DC Electric System

August 25, 2016

The DC electric system is 12 V.

There are three separate electric systems.


One for each hull, with its own battery bank and connected to the engine alternator when the engines are running .
One for the living accommodations, bridge, outside lights and electronics.
The bridge system can get electricity from either hull system or from both.  Getting electricity from both hulls effectively connects the three systems together.

No part of the DC electric system is connected to the boat hull except for two grounding points on the engines.

Each engine room has a power panel with the grounding post for the service DC system and the Engine DC system.  On the port engine room power panel also the AC system is grounded. 

DC Electric System

 

Each service battery bank connects directly, via a battery switch and a high amperage fuse on the battery panel to its hull panel located above the fuel tank.

Each hull panel controls the way the service batteries are charged. They can be recharged by the corresponding engine alternator, AC battery charger or by solar panels. Ampere meters monitor the charge and discharge of each battery bank.  Due to the high currents involved, big shunts in the hull panels provide the current to the various ampere meters, located on the bridge panel.

When the engines are running and the alternators produce power the automatic charging relays connect the alternators to the service batteries, charging them. 

Each hull panel powers the various hull users with electricity.  A 200 A single pole breaker protects the panel from the heavy users like bridge panel, anchor windlasses or inverter.  The other hull users each have their own single pole breaker.

Either hull panel can provide electricity to the bridge panel, located on the bridge rack, below the steering station.  A four position battery switch on the bridge panel  determines which battery bank provides electricity.  By selecting "Both" on the battery switch the bridge panel will get its power from both hulls, that is form both service batteries, effectively connecting the two service batteries in parallel.

 

Bridge Panel

DC electrical panel bridge 1

On the left and on the right hand side of the panel there are four A-meters and a V-meter.  On top they indicate the voltage and how many A each hull panel is providing to the bridge and below by what the service batteries on each side get charged. (Alternator, AC battery charger or in the future solar panels).

In the middle there is an A - meter and a V - meter that indicate the total current used by the bridge and the voltage.  Below is a 200 A single pole breaker protects the panel from the various users.

These A-meters, although cute, are very prone to breakdown and are obviously not intended for use in the marine environment. 

 

Procedures

Normal Operation

Service battery switches on. There are altogether four service battery switches, two for each bank in each hull.  One one the battery panel, the other on the hull panel.  Make sure that all battery switches are on and the mega fuse on the battery panels are intact.
Hull panel 200 A single pole breakers on.
Hull panel individual user breakers on or off, as required. 

Bridge panel four position battery switch on all.  
Bridge panel 200 A single pole breaker on.
Bridge panel individual user breakers on or off, as required. 

You can monitor the charging and use of the batteries from the ampere meters on the bridge panel.

All the two battery charging systems (alternator and battery chargers) have their own regulating circuit and you can leave them on without causing any harm to the batteries.
Do not disconnect a battery bank when it is being recharged by the alternator or AC battery charger.
Do not run a DC load with only a battery charger on and no batteries connected.  At best you may blow a fuse, at worst you can damage equipment.

 

Troubleshooting

The DC panel contains inside an in-line fuse that protects the power for the digital meters.  Open the panel and check the 2A fuse if the digital instruments on the panel don't operate.


Maintenance

Periodically check the starter batteries for liquid.

 

Equipment

Bridge Panel

 

Photo

 

The DC bridge panels are two standard 19" rack panels and are located in the DC rack of the bridge.
The bottom panel controls and monitors the source of the bridge electricity.
The upper panel has all the breakers for the various users of the bridge electricity.

 Be aware that the DC bridge panel contains an in-line fuse to protect the power used by the digital instruments.

This list shows the main components of the bridge panel.

