Solar powered vw battery charger

I got a 2002 VW solar powered battery charger at a yard sale. Supposedly, VW plugged these devices into the cigarette lighter when shipping cars from Germany. Anyone know if this thing would work on a 1998 Ford Ranger or any other car? I have a chain saw sharpener that works off the cigarette lighter but don’t want to run the truck while I sharpen the saw. The charger name plate shows:
max power 3.2 watts
voltage @ max = 18.8
current @ max = 170mA
sn ico915687
1000 w/m2
25 C cell temp
Not sure what some of these last items mean. Any comments appreciated. Gratefully

The solar ‘‘charger’’ you have is a trickle charger intended to keep a good battery charged up while parked.
– it will work for anything in specs. ie; 12vdc, negative ground, unless the VW charger says otherwise.
– I use one on my 79 pickup which is parked six months at a time. Works great as intended, truck cranks right up unless…
– slight contact corrosion in the lighter socket may leave it un-connected if left for long periods, I wiggle mine once in a while to insure good contact.
– it will not charge up a dead battery.

170mA and 3 watts is enough to make up for the residual drain when a typical car is off (clock etc.).
The chain sharpener uses a lot more than 3 watts.
When I go out gathering wood I bring a couple of sharpened spare chains and an extra bar.
Do the sharpening at home.

1000 w/m2 is 1000 watts per square meter: the average amount of solar energy striking the Earth’s surface.
Irrelevant to the charger, but looks impressive on the face plate, I guess.

One of these sounds like a good solution to a problem I have - keeping a car battery charged when no 120v is available for hooking up a battery tender.

Any need for some kind of charge controller to keep from overcharging, or is 3 watts not enough to worry about?

I don’t think a 3 watt solar charger will overcharge the battery. The maximum current according to the OP is 170 mA. My plug in battery charger tapers off to 2 amperes. At 2 amperes, it is supplying roughly 24 watts of power.

“Any need for some kind of charge controller”

You can’t hurt the system with 170mA.
Every 2 months in the winter I take the battery out and hook it to a regulated power supply overnight.
Floating at 14V it draws about 600mA the next morning, and it’s a pretty small battery (for a Corolla/Matrix).
So with the car’s residual drain and an average size battery the solar charger will probably never get up to 14V.

The problem with a solar charger like this is with current solar technology, you need a really huge solar array to generate enough electricity to be useful. 170mA is not even a quarter of an amp. Just ONE of the bulbs that illuminates your dashboard draws more current than that. Your trunk light if you have one likely uses 5X that amount. So it will help keep the battery charged, in much the same way as a leaky faucet will eventually fill a bathtub, but very slowly at best.

You should be able to use this device on any car with a 12V negative ground electrical system.

You need a 6-7 watt panel to be useful…And the panel needs full, direct sunlight to work…You can find them on eBay…