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What is a battery? It's stored
chemical energy that's released in electric form. It requires
"replacement".
1. Starting batteries --
Requires lots of energy for a short period of time. Charge it, keep water in it, and avoid corrosion, and you'll get full life from them. "Cold cranking amps" -- turn your engine in any weather condition. Hot weather discharges them faster. And the hotter it is the faster they'll recharge. Thin plates are the storage parts. They react w/the sulphuric acid. Hydrometer measures -- higher it floats, more sulphuric acid. It's still the best instrument to find out if battery is charged. Starting batteries are good for short bursts of heavy power, and capable of rapid recharge. They're good for about 15-30 cycles -- i.e., deep discharges and recharges.
2. House Batteries --
These batteries require a little bit of energy for a long period of time. Typically if you are at a campground with "hookups", your 110 volt power source will operate your power converter which will place a 2 amp trickle charge on your battery, thus maintaining the battery. Note: this it not to be use to charge a heavily depleted battery unless you have a very long time to wait. If you are "dry camping" then you want to start your RV engine and idle it for 1/2 hour to 45 minuets once or twice a day to charge your house battery. the house battery is connected to the 85 amp alternator in your motorhomes engine and it is designed to be charged by the engine. Note; be sure to monitor the engine temperature as you do not want to overheat the RV's engine doing this.
Golf cart batteries: The best wet deep cycle batteries out there. But need more of them and more maintenance. They're 6 volts, so need two to get 12 volts. Issue is needs more connections, some loss in that, plus more chance of corrosion. But need to add water more often, and equalize more often. AGM is 2-3 times more expensive. More suited for float charge
AGM (glass mat batteries) should never be equalized (Heart's claims to the contrary).. Both gel cell and glass mat are completely sealed. Problem is overcharging causes leakage, so they can't be charged at more than around 14.2 volts. Charge slower and longer. AGM works better on smaller batteries than larger batteries. [Note: As of this writing GNB did not make a D8 version of AGMs, though a competitor did] AGM is next generation up from gel cell batteries.
3. Trojan T 105 golf cart type battery is at the top of the recommended batteries.
RV/Marine batteries are a bit of a hybrid -- 300 - 400 cycles. True deep cycle batteries last for 700 - 800 cycles. These are typically much heavier than the other two types. For purposes of designing an RV solar system, "true deep cycle" batteries are by far the best bet. This is a six volt battery, so one must buy them in pairs. The disadvantage is they are somewhat larger, and often don't fit in RV battery boxes. Trojan SCS 12 Volt battery is a more standard size, and is the next best bet. The benefit of the Trojan, in the instructor's view, is that they simply last longer. Some of the students noted they had found Trojan batteries through Price/Costco at about $50 per unit. A tip when buying batteries: "H5" stamped on top of lead battery post means battery was manufactured in August (corresponds to "H") of 1995. It's a good idea to check this when buying batteries, to get the more recently manufactured batteries. And if you use more than one tied together, get batteries of same manufacture date.
Electrolyte should be 1/8 inch below barrel. Overfilling invites corrosion. If you do overfill a cell, hose it off immediately. Note: You don't need distilled water -- you can use any water you can drink.
Voltmeter -- tells voltage, but can a false reading if the batteries have just been used. Need to take "surface charge" off.
Amp hours: Generator recharges at around 30 amps. 2 8D batteries have 480 AH 12.65 V full 12.25 V is 50% state of charge. 1200 gravity on hydrometer.
Battery terminals should be
cleaned with a paste of baking soda periodically to protect against corrosion.
Apply a thin coating of Vaseline once it's clean.
Fill batteries with distilled water, never tap water.
Where batteries are in parallel, they must be the same type, same age, same
everything. Two six volt golf cart batteries cabled in series are almost
twice the reserve power of two 12 volt batteries in parallel. This despite the
fact that the amp hour ratings would appear to be similar. T145's by Trojan are
the top of the line golf cart battery. (We note another speaker recommended
T105s by Trojan as superior to the 145's-- but both recommended Trojan as the
top brand name.)
The Basics Questions every RVer should consider are these:
1. How much electrical energy does your RV require each day -- measured in amp hours?
2. How large should your battery capacity be to support your daily electrical needs.
3. What type of charging device do you need; and how much output should be produced to recharge your batteries quickly and efficiently?
The key is "amp hours". What's the rating? House batteries want true deep cycle batteries. Starting batteries are rated in terms of cold cranking amps. It's inappropriate to use starting batteries for house batteries, as starting batteries deliver high amps but discharge quickly.
How many times can a battery be discharged and recharged. A rule of thumb is don't ever go below 50% of your rated capacity before recharging. If batteries become deeply discharged, special precautions are needed for recharging.
For wet cell, batteries, refill with distilled water only. But don't overfill batteries either. Escaping electrolyte causes corrosion. What is full? There is a fill line about 3/4 inch from top of battery -- usually the bottom of the tube. Keep batteries free from corrosion. And make sure connections are both clean and tight.
Danger: Don't wear jewelry when working around batteries. And wear safety glasses.
- Unplug the 120-volt AC power cord to turn the power converter off.
- Press "BATTERY" rocker switch on the panel.
- Turn on a light or any 12-volt appliance. The battery must be checked with a load.
- Read battery condition on the meter, Red is low, yellow is fair and green is good.