1 Battery switch, 4 positions Blue Sea Systems 9001
1 High ampere circuit breaker, 200 A Blue Sea Systems 7269
9 Ampere meter 200A, DC (millivoltmeter) Datel DMS-20PC-0-DCM
1 Shunt 500 A - 50 mV Empro HA-500-50
3 Volt meter, DC Datel DMS-20PC-0-DCM
1 Red LED Indicator Blue Sea Systems 8171
1 In-line fuse holder, fuse style AGC/MDL Ancor 607016
1 Fuse 2 A, AGC Ancor 601005
2 250 A common bus, 4 stud Bluesea 2106

 

Bridge Panel Breakers Function

Breaker Max.
A
Breaker A Comment
       
Top row (from left to right)      
Navigation lights   10  
Anchor light   10  
Search light (Golight, 15 A min. breaker ) 15 20  
Aft beam 10 10  
? 10 20  
Stereo 2 10  
Instruments 5 20  
Instrument lights 5 10  
VHF ? 10  
SSB ? 30  
Radar ? 40  
Computer ? 20 Computer below
Windshield wipers (Speich, 5A each) 25 10 Only one connected
Electronic horn (Vetus, M91/2) 20 20  
NC      
? - 10  
       
Second row      
Port cabin lights (6 x 4.16 A 50W) 25 20  
Starboard cabin lights (6 x 4.16 A 50W) 25 20  
Bathroom lights 17 20  
Bridge and outside bridge lights 20 20  
Galley and dinette lights 25 20  
Boat deck lights ? 20  
Aft deck lights 25 20  
Emergency lights LED only 10 10  
Radar arch lights ? 20  
? ? 10  
NC      
NC      
NC      
NC      
NC      
Bridge panel outlets - 10  

 

NC Not connected, no breaker
?    Not connected, yes breaker

 

Port Hull Panel

Photo

The Port Hull Panel is located above the port tank.

This list shows the main components of the port hull panel.

1 Battery switch Blue Sea Systems 9006
1 High ampere circuit breaker, 200 A Blue Sea Systems 7269
3 Shunts 500 A - 50 mV Empro HA 500 - 50
1 Shunt 10 A 100 mV (future for solar panels) Empro HA-10-100
1 Single pole breakers Ancor marine

 

Port Hull Panel Breaker Function

Breaker Max.
A
Breaker A

Comment

       
Top row (from left to right)      
NC      
NC      
NC      
Port fresh water system pump 15 20 Motorized breaker?
NC     Motorized breaker
NC     Motorized breaker
NC     Motorized breaker
       
Second row      
NC      
NC      
Port 12 V hull outlets 20 20  
Port WC (5 A + 25 A) 30   40  
NC   20  
Webasto 10 20  
NC      
NC      
Port emergency lights   10 To relays
Port hull lights   20  To relays
       
Third row      
NC      
NC      
     
NC      
NC      
Port fuel pump (Marco 7.5 A)   10  
Port engine room blower Jabsco   20 To relays
Port sea water 1 pump   20  
Port sea water 2  pump   30  
Port bilge pumps (Rule 1500 4.8 A each)   20  
       
Inverter 80 200 Direct from the main breaker

 

 

Starboard Hull Panel

stbd dc hull panel

The Starboard Hull Panel is located above the starboard tank.

This list shows the main components of the starboard hull panel.

1 Battery switch Blue Sea Systems 9006
1 High ampere circuit breaker, 200 A Blue Sea Systems 7269
3 Shunts 500 A - 50 mV Empro HA 500 - 50
1 Shunt 10 A 100 mV (for solar panels) Empro HA-10-100
  Single pole breakers Ancor marine

 

 

Starboard Hull Panel Breaker Function

Breaker Max.
A
Breaker A

Comment

       
Top row (from left to right)      
Steering hydraulic pump 15 20 Motorized breaker
Black water waste pump 21.5 20 Motorized breaker
NC       
Starboard fresh water system pump   30 Motorized breaker
NC
NC      
NC      
       
Second row      
Starboard  hull lights 20 20 To relays
Starboard emergency lights     To relays
Starboard aft steps lights 10 10 To relays
Starboard  step lights 10 20 To relays
       
       
NC 5 10  
Port WC (5 A + 25 A) 5 40  
Starboard 12 V hull outlets 5 10  
NC      
       
Third row      
Starboard bilge pumps (Rule 1500 4.8 A each) 4.8 20  
Starboard sea water 2  pump ? 30  
Starboard sea water 1 pump   20  
Starboard fuel pump (Marco 7.5 A) 7.5 10  
Starboard engine room blower Jabsco 4" 11 20 To relays
NC      
NC      
NC      
NC      
NC      
       
Tender crane Direct from the main breaker
Anchor windlasses 80 200 Direct from the main breaker

 

Bilge Pumps Panel

Photo

The bilge pumps panel in the rack on the bridge contains three and two way switches and LED's to control the bilge pumps of both sides.

