MElec-Ch3 - 1 Chapter 3 Direct Current Power Direct Current Power

MElec-Ch3 - 2 Overview Batteries Safety Precautions Marine Storage Battery Charging Systems Battery Utilization Batteries Safety Precautions Marine Storage Battery Charging Systems Battery Utilization

MElec-Ch3 - 3 Batteries Cells and Battery Battery Chemistry  Primary Cells  Secondary Cells Series and Parallel Connections Cells and Battery Battery Chemistry  Primary Cells  Secondary Cells Series and Parallel Connections

MElec-Ch3 - 4 Cells and Batteries Cells generates DC by chemical reaction  Two dissimilar electrodes (conductors)  Immersed in electrolyte (current carrying solution)  Voltage function of electrode material Difference on the Galvanic Scale Covered in Chapter 5 Battery  Group of cells connected together  Classes – Primary and Secondary Cells generates DC by chemical reaction  Two dissimilar electrodes (conductors)  Immersed in electrolyte (current carrying solution)  Voltage function of electrode material Difference on the Galvanic Scale Covered in Chapter 5 Battery  Group of cells connected together  Classes – Primary and Secondary

MElec-Ch3 - 5 Primary Cells Primary cells can not be recharged  Chemical process is not reversible  aka “Dry Cell” Common chemistries  Zinc-carbon  Alkaline (zinc and manganese oxide) Use  Flashlights  Portable radios Nominal voltage 1.5 VDC Primary cells can not be recharged  Chemical process is not reversible  aka “Dry Cell” Common chemistries  Zinc-carbon  Alkaline (zinc and manganese oxide) Use  Flashlights  Portable radios Nominal voltage 1.5 VDC

MElec-Ch3 - 6 Secondary Cells Secondary Cells can be recharged  Reversible chemical reaction  aka “rechargable ” Common chemistries  Lead-acid (2.1 VDC)  Nickel-cadmium (1.2 VDC)  Nickel-metal hydride (1.2 VDC) Use  Cars and Boats Secondary Cells can be recharged  Reversible chemical reaction  aka “rechargable ” Common chemistries  Lead-acid (2.1 VDC)  Nickel-cadmium (1.2 VDC)  Nickel-metal hydride (1.2 VDC) Use  Cars and Boats

MElec-Ch3 - 7 Series and Parallel Connections A A Series A A Parallel A A A A Common Dual Voltage

MElec-Ch3 - 8 Safety Precautions Lead-Acid batteries  May produce explosive gases  Contain acid  Battery acid & seawater produce Chlorine Gas Charge batteries in well-ventilated area  Keep sparks, flames and cigarettes away Wear eye, face and hand protection  Baking Soda is effective neutralizing solution Lead-Acid batteries  May produce explosive gases  Contain acid  Battery acid & seawater produce Chlorine Gas Charge batteries in well-ventilated area  Keep sparks, flames and cigarettes away Wear eye, face and hand protection  Baking Soda is effective neutralizing solution

MElec-Ch3 - 9 Warning Message

MElec-Ch Marine Storage Batteries Types Technologies Sizes Marine Battery Ratings Selection, Installation and Maintenance Types Technologies Sizes Marine Battery Ratings Selection, Installation and Maintenance

MElec-Ch Types Starting battery  Large amount of current for very short time  Not fuse protected Deep-Cycle battery  Power for many hours  Can be discharged to 50% capacity  Protected by large (200 to 400A) fuse Dual-Purpose battery  Large plates (like starting)  Thick plates (like deep-cycle) Starting battery  Large amount of current for very short time  Not fuse protected Deep-Cycle battery  Power for many hours  Can be discharged to 50% capacity  Protected by large (200 to 400A) fuse Dual-Purpose battery  Large plates (like starting)  Thick plates (like deep-cycle)

MElec-Ch Technologies Flooded  Sometimes called “flooded” or “free-vented” Gelled Electrolyte (Gel)  Also called Valve-Regulated Lead Acid (VRLA) Absorbed Glass Mat (AGM)  Also called Valve-Regulated Lead Acid (VRLA) Flooded  Sometimes called “flooded” or “free-vented” Gelled Electrolyte (Gel)  Also called Valve-Regulated Lead Acid (VRLA) Absorbed Glass Mat (AGM)  Also called Valve-Regulated Lead Acid (VRLA)

MElec-Ch Flooded Traditional marine battery  Electrolyte is water-diluted sulfuric acid  Electrodes are lead  Free vented – charging gases escape Advantages  Low initial cost  Good deep-cycle performance Disadvantages  Spillable electrolyte  High self-discharge rate Traditional marine battery  Electrolyte is water-diluted sulfuric acid  Electrodes are lead  Free vented – charging gases escape Advantages  Low initial cost  Good deep-cycle performance Disadvantages  Spillable electrolyte  High self-discharge rate

MElec-Ch Gelled Electrolyte (Gel) Gelled Electrolyte  Electrolyte is a gel Mixture of sulfuric acid, fumed silica & phosphoric acid  Pressure-relief vents (charging gases can’t escape) Advantages  Spillproof / leakproof (can be used in any orientation)  Lowest cost per cycle  Low self discharge rate Disadvantages  High initial cost  Can be damaged, if charged at wet cell rate Gelled Electrolyte  Electrolyte is a gel Mixture of sulfuric acid, fumed silica & phosphoric acid  Pressure-relief vents (charging gases can’t escape) Advantages  Spillproof / leakproof (can be used in any orientation)  Lowest cost per cycle  Low self discharge rate Disadvantages  High initial cost  Can be damaged, if charged at wet cell rate

MElec-Ch Deep-Cycles Gel Battery

MElec-Ch Absorbed Glass Mat (AGM) Designed for military aircraft  Use matted glass fibers between plates Advantages  Spillproof / leakproof (can be used in any orientation)  Most shock and vibration resistant Disadvantages  Capable of fewer discharge cycles Designed for military aircraft  Use matted glass fibers between plates Advantages  Spillproof / leakproof (can be used in any orientation)  Most shock and vibration resistant Disadvantages  Capable of fewer discharge cycles

MElec-Ch Advantages / Disadvantages

MElec-Ch Sizes

MElec-Ch Battery Ratings Ampere-hour (Ah) – Storage capacity Open Circuit Voltage (V) – Battery at rest Starting batteries  Cold Cranking Amps (CCA) – 30 sec at 0 F  Marine Cranking Amps (MCA) – 30 sec at 32 F  Reserve Capacity (RC) – minutes of 25 A at 80 F Deep-cycle batteries  Rated Capacity – Amp-hours for 20 hr at 80 F  Deep Cycle Capacity Ability to provide small amounts of current over time Ability to withstand long, deep discharges Ampere-hour (Ah) – Storage capacity Open Circuit Voltage (V) – Battery at rest Starting batteries  Cold Cranking Amps (CCA) – 30 sec at 0 F  Marine Cranking Amps (MCA) – 30 sec at 32 F  Reserve Capacity (RC) – minutes of 25 A at 80 F Deep-cycle batteries  Rated Capacity – Amp-hours for 20 hr at 80 F  Deep Cycle Capacity Ability to provide small amounts of current over time Ability to withstand long, deep discharges

MElec-Ch Battery Ratings by Battery Type

MElec-Ch Selection, Installation and Service Selection  DC Power Requirements  Typical 24-hour load Installation Maintenance (Service)  Water  Cleaning Terminals  Winter Lay-up Selection  DC Power Requirements  Typical 24-hour load Installation Maintenance (Service)  Water  Cleaning Terminals  Winter Lay-up

