Repeater-Builder Backup and Alternative Power Information Index

Back to Home Main, Backup and Alternative Power Projects, Articles and Reference Material
Maintained by Robert Meister WA1MIK
and by Mike Morris WA6ILQ

The information presented on this web page is copyrighted by the original author / provider (i.e. APC, Falcon Electric, the ARRL (QST)). Other information is copyright by repeater-builder.com (the author's copyright, if any, supercedes it).

This page contains articles related to alternative and backup power systems, such as Uninterruptable Power Supplies (UPSes), Battery Backups (BB), Photo-Voltaic (PV), and other sources of energy besides the regular commercial (mains) power.

Repeater-Builder welcomes comments and articles about implementation and modification of such systems. Just drop an email to the web page maintainer.

Background Information:

AC Power Information - Safety Issues when dealing with commercial AC power by Mike Morris WA6ILQ
This is here just because Backup and alternative power systems run at high voltage levels. This article covers several safety topics, like "the black wire can kill you".

Some Thoughts on Off-The-Grid (Solar, Micro-Hydro or Wind Powered) Repeater Systems by Mike Morris WA6ILQ
Another web page by WA6ILQ... just some random thoughts, not a really polished article. Several relevant topics are covered.

A chart of non-locking electrical connectors used in the USA 480 kB PDF; published by Qualtek
NEMA is organization that designs the connectors, and yes, there is a good reason for each one.

A chart of locking (twist-lock) electrical connectors used in the USA 590 kB PDF; published by Qualtek
Yet another NEMA connector chart... this one covers the twist-lock connectors.

NEMA, IEC, and International power connectors and cable information can be found here. Click on Product Resources.

12V 18AH battery datasheet 1.4 MB PDF; published by Power-Sonic/Panasonic
In all my years of buying UPS batteries, I've never gotten a datasheet with them. And who pays list price these days? Not me. The "Charging" section on page 2 is worth reading if you want to maximize battery life. Don't just install them in the UPS.
12V 7AH battery datasheet 453 KB PDF; published by Power-Sonic/Panasonic

Motorola HLN9455A Battery Revert Kit (option) 1.63 MB PDF
This is here because the manual for the optional battery revert kit for their tabletop repeaters (like what you would find in a high school or a shopping mall) has a very good section on sizing your backup battery.
More comments on the Revert Kit are about 1/3 of the way down on this page.

UPS-related Information:

UPS Technologies An explanation of the major UPS technologies, common power problems, and information about choosing the right unit to solve them. Summarized from information on the web.

Testing the switching time of UPS units By Robert W. Meister WA1MIK
Some units switch from mains power to the inverter faster than others. The author ran some tests and captured some waveforms from a couple of common UPS models.

Modifying an APC SU1000 for extended run-time By Robert W. Meister WA1MIK
The run-time of a UPS is directly related to the battery capacity (amp-hours). It's relatively easy to install larger batteries in a lot of the different APC units (a SU1000 model is shown). This article shows you how to do it.

Falcon Electric, Inc's explanation of various standby and UPS power systems Offsite link to their article (opens in a new window).

The SBS and UPS tutorial 242 kB PDF file from Falcon Electric
Great explanation of the various technologies.

On-Line UPS Block Diagram 206 kB PDF file (from Liebert's GXT2 On-line UPS Owner's Manual)
Probably typical of the true on-line units.

APC Corp Application Note #12, The APC Computer Interface Port 140 kB PDF
"This application note provides technical information regarding APC UPS computer interface ports. This information is for customers attempting to use the port for unsupported purposes."
Note that this is for the older units that have a female DE-9 connector on the back. With the information from this applications note you can interface digital inputs on your repeater controller and detect the presence of AC power, etc.

Generators and UPS Compatibility Technical information from Cummins. 550 kB PDF file.
This white paper discusses problems that can be encountered in operating UPS equipment on generator sets, explains the reasons behind some problems, and identifies steps that can be taken to minimize compatibility problems between generator sets and UPS equipment.
Note from the page maintainer: A number of the home-computer-grade small UPS units will NOT return to line-power mode when being fed by a generator unless the line power is a sine wave of exactly 60 Hertz. This frequency sensitivity can be a problem on small residential standby generators.

Alternative Power-related Articles and Information:

Exercise those backup batteries regularly by George Odom K4ETN
Periodically disconnect AC power to exercise your battery backup systems.

Solar Power for Your Ham Station A reprint of an article from QST April 1996. 186 kB PDF file.

Solar Charge Controller A build-your-own article from Home Power Magazine, Issue #63 (Feb/Mar 1998). 330 kB PDF file.

Storage Battery Maintenance and Principles A reprint of an article published by the Department of the Interior, Bureau of Reclamation, December 1997. 1.2MB PDF file.

