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Re-purposing a panel for safety - patio lighting...

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Good day.
If you have a spare ~40V/10A/400W solar panel leftover, how would you implement night lighting around your house, fully independent standalone from the house electricals ?
Charge three 12V lead-acid car batteries in series plus a DC-DC converter to make 12V to feed lights ? A DC-DC converter to charge a single car battery with 14V from the panel ?
12V LEDs are abundant as automotive gadgets for illumination. A dusk-to-dawn circuit is easy to make. What else would you consider to make it work ?

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I would use a deep-cycle battery as starter batteries will be destroyed after 10 cycles (I made the same mistake when I got on solar myself). The types of deep-cycle batteries you want to use can be any, depending on your preferences.

If your planning on keeping your battery voltage to just 12V, you wouldn't need a DC-DC converter; perhaps wire those lights with an install kit for vehicles with a rocker switch?

Keep in mind if you're planning on using lights such as your attached photo, determine how many amps they will pull. My SUV's lights eat 7.8amps per hour; I had to wire those directly to their own 50ah LiFePO4 (all of my other lights dimmed when they turned on).
 
after all the cost is figured in wouldnt it just be cheaper/easier to buy a few solar lights?
While I've thought that same thing too, I can vouch those solar lights are terrible quality nowadays and fail/go dead after a couple seasons due to their tiny panels being baked.

My guess is he has a spare panel and wants to use it (400 watts is massive for night lights, but its an idea). I once repurposed a 50 watt panel as a jump starter just because it sat around. If he's going to use these lights for years, a small setup might work out to be smarter.
 
While I've thought that same thing too, I can vouch those solar lights are terrible quality nowadays and fail/go dead after a couple seasons due to their tiny panels being baked.

My guess is he has a spare panel and wants to use it (400 watts is massive for night lights, but its an idea). I once repurposed a 50 watt panel as a jump starter just because it sat around. If he's going to use these lights for years, a small setup might work out to be smarter.
yeah you are right even the good ones only seem to last 2 years.. if you are lucky. and i have a spare 100w panel i want to use as a battery tender but havent yet figured out a cheap enough charge controller to justify buying.
 
yeah you are right even the good ones only seem to last 2 years.. if you are lucky. and i have a spare 100w panel i want to use as a battery tender but havent yet figured out a cheap enough charge controller to justify buying.
If i may suggest... if you aren't picky on PWM or MPPT, I've installed a Voyager 20A controller on my boss's work truck. They're not too expensive ($44cdn; much cheaper for americans) but its been working out quite well on his truck.
 
Many of the cheaper/smaller charge controllers are designed for both managing a battery and running a load at certain times, like night time lighting. Some are also in weather proof cases. It seems one of those would be well suited to this project. I can't really say which ones of these would be good or bad, but there seem to be a lot of them to choose from.
 
o_O To bring down 40V panel to 13.8 V battery. Or, to bring down 36V battery series to 12V lights.
The 12V lights in the image take 1.2 Amperes each.

Will check for a charge controller that can accept a big 40V panel.
Sorry, I totally misread 40V panel lol. You might have to go with an MPPT controller; I know none of my PWMs could handle that high of voltage.
 

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