Battery for electric fence...how long before discharge?

[RalphVa]

I started off running the electric fence around my 50x75 garden plot about 15 years ago with just the battery and an non-electronic fence charger, with a small utility battery like you can buy at Walmart or almost anywhere. I had a spare battery and swapped them out. The battery would last way past a month, but I'd just swap them out about every month.

Then I got a little solar panel (at the "mule gate" one at TSC). Maybe 3 years on, I replaced the non-electronic with an electronic fence charger. Bet it would probably go on forever, but I've never run it without the solar panel charging the battery. I even stuck a battery tender in there to keep from overcharging the battery. Otherwise, they lasted only 2 or 3 years. Now, the one I have is going on about 4 years. The electronic chargers just keep going, too, vs. having to send the non-electronic ones back about every 6 months.

Ralph

 

[RalphVa]

I've a solar gate, too. I added a 2nd solar panel to what the vendor supplied for it. Still, the big marine battery had to be removed and charged off line about once/yr, even after we took out a couple trees nearby. My substitute battery for when it was charging is just one of those little utility batteries. I've just left it in the last time I put the marine battery on charger. It's staying up and even got above 13 volts (the marine battery never saw 13 volts except on the day down from being recharged). Just checked it (do it monthly). It's 12.93 even with all the cloudy days and rain we've had.

I think those big batteries (marine or whatever) have too much internal leakage for solar panels to keep them up.

My diesel generator also has a big battery. I tried keeping it up with a solar panel and couldn't do it. However, its battery runs 2 LCD panels: the one on the generator and the one on the in-house panel. Those probably have far more drag than any internal leakage.

Ralph

 

[RPW]

Keep in mind that a battery needs to be charged at a specific rate. To little and you won't get a full charge. To much and you will damage the battery. What I use on my gates (2) is 2 18ah batteries in parallel with 30 watts (about 5 amps) through a solar charger. Batteries stay fully charged through repeated cycling of the gates.