Practical Battery Back-Up for Amateur Radio Stations - Part 1 from QST March 1990, by George Thurston W4MLE (SK) 1.16 MB PDF
Despite it being over 20 years old this three-part article is well worth reading for the background info and overall theory.
There is a download link below where you can get all three parts as one file.

Practical Battery Back-Up for Amateur Radio Stations - Part 2 from QST April 1990. 1.5 MB PDF file.

Practical Battery Back-Up for Amateur Radio Stations - Part 3 from QST May 1990. 1.0 MB PDF file.

Practical Battery Back-Up for Amateur Radio Stations - all three parts as a single file from QST for March, April and May 1990. 3.7 MB PDF file.

Low-Voltage Battery Disconnect Another build-your-own article from Home Power Magazine, Issue #60 (Aug/Sep 1997). 200 kB PDF file.

A Battery Voltage Monitor By Ronald Varner WB3CEH from QST for October 1998 673 kB PDF
A simple 1-chip circuit with an adjustable threshold.

A Latching Low Voltage Disconnect By Sam Ulbing, N4UAU from QST for June 1999 183 kB PDF
The latching circuit in ths article is attractive since the circuit in the Varner article above has a flaw: no hysteresis. Every time the low voltage disconnect triggered it disconnects the load, then the battery voltage rises and the circuit would reconnect the load. Depending on the battery capacity, the battery state of charge, the draw of the load, etc. the above disconnect circuit switches the load on and off at a rate of 1 to 2 cycles per minute.

Sealed Lead Acid Battery Charger by Luke Enriquez VK3EM.

An Automatic Sealed-Lead-Acid Battery Charger By Bob Lewis AA4PB from QST for May 2001 136 kB PDF
This is a clever little charger that not only charges your batteries, but can keep them on trickle charge safely.

The Micro M+ Charge Controller By Mike Bryce WB8VGE 289 kB PDF
This unit is an excellent small (4 Amps max) solar panel charge controller for charging gel cells or just about any lead acid battery. It has a standby current of under 1 mA.

The 12-volt Pup By Yaniko Palis VE2NYP from QST for June 1970 385 kB PDF

A 12V dc Boost Regulator for Battery Operation By Daniel Kemppainen N8XJK from QST for November 2004 610 kB PDF

Those NiCad Batteries and How to Charge Them By David W. Potter W2GZD from QST for October 1981 162 kB PDF
NiCads have fallen out of favor but it's worth reading to see where we've been.

High efficiency lead-acid battery charger using power components By Vicor Corporation 131 kB PDF

Ni-MH Battery Handbook By Panasonic Corporation 3.7 MB PDF

Reader comments about batteries Compiled by Mike Morris WA6ILQ
Discussions on various battery technologies and a few war stories.

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This page originally posted 23-Dec-2007.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.

	AC Power Information - Safety Issues when dealing with commercial AC power by Mike Morris WA6ILQ This is here just because Backup and alternative power systems run at high voltage levels. This article covers several safety topics, like "the black wire can kill you".
	Some Thoughts on Off-The-Grid (Solar, Micro-Hydro or Wind Powered) Repeater Systems by Mike Morris WA6ILQ Another web page by WA6ILQ... just some random thoughts, not a really polished article. Several relevant topics are covered.
	A chart of non-locking electrical connectors used in the USA 480 kB PDF; published by Qualtek NEMA is organization that designs the connectors, and yes, there is a good reason for each one.
	A chart of locking (twist-lock) electrical connectors used in the USA 590 kB PDF; published by Qualtek Yet another NEMA connector chart... this one covers the twist-lock connectors.
	NEMA, IEC, and International power connectors and cable information can be found here. Click on Product Resources.
	12V 18AH battery datasheet 1.4 MB PDF; published by Power-Sonic/Panasonic In all my years of buying UPS batteries, I've never gotten a datasheet with them. And who pays list price these days? Not me. The "Charging" section on page 2 is worth reading if you want to maximize battery life. Don't just install them in the UPS. 12V 7AH battery datasheet 453 KB PDF; published by Power-Sonic/Panasonic
	Motorola HLN9455A Battery Revert Kit (option) 1.63 MB PDF This is here because the manual for the optional battery revert kit for their tabletop repeaters (like what you would find in a high school or a shopping mall) has a very good section on sizing your backup battery. More comments on the Revert Kit are about 1/3 of the way down on this page.