MElec-Ch Selection Starting Battery replacement  Same Group Size and MCA  Initial Cost or Life Cycle Cost? Flooded – Less expensive to buy House (Deep-cycle) Battery replacement  Consider increased capability Double battery life if depth of discharge only 25%  Initial Cost or Life Cycle Cost? Gel - Capable or more discharge cycles Ratios (Battery size to largest expected load)  Flooded – 4 to 1  Gel and AGM – 3 to 1 Starting Battery replacement  Same Group Size and MCA  Initial Cost or Life Cycle Cost? Flooded – Less expensive to buy House (Deep-cycle) Battery replacement  Consider increased capability Double battery life if depth of discharge only 25%  Initial Cost or Life Cycle Cost? Gel - Capable or more discharge cycles Ratios (Battery size to largest expected load)  Flooded – 4 to 1  Gel and AGM – 3 to 1

MElec-Ch DC Power Requirements What source of DC power?  Powerboat normally powered off an alternator  Sailboats normally powered off House Battery  If anchored – Generator or House Battery? How often between battery charging? Limit depth of discharge to 50%  For minimal charging time - Limit depth to 35%  Battery life cut in half, if discharge to 75% Following table gives typical DC power demands What source of DC power?  Powerboat normally powered off an alternator  Sailboats normally powered off House Battery  If anchored – Generator or House Battery? How often between battery charging? Limit depth of discharge to 50%  For minimal charging time - Limit depth to 35%  Battery life cut in half, if discharge to 75% Following table gives typical DC power demands

MElec-Ch Typical 24-hour Load

MElec-Ch Installation Flooded batteries require  Vented battery compartment  Easy access to add water All batteries  Should be in acid-resistant box  Secured with insulated cover  Starting battery located near engine  Don’t mix battery age in a battery bank  Don’t mix battery chemistry in battery bank Flooded batteries require  Vented battery compartment  Easy access to add water All batteries  Should be in acid-resistant box  Secured with insulated cover  Starting battery located near engine  Don’t mix battery age in a battery bank  Don’t mix battery chemistry in battery bank

MElec-Ch Maintenance (Service) Flooded-cell require distilled water  Rapid loss in single cell indicates bad battery  Rapid loss in all cells indicates high charging voltage Never force open or add water to Gel or AGM Clean and tighten terminals twice a year  Use special battery tools (illustrated on next slide)  Can remove corrosion with Baking Soda solution Don’t get solution into battery fill ports  Apply battery “grease” to terminals Flooded-cell require distilled water  Rapid loss in single cell indicates bad battery  Rapid loss in all cells indicates high charging voltage Never force open or add water to Gel or AGM Clean and tighten terminals twice a year  Use special battery tools (illustrated on next slide)  Can remove corrosion with Baking Soda solution Don’t get solution into battery fill ports  Apply battery “grease” to terminals

MElec-Ch Battery Tools Dirty or loose battery terminals can materially reduce the energy available from a battery Use proper battery tools to prevent damage to battery Dirty or loose battery terminals can materially reduce the energy available from a battery Use proper battery tools to prevent damage to battery Battery Terminal Puller Battery Terminal Cleaner

MElec-Ch Winter Lay-up Fully charge and service before winter lay-up  Flooded batteries should be equalized Disconnect negative battery terminal cable Flooded deep-cycle should be charged every 50 days Gel and AGM should be charged every 6 months  Also flooded starting Continuous trickle charge not recommended  Unless have automatic cutoff Fully charge and service before winter lay-up  Flooded batteries should be equalized Disconnect negative battery terminal cable Flooded deep-cycle should be charged every 50 days Gel and AGM should be charged every 6 months  Also flooded starting Continuous trickle charge not recommended  Unless have automatic cutoff

MElec-Ch Charging Systems Basic Considerations Degree of Charge Alternators AC Battery Chargers Inverter/Charger Other Basic Considerations Degree of Charge Alternators AC Battery Chargers Inverter/Charger Other

