Product Manual

34
SOLAR BATTERY CHARGING
35
MORNINGSTAR CORPORATION
4.0
can be used to adjust these values. Refer to Section 9.0 for more information
about charging sealed batteries.
4.5 Float
When a battery becomes fully charged, dropping down to the float stage will
provide a very low rate of maintenance charging while reducing the heating
and gassing of a fully charged battery. When the battery is fully recharged,
there can be no more chemical reactions and all the charging current is
turned into heat and gassing.
The purpose of float is to protect the battery from long-term overcharge.
From the PWM absorption stage, charging is dropped to the float voltage.
This is typically 13.4V, and is adjustable with the PC software.
The transition to float is based on the previous 24 hour history. Factors
include the battery voltage, the state of charge the night before, the battery
type, and the PWM duty cycle and stability of the duty cycle. The battery will
be charged for part of the day until the transition to float.
If there are loads for various periods of time during float, the TriStar will
cancel float and return to bulk charge.
Float is temperature compensated.
5.0 Load & Lighting Control
This section describes the user selectable load control settings (5.1) and the
low voltage load disconnect (LVD) warning indications (5.2). Load information
and general cautions are provided in the remaining sections.
5.1 Load Control Settings
The primary purpose of a low voltage load disconnect function (LVD) is to
protect the system battery from deep discharges that could damage the
battery.
In the Load Control mode, the TriStar provides for seven standard LVD
settings that are selected by the DIP switches. These are described in the
table below. Custom LVD settings are possible using the PC software
(see
Section 7.0) .
DIP 12V 24V 48V Battery 12V 24V 48V
Switch LVD LVD LVD SOC%
LVD
R
LVD
R
LVD
R
off-off-off 11.1 22.2 44.4 8 12.6 25.2 50.4
off-off-on 11.3 22.6 45.2 12 12.8 25.6 51.2
off-on-off 11.5 23.0 46.0 18 13.0 26.0 52.0
off-on-on 11.7 23.4 46.8 23 13.2 26.4 52.8
on-off-off 11.9 23.8 47.6 35 13.4 26.8 53.6
on-off-on 12.1 24.2 48.4 55 13.6 27.2 54.4
on-on-off 12.3 24.6 49.2 75 13.8 27.6 55.2
on-on-on Custom Custom Custom
Table 5.1
The table above describes the standard selectable LVD battery voltages for
12, 24 and 48 volt systems. The LVD
R
values are the load reconnect setpoints.
The “Battery SOC %” provides a general battery state-of-charge figure for
each LVD setting. The actual battery SOC can vary considerably depending
on the battery condition, discharge rates, and other specifics of the system.
NOTE: The lowest LVD settings are intended for applications such as telecom that
only disconnect the load as a last resort. These lower LVD settings will deeply
discharge the battery and should not be used for systems that may go into LVD more
than once a year.
REMARQUE : Les réglages les plus bas du disjoncteur basse tension sont prévus
pour les applications comme celles de télécom qui ne déconnectent la charge
qu’en dernier recours. Ces réglages les plus bas du disjoncteur basse tension
déchargent fortement la batterie et ne doivent pas être utilisés avec les systèmes
qui risquent de déclencher le disjoncteur basse tension plus d’une fois par an.
The LVD values in table 5.1 above are current compensated. Under load, the battery
voltage will be reduced in proportion to the current draw by the load. A short-term
large load could cause a premature LVD without the current compensation. The
LVD values in the table above are adjusted lower per
the following table: