DIYbanter - View Single Post - What would cause a solar panel battery charger to die?

J Burns

On 8/10/15 12:34 AM, wrote:
I bought one of the solar chargers they sell at Harbor Freight for
around $20. They are made to charge a 12 volt battery at 1.5 watts.
Granted that is not a lot of power, but just to keep a battery topped
off, it worked fine.

How do you know it worked fine? A calibrated DMM will tell you if a
battery is topped off.

I particularly bought it to keep a car battery charged for a battery
powered electric fencer, but I also took it when I went camping, so keep
my car battery charged after running my laptop computer off the car's
battery without starting the car to recharge the battery. The computer
often ran for several hours to play movies.

If I were drawing power from a car battery that I wanted to start my car
after several days. I'd have a DMM to check its state of charge.

It sounds as if the HF unit produces 120 ma during the hours it gets
full sun. If you know how many amps the laptop draws, you can calculate
how many hours of charging you would need for each hour of computer use.

If a cheap solar trickle charger keeps a battery charged, it will kill
it anyway. Conventional trickle chargers use DC, and that causes
premature failure.

Pulsetech makes chargers for the military, commercial applications, and
consumers. They use pulses instead of DC. Amazon is advertizing a 2 Watt
Pulsetech solar maintainer for $63. It's probably well made. There are
probably other good pulse solar chargers on the market.

It might be advantageous to get an AGM battery to run your computer on
camping trips. That way, you're not risking having a car that won't
start. If you have to start the car to charge the battery to see more
movies, an AGM will charge 5 times faster than a conventional battery.
It won't get acid on your clothes, and it handles deep cycling well.