net metered system question [RE-wrenches]

[David Palumbo, Independent Power & Light]

Bill Brooks (and wrenches),

Bill Brooks wrote << 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 helps explain things Bill. It has been my sense that the controller
settings probably were the culprit.
The Pulse charge controlling set points have been accurately set with a
Fluke meter. But with two different temp comp probes and with the Trace's
internal voltage measuring inaccuracies it seems wise to set the Pulse
controller set points even higher in light of your information.

The numbers you quote Bill (1.5 to 2 volts higher), I assume this is
appropriate for the 48 volt system in question.

	To refresh peoples memories on my original set points;
<<	The system has been programmed as follows:
Trace bulk charge voltage 58.6, Absorption time 2 hours,
Float Voltage 54.0 (I don't want to set this any higher because the battery
box vent fans would stay on all the time as they are set to come on at
54.4v).
Pulse Charge Controller settings: Bulk 60.0 volts, Float 55.5 volts,
Equalize automatically every 30 days to 61 volts.
	Both the Trace and Pulse settings are temperature compensated.
The temp comp differential has been running from 1v to 1 1/2 volts (for
example temp comp volts 54.0, actual volts 55.2v.>>

Thank You,

David Palumbo

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