Some bilge pumps can be turned off, turned on and turned to automatic.
The wire that goes directly to the pump (manual turn on and off) is brown, while the wire that goes to the float switch (automatic turn on and off) is white.
More details in the Bilge Pumps section.

Other bilge pumps are only powered from this panel and not turned on.  The switch that turns them on is located by the bilge pump itself. 

The switches (and therefore the pumps) are directly fed from the Hull Relay and Bilge Pumps junction boxes on their respective sides.

This list shows the main components of the bridge panel.

 

Three way switches  

 

Red LED indicator Blue Sea Systems 8171

 

 

Relay and Bilge Pumps Junction Boxes

 

The port and starboard Relay and Bilge Pumps Junction Box are located above the fuel tanks.

They contain at the top the relays of the 6 hull lights and the engine room blower.
In the middle the terminal blocks for the bilge pump wires.
On the bottom the negative bus.

The enclosure is a waterproof  IP65 polyester box.

 

 

Battery Panels

 

Four small battery panels are located in pairs above the fuel tanks, near the batteries.  Two are for the service batteries and two are for the engine starter batteries.

To protect the lines from the batteries to the hull panels or engines a high amperage fuse (ABYC rule 183.460) and a battery switch is installed within 72" (180 cm) of the battery), on the battery panels. 

Since the main DC circuit breaker of each service side has an ampacity of 200 A, the fuses near the batteries have an ampacity of 250 A, to be sure that the circuit breaker trips first.

This list shows the main components of each battery panel.

1 Battery switch Blue Sea Systems 9006

1

High Ampere fuse block Blue Sea Systems 2002


 

Service Batteries

There are two service battery banks, one for each hull, located in the wing deck, under the wheelhouse.

Each battery bank consists of two Fullriver DC335-6 AGM deep cycle batteries connected in series.
These batteries are non spillable, valve regulated lead-acid batteries.

It is possible at a later date to put four batteries in each bank.  Not to mix different age batteries, the four old batteries will then make one bank, the new ones the other.

The aluminum box for the service batteries measures on the inside 503 x 267 mm.

Four service batteries were purchased April 2013 from AGF Electronics. 
The old, discarded batteries batteries were purchased September 2007 from Atom batterie. 

Each battery has the following specifications: 

Rated capacity (20 hr)

335 AH
Reserve Capacity Minutes to 5.25 V 184@75 A
Length 295 mm
Width 178 mm
Height 345 mm
Weight 47.8 kg

  

6 Volt deep cycle batteries Fullriver DC335-6


The following manual provided by the manufacturer is also part of this section:

Fullriver Batteries - Data Sheet

 

 

Battery Chargers

Photo

The two battery chargers are located in the port and starboard hulls, above the fuel tank.
Each charger has an output of 12V electronically regulated, 50 A.

The two chargers have been regulated to stop charging when two Fullriver batteries reach 14.0V
To regulate the maximum charging voltage unscrew the AC input socket and regulate the trimmer with two wires to the desired voltage using a voltmeter and NO load to the charger.  In the event that the A output has to be changed regulate the trimmer with 3 wires.

Port charger purchased April 2010 from AGF electronics.
Starboard charger purchased April 2013 from AGF electronics.

Battery charger AGF Electronics    12V 50A

AGF Electronics

The following manual provided by the manufacturer is also part of this section:

AGF Battery Charger manual

 

 

Solar Panels

There are two solar panels on the roof above the steering station.

Each panel has a maximum output of 220 W and is 166 cm long and 99 cm wide.

Solar panel

 

Solar panel label

Purchased March 2013 from AGF electronics.

