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8.2 Troubleshooting Guide
Problem and symptoms Possible Cause Solution
Low output voltage
(96 to 104 V AC)
Using an average reading
voltmeter.
Use true RMS reading meter. See section 2.2
of manual
Low output voltage and current
indicator in red zone.
Overload. Reduce load.
No output voltage and
voltage indicator in lower red zone
Low input voltage. Recharge battery, check connections and cable.
No output voltage,
no voltage indication.
1. Inverter switched off.
2. No power to inverter.
3. Internal fuse open.
4. Reverse DC polarity.
1. Turn inverter on.
2. Check wiring to inverter. Check battery fuse
3. Have qualified service technician check and replace.
4. Have qualified service technician check and
replace fuse, Observe Correct Polarity.
No output voltage,
voltage indicator in upper red zone.
High input voltage. Make sure that STP-3000 is connected to 12V
battery, check regulation of charging system.
Low battery alarm on all the time,
voltage indicator below 11V.
Poor DC wiring, poor battery
condition.
Use proper cable and make solid connections.
Change battery or use new battery.
No output voltage, OVERTEMP indicator
on, load in excess of 3000W with 250/300A
input current.
Thermal shutdown. Allow the STP-3000 to cool off. Reduce load if
continuous operation required.
No output voltage, OVERTEMP indicator on,
load less than 3000W with
300A input current.
Thermal shutdown. Improve ventilation, make sure ventilation openings in
The STP-3000 are not obstructed, reduce ambient
temperature.
OVERLOAD indicator on. 1. Very high power load. 1. Remove or reduce load.
Appendix A - Battery Sizing
For continuous usage, deep-cycle batteries are rated by
reserve capacity
in minutes or by
ampere-hour
capacity. Reserve capacity measures the
duration a battery delivers its rated current – normally at 25 amperes. A battery of 60 minutes reserve capacity can deliver 25 amperes for 60 minutes
before completely discharged. The measure of cranking amperes used to rate starting batteries in automotive is not suitable for deep-cycle batteries.
It is better to size your batteries more conservatively for unexpected variations. More reserve capacity means your batteries will not be discharged as
deeply so that battery life will not be unduly shortened. It is recommended that the consumed ampere-hour loading should be kept less than 50% of
the battery's rated capacity.
Ampere
–hour (AH) capacity measures battery amperage being delivered for a rated duration – normally at 20 hours. A typical marine or RV battery
rated for 120 ampere–hour delivers 6 amperes for 20 hours.Battery capacity varies inversely with discharge current. At 5 amperes loading, a battery
of 100AH discharges for 20 hours but at 20 amperes loading, the same battery may only last for 4 hours with its capacity reduced to 80 ampere-hours.
It is therefore not suitable to compare rated ampere-hour capacity directly with battery reserve capacity.Observe the following steps to determine your
battery capacity requirements:
STEP 1 - Determine the wattage of each appliance to be driven by the
Sima STP-3000
. Multiply any current ratings by 115 to obtain the power
consumption in watts.
STEP 2 - Estimate duration of tool operation between battery charge-discharge cycles or each appliance being driven by the
Sima STP-3000
.
STEP 3 - Calculate the total watt-hours of operations, total running time in hours, and average power consumption as exemplified below:
Average Power Consumption = 3275 watt-hrs ÷ 1.8 hours = 1819.44 watts
For
Sima STP-3000
inverter, Ampere-Hour Consumed = 3275 ÷ 10 = 327.5 ampere-hours
STEP 4 - Locate the battery size meeting the required operating time at the calculated power consumption level from Table 3. For the example
shown, operation duration of
1.8
hours at
1819.44
watts requires the smallest battery size as two 400 amp-hr batteries in parallel,
offering about
10 to 12 hours
of operating time.
Table 3. 12-Volt Battery Sizing Chart (for reference only)
Example for Step 3 of Battery Sizing
Equipment Power Consumption Operating Time Watt Hours (Power x Operating Time)
Coffee Maker 1000 watts 0.3 hour 300
Cordless Steam Iron 1200 watts 0.5 hour 600
Vacuum Cleaner (380W) 1600 watts 0.25 hour 400
Washing Machine 2000 watts 0.25 hour 500
Window Type (12100Btu/h) 2950 watts 0.5 hour 1475
Totals 1.8 hours 3275 watt-hours
BATTERY SIZE
AMP-HRS: 50 75 100 200 400
Inverter
output
power
(watts)
Typical Load
Reserve
capacity
90 minutes 140 minutes 180 minutes 400 minutes 900 minutes
50 Stereo system 9 HOURS 14 HOURS 20 HOURS 40 HOURS 80 HOURS
100 19” colour TV 4 HOURS 6 HOURS 10 HOURS 20 HOURS 40 HOURS
200 Computer system 2 HOURS 3 HOURS 4.5 HOURS 10 HOURS 20 HOURS
300 Blender 1.3 HOURS 2.2 HOURS 3 HOURS 6 HOURS 12 HOURS
400 Power drill 1 HOUR 1.5 HOURS 2 HOURS 4.5 HOURS 10 HOURS
600 Small coffee maker 1 HOUR 2.5 HOURS 6 HOURS
800 Small microwave 1.5 HOURS 4 HOURS
1000 Automatic Toaster 1 HOUR 3 HOURS
1200 Cordless Steam Iron 0.5 HOUR 2 HOURS
1500 Full size microwave 0.5 HOUR 2 HOURS
2000
Grill Microwave
Oven 42L(1.5Cu.ft)
0.3 HOUR 1 HOUR
2500
Hair dryer &
washing machine
0.2 HOUR 0.7 HOUR
2950
Window Type
(12100Btu/h)
Operating
time
N.R. N.R.
N.R
0.15 HOUR 0.5 HOUR
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