18-04-2013, 02:13 PM
ELECTRIC FENCE ENERGIZERS
[attachment=53139]
The effectiveness of any electric fence, whether it's a one wire fence subdividing a pasture or a 9 wire
fence protecting stock from predators, depends on the ability of the fence to deliver an unpleasant shock
to animals that touch it. The ability of a fence to deliver that shock depends on three things:
1. The energizer
2. Grounding
3. The fence design
RELEASING PULSES
An energizer (also called a charger or controller) regulates the flow of electricity in an electric fence. It
stores electrons in a "capacitor" and then releases them in a "pulse." After each pulse the capacitor stores
up electrons for the next pulse. (If you touch an electric fence between pulses you will not get shocked.)
ENOUGH IS ENOUGH
Your fence, regardless of the animal being controlled, does not need more than 5000 volts. Commonly
the best energizers will deliver 4500 to 7000 volts. Energizers are available that produce even higher
voltage. In fact one cheap charger blew my voltmeter off the scale (it reads up to 10,000 volts) and
knocked me on my #%$(@&)! Avoid these cheap high impedance "weed chopper" type chargers.
EFFECTIVE POWER
We can measure the voltage in an electric fence with a voltmeter, but the voltage rating of an energizer
tells you next to nothing about the effective power of the energizer. The "joule" rating is the critical
statistic. Joules measure the total amount of energy released per pulse. Double the joules and you'll
double the shock.
Most U.S. made energizers have very low joule ratings. Generally DC energizers are below 0.08 joules
and AC chargers are below 0.2 joules. Several models of New Zealand style energizers (Gallagher, Pel,
Speedrite, Halman, etc... ) have much higher ratings (over 10.0).
POWER SOURCE
If mainline power is available and dependable, 110 or 220 volt AC (plug it in the wall socket) energizers
are usually most practical for permanent fences. Will they raise your electricity bill? Well, depending on
the size of the unit, they typically draw 2 to 25 watts a day. The operational cost of an energizer drawing
17 watts a day would be about $1.50/month (assuming an electrical rate of $0.12/kilowatt hour).
AC chargers have several advantages over DC (battery powered) energizers:
They require no battery maintenance
They are generally placed in or close to buildings (reducing the risk of vandalism)
Where mainline power is unavailable or unreliable, battery powered energizers are a practical alternative.
Some portable DC energizers can be powered by dry cell batteries. For example, I have a small energizer
I use for short (<1/2 mile) temporary fences that is powered by 6 "D" dry cell batteries. The batteries
need to be replaced about every 3 or 4 weeks. Beware - manufacturer estimates of battery life are usually
optimistic. My energizer claims the batteries will last "up to 6 weeks."
For longer or permanent fences, or for short temporary fences passing through tall wet grass (high
leakage), larger energizers powered by 12 volt rechargeable wet cell batteries should be used. Deep cycle
batteries are the batteries of choice. They can be completely discharged and recharged repeatedly.
Conventional car batteries can be used but they are not designed to be totally discharged. They will only
recharge up to about 60 to 75% of their original capacity.
[attachment=53139]
The effectiveness of any electric fence, whether it's a one wire fence subdividing a pasture or a 9 wire
fence protecting stock from predators, depends on the ability of the fence to deliver an unpleasant shock
to animals that touch it. The ability of a fence to deliver that shock depends on three things:
1. The energizer
2. Grounding
3. The fence design
RELEASING PULSES
An energizer (also called a charger or controller) regulates the flow of electricity in an electric fence. It
stores electrons in a "capacitor" and then releases them in a "pulse." After each pulse the capacitor stores
up electrons for the next pulse. (If you touch an electric fence between pulses you will not get shocked.)
ENOUGH IS ENOUGH
Your fence, regardless of the animal being controlled, does not need more than 5000 volts. Commonly
the best energizers will deliver 4500 to 7000 volts. Energizers are available that produce even higher
voltage. In fact one cheap charger blew my voltmeter off the scale (it reads up to 10,000 volts) and
knocked me on my #%$(@&)! Avoid these cheap high impedance "weed chopper" type chargers.
EFFECTIVE POWER
We can measure the voltage in an electric fence with a voltmeter, but the voltage rating of an energizer
tells you next to nothing about the effective power of the energizer. The "joule" rating is the critical
statistic. Joules measure the total amount of energy released per pulse. Double the joules and you'll
double the shock.
Most U.S. made energizers have very low joule ratings. Generally DC energizers are below 0.08 joules
and AC chargers are below 0.2 joules. Several models of New Zealand style energizers (Gallagher, Pel,
Speedrite, Halman, etc... ) have much higher ratings (over 10.0).
POWER SOURCE
If mainline power is available and dependable, 110 or 220 volt AC (plug it in the wall socket) energizers
are usually most practical for permanent fences. Will they raise your electricity bill? Well, depending on
the size of the unit, they typically draw 2 to 25 watts a day. The operational cost of an energizer drawing
17 watts a day would be about $1.50/month (assuming an electrical rate of $0.12/kilowatt hour).
AC chargers have several advantages over DC (battery powered) energizers:
They require no battery maintenance
They are generally placed in or close to buildings (reducing the risk of vandalism)
Where mainline power is unavailable or unreliable, battery powered energizers are a practical alternative.
Some portable DC energizers can be powered by dry cell batteries. For example, I have a small energizer
I use for short (<1/2 mile) temporary fences that is powered by 6 "D" dry cell batteries. The batteries
need to be replaced about every 3 or 4 weeks. Beware - manufacturer estimates of battery life are usually
optimistic. My energizer claims the batteries will last "up to 6 weeks."
For longer or permanent fences, or for short temporary fences passing through tall wet grass (high
leakage), larger energizers powered by 12 volt rechargeable wet cell batteries should be used. Deep cycle
batteries are the batteries of choice. They can be completely discharged and recharged repeatedly.
Conventional car batteries can be used but they are not designed to be totally discharged. They will only
recharge up to about 60 to 75% of their original capacity.