12 VDC Power Sources For Your RV

Transcription

1 12 VDC Power Sources For Your RV Win Semmler RVIS, LLC

2 Sources of 12 VDC For Your RV Batteries Converters Alternators Solar

3 Batteries A group of cells that generate electricity from a chemical reaction Cells consist of two electrodes When immersed in electrolytes a chemical reaction results The two electrodes have a difference of potential, resulting in voltage output from the cell

4 Two Types of Batteries Dry Cell Flashlights, smoke detectors, wall clocks Rechargeable and non-rechargeable Wet Cell Used as 12 VDC power source in RV's and other vehicles Can be recharged Needs regular maintenance

5 Dry Cell Batteries Common for consumer electronics AAA, AA, C, D, and 9-volt Not actually dry, electrolyte is a moist paste When dry, no longer able to transform chemical energy to electrical energy

6 Wet Cell Batteries When discharging cells supplying current to a load When charging electrolytes are reformed as chemical reaction is reversed Cycling the process of discharging and recharging Charging current must be supplied by an external DC source

7 Types of Wet Cell Batteries Lead-Acid Cell Gel Cell AGM Absorbed Glass Mat Lithium

8 Lead-Acid Cell Batteries Most common in RV industry Case usually hard rubber, plastic, or other material resistant to electrolyte and mechanical shocks Vent plugs to allow for escape of gases Cells have two plates: + and Plates are made of lead, lead peroxide, or lead dioxide Insulating material used as separators between each set of plates Liquid in battery a solution of sulfuric acid and water Each cell generates 2.1 volts 12 VDC has 6 cells, 6 VDC has 3 cells

9 Lead-Acid Battery

10 Gel Cell Batteries Electrolytes permanently locked in a thixotropic gel which becomes fluid when stirred or agitated Advantages No electrolyte leakage Can install on side or hard to reach locations Even if left discharged for 30 days, charging will bring it up to 100% capacity Will not sulfate like lead-acid Don't need to check fluid levels No terminal corrosion However susceptible to overheating during charging

11 Absorbed Glass Mat (AGM) Batteries Increased safety, efficiency, and durability Electrolyte absorbed and held in place by microfibrous silica glass mats sandwiched between plates Faster battery recovery from a discharged state Significantly longer life

12 Lithium Batteries Can use 100% of the rated capacity vs 50% for AGM 70% lighter than lead-acid batteries Can last cycles vs for most lead-acid No leaking, gassing or corrosion Require no maintenance and can hold full charge for over a year Very expensive (approx $1200 for 100 amp hr 12 VDC)

13 Battery Safety Lead-acid contain sulfuric acid Hazard potential while charging and discharging

14 Battery Safety Precautions Safety goggles & protective clothing Use nonmetallic containers/funnels Provide adequate ventilation Hydrogen & oxygen gases can explode if spark or flame nearby Always disconnect ground first to eliminate spark potential

15 Chassis Battery Wet cell that is rechargeable Supports automotive requirements (lights, radio, heater, etc.) Needs to provide short burst of high current to start engine Alternator Creates electricity for accessories while engine is running Supplies some energy to put back into battery

16 Deep Cycle Battery Similar appearance to chassis but usually a little larger Made with high density active materials allowing plates to be repetitively cycled without loss of composition Some can be drained to 0 volts before recharging Supply continuous DC power for long duration Because they can be repeatedly recharged they are used as the DC power source Called House or Coach battery

17 Maintenance Free Batteries Completely sealed no vent caps Terminals should be inspected & cleaned Built In electrolyte reserve keeping plates covered and working Available for House or Chassis

18 Power Converters Changes 120 VAC to 12 VDC Most equipped with a battery charger If replacing be sure to replace with one Listed for RV use Three types Linear Ferroresonant Switchmode

19 Linear Converter Least expensive has been extremely popular among manufacturers for many years Change in AC voltage results in a change to DC voltage Low AC ==> lights dim High AC ==> burned out bulbs Heavy, produce heat, audible hum

