Battery isolation Necessary?
Battery isolation Necessary?
Is adding a battery isolater necessary i've never found them usefull, however i know exactly what they do. Im about to add a second battery and wondering if you really need it, i think its one of those products they just try to sell you as a item you NEED for a dual battery setup. Btw this is just my personal opinion. I've installed 2 batteries in multiple cars and never used it and never had a problem im just curios to see some info on these isolatrs which i don think you really need.
AN INTRODUCTION TO AUTOMOTIVE BATTERIES
An automotive battery is an electricity storage device. It produces DC (direct current) current for operation of the car’s starter and electronic accessories. A battery is an electrochemical device, meaning that it uses a chemical reaction to store or release electrical energy. This is in the same manner as that of an alternator being an electromechanical device, because it uses a mechanical motion to create an electric current.
Batteries do not create an indefinite source of electricity. A battery can only store electricity. They must be recharged by an outside source. This is the purpose of the alternator. It charges the battery between starting and using accessories while the engine is running. When the car’s engine and accessories do not require the full output of the alternator, a portion of its output is taken by the battery to recharge it. Once the battery is fully charged to 12.6 volts, it requires less power from the alternator. This system of discharging and charging is called a cycle. If a battery is drained until it is nearly dead, the charging process completes what is called a deep cycle. Most automotive batteries are not capable of deep cycling and typically cannot handle this type of use more than once or twice. Repeated deep cycling of a battery will result in the battery’s inability to hold a charge for a long period of time, causing the battery to be dead by morning, or when you come out of a store or restaurant. Special batteries have been designed to handle this use, and are available from most audio store and parts stores. They are typically more expensive, and usually do not have the cranking power for starting. This is changing now, with batteries such as the Optima Yellow Top and Optima Blue Top. These batteries are designed for starting/deep cycling applications. Many other manufacturers produce a starting/deep cycle battery, but those two are the most popular brands.
WHAT BATTERY DO I NEED?
To understand what battery you need for your application, you will need to know a few things. First of all, will you be using this battery for starting or accessories or both? If you only need it for starting purposes, you will need to match the batteries Cranking Amps and Cold Cranking Amps with the specific needs for your car. You can do this by getting a battery that meets or exceeds the rating of your existing battery. If you want a second battery for accessories that will be run with the car off, you want to get a deep cycle battery with a significant Reserve Capacity. The battery’s Reserve Capacity tells you how long the battery can supply a 10 amp current before falling to 10.7 volts while at 80 degrees Fahrenheit. To do both starting and accessories, you will need a deep cycle battery with significant Cranking power and reserve time. You will need enough power to start your car, and some time to run your stereo or other accessories. You could still be stuck with a dead battery, but you may have a longer time to wait to start your car, and better battery life in this application. This is acceptable for short draws or low amperage applications. You won’t run a pair of 1500 watt amplifiers for very long at full volume and still start the car, but you could play the radio alone for quite some time, upwards of two hours for some batteries, and depending on the radio’s current draw and what other accessories may be on at the time.
I WANT TO PLAY MY SYSTEM WITH THE CAR OFF FOR A LONG TIME
If you want to run a large system with a high current draw while the car is off, you’ll need to add a second battery that is isolated from the main starting battery. By isolated, I mean only when the car is not running. This prevents two things. First, it prevents whatever you are running from draining your starting battery. If your starting battery is dead, you’ve done no good by adding a second battery. All you did was play your system longer before you car could no longer start. Second, you need to prevent the two batteries from draining each other. That’s right. Even two IDENTICAL brand, model and rating batteries will slowly drain each other dead over a period of time. This may be a week or overnight depending on the condition of the batteries, or how closely matched they are. This would be quite damaging to the batteries. You could totally drain your starting battery and your deep cycle, but now the starting battery will dissipate its charge more quickly and will drain your deep cycles faster with it. This draining of two batteries by each other is due to the slight electrical difference in each circuit. The internal resistance of each battery may be different, its capable charging voltage may be different, many other things can allow this. But what prevent these two scenarios from playing out?
