Re: Charging 2*SLA battery from Solar

On Mon, 02 Apr 2007 00:53:04 +0100, Pete D <nospam@xxxxxxxxxxxx>
wrote:

I have an application that requires 2 12V 7.5 AHr lead acid batteries
to
be charged from 2 nominally 12V but actually nearer 18V with no load
1.5A solar panels, in the end i hope to get away with 1A solar panels
but first I need to accomodate 1.5A panels.
I don't just want to put a diode in series for risk of overcharging
the
batteries.

If I could find a suitable charge controller at a reasonable price I
could buy them in, but I cannot find one.

so looking at building something, I have PIC in circuit anyway for
other
reasons, I am considering PWM'ing the solar output to keep it at
27.6V
but this area is new to me, indeed I am not sure this is the best
approach, any ideas on whether this is a suitable approach or if not
what is?

Pete D


What do you consider "a reasonable price"?

Also, the price depends on where you are located or trying to buy
from. You didn't say you were in the UK....

You don't need a 'big' controller, something like the SG4 would be
suitable
http://www.midsummerenergy.co.uk/buy_solar_panels/morningstar_controllers_solar_regulators.html

or this
http://www.sunshinesolar.co.uk/item--Charge-Controller-SolarPRO-%3CBR%3E7-AMP-105W--regulator7amp

If UKP26 is too much then maybe you could consider buying it in from
thr US http://store.solar-electric.com/sg-4.html where they have it on
special for USD28.50. Surely this isn't too expensive - after all
building one yourself will probably cost twice as much after buying in
all the bits.
.

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