What is this supposed to charge?
Posted by AngelEggTarot@reddit | preppers | View on Reddit | 22 comments
I found this small (about it 15”x 5”) solar panel at a yard sale this weekend for $1… I can’t upload photos, so here’s what it says on the back:
Megsun
2.5 watts
Model # sr-25
Max power 2.5 w
Current at pmax 139 a
Voltage at pmax 18v
And under the made in china area it has FJ.210.607
I tried looking it up, but couldn’t find it anywhere online. I’m confused as to what it’s supposed to (solar) power due to the fact that it has a car cigarette lighter plug adapter at the end of the cord. What kind of device is this supposed to plug in and power with that type of adapter? I’m used to seeing devices being plugged into a car cigarette lighter in order to *get* charged…. Obviously a solar panel gets charged from the sun, so….
Thanks in advance
fenuxjde@reddit
I have one of those that connects to the battery terminals on my car and sits on the windshield. Keeps the battery full while I'm on trips.
Necessary-Film7832@reddit
Please tell me more about this and where can I get it and what is it called. I don't drive much and my 12 volt keeps going bad even though it's new.
SkyOne5846@reddit
It’s just a small solar trickle charger for a car battery. The cigarette plug is meant to send a bit of charge into the car to help keep the battery from draining, not to power anything. It’s really low output, and if your car socket turns off with the engine, it won’t do much anyway
LavenderHaze0929@reddit
For a dollar, it's still a cool piece of tech! Maybe you can use it to power some very low-draw LED lights or a small fan in a pinch.
AngelEggTarot@reddit (OP)
Awesome, thanks. How can I do that though? Would I have to cut off the car adapter cig lighter part and strip the wires, or can I purchase another adapter that the cig lighter can plug into?
Still_Effective_8858@reddit
It sounds like a trickle charger for a car battery. It would very slowly charge a car battery or maintain its charge, but not power up devices.
LavenderHaze0929@reddit
That’s the whole point of these little guys. Super handy for maintaining charge without overdoing it.
Electrical_Pear_5456@reddit
Sounds like a trickle charger for car batteries. Handy if you park outside a lot. Just keep in mind, 2.5 watts is pretty low, so it's more for maintaining charge than actually charging a dead battery.
AngelEggTarot@reddit (OP)
Yes, but if my cig lighter doesn’t work unless the car is turned on, how would this device be useful in that sense?
WhereDidAllTheSnowGo@reddit
It can charge a 12V battery
Test it with a multimeter in full sun… open circuit should be 18v ish, battery 10-13V, battery with panel a volt or two higher
AngelEggTarot@reddit (OP)
Very cool. I actually have rechargeable 12 v batteries. How would I set it up to charge them? Thanks.
WhereDidAllTheSnowGo@reddit
Red wire to plus
Black wire to neg
AngelEggTarot@reddit (OP)
Ah, so I would have to strip the wires. I thought you meant I could charge it somehow with the car cig lighter adapter. 😆 Thanks!
WhereDidAllTheSnowGo@reddit
You can always get an outlet with pigtails.
https://a.co/d/08eE3iKB
Hefty-Squirrel-6800@reddit
You simply run the cigarette lighter back to the car's fuse box and connect it to a hot lead. If you are worried about the cigarette lighter catching the car on fire when it is parked, add a switch to turn it on or off as you wish.
Much simpler solution.
Xsiah@reddit
With a pair of wire cutters and a little gumption it could charge lots of things
mmaalex@reddit
You put it on the dash of your car and it keeps the battery trickle charged. It only works if you have always live cig lighter outlets
RedOctobyr@reddit
Though there are versions which connect to the OBD2 port under the dashboard, which always has power. So you can keep the battery topped off without any wiring, or running a cord under the hood, even if the cigarette lighters turn off when the car is off
You can probably get a cigarette lighter to OBD2 adapter to use this panel, but at some point it probably makes more sense to just get one set up for OBD2, if that was needed.
mmaalex@reddit
Then theres the fact that a 5W panel is probably going to be pretty ineffective keeping a car battery charged since it wont ever actually make 5W flat on the dash due to shading, the angle, and just general degradation of cheap panels over time.
RapidXpansion@reddit
Do a quick voltmeter check to make sure its putting out the voltage specc'd on the label.
A car battery will be a power sink, effectively sucking down as much wattage as the panel will provide and causing the voltage to drop because it is pulling current.
Since the wattage is so low, it can't really cause battery issues. The only thing is that at night, the battery could lose power to the solar panel unless it has a blocking diode, which is prob does.
PrisonerV@reddit
Its not worth the $1
dittybopper_05H@reddit
It's a trickle charger for maintaining your car battery, especially if you don't drive the car very often.