A DUAL BATTERY ISOLATOR
A dual battery isolator is either an electronic, electrical or electromechanical device that separates the positive terminals of two batteries that share a charging system when the batteries are NOT being charged. The isolator is switched either by the car’s ignition switch, or by internal circuits in the isolator that detect the line voltage and can open or close the circuit. There are MANY different types of isolators. Just go to www.yahoo.com and search for “dual battery isolator” and look through the different companies you find. You’ll see every different types of isolators that are suitable for your needs. I won’t go into individual design of all the types but I will describe, briefly, the 3 major systems for preventing the draining of both batteries by the same current draw.
Diode isolators use a group of diodes to resist current flow in one direction. Since you’ll remember that your car battery stores DC, you’ll know that the power can flow only one way, but, this flow can be from one positive to another. This means that the power would flow out of one battery, and into the other. The diode isolator splits the positive wire from the alternator and runs the power through 2 groups of high amperage diodes to direct the charging voltage to each battery. When the charging system is not running (the engine is off), the diodes prevent power from flowing away from the positive terminal of either battery. There is no switching system or moving parts to this isolator, but it is typically very susceptible to power surges that can damage the diodes and can be limiting in the maximum amount of current available for charging and running accessories with the engine on.
A solenoid isolator operates much like the starter solenoid on your starter. It is similar to a relay, but is designed to carry a significantly higher amount of current, and for longer periods of time. This type of isolator is not as limiting in its current capability, but it has moving parts and requires that you connect a control wire to the car’s ignition circuits so the solenoid only closes when you are in the run position on the ignition switch. This unit can only be switched so many times and will eventually fail from continued use.
The third type of isolator is the electronic isolator. These units may use semi-conductors or internal relays like a remote starting system. They use internal electronic circuits to detect a charging voltage greater than 13 volts. When this voltage, higher than the voltage on a charged battery, is detected, the isolator will allow the circuit to close and the second battery to charge.
For all three types of isolator, you still use the battery your accessories are connected to for engine-off power. You batteries still charge from the alternator, and you accessories still receive power from the alternator when the car is running. This is an ideal configuration for your car’s electrical system. A second battery, paired with a proper isolator, a strong starting battery and high output alternator is a excellent foundation for any system. You’ll be able to reach maximum output while running your engine, and play your system for a long period of time with the engine off. Additionally, if you ever leave you headlights on, you can typically turn the key to run for a few moments and get the car started, or simply connect a jumper cable from the lead to the second battery and the starting batteries positive and get started that way
An automotive battery is an electricity storage device. It produces DC (direct current) current for operation of the car’s starter and electronic accessories. A battery is an electrochemical device, meaning that it uses a chemical reaction to store or release electrical energy. This is in the same manner as that of an alternator being an electromechanical device, because it uses a mechanical motion to create an electric current.
Batteries do not create an indefinite source of electricity. A battery can only store electricity. They must be recharged by an outside source. This is the purpose of the alternator. It charges the battery between starting and using accessories while the engine is running. When the car’s engine and accessories do not require the full output of the alternator, a portion of its output is taken by the battery to recharge it. Once the battery is fully charged to 12.6 volts, it requires less power from the alternator. This system of discharging and charging is called a cycle. If a battery is drained until it is nearly dead, the charging process completes what is called a deep cycle. Most automotive batteries are not capable of deep cycling and typically cannot handle this type of use more than once or twice. Repeated deep cycling of a battery will result in the battery’s inability to hold a charge for a long period of time, causing the battery to be dead by morning, or when you come out of a store or restaurant. Special batteries have been designed to handle this use, and are available from most audio store and parts stores. They are typically more expensive, and usually do not have the cranking power for starting. This is changing now, with batteries such as the Optima Yellow Top and Optima Blue Top. These batteries are designed for starting/deep cycling applications. Many other manufacturers produce a starting/deep cycle battery, but those two are the most popular brands.