2 Photon Energy Systems PM 0220

 

Solar Panels Controller

There are two controllers for the solar panels, one for each panel.

The MPPT controller consists of two pieces:  the controller and the MeTer remote meter display board.

Each controller is rated for a maximum of 20A.  The output voltage can either be 12 orn 24 V and the controller switches automatically to the proper voltage according to the batteries connected.

 

2 MPPT solar charge controllers 1205 Tracer-2210 0RN 1303-0488
2 MeTer remote meters MT-5  201209

Purchased March 2013 from AGF electronics.

 

The following manual provided by the manufacturer is also part of this section:

Epsolar manual

 

Hardware

Single Circuit ON/OFF Battery Switches

Size 69 x 69 mm

Mini battery switch Blue Sea Systems 9006

Size 56 x 56 mm

Single Circuit battery switch Blue Sea Systems 6006

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea Systems - Battery switches.

 

4 Position Battery Switch

Battery switch, 4 positions Blue Sea Systems 9001

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea Systems - Battery switches.

 

Automatic Charging Relay

The automatic charging relay automatically combines batteries during charging, isolates batteries when discharging and when starting engines.

 

2 Automatic Charging Relay Blue Sea Systems 7610

Blue Sea Systems

 The following manual provided by the manufacturer is also part of this section:

Blue Sea Systems - Automatic Charging Relay Manual

 

Single Pole Breaker

The Ancor circuit breakers have amperages from 5 to 50 A.  Easy to get, since they are sold by West Marine.

The actual manufacturer is Carling Technologies.

Width 20 mm.

Circuit breakers, 1 pole  5 - 50 A, red Ancor Marine

Ancor Marine Products

 

High Ampere Single Pole Breaker

The Blue Sea single pole circuit breakers are the smallest for the high amperages.

Width  38 mm (plus 21 mm) ,  height 63 mm.

High Ampere circuit breaker, 1 pole  200 A Blue Sea Systems 7269

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea Systems - High load breaker catalog

 

285 Series Circuit Breaker

The 285 Series Blue Sea circuit breakers provide high ampere circuit protection and switching

Two surface mount 80 A breakers protect the aft warping capstans.

Blue sea 285 breaker      Blue sea 285 breaker 2   

High Ampere circuit breaker, 1 pole 80 A Blue Sea 285 Series Circuit Breaker

Blue Sea Systems

 

Weather-Resistant Rocker Switches

Various types available from Cole Hersee Co.

SPST Off - Momentary On

cole hersee rocker switch

Rocker Switch SPST   Off - Momentary On Cole Hersee 58332-20BP
Rocker Switch DPST Cole Hersee 58332-29BP

Cole Hersee Co.

 

Ampere Meter

The Datel ampere meters are really millivoltmeters and have to be assembled from 3 different parts.

Datel 200 Ampere DC meter Datel DMS-30PC-0-RS-C
Converter and isolation Board Datel DMS-EB--DC/DC-C
Voltage regulator chip LM7805 (Datel 39-0304000)

To assemble the meter proceed in following way:

1    Cut the SG4 trace on the converter and isolation board
2    Solder the voltage regulator chip LM 7805 with the metal tab adjacient to U1 on the converter
        and isolation board
3    Solder the converter and isolation board to the DMS-30PC-0-RS-C meter
4    Attach 4 small wires to the connector that goes to the converter and isolation board
        #1    blue     + input Hi
        #2    black    - input Low
        #5    red       + 12 V
        #6    black    - 12 V ground

Datel

The three components can be purchased from Mouser electronics, Texas.

The following data sheet provided by the manufacturer is also part of this section:

Datel DC meters
Datel meters

 

Volt Meter

Datel Volt DC meter Datel DMS-20PC-0-DCM

Datel

The following data sheet provided by the manufacturer is also part of this section:

Datel DC meters
Datel meters

 

High Ampere Shunt

Length 15.2 mm, width 32 mm

High Ampere shunt Empro HA-500-50
High Ampere shunt Empro HA-10-100

Empro manufacturing

The following data sheet provided by the manufacturer is also part of this section:

Empro Manufacturing - Data Sheet

High Ampere Fuse Block

 

High amperage fuse block systems Blue Sea Systems 5001
High amperage fuses 250 A Blue Sea Systems 5007

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea Systems -  Electric Mega Fuses

 

Terminal Blocks

Various kinds of terminal blocks are used.
Both 20A and 30A size are used in 2, 4 and 8 circuit configurations.
Where necessary jumpers allow creation of common circuits.

