Actually, PV is not a particularly excellent battery charger, except for the
single fact that it runs from sunlight.
Everything else mentioned can be done by any decent AC battery charger.
..................................................................................................
Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
..................................................................................................
----- Original Message -----
From: <[email protected]>
To: "RE-wrenches" <[email protected]>
Sent: Thursday, March 25, 2010 3:40 AM
Subject: Re: [RE-wrenches] PV excellent battery charger
My understanding is that the voltage, in excess of battery voltage, from
the array, represents energy that is dissipated as heat in the batteries.
This extra voltage, multiplied by the amperage is wattage. This extra
power can produce more amps at a reduced voltage. It is amperage that
charges the battery.
Thanks,
Drake
MPPT doesn't really do that much for the battery, it just makes the PV
modules more effective.
The real magic is:
A) the 3 stage charging (compared to traditional single stage AC
chargers)
B) Temperature compensation
C) PWM that helps pulse off sulfation
D) Slower charge rates let batteries charge more fully without damage
from
overheating.
R. Walters
[email protected]
Solar Engineer
On Mar 24, 2010, at 7:04 PM, [email protected] wrote:
Can anyone tell me why PV is considered an excellent battery charger? I
think it is, only after the addition of a MPPT charge control.
Otherwise,
the battery drags the PV voltage below Vmp.
One of the NABCEP objectives for the entry level class is to explain why
PV modules make excellent battery chargers and show this through the IV
curve.
Thank you,
Drake
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