Both sets of batteries will be kept charged by the chassis charging system while on the road. The AC/DC power converter will charge the coach battery when plugged into 120-volt service. On those occasions when the battery needs to be charged from a different charging source, please follow these safety guidelines:
1. Leaving a charger connected to a battery for an extended period of time can shorten battery life.
WARNING
NEVER EXPOSE THE BATTERY TO OPEN FLAME OR ELECTRIC SPARK. CHEMICAL ACTION IN THE BATTERY GENERATES HYDROGEN GAS that IS FLAMMABLE AND EXPLOSIVE. DO NOT ALLOW BATTERY ELECTROLYTE (ACID) TO CONTACT SKIN, EYES, FABRICS, OR PAINTED SURFACES.
2. Do not smoke near batteries being charged or which have been recently charged. Please note that batteries are being charged while you drive, and while you are connected to 120-volt power through the converter/charger circuit.
3. Do not break live circuits at the terminals of the battery. Use care when connecting or disconnecting booster leads or cables. These actions, and poor connections, are a common cause of electrical arcs which can cause explosion,
4. Check and adjust the electrolyte level before charging. Fill each cell to the indicator with distilled water.
5. Always remove vent caps before charging the battery.
6. Do not charge the battery at a rate that causes the electrolyte to spew out.
Most modern battery chargers offer three stage charging: Bulk stage/constant current up to a stated voltage level; acceptance charge, which brings the battery to a fully charged status; then a finishing or float charge, which simply maintains full charge state. Older converters only have small amp charging capacities, like 5 amps. And taper chargers are particularly hard on batteries. Consider adding a timer to a taper charger to minimize damage to battery.
Note: A fourth stage is an equalizing, or "planned overcharge" process. It is beneficial, but it must be done with caution. Need to be present, watching what's happening, and keeping batteries ventilated. Best to slide the batteries out. And always make sure batteries are fully charged before initiating the equalizing charge. Heart Interface has a Technical Note on how to equalize safely which they will send out upon request.
Monitors for battery systems are becoming increasingly popular for rigs with more sophisticated battery systems. Voltage, when charging, is a helpful number. An amp meter tells you what your loads are. "Amp hours consumed" is a more credible way to know what the state of charge of your battery is. It also tells you how much longer you can keep running at the existing draw before your stated capacity will be used up. (But remember to try to stay w/in 50% of stated capacity).
High temperature will greatly diminish battery life.
If you don't recharge every week, eventually the battery will form sulfate crystals which will reduce efficiency. Equalization is a planned overcharge, which drives the accumulated crystals back into the solution. This means each of the six cells will be "boiled" to bring them all into equal status.
- Alternator/generator. Alternator charges both house and starting batteries.
- Shore Power
- Solar panels
- Inverter/charger
Charging is converting electrical energy to chemical energy; discharging is the reverse...converting chemical energy to electrical energy. Voltage (only) is not a reliable indicator of state of charge, unless one watches it for 24 hours.
WARNING
DISCONNECT THE 120-VOLT ELECTRIC CORD AND THE NEGATIVE TERMINAL FROM THE COACH BATTERIES BEFORE WORKING ON EITHER ELECTRICAL SYSTEM.
WARNING
REMOVE RINGS, METAL WATCHBANDS, AND OTHER METAL JEWELRY BEFORE WORKING AROUND A BATTERY. USE CAUTION WHEN USING METAL TOOLS. IF A TOOL CONTACTS A BATTERY TERMINAL OR METAL CONNECTED TO IT, A SHORT CIRCUIT COULD OCCUR WHICH COULD CAUSE PERSONAL INJURY OR FIRE.
WARNING
DO NOT ALLOW BATTERY ELECTROLYTE TO CONTACT SKIN, EYES, FABRICS, OR PAINTED SURFACES. THE ELECTROLYTE IS A SULFURIC ACID SOLUTION THAT COULD CAUSE SERIOUS PERSONAL INJURY OR PROPERTY DAMAGE. WEAR EYE PROTECTION WHEN WORKING WITH BATTERIES.
Check the external condition of the battery periodically. Look for cracks in the cover and case. Check the vent plugs and replace if they are cracked or broken. Keep the battery clean. Accumulations of acid film and dirt may permit current to flow between the terminals and discharge the battery.
To clean the battery, wash it with a diluted solution of baking soda and water to neutralize any acid present, then flush with clean water. Foaming around terminals or on top of the battery is normal acid neutralization. Avoid getting the soda solution in the battery. Be sure the vent caps are tight. Dry the cables and terminals. Don't use grease on the bare metal inside the cable terminals to prevent corrosion. Grease is an insulator. Electricity will not flow through it. A plastic ignition spray will protect the terminals after you have cleaned and reinstalled them.
Check the battery, including water level, often. Keep the carrier and hold down hardware clean and free of corrosion and chemical accumulation.
Selecting A Replacement Battery
When the battery requires replacement, always choose a battery with the same physical and electrical characteristics as the original equipment.
This system provides grounded electrical service for appliances such as air conditioners, TV, microwave
, ovens, etc. The 120-volt system also provides a power, source for the converter.Your motor home is equipped with a heavy duty power cord to connect to an external 120-volt, 30 amp service. The cord and connector are molded together to form a weatherproof cable assembly. Do not cut or the cable in any way. Do not remove the ground pin cable connector, or defeat the ground circuit in the home.
WARNING
DO NOT OPERATE THE 120-VOLT ELECTRICAL SYSTEM WITHOUT A PROPER GROUND. ELECTROCUTION OR SEVER ELECTRICAL SHOCK COULD RESULT.
Please read our Electrical page for more information.
NOTE: This online manual is a work in progress and is subject to change at any given time. It is also a generic peace of work and is meant only as a general guide. Each Caravan/RV is distinct and individual in it's own right, do not take anything written here literally as it may or may not apply to the exact Caravan/RV you will be using.