Hi Mr. Rawles,
I had a question about the article titled Letter Re: For Want of a Battery.
In it you said to connect the Northern
Tool & Equipment Solar-Powered Trickle
Charger — 5
Watt Item # 339973, with this
battery pack . How does the panel connect to the battery pack? And
does your recommended
Accupower
AccuManager 20 Battery Charger (a battery charger for AA, AAA,
C, D, and 9 volt rechargeable batteries connect to
the 12 volt battery pack via the cigarette lighter plug? Also, could
you please tell me how many AA batteries you could charge from one 12
volt battery pack. Thanks for your time and your blog. Signed, - LZ
JWR Replies: Unless it already has one installed, you would
have to wire a cigarette lighter-type plug on to the lead wires from the photovoltaic
panel. Those are
available for any electronics
supply
store
such
as Radio
Shack. Typically with DC wiring the red or white wire is positive, and that
would go to the "tip" terminal
on the lighter plug. (Note: Be sure double check the polarity with a volt-ohm
meter before plugging it in!) One nice thing about jump packs is that they
have a built-in charge controller.
If
you upgrade to larger capacity storage--such as a standard car battery or
better yet a pair of golf cart batteries--either add a charge controller
to the circuit or
be very careful about checking voltage regularly during
charging so that you don't "cook" your battery.
I own an AccuManager
20 Battery Charger. They were designed by a company in Germany, but I was sad
to see that they are now made in mainland China. However, they do work well.
They are a "smart" charger--
so they will not over-charge your batteries. They come with both a 12 VDC cord
(with cigarette lighter plug) and a 120 VAC adapter.
The charger has six "channels",
so it can simultaneously hold four AAA, AA, C, D cells, and two 9 VDC batteries.
You can recharge at least 20 AA cells from a jump pack that is fully charged.
With a five watt photovoltaic panel it might take two or three days to charge
your jump pack. A 10 watt panel (or two 5 watt panels wired parallel) works
much
better,
and a 20 watt panel works even better still. Your ability to "make do" with
a smaller panel depends on your budget, how many
batteries you need to keep charged, and your time available to re-position
the panel to keep it in full sunlight throughout the day.
