RV Power Products - Solar Boost 3048
15
BATTERY AND PV WIRING
Wiring requirements for Solar Boost 3048 are different than conventional PV controllers. While the performance of
other controllers may be affected somewhat by wiring, wiring and connections used with Solar Boost 3048 can have a
significant effect on current boost performance. Solar Boost 3048 increases charge current by transforming previously
wasted power into useable charge current. The effect wiring has on current boost performance is that power wasted
heating wires or connections is power that is unavailable to charge the battery. Solar Boost 3048’s PV and battery
compression terminals will directly accept wire size up to 1/0 AWG.
PV
−−−−
and BAT
−−−−
connections must not be connected together
as shown in Figure 3 or the system will not function properly.
Resistance between these terminals is less than 3m
Ω
Ω
Ω
Ω
and
therefore provides earth ground connection to the PV array.
A desirable installation would produce a total system wiring voltage drop of 3% or less, which can be achieved
using the wire sizes shown in Table 3. Table 3 is meant to serve as a wire size guide which will lead to good boost
performance with reasonable wire sizes. The lengths shown are one way for the wire pair between the PV array and
battery, with Solar Boost 3048 placed somewhere in the middle. Typically the Solar Boost 3048 is installed in a power
room near the batteries, and the majority of the wiring travels from the Solar Boost 3048 to the PV array.
Larger wire sizes will improve boost performance whereas smaller wire sizes will reduce boost performance.
When considering wiring, fuse, and connection options
think big and short
as larger heavier components and shorter
wire lengths offer less resistance and voltage drop. Note that the lengths shown in Table 3 are for a total PV short
circuit current of 24 amps. If current is halved, length can be doubled. If the preferred wiring described here is not
practical or possible, Solar Boost 3048 will still function properly but current boost performance may be diminished.
All wiring must be completed in accordance with applicable codes and standards. At a minimum there must be a
fuse or circuit breaker located close to the battery rated at 40 amps maximum.
MAXIMUM CONDUCTOR PAIR LENGTH
FOR A 3% VOLTAGE DROP AT 24 AMPS
WIRE GAUGE
AWG
24 VOLT SYSTEM
FEET / METERS
48 VOLT SYSTEM
FEET / METERS
6 AWG
42.8 / 13.0
85.6 / 26.1
4 AWG
68.1 / 20.7
136.1 / 41.5
2 AWG
108.2 / 33.0
216.5 / 66.0
1/0 AWG
172.2 / 52.5
344.5 / 105.0
2/0 AWG
219.3 / 66.8
438.6 / 133.7
3/0 AWG
276.5 / 84.3
552.9 / 168.5
4/0 AWG
348.7 / 106.3
697.4 / 212.6
TABLE 3
OPTIONAL BATTERY TEMPERATURE SENSOR
The optional SensorLug battery temperature sensor is used to control charge voltage based on measured battery
temperature. The SensorLug is electrically isolated and mounts directly to any battery terminal. Note that connections
are polarized (red/black), and must be connected as shown in Figure 3. For temperature compensation to operate, it
must be enabled as described in the Setup section. Solar Boost 3048 will not provide output current if temperature
compensation is enabled with the SensorLug connection open (not installed), or if the SensorLug is shorted or installed
reverse polarity.
