>> Based on the google research I did before I built the circuit it was
>> consensus that it's probably not good for the panels to have power
>> pushed back into them at night so I went ahead and added the schottky
>> diode.

A series reverse diode or equivalent is, alas, essential.
It's easy to not realise that they work "somewhat strangely" compared
to what may be logically expected.

Photovoltaic cells are diodes, but in photo voltaic generation mode
the Anode is positive relative to the Cathode so current flow when
delivering energy is against the flow that the diode will usually
permit. It makes sense when you look at the underlying theory but
Murphy had fun here.

The effect on the panels may be minimal depending on dissipation. They
may well survive OK in low energy systems.
BUT this will be fatal for battery stored energy.
When PV panel voltage falls below battery voltage the battery *will*
discharge into the panel.

Here's a basic tutorial on what is involved.

    http://cnx.org/content/m11343/latest/

When using low voltage low current panels such as in path lights, use
of a 1A Schottky at as low a reverse  voltage as is sensibly available
is liable to pay (very) slight dividends.
A 1N5817 / SS12 diode is 20V rated (afair) and the 1N5818 / SS14 and
1N5819 are higher (30V, 40V, ...). They usually cost the same.
Often but not always the lower Vr diode will have usefully lower
Vforward - maybe more than 0.1V lower.
When you have lots of light and Vpv >> Vbattery it matters little but
as Vpv approaches Vbattery an extra 0.1V can help. Albeit, only
sometimes.

In the unlikely event that MPPT is being used, in a 3V system a 0.1V
drop may give an extra 3% energy.

Usually other factors swamp such small gains.

              Russell McMahon
--=20
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