1st Post, Solar Shed Lighting, Need Guidance!

[Msollars]

So here are the details that I have

I'm wanting to use some materials that I already own to light the inside (and outside) of a newly built 12x16 shed in my backyard.

I currently have......

1. (several) indoor rated 8.5 watt philips led bulbs (60watt equivalent)
2. 300watt msw inverter
3. 85AH Deep Cycle Battery

The shed will mostly be used for garden/lawn equipment, sporting goods, long term plastic clothing tub storage, etc. It has a 12x8 lofted area, the area underneath the loft, and the open ceiling 12x8 section. (14' peak)

Use: i'm guessing the inside will see a few hours at a time, tops......maybe 2 times per week. I'd also like to do some motion/dusk to dawn security lighting on the outside of the shed. This could be tied to the indoor system, or a separate solar motion light, or the like.

My questions are:

1. What size panel would i need to recharge the system based on my stated use time and lighting requirements?
2. would i need to wire all the inside lighting in series or parallel. (maybe 12 bulbs inside total)?
3. I'm an idiot about this stuff, so what red flags / problems do you see with any part of this system.

Thank you all so much,

Matt

[Sunking]

I currently have......

1. (several) indoor rated 8.5 watt philips led bulbs (60watt equivalent)
2. 300watt msw inverter
3. 85AH Deep Cycle Battery

My questions are:

1. What size panel would i need to recharge the system based on my stated use time and lighting requirements?
2. would i need to wire all the inside lighting in series or parallel. (maybe 12 bulbs inside total)?
3. I'm an idiot about this stuff, so what red flags / problems do you see with any part of this system.

Welcome Matt. Lets get right into the meat of it. The Kill-Joy the 85 AH Battery. Nothing else matters because you are married and restricted to a 85 AH battery. You made the battery the end result, not what you want it to do. If you use 50% of the battery capacity only yields you 600 usable watt hours and would take a couple of days to fully recover. For everyday use only 200 watt hours. Based on your battery size ideally you need a 160 watt Battery Solar Panel, or two 80 watt panels with a 10 amp charge controller. There is not much wiggle room with your battery. The minimum panel wattage required to maintain the battery is 130 watts, and maximum is 190 watts. Your battery's capacity is limited to around 300 watt hours per day assuming you can fully recharge it in a day. Does not matter if it is not enough power for you, that ball-n-chain you are married too only allows up to 300 watt hours in a day and you are stuck with it.

[Msollars]

thanks for the quick reply.

can you go into a little more detail about my watt hour needs?

say 12, 8.5watt led bulbs.....through a 300watt msw inverter. how long can i run that setup before i reach the 50% battery drain limit......and then how long to recharge with say a 100watt panel.

thanks, and thank you for your patience with these 'elementary' questions...
Matt

[SunEagle]

thanks for the quick reply.

can you go into a little more detail about my watt hour needs?

say 12, 8.5watt led bulbs.....through a 300watt msw inverter. how long can i run that setup before i reach the 50% battery drain limit......and then how long to recharge with say a 100watt panel.

thanks, and thank you for your patience with these 'elementary' questions...
Matt

Matt

It comes down to simple math. 12 x 8.5 watts = 102watts. The inverter also uses some wattage (due to how efficient it is) even if none of the lights are on so maybe add another 18 watts to that 102.

With a load of 120 watts and a run time of 2 hours comes to, 120 x 2 = 240 watt hours. So that battery can run all your lights for about 2 hours and gets discharged 25% which is the most you want to do to get a long life out of it. A 50% DOD will probably cut the battery life in half.

Now a 100 watt panel with a PWM charge controller is really only a 67 watt panel. If you use 240 watt hours it will take more than 4 good sunlight hours to put back that 240 watt hours due to system losses. If you use more than 240 watts you probably won't be able to recharge that battery in a day. Also with only a 100 watt panel (~ Imp = 5.5amps) you can't provide the right amount of charging amps to go back into that 85Ah battery. You need somewhere around 9 to 10 amps which means about 190 watts of panels using a PWM CC.

[emartin00]

I think you would save yourself a fair amount of power if you just bought some 12V LED lights. If you are using the standard 8.5W, 120V household bulbs, then you are converting power to AC, and then the bulb is converting it back to DC. 12V led lights would run right off the battery and you wouldn't even need an inverter.

Also, do you really think you need 12 bulbs? Unless you have a massive shed, 12 LED bulbs is probably way overkill.

[lkruper]

So here are the details that I have

I'm wanting to use some materials that I already own to light the inside (and outside) of a newly built 12x16 shed in my backyard.

I currently have......

1. (several) indoor rated 8.5 watt philips led bulbs (60watt equivalent)
2. 300watt msw inverter
3. 85AH Deep Cycle Battery

The shed will mostly be used for garden/lawn equipment, sporting goods, long term plastic clothing tub storage, etc. It has a 12x8 lofted area, the area underneath the loft, and the open ceiling 12x8 section. (14' peak)

Use: i'm guessing the inside will see a few hours at a time, tops......maybe 2 times per week. I'd also like to do some motion/dusk to dawn security lighting on the outside of the shed. This could be tied to the indoor system, or a separate solar motion light, or the like.

My questions are:

1. What size panel would i need to recharge the system based on my stated use time and lighting requirements?
2. would i need to wire all the inside lighting in series or parallel. (maybe 12 bulbs inside total)?
3. I'm an idiot about this stuff, so what red flags / problems do you see with any part of this system.

Thank you all so much,

Matt

How far away is your utility power to the shed?

[Msollars]

Thank you for the replies.
The "12" bulb number just came from a rough layout of the shed so far. I could probably even drop to as low as 3 bulbs....one for the loft area, one for under the loft, and one for the 12x8 open half of the shed. (i just like well lit areas, and am not sure how to judge the lumen output of 12v bulbs.....though i'm guessing 1 lumen = 1 lumen....no matter the voltage)

If i go with the 12v bulbs.......are there certain bulbs you recommend. You know the amount of space i'm lighting, and my 'well lit' requirement....what would you suggest.

Thanks again, so much for the help....i really do appreciate it.

Matt

[Msollars]

Utility power is probably 25-30 feet, but i'm trying not to tie it to the house utilities. Our building code guy said that if it's tied to the house, either physically connected, or running house utilities (power, water, etc) then i'll have to pay taxes on the structure.

Matt

[SunEagle]

Thank you for the replies.
The "12" bulb number just came from a rough layout of the shed so far. I could probably even drop to as low as 3 bulbs....one for the loft area, one for under the loft, and one for the 12x8 open half of the shed. (i just like well lit areas, and am not sure how to judge the lumen output of 12v bulbs.....though i'm guessing 1 lumen = 1 lumen....no matter the voltage)

If i go with the 12v bulbs.......are there certain bulbs you recommend. You know the amount of space i'm lighting, and my 'well lit' requirement....what would you suggest.

Thanks again, so much for the help....i really do appreciate it.

Matt

Using 12volt lamps will eliminate the losses through a DC to AC inverter but may require larger wire size between the battery system and the lamps.

You can find a lot of different selections of 12volt lights at RV dealers and websites since just about all of those items run off of batteries.

As you found out you might not need to run all 12 lamps at the same time for any length of time which will help keep the solar/battery system in check. But if you underestimate your daily "watt hour" usage you can easily over discharge your battery.

[emartin00]

Using 12volt lamps will eliminate the losses through a DC to AC inverter but may require larger wire size between the battery system and the lamps.

In theory, yes, but if he is wiring for standard 120V light fixtures, he's probably using 14-16AWG wire. Unless you use really big 12V lights, you don't need any more than that.

[SunEagle]

In theory, yes, but if he is wiring for standard 120V light fixtures, he's probably using 14-16AWG wire. Unless you use really big 12V lights, you don't need any more than that.

If the OP is "just" using low wattage LED 12v lights then yes the wire size won't change. If he decides to power something bigger like a Cooling system or large fan then you need to at least look at what the distance is between the battery and load.

Even in vehicles some of the 12volt devices father away from the battery use larger wire then those closer to the battery.