MElec-Ch Basic Considerations Charging requires more charge (in amp-hours) than removed  Flooded 115 to 120%  VRLA 105 to 114% Phases  Bulk at 20 to 40% of battery's capacity Continues until 75% full  Acceptance charging rate is steadily reduced Continues until accepted current equals 2% capacity  Float current is only 0.1 to 0.2 Amps Maintenance, not charging Charging requires more charge (in amp-hours) than removed  Flooded 115 to 120%  VRLA 105 to 114% Phases  Bulk at 20 to 40% of battery's capacity Continues until 75% full  Acceptance charging rate is steadily reduced Continues until accepted current equals 2% capacity  Float current is only 0.1 to 0.2 Amps Maintenance, not charging

MElec-Ch Basic Considerations - 2 Proper Charging Voltage depends on  Temperature (table on slide 33 based on 80 F) Higher temperatures require lower voltage  Battery Chemistry  Table gives charging voltage by phase & chemistry Flooded-cell Equalization  Prevents “sulfation”  Recommended every 20 to 50 cycles  Over charge, after acceptance phase, to dissolve lead sulfate crystals on battery’s plates  High voltage may damage electronic equipment Proper Charging Voltage depends on  Temperature (table on slide 33 based on 80 F) Higher temperatures require lower voltage  Battery Chemistry  Table gives charging voltage by phase & chemistry Flooded-cell Equalization  Prevents “sulfation”  Recommended every 20 to 50 cycles  Over charge, after acceptance phase, to dissolve lead sulfate crystals on battery’s plates  High voltage may damage electronic equipment

MElec-Ch Degree of Charge Flooded cell with hydrometer (most accurate) Gel and AGM with volt meter  Can also use volt meter on flooded cell Next slide gives voltages for rested batteries  Not charged or discharged for 24 hours  Can also bleed off surface charge Use large light bulb for several minutes Flooded cell with hydrometer (most accurate) Gel and AGM with volt meter  Can also use volt meter on flooded cell Next slide gives voltages for rested batteries  Not charged or discharged for 24 hours  Can also bleed off surface charge Use large light bulb for several minutes

MElec-Ch Lead-acid 12 volt Voltages

MElec-Ch Alternators Alternator converts AC to DC with diodes  Don’t disconnect battery while alternator running “Zap-Stop” ® will protect diodes from damage Alternator sized at 25-40% of battery capacity Charging Diodes (Isolators)  Permit charging of two batteries  Have approx 0.6 to 0.7 voltage drop Increase alternator voltage for correct voltage at battery  Illustrated on next slide Alternator converts AC to DC with diodes  Don’t disconnect battery while alternator running “Zap-Stop” ® will protect diodes from damage Alternator sized at 25-40% of battery capacity Charging Diodes (Isolators)  Permit charging of two batteries  Have approx 0.6 to 0.7 voltage drop Increase alternator voltage for correct voltage at battery  Illustrated on next slide

MElec-Ch Multiple Battery Charging Engine Driven Alternator Battery Isolators AC Charger (Two-outputs) Starting Battery House Battery + #1 + # Negative Common

MElec-Ch AC Battery Chargers Basic charger (not recommended)  Single output voltage  Can’t do bulk, acceptance, and float charging  Can’t handle multiple chemistries Basic charger (not recommended)  Single output voltage  Can’t do bulk, acceptance, and float charging  Can’t handle multiple chemistries

MElec-Ch AC Battery Chargers - 2 SCR multi-stage (recommended)  Three phase charger (bulk, acceptance & float) Also will do equalization  Independent multiple outputs Independent setting for Flooded, Gel and AGM Independent as to phase  Best for Deep-Cycle SCR multi-stage (recommended)  Three phase charger (bulk, acceptance & float) Also will do equalization  Independent multiple outputs Independent setting for Flooded, Gel and AGM Independent as to phase  Best for Deep-Cycle 2 10 A temperate climate 3 40 A cold, warm or hot climates

