Oct 22, 2011 at 2:20 pm #1280975
For the moment let's keep the discussion away from the "why" and more on the "how" :)
Electro Bear Guard makes a 2.5lb fence kit for $395 : http://www.electrobearguard.com/Kit_Content_2.html
The price is too high and, looking at the construction, I'm convinced it could be even lighter. So I'd like to go DIY.
I'm pretty sure the Sureguard energizer they're using is the lightest available (and is uses AA's rather than D's – very important for weight reasons!)
So I found a source for the Sureguard M2 energizer alone for $249.
Any ideas on what the wire should be made of? "Polywire" seems to be the most common electric fence wire, which seems to be a few think strands of stainless steel intertwined with nylon or something, I guess for strength. I also found some single-strand aluminum wire. My thinking is that although the voltages are very high, the current is so darn low that the gauge of the wire really won't matter at all.
The fence poles could use the most improvement in terms of weight. The Electro Bear Guard poles are collapsable aluminum and it seems like they comprise the majority of the fence's weight.
I'm tempted to find the lightest source of carbon fibre poles available and go that route instead.
Does anyone have any ideas for sources of super light, cheap carbon fibre tubing, strength no object?
My other thought is to forgo poles entirely and use the environment – ie wrap the wire around trees. But obviously you probably can't do this without some insulation from the tree. Perhaps a few rubber pads would do it. Not sure what happens when it rains though.
Any discussion is welcomed!Oct 22, 2011 at 6:06 pm #1793884
Here ThereBPL Member
"a few think strands of stainless steel intertwined with nylon or something, I guess for strength."
Actually it's for visibility. A lot of creatures have trouble seeing plain wire, especially in low visibility conditions or at night, and ideally you don't want something large to come crashing through the wire breaking the circuit and rendering it useless before that thing ever even saw the wire in the first place.
You also don't want to lose track of where the wires are when your bladder calls in the middle of the night…Oct 22, 2011 at 7:14 pm #1793899
That makes a whole lot of sense.
I guess any portable solution really relies on the animal being at least somewhat cautious approaching the fence, because it's so easy to just rip the whole thing down in one swipe.
So what happens under thick canopy at night? Bears are really just navigating with their noses in that situation, right? Is the fence pretty much useless?Oct 22, 2011 at 7:44 pm #1793908
Here ThereBPL Member
All of my experience with electric fences comes from trying to keep horses, cows, and goats in, and occasionally needing to make repairs from reckless deer. We would always walk our animals around the perimeter so they knew where the fence was, and keep a couple of yards mowed down on either side to make sure it was clearly visible. I'm guessing you won't be showing the bears the perimeter of the fence, or mowing to make it more visible in a backpacking scenario.
I'm definitely not a bear expert, but I'm having a hard time believing that a battery powered electric fence would deter a bear, especially in dense canopy where it might not even see it until it was breaking it. I certainly wouldn't bet anything important on it.Oct 22, 2011 at 7:56 pm #1793911
Josh LeavittBPL Member
@joshleavittLocale: Ruta Locura
"So what happens under thick canopy at night? Bears are really just navigating with their noses in that situation, right? Is the fence pretty much useless?"
Electric deterrents actually work better at night because the bears have to use their noses, just like you mentioned. A sureguard to the nose is very effective(I have hours and hours of video of this). I can get you sureguard controllers for less(limited quantities) and I can help you source tubes. I used some glass/carbon hybrids, tough, light, and affordable.Oct 22, 2011 at 7:56 pm #1793912
you could seriously hurt yourself with this thing as well, espeically considering your trying to myog it. If its strong enough to deter a bear, its strong enough to stop your heart. In the backcountry thats not good.Oct 22, 2011 at 10:02 pm #1793931
Steofan MBPL Member
@simauliusLocale: Bohemian Alps
I have seen bears walking along vacuuming their way through the woods as if they were only a stomach with legs underneath and a nose leading the way. If a 9,500 volt pulsed shock on the snout doesn't turn a bear around, you will need a backup plan that includes the use of deadly force.
Wow. That is one serious fence.
Thanks for including the website. It made for some very educational reading.Oct 22, 2011 at 11:32 pm #1793942
Justin BakerBPL Member
@justin_bakerLocale: Santa Rosa, CA
or if a ranger decides to walk into your camp to talk to you…Oct 23, 2011 at 12:17 am #1793950
Josh – super helpful, thanks. I'll send you an IM once I have an idea sorted out.
Did you build something similar?
Do you use any earth wires or only live wires?
What do you think about poly tape rather than wire? For increased visibilty.
Any thoughts on using trees as posts? What would you insulate with?
As for all the safety concerns, the fence will of course be flagged with hi vis tape.
It'd be pretty hard to stop your heart with an AA pulse energizer…you'd have to hold the live wire in one hand and a ground wire in the other and intentionally keep hanging on between pulses… even then, it might never have any effect on your heart.
Anyway, I definitely consider it less of a potential danger than a bear intrusion.Oct 23, 2011 at 1:38 pm #1794041
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
> you could seriously hurt yourself with this thing as well,
Well, yes, that is the whole idea. They give a really good kick.
> If its strong enough to deter a bear, its strong enough to stop your heart.
Sorry, but no way.
Look, tens (hundreds?) of thousands of farmers use electric fences to manage animals. And every one of them has leant on the fence a few times at least. (Speaks from experience here!)
Afaik, there have been no recorded instances of someone's heart being affected like that. Too much muscle length in the way. You just get a good jolt.
Can a battery-powered unit give a big enough jolt? Of course. They are very common in some places, up in the mountains.
