net metered system question [RE-wrenches]

[Bill Brooks]

David and other wrenches.

John Berdner might want to chime in on this, but the pulse charge controller
begins to regulate the input current as the battery nears the set point
(about 1 Volt before setting). This is why it is prudent to set the
secondary charge controller (pulse in this situation), well above the
setpoint of the primary charge controller (SW inverter in this situation).
My feeling is that a minimum is one full volt higher for the secondary
setting. In the case of the pulse unit, it may need to be 1.5 or 2 volts
higher. This will also take care of the problem that the temperature
compensation probes are do not have the exact same correction factor and can
interfere at the high temperature end of the spectrum.

This is a very important issue. If you are not calibrating your charge
controller settings with an independent (reliable) meter, you are likely to
have this problem over and over again. This is especially true with the
Trace C-40. The potentiometer settings are not intended to be perfectly
accurate, so setting each controller to "11:00" or some similar method does
not necessarily work. The controller settings must be confirmed.

Bill.


> -----Original Message-----
> From: David Palumbo, Independent Power & Light [mailto:ipl at sover.net]
> Sent: Monday, March 05, 2001 9:04 AM
> To: RE-wrenches at topica.com
> Subject: RE: net metered system question [RE-wrenches]
>
>
>
>
>
>
>
> 	<<If all of your SW setup values are actually where they
> belong, and the
> charge controller is operating properly (above the SW bulk voltage), then
> you probably have MOSFET damage in the inverters. The inverters will
> produce output that seems "normal", but they won't feed back the
> grid. Your
> best bet here is to look at the wave form on an oscilloscope, if possible.
> 	This was the situation with my SW 2512, it would connect to
> the grid and
> *act* like it was feeding the utility, but the batteries would
> boil away at
> 15+ volts (there's no other charge controller in my system). The inverter
> would power loads from the batteries in a seemingly normal manner. When I
> took apart the cabinet, I found four fried MOSFET's, all connected to one
> of the three transformers. The result of this failure was that
> the inverter
> could meet the voltage of the grid, but not exceed it enough to cause
> current to flow back unto the utility. No error indications were noted on
> the front panel, or in the faults menu.
> 	Time to exercise your (entended?) warranty.>>
>
> Sharkey et all,
> 	After I posted my original message the wrench on site got
> the system to
> sell back several amps (late afternoon) on each inverter by adjusting the
> charge controller float setting upwards. So it looks like the Pulse
> controller was holding back on pv amps. Now I have to figure out why.
> 	We would appreciate any other suggestions.
>
> David Palumbo
> IP&L
>
>
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For info contact list moderator by email:
 michael.welch at homepower.com

____________________________________________________________
T O P I C A  -- Learn More. Surf Less. 
Newsletters, Tips and Discussions on Topics You Choose.
http://www.topica.com/partner/tag01