than panel wattage. No problem with a 1000 watt panel on a 12 volt 400 AH battery and 50 watt Inverter. But a 50 watt panel with 1000 watt inverter is a NO GO.

Everything thing has to be matched up. Otherwise it is like a motorcycle trying to pull a 18-wheel truck. Not going to work.