WHAT BATTERY DO I NEED?
To understand what battery you need for your application, you will need to know a few things. First of all, will you be using this battery for starting or accessories or both? If you only need it for starting purposes, you will need to match the batteries Cranking Amps and Cold Cranking Amps with the specific needs for your car. You can do this by getting a battery that meets or exceeds the rating of your existing battery. If you want a second battery for accessories that will be run with the car off, you want to get a deep cycle battery with a significant Reserve Capacity. The battery’s Reserve Capacity tells you how long the battery can supply a 10 amp current before falling to 10.7 volts while at 80 degrees Fahrenheit. To do both starting and accessories, you will need a deep cycle battery with significant Cranking power and reserve time. You will need enough power to start your car, and some time to run your stereo or other accessories. You could still be stuck with a dead battery, but you may have a longer time to wait to start your car, and better battery life in this application. This is acceptable for short draws or low amperage applications. You won’t run a pair of 1500 watt amplifiers for very long at full volume and still start the car, but you could play the radio alone for quite some time, upwards of two hours for some batteries, and depending on the radio’s current draw and what other accessories may be on at the time.
I WANT TO PLAY MY SYSTEM WITH THE CAR OFF FOR A LONG TIME
If you want to run a large system with a high current draw while the car is off, you’ll need to add a second battery that is isolated from the main starting battery. By isolated, I mean only when the car is not running. This prevents two things. First, it prevents whatever you are running from draining your starting battery. If your starting battery is dead, you’ve done no good by adding a second battery. All you did was play your system longer before you car could no longer start. Second, you need to prevent the two batteries from draining each other. That’s right. Even two IDENTICAL brand, model and rating batteries will slowly drain each other dead over a period of time. This may be a week or overnight depending on the condition of the batteries, or how closely matched they are. This would be quite damaging to the batteries. You could totally drain your starting battery and your deep cycle, but now the starting battery will dissipate its charge more quickly and will drain your deep cycles faster with it. This draining of two batteries by each other is due to the slight electrical difference in each circuit. The internal resistance of each battery may be different, its capable charging voltage may be different, many other things can allow this. But what prevent these two scenarios from playing out?
A DUAL BATTERY ISOLATOR
A dual battery isolator is either an electronic, electrical or electromechanical device that separates the positive terminals of two batteries that share a charging system when the batteries are NOT being charged. The isolator is switched either by the car’s ignition switch, or by internal circuits in the isolator that detect the line voltage and can open or close the circuit. There are MANY different types of isolators. Just go to www.yahoo.com and search for “dual battery isolator” and look through the different companies you find. You’ll see every different types of isolators that are suitable for your needs. I won’t go into individual design of all the types but I will describe, briefly, the 3 major systems for preventing the draining of both batteries by the same current draw.
Diode isolators use a group of diodes to resist current flow in one direction. Since you’ll remember that your car battery stores DC, you’ll know that the power can flow only one way, but, this flow can be from one positive to another. This means that the power would flow out of one battery, and into the other. The diode isolator splits the positive wire from the alternator and runs the power through 2 groups of high amperage diodes to direct the charging voltage to each battery. When the charging system is not running (the engine is off), the diodes prevent power from flowing away from the positive terminal of either battery. There is no switching system or moving parts to this isolator, but it is typically very susceptible to power surges that can damage the diodes and can be limiting in the maximum amount of current available for charging and running accessories with the engine on.
A solenoid isolator operates much like the starter solenoid on your starter. It is similar to a relay, but is designed to carry a significantly higher amount of current, and for longer periods of time. This type of isolator is not as limiting in its current capability, but it has moving parts and requires that you connect a control wire to the car’s ignition circuits so the solenoid only closes when you are in the run position on the ignition switch. This unit can only be switched so many times and will eventually fail from continued use.
