6-4
6.4.4 Maximum Diversion Load
The diversion load should never exceed the SunStar’s current rating (30A or 45A or 60A).
Note that the load is not limited by the source (wind, hydro), and will draw its rated current
from the battery.
The following table specifies the absolute maximum diversion loads that can be used with
each SunStar version. These loads (heating elements) are rated for the same voltage as the
system voltage.
Nominal
Voltage
SS-30C SS-45C SS-60C
48V
1800W at 60V
2700W at 60V
3600W at 60V
24V
900W at 30V
1350W at 30V
1800W at 30V
12V
450W at 15V
675W at 15V
900W at 15V
These maximum power ratings are translated to the equivalent at 120 volts in the following
table. If using heating elements rated for 120 volts, the power ratings of all the elements can
be simply added up and the sum compared with this table and no further math is required.
Nominal
Voltage
SS-30C SS-45C SS-60C
48V
7,200W at 120V
10,800W at 120V
14,400W at 120V
24V
14,400W at 120V
21,600W at 120V
28,800W at 120V
12V
28,800W at 120V
43,200W at 120V
57,600W at 120V
To illustrate the same point from the opposite perspective, a heating element rated for 120
volts will draw reduced load current as indicated by the following table. A standard 2,000
watt / 120 Vac heating element is used as the reference.
Voltage Power
Current
120V
2000W 16.7A
60V (48V nominal)
500W 8.3A
30V (24V nominal)
125W 4.2A
15V (12V nominal)
31W 2.1A
Whether using dc rated loads (the first table) or 120V elements, the total diversion load
current must not exceed the current rating of the SunStar.
6.4.5 Minimum Diversion Load
The diversion load must be large enough to divert all the current produced by the source
(wind, hydro, etc.). This value is the maximum battery voltage times the maximum source
current.
For example, if a hydro source can generate up to 30 amps of current in a nominal 48 volt
system (60V maximum), the minimum diversion load size = 60V x 30A = 1,800 watts (for
loads rated at 60 volts).
General Sizing Example
Consider a 24V system with a wind turbine that is rated to generate 35A of current. A
