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Solar LED 2835 strip with rechargeable battery, controller and night sensor? Answered

 Needing help with a solar set up to recharge and power a small led strip with 2835 LEDs.
I need a small strip of bright LEDs to light up a address block during the night and it is in a rock column.  I want the set up to be as visually minimal as possible.  My plan is to have a solar panel charging a battery during the day, have the sensor turn the light on at dusk and off at dawn.  I have a reel of 2835 LEDs and I want to cut a 1 Ft length of them and mount below the address block to illuminate it.  I already have all the mounting details set and how I plan on running the wires.  I will put the battery, controller and dimmer in a box on the back of the column and close it off and run the wires through the mortar to the LED strip which will be sitting on a rock shelf.  The solar panel will be mounted on the top of the column which is almost totally flat.  My questions and assistance needed is on the design of the solar components, battery, controller, wiring, design and if it I have it all correct and it will work.  I have done hours of research on the net and think I have an understanding of this, but would like one you electronic wizards to proof my concept and provide any input on things I might need to add, change or improvements to make it better or more cost effective.  I also searched previous forum questions and didn't see anything exactly like this.
Pic is attached on my general layout, but here is what I have come up with so far:

-12v 10w Solar panel, $20
-Charge Controller, $6
-20a Fuse, $0
-12v 5ah battery, $16
-LED dimming controller, $6
-12v Photocell, $3
-2835 LED 1 foot strip (cut from reel), $0
--I can provide links and further details to the components if needed, but they are all standard items that you can get on ebay or amazon
Total cost not including box housing is approx. $51   (seems like there should already be something like this available much cheaper, but I have searched a lot and can't find anything.  I don't want one of those bulky solar LED lights and I want something that will stay on for at least 8 hours at night)

I did the research and 1 ft of the 2835 leds uses about 4 watts.  Looking at all the formulas I found and the battery I intend to buy, 5ah, I calculated it would run the LEDs for 14 hours.   4/12 = .34   * 1000 = 340    Battery is 5000mah so  5000 / 340 = 14.7 hrs
Does this sound correct?

Next was determining the solar panel required. I came up with the 10w panel to have enough to charge the battery.   10w / 12v = .83    battery again is 5ah, so 5 / .83 = roughly 6 hours
Is this correct also?

The other items are components to complete the circuit, protect the battery and controller and have the ability to dim the lights if they are too bright.

I'm hoping I researched enough and did correct calculations and didn't miss anything. But please provide input, thoughts and anything I might have missed.

6 Replies

user
iceng (author)2017-01-19

Since the solar panel can only supply 833 ma why do you need a 20,000 ma fuse ?

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user
travislikestolearn (author)iceng2017-01-20

Thanks for the reply. I was matching the 20A fuse with the 20a charge controller. Maybe I only need a 5A fuse to match the 5A battery?

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user
Downunder35m (author)2017-01-19

Unless your address block is massive I would opt for a ready made solution.
The best I found so far are solar entrance lights as used for sheds or gates.
They come with 10mm!!! LED's and two AA batteries.
You could just solder the three LED's off and place them where required to light up your sign.
In case the light angle is too narrow simply flatten and polish the top of the LED's.
If you need much more light go with a garden shed light that includes the batteries and solar panel, often available for under 30 bucks.
Same story as above, get the LED's out or disconnect and modify to suit your needs.
The 12V models usually offer 12V for the LED's as well and could power your strip directly.

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user

Thanks. I would love to find a ready made solution. The issue I have is they are usually too big, especially the solar panel mounting and I'm trying to keep this as "invisible" as possible. Also, a bigger concern I had with those shed and gate lights is that most are not designed to stay on all night long. Most I see seem to quote 4 hour continuous on use. I'm wanting something that has enough capacity to stay on 8 to 10 hours continuous. Maybe modifying the light to remove most of the LEDs and only use 3 could extend the on time of those lights. I just didn't want to spend the $30 to play around with one and find out it doesn't have the capacity I need. Since I would only need to spend about $20 more on the solution I came up with if my calculations are correct. I'm sure there is a premade solution out there, I just can't seem to find one that fits my needs when I'm searching.

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user

I only had a very quick look on Fleabuy and found this.
It is underrated for all night use, but a slightly bigger or second panel and a decent 3.7V battery would solve that issue.
If in doubt you can just add multiple panels on top of your sign, for example from cheap solar garden lights.
Comes down to usage time, amps required for thistime and how much sun you get to recharge.
The battery should be big enough to cater for twice the max time and the panels big enough to allow a full charge on a single day with slight cloud cover.

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