Hi All,
Wanted to get your opinion on this idea I have for my solar garden post lights.
I have 8 post lights that are working and looking very well, however due to different light going to each of them (angle to the sun, shade from trees houses, etc) they charge the batteries differently and lights die at different times. These lights use a AA NiMH battery (600 or 800 mAh) that gets charged by the solar panel on each light. They also are prone to failure and I have discovered that the failures occur in the solar panel of the light - for some reason (water damage, frost, etc) they stop providing power, otherwise the battery, board and light are working fine if I install a charged battery.
I was thinking of getting a single solar panel - like a 5W or 10W and mounting it somewhere in the middle of all the lights, then having a cable (thinking of 14g or 12g amazon speaker cable) going to each of the lights circuit board (disconnecting the light's own solar panel) and charging the battery, then when the power gets cutoff in the evening the board of each light will activate it (they work by sensing low enough power - there is no photo sensor).
To convert the power from the solar panel I have these boards I got from ebay that step down the voltage and are adjustable, so I can reduce the voltage to around 1.4-1.5 since that is how much the lights own panel generate. The boards have wide input voltage range (if not mistaken something like 3-4V up to 30V) so that should make sure they will provide enough voltage even in lower light scenario.
Now the questions I have here are these:
Will the 14g cable be thick enough to connect these 8 lights - I am thinking of connecting them in parallel but with a single cable run - cut and soldered at each light? I dont want to risk cable burning and setting my wooden fence on fire...
What kind of losses can I expect between the lights that are next to the solar panel and the ones at the end of the run? Do I need to compensate by increasing the voltage a bit?
How do I calculate the power requirement for the voltage conversion board - I think it is capable of handling like 3-4amps - would that be enough for the 8 1.2V batteries it will need to charge?
I am also thinking of replacing the batteries with higher capacity ones - like the Amazon 2400 mAh NiMH AA batteries for higher capacity and longer lasting light production.
Am I missing something from this design, does it make sense...?
Let me know what do you think.