 

 

Terminal blocks medium (20A) Blue Sea Systems 2402, 2404, 2408
Terminal blocks large (30A) Blue Sea Systems 2402, 2504, 2508
Terminal Block Jumpers for 30A (5 in a box) Blue Sea Systems 9217

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea System - Terminal blocks catalog

 

Power Post

These high amperage cable connector come in two sizes: main terminal diameter 3/8" and 5/16".

Also available are through connectors.

Big single cable connectors 3/8 Blue Sea Systems 2003
Medium single cable connector 5/16 Blue Sea Systems 2002
Medium single cable through connector Blue Sea Systems 2011

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea System - Posts catalog

 

Maxi Bus

The following maxi buses are used:

4 terminals with 5/16-18 studs
12 screws 

 

Maxi Bus 4 stud Blue Sea Systems 2106
Maxi Bus 12 screws  Blue Sea Systems 2105 

Blue Sea Systems

The following catalog provided by the manufacturer is also part of this section:

Blue Sea System - Maxi Bus Catalog

 

12 Volt Outlet and Plug

Throughout the hulls there are heavy duty 12 V outlets.

12V outlets, heavy duty Gewiss GW 62 555
12V plugs, heavy duty Gewiss GW 60 081

Gewiss

 

12 V Stainless Steel Receptacle

On the bridge, below the instrument panel, are two 12 V stainless steel receptacles.

Seafit receptacle

They are the standard automotive cigarette lighter type.

Each socket can carry a maximum of 15 A.

12V receptacles, stainless, cigarette type. Seafit model 371849

The following data sheet provided by the manufacturer is also part of this section:

Seafit socket data sheet

 

LED Indicator Light

        LED indicator light

LED indicator light, 12V Red Blue Sea Systems 8171
LED indicator light, 12V Green Blue Sea Systems 8172

Blue Sea Systems

 

LED Utility Strip Light

Used to light the electrical panels on the bridge.


LED utility strip light, 12V Red West Marine 9265869

 

Wall Switches, DC Outlets and Enclosures

 

 

 

The switches to turn on lights and equipment are really pushbutton contact switches since they command relays.

The polyester enclosures are by IP65 standard waterproof.

Switch boxes, Idrobox Luna, 4 modules Bticino 24404
Momentary switches, Luna Bticino C4005L
Polyester enclosure  Gewiss 46 003


Bticino
Gewiss

 

Junction Boxes

Junction boxes,  90 x 130 mm Gewiss GW 44 205

 

Light and Equipment Latching Relays

To turn on lights or other equipment 12 V modular latching relays are used.

Hager latching relay

They can be either of the following two makes, but Hager is preferred since the wire terminals are bigger.;

Latching relay Hager EPN521 16AX 250 V AC - 12 V AC
Latching relay Finder 20 22 8 012 16 AX 250 V AC - 12 V AC

Hager
Finder

 

Twin Block Connector

Used to join two heavy cables together.

The following sizes are used:

120 square mm
50 square mm

Twin block cable connectors BM 95263

BM
Rozzano (MI)
Italy

 

Cable Glands

Used to protect electric cables when passing through aluminum bulkheads or entering enclosures.

The following sizes are available:

PG 16            hole size 21 mm
PG 13.5
PG 21
PG 29
PG 36
PG 42
PG 48

Gewiss cable glands, various sizes GW 52 009

Gewiss

Heatshrink Tubes

Used to insulate wire connections.