	UPS Technologies An explanation of the major UPS technologies, common power problems, and information about choosing the right unit to solve them. Summarized from information on the web.
	Testing the switching time of UPS units By Robert W. Meister WA1MIK Some units switch from mains power to the inverter faster than others. The author ran some tests and captured some waveforms from a couple of common UPS models.
	Modifying an APC SU1000 for extended run-time By Robert W. Meister WA1MIK The run-time of a UPS is directly related to the battery capacity (amp-hours). It's relatively easy to install larger batteries in a lot of the different APC units (a SU1000 model is shown). This article shows you how to do it.
	Falcon Electric, Inc's explanation of various standby and UPS power systems Offsite link to their article (opens in a new window).
	The SBS and UPS tutorial 242 kB PDF file from Falcon Electric Great explanation of the various technologies.
	On-Line UPS Block Diagram 206 kB PDF file (from Liebert's GXT2 On-line UPS Owner's Manual) Probably typical of the true on-line units.
	APC Corp Application Note #12, The APC Computer Interface Port 140 kB PDF "This application note provides technical information regarding APC UPS computer interface ports. This information is for customers attempting to use the port for unsupported purposes." Note that this is for the older units that have a female DE-9 connector on the back. With the information from this applications note you can interface digital inputs on your repeater controller and detect the presence of AC power, etc.
	Generators and UPS Compatibility Technical information from Cummins. 550 kB PDF file. This white paper discusses problems that can be encountered in operating UPS equipment on generator sets, explains the reasons behind some problems, and identifies steps that can be taken to minimize compatibility problems between generator sets and UPS equipment. Note from the page maintainer: A number of the home-computer-grade small UPS units will NOT return to line-power mode when being fed by a generator unless the line power is a sine wave of exactly 60 Hertz. This frequency sensitivity can be a problem on small residential standby generators.

	Exercise those backup batteries regularly by George Odom K4ETN Periodically disconnect AC power to exercise your battery backup systems.
	Solar Power for Your Ham Station A reprint of an article from QST April 1996. 186 kB PDF file.
	Solar Charge Controller A build-your-own article from Home Power Magazine, Issue #63 (Feb/Mar 1998). 330 kB PDF file.
	Storage Battery Maintenance and Principles A reprint of an article published by the Department of the Interior, Bureau of Reclamation, December 1997. 1.2MB PDF file.
	Practical Battery Back-Up for Amateur Radio Stations - Part 1 from QST March 1990, by George Thurston W4MLE (SK) 1.16 MB PDF Despite it being over 20 years old this three-part article is well worth reading for the background info and overall theory. There is a download link below where you can get all three parts as one file.
	Practical Battery Back-Up for Amateur Radio Stations - Part 2 from QST April 1990. 1.5 MB PDF file.
	Practical Battery Back-Up for Amateur Radio Stations - Part 3 from QST May 1990. 1.0 MB PDF file.
	Practical Battery Back-Up for Amateur Radio Stations - all three parts as a single file from QST for March, April and May 1990. 3.7 MB PDF file.
	Low-Voltage Battery Disconnect Another build-your-own article from Home Power Magazine, Issue #60 (Aug/Sep 1997). 200 kB PDF file.
	A Battery Voltage Monitor By Ronald Varner WB3CEH from QST for October 1998 673 kB PDF A simple 1-chip circuit with an adjustable threshold.
	A Latching Low Voltage Disconnect By Sam Ulbing, N4UAU from QST for June 1999 183 kB PDF The latching circuit in ths article is attractive since the circuit in the Varner article above has a flaw: no hysteresis. Every time the low voltage disconnect triggered it disconnects the load, then the battery voltage rises and the circuit would reconnect the load. Depending on the battery capacity, the battery state of charge, the draw of the load, etc. the above disconnect circuit switches the load on and off at a rate of 1 to 2 cycles per minute.
	Sealed Lead Acid Battery Charger by Luke Enriquez VK3EM.
	An Automatic Sealed-Lead-Acid Battery Charger By Bob Lewis AA4PB from QST for May 2001 136 kB PDF This is a clever little charger that not only charges your batteries, but can keep them on trickle charge safely.
	The Micro M+ Charge Controller By Mike Bryce WB8VGE 289 kB PDF This unit is an excellent small (4 Amps max) solar panel charge controller for charging gel cells or just about any lead acid battery. It has a standby current of under 1 mA.
	The 12-volt Pup By Yaniko Palis VE2NYP from QST for June 1970 385 kB PDF
	A 12V dc Boost Regulator for Battery Operation By Daniel Kemppainen N8XJK from QST for November 2004 610 kB PDF
	Those NiCad Batteries and How to Charge Them By David W. Potter W2GZD from QST for October 1981 162 kB PDF NiCads have fallen out of favor but it's worth reading to see where we've been.
	High efficiency lead-acid battery charger using power components By Vicor Corporation 131 kB PDF
	Ni-MH Battery Handbook By Panasonic Corporation 3.7 MB PDF
	Reader comments about batteries Compiled by Mike Morris WA6ILQ Discussions on various battery technologies and a few war stories.