The third type of isolator is the electronic isolator. These units may use semi-conductors or internal relays like a remote starting system. They use internal electronic circuits to detect a charging voltage greater than 13 volts. When this voltage, higher than the voltage on a charged battery, is detected, the isolator will allow the circuit to close and the second battery to charge.
For all three types of isolator, you still use the battery your accessories are connected to for engine-off power. You batteries still charge from the alternator, and you accessories still receive power from the alternator when the car is running. This is an ideal configuration for your car’s electrical system. A second battery, paired with a proper isolator, a strong starting battery and high output alternator is a excellent foundation for any system. You’ll be able to reach maximum output while running your engine, and play your system for a long period of time with the engine off. Additionally, if you ever leave you headlights on, you can typically turn the key to run for a few moments and get the car started, or simply connect a jumper cable from the lead to the second battery and the starting batteries positive and get started that way
HOW TO INSTALL A SECOND BATTERY.
Before you start any project, you need to decide what tools and materials you need. This will depend on what you have done already. Have you done The Big 3? Do you have a High Output Alternator? Or have you done nothing else at this time?
Typical Tools Needed:
-Large gauge wire cutters
-Standard wire cutters/strippers
-Assorted flat and phillips screwdrivers
-Pliers
-A vice or large vice-grips
-1/4" and 3/8" Drive socket sets
-Battery terminal cleaning brush
-Battery terminal puller(for top post only)
-Assorted wrenches
-Drill with drill bits and wire brush
-3/4" metal hole saw or paddle bit
-Digital multimeter
Typical Materials Needed
-"x" feet of large gauge wire for power
-"x" feet of large gauge wire for grounds at the new battery and isolator (if required)
-3 to 7 ring terminals for above wire, dictated by your termianls, isolator and installation needs
-"x" feet of black plastic wire protector
-Zip ties
-Electrical tape
-"x" gauge wire grommets for passing through metal
-Positive battery terminal with enough points for stock wires plus all added wires
-Positive battery terminal with enough points for charging wire plus amp power wires
-Negative battery terminal with enough points for battery ground and amplifier grounds
-18 gauge wire for islator control
-Small ring terminal for 18 gauge wire
-Machiene screw to attach battery ground if none is available near battery location
-*Battery enclosure with vent tubes if battery is to be in trunk, hatch or ext. cab area (can be home made or have a window for viewing)
-And of course a second battery (deep cycle)
*This applies to ALL conventional automotive batteries. Even "sealed" batteries are vented in some way to release the gasses created by the discharge/charge cycle. This gas is toxic, corrosive and flamable and must be released outside the vehicle.
This set of instructions is just for the installation of the battery itself. Hooking up the amps is the same as when running to the main battery, but the wires are shorter and the ground can go directly back to the battery.
To start with, disconnet your ground to the main battery to prevent sparks and damage to electrical components.
Next, install the main charging wire like you would for any amplifier installation. This wire should be rated to handle at LEAST the maximum rated current draw of all your amplifiers or accesories you intend to run off the second battery. This wire will carry power to charge the rear battery and operate all your accesories when the engine is running. After the wire is through the firewall, leave some slack in the engine compartment and wait to run the wire to the trunk or wherever the battery is to be installed.
Next, fuse the main wire within 18 inches of the battery. This will protect the wire from a short drawing excessive current from the orriginal battery. Fuse above the total accesory current draw, but no more than the wires rated ampacity.
You can skp the above steps if you already have a suitable wire run from a previous installation.
Find a sutable location near the main battery for the isolator. The isolator needs to be securely mounted to the inner fender or firewall, away from the exhaust or anywhere fluids may be spilled when refilling them.
Route the wire to the isolator and cut it so there is some slack between the isolator and the main battery. Install a ring terminal on both ends of the wire at the isolator.
If your isolator has only 2 power terminals, connect the wire from the main battery to the input terminal and the wire to the rear of the car to the output terminal. If you have three terminals on your isolator, connect the wire from the main battery to the input terminal and connect the wire to the rear of the car to the terminal for the auxilary or isolated battery.
