Hi,
So I lost my beloved car a few years ago and never got round to buying another one, so i stripped the sound system out one day in the hope i could make a portable one..
I'm sory I didn't strip mine, when it went up the river - played wav's and MP3's from SD-cards and USB flash drives and had lots of other smart functionality
12V Battery 12AH
Solar Panel
- No idea the specs of it but its just a medium size panel not to big not too small..
- I hardly know much about solar power, all i see is the panel and a coper filled wire coming from it.
You NEED specs!
Here's how to get them:
You need:
1 DMM
1 very sunny day (2 overcast days won't be a proper substitute)
1 pencil
A notepad
Setup the panel perpendicular to the sun, so that it gets the maximum possible amount of light (i.e. at a 90° angle). Setup the DMM to read 20V DC (or 200V DC if it over ranges).
Try slight angling of the panel in each axis until you get the maximum voltage reading.
Jot down the voltage reached.
Change the DMM to read current, start on a 2A DC range and switch towards a larger sensitivity until you are on the most sensitive range that can still get the reading.
Jot down this short circuit current reading.
Repeat a few times to be sure you get the maximum readings on both counts.
Serve numbers (here) while hot.
Now you can either calculate the function or draw an X/Y diagram with current [A] on the vertical (Y) axis and voltage [V] on the horizontal (X) axis.
This will reveal how much current is available at any given voltage.
Now since you didn't give the size of the panel, it's hard to judge the possible output, but to compare, I have a panel which is 30cm (1') x 10cm (4") and it gives around 100mA max. at 1000W per square meter (which you'll never really get in real life) and another panel of 30cm (1') square giving 275mA under the same conditions.
They're both intended to connect to car batteries for trickle charging (diode included in the panels).
A current of 100mA won't overcharge your 12Ah battery if the voltage is OK
If you post the numbers measured, it will be a quick matter to decide whether it would work for your 12Ah battery or not. If it's indeed made for car trickle charging, all you need is a diode thet can handle the max. current. Best is a
Schottky diode, as it has the lowest voltage drop, but a simple 1N400x could probably be used in a pinch.