Inverters and Stuff
Today 10:00 – 11:30
Marshall Godwin
Introduction
• Topic
• Using 2003 Discovery as reference system
• Verify applicability to your coach
• Speaker
• Marshall Godwin
• DOAI VP of Development
2
Terms
• DC – Direct Current
• AC - Alternating Current
• Volts (E) 12Vdc, 120Vac
• Current (I) – measured in amps
• Power (P) – measured in watts
P=IxE
I=P/E
• Converter/Inverter/Charger = Inverter
3
Discovery Power Sources
• Alternating Current Sources (AC Power)
• 1) Shorepower
• 2) Generator
• Direct Current Sources (DC Power)
• 3) Batteries (Coach and Chassis)
• 4) Alternator
• 5) Solar Panels
4
Five Sources of Power in Your Discovery
Below Drawing Does Not Accurately Reflect Discovery System
5
Batteries
• Chassis Batteries
• (2) 12V maintenance free Alliance
A1031MFs connected in parallel
• Each battery rating
• CCA – 760 amps @ 00F, for 30 seconds
6
Chassis Battery Configurations
• Parallel - Increases Amp Capacity
• Two batteries in parallel will double the Amp
rating of the battery bank while the voltage will
be the same as each individual battery.
+
12V
760 CCA
-
+
12V
760 CCA
-
+
12V
1520 CCA
-
7
Batteries (Con’t)
• Coach (or House) Batteries
• (4) 6V flooded (wet cell) Trojan T105s connected 2
in series tied in parallel with the other 2 in series
• Each battery rating
• Amp Hours;
• Total battery capacity with a constant discharge
rate over a 20 hour period: 225 amps (11.25 per
hour) before discharge (10.5v)
• Reserve Minutes:
• Capacity of Battery at constant discharge of 25
amps: 447 minutes (7.45 hours) before discharge
8
Coach Battery Configuration
• Series - Increases Voltage
• Two batteries in series will double the output
voltage
+
+
6V
225 AH
6V
225 AH
-
-
+
12V
450 AH
+
+
6V
225 AH
6V
225 AH
-
-
-
Avoid discharge below 50% to prolong battery life
9
Battery Test
State of charge as related to specific gravity
and open circuit voltage
% of
Charge
Specific
Gravity @ 80F
Open-Circuit Voltage
6V Battery 12 Battery
100
90
80
70
60
50
1.277
1.258
1.238
1.217
1.195
1.172
6.37
6.31
6.25
6.19
6.12
6.05
12.73
12.62
12.50
12.37
12.24
12.10
40
30
20
10
1.148
1.124
1.098
1.073
5.98
5.91
5.83
5.75
11.96
11.81
11.66
11.5
Adjust for temperature by adding .004 to readings for every
10 deg above 80 F and subtract .004 for every 10 deg
below 80 F
10
Xantrex Inverter/Charger
• Freedom 458 and Freedom Combi 10
• Inverter – Modified Sine Wave
• Continuous Power: 2000w (1000w)
• Efficiency:
• Full Load: 85%
• Peak Efficiency: 92%
• Example: 1200 watt load (microwave, hairdryer,
toaster)
•
•
•
•
I = P/E
Current =1200/12
Current = 100 amps + efficiency loss
Current = 118 amps
• No load (idle mode) current draw - .12 amps
11
Freedom 458
12