Heatshrink tubes, various sizes 3M

3M

 

DC Users Calculations

# User Max.
A
Breaker A Cont. Load Interm. Load

Model

             
1 Navigation lights 8 15 X    
2 Anchor light 2 10   X  
3 Search light 10 15 X    
4 Aft light 10 15 X    
             
5 Anchor windlasses (each) 80     X  
6 Anchor chain washdown valve 2     X  
7 Tender crane 90     X  
             
8 Port forward bilge pump 4 10 X    
9 Starboard forward bilge pump 4 10 X    
10 Port middle bilge pump 4 10 X    
11 Starboard middle bilge pump 4 10 X    
12 Port engine room bilge pump 4 10 X    
13 Starboard engine room bilge pump 4 10 X    
14 Port engine room blower 12 20   X

Jabsco PAR Marine blowers 4"

15 Starboard engine room blower 12 20   X Jabsco PAR Marine blowers 4"
16 Port engine room fire  pump 25     X  
17 Satrboard engine room fire pump 25     X  
             
18 Port fresh water system pump 15 20   X Jabsco 
19 Starboard fresh water system pump 15 20   X Jabsco 
20 Water maker  21.5 25   X  
22 Inverter 80     X  
             
24 Instruments 1 2 10 X   Multiview ST80 etc (120 mA)
25 Instruments 2 5 10 X    
26 VHF 1.5 10 X    
27 SSB 5.8 10   X  
28 Radar     X    
29 Computer     X    
30 Stereo equipment     X    
31 Auto pilot  10 10 X    
33 Instrument lights 5   X    
34 Horn 20     X  
35 Windshield wipers (5) 2     X  
             
38 Port cabin lights 5 10   X  
39 Starboard cabin lights 5 10   X  
40 Port head lights 5 10   X  
41 Starboardort head lights 5 10   X  
42 Port bridge lights 5 10   X  
43 Starboard bridge lights 5 10   X  
44 Bridge night lights 5 10   X  
45 Galley lights 5 10   X  
46 Dinette lights 5 10   X  
47 Step lights 3 10   X  
48 Boat deck lights 10 20   X  
49 Aft deck lights 10 20   X  
             
50 Port cabin and head 12 V outlets 5 10   X  
51 Starboard cabin and head 12 V outlets 5 10   X  
52 Bridge 12 V outlets 5 10   X  
53 Galley and dinette 12 V outlets 5 10   X  
54 Port engine room 12 V outlets 5 10   X  
54 Starboard engine room 12 V outlets 5 10   X  
56 Cabin air circulation blower 5 10   X  
             
57 Black waters waste pump 6 10   X Vetus
59 Gray waters waste pump 6 10   X Vetus
62 Port WC 20     X  
63 Starboard WC 20     X  

The breakers have been divided into continuous and intermittent load to calculate the ampacity of the main DC circuit breaker according to the ABYC load calculation method.  The largest intermittent load or 10% of the total intermittent load, whichever is greater, will be used for the calculation.  The total load is the sum of the total continuous duty loads plus the intermittent load, as defined before.

Total continuous duty loads:  ~110
Total intermittent duty loads:   ~720
10% of total intermittent duty load:   72
Largest intermittent duty load:  80
Total load 190

The main DC circuit breaker has an ampacity of 200 A.

 

 

Wire Equivalents and Sizes

AWG = American Wire Gauge

1/0  AWG  53.49 mm2
1  AWG  44.21mm2
2  AWG  33.62 mm2
4  AWG  21.15 mm2
6  AWG 13.30 mm2
8  AWG  8.37 mm2
10  AWG  5.26 mm2
12  AWG  3.31 mm2
14  AWG  2.08 mm2
16  AWG  1.31 mm2

 

Wire Sizes

Wire size calculated for a 10 m distance, one way, since the return is done with oversized common negative wires.

Load,
A
3%  voltage drop,
 AWG 
3 % voltage drop
 mm2
10%  voltage drop,
 AWG 
10 % voltage drop
 mm2
10

 10

5.26

 14

2.08
20  6 13.30  12 3.31
30 4 21.15 10 5.26
50  2 33.62 8 8.37
100  0 53.49  4 21.15

 

 

2016-08-25
cat_08_e dc electric system.htm