Troubleshooting

MAGNALOCKS

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

TOUCH SENSE BARS

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

SHEAR ALIGNING MAGNALOCK

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

BPS SERIES POWER SUPPLIES

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

DK SERIES KEYPADS

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

DIGITAL ENTRY SYSTEMS

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

EXIT CONTROL/PUSH BUTTONS - CABINET LOCKS - LATCH/BOLT MONITORS - MAGNALOCKS - EXIT DELAY - KEYSWITCHES - LOCK CONTROL PANELS

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

MAXIMUM SECURITY SWITCHES - MOTION DETECTOR EXIT PACKAGE - POWER SOURCES

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.

UNLATCH SERIES DOOR STRIKES

I have used the Securitron power supplies on various access control projects. Do you offer anything for our CCTV installations?


Most CCTV installations require 24vac for camera power and Pan & Tilt power. For those requirements we offer the BACS-24-10. It supplies 10 amps of 24vac power. It includes a CCS-8A circuit board with eight individually switched outputs. Each of the eight outputs includes its own automatic circuit breaker. Additional outputs can be added with CCB-8A slave boards.

I have a requirement that states that I must automatically unlock all my doors upon the activation of the fire alarm system. I plan to use a common power supply for my locks, but which Securitron power supply must I use?


Any of the Securitron BPS series power supplies can be interfaced with a fire alarm system. The fire alarm system must provide a relay output for connection to switch the BPS power supply. The fire alarm relay must be able to carry the entire load of the power supply, i.e. if you have a BPS-24-10 then your fire alarm relay must be able to handle 10 amps at 24VDC.

If the main electrical power is lost & the lock power supply goes to battery backup it may create a condition where the locks unlock if main power is not returned before the batteries discharge. Is there anyway to set off an alarm should main power fail?


Yes, we manufacture the PSM - Power Supply Monitor for that very purpose. Available in either 12 or 24 volt versions it will work with any of our BPS power supplies of 2 amp or greater capacity. It also does three checks of the battery pack each day to make sure the batteries are fully charged.

I am configuring my system. The various components when added together are going to draw approximately 830mA at 12VDC. We need to have battery back up. Is the Securitron BPS-12-1 the correct power supply to use with this system?


No, we recommend that you allow 25% for a "Margin of Error" on any of our power supplies. This 25% allows for the current draw of the charging circuit as well as possible extra draw from long cable runs, etc. Therefore, 750mA is the largest load we would recommend for the BPS-12-1. The appropriate supply for your application is the BPS-12-3.

We have configured our system. We intend to use a Securitron BPS series power supply. We now need to figure out the size of our battery back up. What is the best method to calculate this requirement?


In order to calculate your battery requirement you need to know two things. First, what is my total load or current draw, and second how long (maximum length of time) do I need to maintain the load on battery. Add up all of the current draws of the items in your system. For example you might have a system with (2) M62 Magnalocks drawing 125mA each, (2) TSB-3 Touch Sense Bars drawing 25mA each, (2) DK-26 Digital Keypads drawing 190mA each, and (1) DT-7 seven day timer drawing 160mA all at 24vdc. Your total current draw will be 840mA. You would, therefore, need the BPS-24-2 power supply. If you need to back up this supply for four hours then you could use the chart below. The closest rating above 840mA is the 1A line. Go over to the 4 hour back up time and you will see that you would need 8 AH of batteries to maintain this system for four hours. If you use 12vdc batteries then you will need (2) 12v/8 AH batteries wired in series for this 24vdc supply.