MElec-Ch Inverters / Chargers Charger converts 120 VAC to DC Inverter converts 12 VDC to 120 VAC  More on inverters in Chapter 4 on AC Advantages  Lighter & cheaper than separate systems Charger converts 120 VAC to DC Inverter converts 12 VDC to 120 VAC  More on inverters in Chapter 4 on AC Advantages  Lighter & cheaper than separate systems 2Kw inverter 100A charger 3-stage multiple batteries

MElec-Ch Other Solar Panels  Low power output  Requires controller or regulator Wind Generator  Ideal wind of 5 to 30 Kt  Should be feathered or stopped at over 35 Kt  More power than solar Solar Panels  Low power output  Requires controller or regulator Wind Generator  Ideal wind of 5 to 30 Kt  Should be feathered or stopped at over 35 Kt  More power than solar

MElec-Ch Battery Utilization Separate Starting and House Battery Switches Battery Monitor Typical 12 volt System Separate Starting and House Battery Switches Battery Monitor Typical 12 volt System

MElec-Ch Starting and House Batteries Two battery banks are recommended  Starting – Large amount of current for short period Half of breakdowns are – engine won’t crank  House – Sustained power over long period of time Discharge limited to 50% Old concept was “Off-1-Both-2” battery switch Two battery banks are recommended  Starting – Large amount of current for short period Half of breakdowns are – engine won’t crank  House – Sustained power over long period of time Discharge limited to 50% Old concept was “Off-1-Both-2” battery switch

MElec-Ch Battery Switches Battery switches (current thinking)  Dedicated “Off-On” switch for each battery Each battery charged separately Prevents weaker battery discharging stronger one When need extra current to crank engine  Close switch #3 to parallel both batteries Switch must be opened after engine is started Battery switches (current thinking)  Dedicated “Off-On” switch for each battery Each battery charged separately Prevents weaker battery discharging stronger one When need extra current to crank engine  Close switch #3 to parallel both batteries Switch must be opened after engine is started

MElec-Ch Battery Switches Starting Battery House Battery Negative Common to Starter Solenoid to Power Panel SW 1 SW 2 SW 3 F 1

MElec-Ch Battery Monitors Battery Monitors keep track of  How much energy stored in battery  How much energy has been removed  How much energy is left in battery  Time remaining at current discharge rate Sophisticated, computer based device Voltmeter only provides current status Battery Monitors keep track of  How much energy stored in battery  How much energy has been removed  How much energy is left in battery  Time remaining at current discharge rate Sophisticated, computer based device Voltmeter only provides current status

MElec-Ch Typical 12-volt System Next slide illustrates  Starting and House battery Charged by alternator and charging diodes Charged by two output, three stage battery charger Dedicated “Off-On” switches for each battery Separate battery paralleling switch  Wires are color coded with size shown Note bilge pump wiring –Fuse in negative lead –Pump operated by either float switch or panel switch  Uses voltmeter to determine battery charge Next slide illustrates  Starting and House battery Charged by alternator and charging diodes Charged by two output, three stage battery charger Dedicated “Off-On” switches for each battery Separate battery paralleling switch  Wires are color coded with size shown Note bilge pump wiring –Fuse in negative lead –Pump operated by either float switch or panel switch  Uses voltmeter to determine battery charge

MElec-Ch Typical 12 volt Diagram

MElec-Ch Summary Types of Marine Batteries  Flooded-cell, Gel and AGM  Starting, Deep-cycle and Dual-purpose Charge batteries in three phases  Bulk, Acceptance and Float  and if lead-acid, periodically equalize Keep binding posts & cables clamps clean Recommend battery charger / inverter Independent battery banks recommended Types of Marine Batteries  Flooded-cell, Gel and AGM  Starting, Deep-cycle and Dual-purpose Charge batteries in three phases  Bulk, Acceptance and Float  and if lead-acid, periodically equalize Keep binding posts & cables clamps clean Recommend battery charger / inverter Independent battery banks recommended