On Tue, 17 Jun 2014 02:40:19 +0100, Johny B Good wrote:

Mindful of the comments I'd seen recently about these solar panels
having high reverse leakage sufficient to undo the benefit, I checked
and measured a mere 2 micro-amps (using both a digital meter and an
analogue one on its 30 micro-amp range as a sanity check).

Rescued mine from the garage, not a lot inside. Connected across the
PV panel is a blue LED and 5k1 resistor. The ouput has a 1N400? diode
in series, that's the sum total of bits inside. Don't know what the ?
is as that's against the tiny bit of PCB.

The 1N400? range is supposed to have between 5 uA and 50 uA at max
reverse voltage and 25 to 125 C junction temp. Testing gave an open
circuit output voltage of about 19 V. Apply a load and it could
produce about 24 mA @ 12 V ish. Not measured the drak leakage, might
do that later.


I'm not sure if this is typical of a decent quality of SLA but if it
is, it would seem best _NOT_ to keep them on a float charge long
term.

They ought to be OK provided the float is within the spec of the
battery, taking into account the battery temperature. The SLA's in
the alarm panels lasted far longer than those in the UPS. APC UPS's
don't keep within spec of the batteries...

--
Cheers
Dave.