[Msollars]

i could not get the 'edit post' to save.

ignore my last post.........




I thought about looking for 12v light bulbs, etc. and this deleted post was asking for suggestions.

I have several of the 8.5watt bulbs already, as well as the inverter.

It sounds like i should consider adding another battery to my 85wh deep cycle. Also, maybe a larger panel than the planned 100 renogy that i was going to purchase.

does this sound right?

[SunEagle]

i could not get the 'edit post' to save.

ignore my last post.........




I thought about looking for 12v light bulbs, etc. and this deleted post was asking for suggestions.

I have several of the 8.5watt bulbs already, as well as the inverter.

It sounds like i should consider adding another battery to my 85wh deep cycle. Also, maybe a larger panel than the planned 100 renogy that i was going to purchase.

does this sound right?

Be careful. Just adding batteries and panels to a system without calculating how they work with each other can lead to one or more components failing.

First you should never add a new battery to an existing. The old one drops the life of the new one. Second you should stay away from wiring batteries in parallel. This can result in uneven charging and discharging.

The first thing to do is calculate what your daily watt hour use will be. Size your battery from that information (figure the battery to be 5 times as much as you need daily) and then size your solar pv wattage and charge controller based on the battery size and worst case sunlight insolation for your area.

You can make your battery work if you decide to use your existing 8.5watt lights and keep close attention to how long and many are used. You will need to increase your panel wattage from that single 100w panel so if you want to keep your system small you should get another one just like the first.

[Motodeficient]

Not trying to hi-jack this thread but I am also trying to add some light to my shed without tying it into the utilities. Maybe the info can help the OP?

Could this be accomplished without a solar panel by charging the battery once in a while? I would use some low-wattage 12v lighting a few hours a week maybe...

What would be the best type of battery to do this with? What type of charger? If I got some of the 12v LED light bulbs that screw in like a regular light bulb, is there a DC shop light that I could plug the 12v bulbs into to connect to the battery?

Amazon links to a good batter, charger, and light fixture that would work for what I am trying to accomplish would be great!!

[lkruper]

Not trying to hi-jack this thread but I am also trying to add some light to my shed without tying it into the utilities. Maybe the info can help the OP?

Could this be accomplished without a solar panel by charging the battery once in a while? I would use some low-wattage 12v lighting a few hours a week maybe...

What would be the best type of battery to do this with? What type of charger? If I got some of the 12v LED light bulbs that screw in like a regular light bulb, is there a DC shop light that I could plug the 12v bulbs into to connect to the battery?

Amazon links to a good batter, charger, and light fixture that would work for what I am trying to accomplish would be great!!

Try this:

1) Pick your 12v bulb[s] and note amps.
2) Multiply amps by number of hours usage per week.
3) Multiply that by 2

This is your battery in AH.

Lets get some bulbs at Amazon: http://www.amazon.com/White-Sunthin-...5%3A2470955011

1) One 7w led bulb at 12v dc. 7w/12v = 0.6 amps.
2) 0.6 amps X 2 hrs per week = 1.2 Amp Hours
3) 1.2 Amp Hour X 2 = 2.4 AH (To make sure you only discharge battery to 50%)

Lets pick a battery. Does not need to be big. Odyssey AGM is a good brand.

http://www.amazon.com/Odyssey-PC680-PC680-P-Battery/dp/B0002ILK6I/ref=sr_1_1?ie=UTF8&qid=1440642506&sr=8-1&keywords=deep+cycle+agm+battery+odyssey&refinements=p_85%3A2470955011

With this battery you can run that one light bulb for 2 hours a week for 7 weeks.

Now lets charge it. You need a small smart charger. Odyssey batteries like Odyssey chargers.

http://www.amazon.com/Odyssey-Battery-Tmax-6A-1B-Amp-Bank/dp/B0045G6Y0U/ref=sr_1_1?ie=UTF8&qid=1440642854&sr=8-1&keywords=battery+charger+odyssey

The battery only weighs 13 pounds and is maintenance free. You can safely charge it in your house and take it back
to your shed.