Connect a control wire, if required by your isolator, to a wire that is only hot when the car's ignition switch is in the RUN mode. This will isolate the batteries anytime the engine is not running, preventing you from draining your main starting battery and keeping the batteries from draining each other when the car is sitting.
Now, continue to run your main charging wire to the area where the battery will be. Keep it away from RCA wires to prevent noise in your system, if one is already installed.
Once your wire is where you need it, test fit your battery enclosure to decide where to drill holes for your vent tubes. Mark and drill your holes with a hole saw or paddle bit large enough to allow the vent tubes to slide easily through (typically between 1/2 and 3/4 of an inch) and feed them through. Use silicone to seal around the tube so exhaust and battery fumes don't get pulled back into the car.
Secure the battery enclosure to the car and place the battery inside. Estimate where to cut your power wire, guess an inch or so long to allow for slack. Yon can leave the wire long if you feel it will be necessary for some upcoming changes.
Install a second fuse in the charge wire within 18 inches of the second battery. This will prevent a short from pulling excessive current from the second battery. This IS necessary even with the fuse at the front.
Now, find a suitable grounding point for the new battery, drill any necessary holes and use the a drill with a wire brush to remove all paint and primer from the area. Make a ground wire long enough to reach that ground from the battery. Use a ring terminal to attach at the chassis. Bolt it down securely, but don't strip out your hole.
Now, connect your charge wire to your battery terminals at the main and secondary batterys and hook the terminals to the batteries. Connect any amplifier power wires at this time also if you wish.
Next, connect the gound wire to the battery terminal for the secondary battery, along with any amp wires if you wish. Once all the wires are connected to the terminal, connect the terminal to the battery and secure the battery to the enclosure with the hold down bracket or strap. Place the cover for your enclosure on and secure it.
Reconnect your main battery's ground wire and make any ground wires needed for your isolator, hook them up. Clean up your tools. Install the fuse at the front of the charge wire, under the hood. Use a meter to check for voltage on the wire going to the trunk, you should get 0v with the key off or in accesory and 12v with the key in the run position. Install the fuse in the charge wire at the rear of the car.
Now you are ready to go out on the town, playing your system or running your accesories as much as your rear battery can handle. If it goes dead, start the car and charge it up. You'll never have a dead battery because you played your stereo too long again. Enjoy and good luck.
Before you start any project, you need to decide what tools and materials you need. This will depend on what you have done already. Have you done The Big 3? Do you have a High Output Alternator? Or have you done nothing else at this time?
Typical Tools Needed:
-Large gauge wire cutters
-Standard wire cutters/strippers
-Assorted flat and phillips screwdrivers
-Pliers
-A vice or large vice-grips
-1/4" and 3/8" Drive socket sets
-Battery terminal cleaning brush
-Battery terminal puller(for top post only)
-Assorted wrenches
-Drill with drill bits and wire brush
-3/4" metal hole saw or paddle bit
-Digital multimeter
Typical Materials Needed
-"x" feet of large gauge wire for power
-"x" feet of large gauge wire for grounds at the new battery and isolator (if required)
-3 to 7 ring terminals for above wire, dictated by your termianls, isolator and installation needs
-"x" feet of black plastic wire protector
-Zip ties
-Electrical tape
-"x" gauge wire grommets for passing through metal
-Positive battery terminal with enough points for stock wires plus all added wires
-Positive battery terminal with enough points for charging wire plus amp power wires
-Negative battery terminal with enough points for battery ground and amplifier grounds
-18 gauge wire for islator control
-Small ring terminal for 18 gauge wire
-Machiene screw to attach battery ground if none is available near battery location
-*Battery enclosure with vent tubes if battery is to be in trunk, hatch or ext. cab area (can be home made or have a window for viewing)
-And of course a second battery (deep cycle)
*This applies to ALL conventional automotive batteries. Even "sealed" batteries are vented in some way to release the gasses created by the discharge/charge cycle. This gas is toxic, corrosive and flamable and must be released outside the vehicle.