20 Ferroresonant Converter DC voltage won't change with AC fluctuations Battery charge function designed into unit Smooth and consistent DC voltage Bigger, heavier, and higher $$$ than linear Some require a battery to obtain full output voltage Charging time can be very long

21 Switchmode Electronic Converter Uses electronic circuitry to convert AC to DC Voltage electronically regulated so it remains constant Relatively light and smaller in size Can power the coach without a battery in place Shorter battery charging time

22 So what is being used today? They use Switchmode or Multi-Stage Converters Most manufacturers using this technology in their new units Recommended replacement for any upgrades Usually include monitor panel for measuring voltage and current flow Highly effective at charging battery as they use many parameters to optimize the process

23 Testing the converter Converters need good AC voltage to work properly Start by checking the voltage at the outlet the converter is plugged into Use a voltmeter or multimeter to confirm voltage to the converter With the converter on, measure battery voltage With converter off, measure battery voltage again. There should be at least a.5 volt drop

24 Solar Panels Produce electricity when sunlight strikes a photovoltaic module Amount of current relational to surface area and sunlight intensity Provide battery charging Factors affecting output and performance Number of panels Construction type Sun's intensity & angle relative to panel surface Most effective when perpendicular to rays and not shaded

25 Solar Panels Sizing is important Know what you want to power How long per day will you run the load Article from Technomadia Solar panel sizing worksheet (send me an )

26 Alternators Create 12 VDC from energy provided by the engine Will deliver a higher current at a lower RPM than a generator

27 Combining Batteries To provide higher voltage, more current, or both Connecting in series = higher voltage Connecting in parallel = higher current (amp hours)

28 Connecting in Series Negative terminal of 1st battery connected to positive terminal of 2nd. Positive terminal of 1st battery & negative terminal of last battery serve as terminals of the series Total voltage = sum of the individual batteries Current capacity (amp hours) is the same as current flows through all batteries

29 Connecting in Parallel Increases current storage (amp hours) capacity All positives are connected together as are all negatives Equivalent to increasing size of electrodes and electrolyte Increases current capacity Voltage output does not change

30 Connecting in Series Parallel Will increase voltage and current or amp hour capacity Not recommended to mix battery sizes in a bank If replacing, take pictures

31 Testing a Battery Stack Connected in Series

32 Testing a Battery Stack Connected in Parallel

33 Testing a Battery Stack Connected in Series & Parallel

34 Battery Sizing / Replacement Replacements should be > or = battery installed Replacing with a smaller battery = poor performance & shorter life If in a group, recommend replacing all at the same time If one is weaker, the others will be affected

35 Battery Maintenance Hydrogen gas keep sparks away Sulfuric acid protect skin and eyes Disconnect grounded terminal first reconnect grounded terminal last Check case, clamps, cables, post for signs of corrosion

36 Battery Gravity Testing Checks state of charge for a lead-acid cell Fully charged cell has a gravity of at 80 degrees fahrenheit As cell discharges, less acid and more water, and gravity lowers At a gravity of cell is discharged

37 Taking Gravity Readings Taken with a battery hydrometer Each cell should be checked All cells should be about the same gravity Do not take reading right after adding water or charging Only add distilled water Gravity changes as temperature changes so use a temperature compensated hydrometer

38 Hydrometer Readings ===> 100% charge ===> 75% charge ===> 50% charge ===> 25% charge ===> discharged

39 Charging Adding active ingredient (chemical) does not recharge, only increases gravity Charging current must be passed through the battery to recharge Safety first Goggles Keep away from sparks and flames Vent caps should be in place To fully charge, amp hours removed must be replaced plus 20% as recharge not 100% efficient Follow charger instructions & battery charging guide VDC = fully charged lead-acid battery VDC = fully charged gel cell battery

40 Overcharging Can raise temperature, boil water, and damage battery Overcharge indicators Frequent water addition Blackened plates Gassing - decomposes water releasing explosive hydrogen gas

41 Additional resources To get your CEU credit Enter Keep your batteries charged. as the first line in an Send to

42 Questions?