Batteries for electric fence

[broadgage]

Originally Posted by Trigon.

The 6v round type is available in the UK, but is expensive.

https://www.tannertrading.co.uk/elec...nd-battery-6v/

Cheers

The price is not that bad for a 90 AH battery. 4 alkaline D cells would give 6 volts, 5 series strings of such cells would give 90 AH.
20 alkaline d cells would cost in the region of £25 depending on brand and where purchased.

If connecting five strings of D cells in parallel, be careful. The short circuit current is about 50 amps, well into the dangerous region as regards fire risk. Fit a one amp fuse.

[McMurdo]

The 6v round type is available in the UK

That's a good find, I'll pass it on to him. I can't see the terminals to see if it will fit the fencer, the ones on the original have binding posts poking up.

[Silicon]

Have you tested it to find out how much radio interference it creates when wired to a fence?

Would a small internal RF choke on the output make any difference?

[broadgage]

When small solar panels were first available, I remember that electric fence energisers were made with a solar panel AND an air/alkaline battery. The solar panel did not charge the battery, but simply powered the fence in place of the battery during daylight, thereby extending the battery life.

A drawback of these mechanical controllers was the audible ticking sound. The more intelligent types of livestock allegedly learnt that they could push the fence down between ticks, without getting a shock.

[stevehertz]

Maybe exactly what is being asked for can't be achieved, and a compromise solution is needed? eg use an external battery in some kind of housing such as a polythene box or a plastic bucket with a cover on it. Farmers are usually ok with rough and ready stuff so long as it works!

[thermionic]

Originally Posted by McMurdo

He used the 7.5v battery and it burned the contacts so it would not operate, I had to re-dress them.

Can you not connect a snubber across the contacts to prevent burning?

[kalee20]

I'd suspect that the contact burning is as much due to the current through the contacts as the voltage across at breaking.

Additionally, a snubber across, will probably decrease the zap energy of the fence!

[McMurdo]

exactly, it's the rate of fall of current that induces the biggest emf. Output emf is important in fences due to the target audience being somewhat hairy/furry/woolly.
Plus 7.2V causes the flywheel to slam into the end stop.

Electric fences can be picked up on LW at the very least, we have a modern one here at home and I check it's working from the comfort of my kitchen on my hacker.

Don't forget that any solution has to involve me making something out of it for my time and the farmer being persuaded to part with funds. Ever tried trading with a farmer??

[Heatercathodeshort]

Three 'fencer' batteries from the Ever Ready catalogue for September 1973. The PP8 was also used in a Roberts[?] radio as was the PP10. Definitely the rechargeable road I think J.

[FRANK.C]

I have repaired many of these mechanical electric fences in the past. Until this post I have never heard of or seen a 6 volt one or a 6 volt round battery for them. They have always been 7.5V.
It is made by Koltec and are still in production to day.
https://www.koltec-electricfencing.c...-energisers/st
I note on the web site that they are 6 volt.

It is not unusual for the points to become worn on them. I have changed many sets of points. I even had to change the balance wheel because the points had wore through and then wore through the balance wheel.
The mechanism looks the same as the 7.5V ones and it is hard to imagine that it would have a different transformer to a 7.5V.


So if it was mine I would adjust the armature to suit 7.5V. This can be done by adjusting the spring pressure with the two nuts at the end of the large spring. There is a weaker spring running through the centre of the larger spring. If it wont adjust the armature will be worn. They do ware from the banging they get.

Frank

[Brigham]

I remember seeing the Ever Ready fencer batteries, but I can't remember what shape they were.
Anyone got a pic?

[Heatercathodeshort]

Hi B. Post 29.John.

[McMurdo]

When I was growing up we had sheep and one day, after an escaped animal nibbled the bark off my mother's dwarf conifers, my dad came home with a new Wolseley Scorpion fence energiser, that took 2 of the PP8 batteries. They didnt last long, and dad had to change them obviously before they stopped working. I always nabbed them, and for my little lamp and switch experiments they would last me months. ISTR they were a layer battery like a radio battery or the older PP3 sort

[G4_Pete]

That brings back some memories , I can still visualise the tabs that let the air in as it was a complete magical mystery to me as a child. My father used to run these type of units off of a 12 Volt Lead acid vehicle battery but he used to have a light bulb in series to limit the pulse current and stop the wheel banging on the end stop. No idea of the bulb rating but I do remember them just glowing on the pulse.

Pete

[QQVO6/40]

Greetings all.

I spent my childhood on a dairy farm.
Had old style impulse electric fence energizers. From memory (such a long time ago) we had 4 of them.
We used a 12 Volt car battery on each one with a car headlight bulb in series to limit the current. Bearing in mind these were originally 6 Volt machines.
One advantage of the bulb was we could look out a certain window of the house at night and see the various lights blinking and so know the fence energizers were working.
Rather advantageous on a cold winter's night.

Cheers, Robert.