This set of instructions is just for the installation of the battery itself. Hooking up the amps is the same as when running to the main battery, but the wires are shorter and the ground can go directly back to the battery.
To start with, disconnet your ground to the main battery to prevent sparks and damage to electrical components.
Next, install the main charging wire like you would for any amplifier installation. This wire should be rated to handle at LEAST the maximum rated current draw of all your amplifiers or accesories you intend to run off the second battery. This wire will carry power to charge the rear battery and operate all your accesories when the engine is running. After the wire is through the firewall, leave some slack in the engine compartment and wait to run the wire to the trunk or wherever the battery is to be installed.
Next, fuse the main wire within 18 inches of the battery. This will protect the wire from a short drawing excessive current from the orriginal battery. Fuse above the total accesory current draw, but no more than the wires rated ampacity.
You can skp the above steps if you already have a suitable wire run from a previous installation.
Find a sutable location near the main battery for the isolator. The isolator needs to be securely mounted to the inner fender or firewall, away from the exhaust or anywhere fluids may be spilled when refilling them.
Route the wire to the isolator and cut it so there is some slack between the isolator and the main battery. Install a ring terminal on both ends of the wire at the isolator.
If your isolator has only 2 power terminals, connect the wire from the main battery to the input terminal and the wire to the rear of the car to the output terminal. If you have three terminals on your isolator, connect the wire from the main battery to the input terminal and connect the wire to the rear of the car to the terminal for the auxilary or isolated battery.
Connect a control wire, if required by your isolator, to a wire that is only hot when the car's ignition switch is in the RUN mode. This will isolate the batteries anytime the engine is not running, preventing you from draining your main starting battery and keeping the batteries from draining each other when the car is sitting.
Now, continue to run your main charging wire to the area where the battery will be. Keep it away from RCA wires to prevent noise in your system, if one is already installed.
Once your wire is where you need it, test fit your battery enclosure to decide where to drill holes for your vent tubes. Mark and drill your holes with a hole saw or paddle bit large enough to allow the vent tubes to slide easily through (typically between 1/2 and 3/4 of an inch) and feed them through. Use silicone to seal around the tube so exhaust and battery fumes don't get pulled back into the car.
Secure the battery enclosure to the car and place the battery inside. Estimate where to cut your power wire, guess an inch or so long to allow for slack. Yon can leave the wire long if you feel it will be necessary for some upcoming changes.
Install a second fuse in the charge wire within 18 inches of the second battery. This will prevent a short from pulling excessive current from the second battery. This IS necessary even with the fuse at the front.
Now, find a suitable grounding point for the new battery, drill any necessary holes and use the a drill with a wire brush to remove all paint and primer from the area. Make a ground wire long enough to reach that ground from the battery. Use a ring terminal to attach at the chassis. Bolt it down securely, but don't strip out your hole.
Now, connect your charge wire to your battery terminals at the main and secondary batterys and hook the terminals to the batteries. Connect any amplifier power wires at this time also if you wish.
Next, connect the gound wire to the battery terminal for the secondary battery, along with any amp wires if you wish. Once all the wires are connected to the terminal, connect the terminal to the battery and secure the battery to the enclosure with the hold down bracket or strap. Place the cover for your enclosure on and secure it.
Reconnect your main battery's ground wire and make any ground wires needed for your isolator, hook them up. Clean up your tools. Install the fuse at the front of the charge wire, under the hood. Use a meter to check for voltage on the wire going to the trunk, you should get 0v with the key off or in accesory and 12v with the key in the run position. Install the fuse in the charge wire at the rear of the car.
Now you are ready to go out on the town, playing your system or running your accesories as much as your rear battery can handle. If it goes dead, start the car and charge it up. You'll never have a dead battery because you played your stereo too long again. Enjoy and good luck.
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