CheersOct 24, 2011 at 1:04 pm #1794389
I slept in a campground that was surrounded by a multi-strand electric fence. It was powered by solar panels, and it probably worked pretty good. I could hear the discharge when tall weeds would brush up against it, and the bears stayed away.
I would use carbon fiber tent poles, about four feet long, for MYOG purposes.
–B.G.–Oct 24, 2011 at 2:24 pm #1794441
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
> I would use carbon fiber tent poles, about four feet long, for MYOG purposes.
Carbon fibre can be conductive, so you would need a good plastic insulator on the end. A bit of beverage tubing might do.
CheersOct 24, 2011 at 3:08 pm #1794457
Dale WambaughBPL Member
@dwambaughLocale: Pacific Northwest
Any stick, bush, or tree will do— if you tie insulators to them and suspend the conductor without contact. I've done that for radio antennas for years.
I've wondered about rigging electric fences around food bait in habituated bear areas and associating a particular scent with them— use something common like vanilla on the tape-style conductors. The bear is attracted to food, gets nose on vanilla fence and gets zapped, learns to associate vanilla with getting zapped. Hikers then use vanilla around campsite, bear stays away.Oct 24, 2011 at 4:12 pm #1794480
An alternative to vanilla might be oil of anise.
Bears mistake that smell with the bear sex attractant.
–B.G.–Oct 24, 2011 at 8:01 pm #1794586
Mark HurdBPL Member
@markhurdLocale: South Texas
"An alternative to vanilla might be oil of anise.
Bears mistake that smell with the bear sex attractant.
Hmmm– The things that could go wrong with this scenario might be more dangerous to you than mere electrocution:^)
-MarkMar 31, 2013 at 7:00 pm #1971522
Old thread but I'd thought I'd let everyone know the project is finally underway. I'm building the ground rod out of Easton aluminum arrow shaft. I will attempt to use no poles (wrap around trees/sticks) using tubular insulation that just wraps around the polywire where it contacts the material. Keeping it as simple and light as possible. I think the whole thing should actually end up around only 1 pound!
Will post again as progress is made. Thanks everyone for their help, and Josh for sourcing a less expensive Sureguard energizer.Mar 31, 2013 at 7:08 pm #1971525
How do you deploy it if there are no trees, bushes, or sticks to hang the wire?
–B.G.–Mar 31, 2013 at 7:17 pm #1971528
My initial thoughts are:
– Haul up a few sticks found on the way up
– Build some rock cairns high enough
But, if both prove impractical, I'll look into lightweight CF tubing.
Though if it is far enough above treeline that there is really nothing around, that probably means there's nothing for bears to eat and no reason for them to be there anyway.Apr 1, 2013 at 12:55 am #1971596
@stingray4540Locale: South Bay
Wow, I'm kind of excited to see the finished product! If you can come in under a pound, and work on getting the popular parks aproval, you might really have something here.
I think, even if you have to CF tubing, it would probably add less than half a pound. Considering the lightest canister is almost 2lb. and is very limited in carry capacity, you would have the lightest, one size fits all solution. Of course, park aproval will be needed to get much interest in it…Apr 1, 2013 at 10:23 am #1971675
"Though if it is far enough above treeline that there is really nothing around, that probably means there's nothing for bears to eat and no reason for them to be there anyway."
Barrow, Alaska hasn't got any trees, but the white bears are there. They would like to stop in for a bite to eat. Same with Churchill, Manitoba.
You might be able to fabricate some carbon fiber tripods with insulators at the top. But then you would worry that the wind might blow them over.
What happens if the hot wire contacts the ground? Most that I've seen will start sparking until the battery is drained.
–B.G.–Apr 1, 2013 at 1:38 pm #1971744
Jon FongBPL Member
@jonfongLocale: FLAT CAT GEAR
Just a thought here, but if you design the electric fence to surround just your food – doesn't that make ith implimentation a lot easier and potentially a lot lighter? It would basically be an electric bear cannister. My 2 centsApr 1, 2013 at 8:05 pm #1971880
Yeah… before anyone gets too excited, this isn't for my food (I will continue PCT hanging well away from camp) but for my campsite.
I know the actual odds of a random attack on an immaculately-kept campsite are almost vanishingly low, but it does happen from time to time, and the basic purpose is to quench my otherwise-unshakable paranoia and just allow me to sleep without a care. Particularly when alone in potential grizzly habitat.
I have had a bear spend way too long circling and sniffing the perimeter of my tent in the middle of the night (read: poking his nose into the fabric inches from my face), and that is not a fun experience. I was younger then and didn't respond appropriately at all (I froze up and didn't make a sound for hours, instead of getting up and scaring him off), but even now, I'm pretty sure that I don't want to even have to make the decision to get up (or not) and open the tent door into the face of a bear at 1AM ever again.
Back to the food ideas. While this sounds like it might be good and effective in one-off scenarios, I wouldn't want to see it becoming common to replace other food storage techniques with small electric fencing. In habituated areas, I imagine the bears will fairly quickly learn that the fencing can be compromised by digging, or knocking down posts, or charging, etc. A setup this light is really quite ineffective against a determined and smart bear over a long period of time.
In my case, the intention is different: a deterrent for over-curiosity from a bear with no specific intent.Apr 10, 2013 at 7:45 pm #1975118
Having spent a lot of time around portable bear fences, I assure you they are not dangerous. The idea behind them is that an animal (which doesn't wear shoes) will ground the full ~.15 joule output typically through their nose, which certainly doesn't take much imagination to understand would hurt a bit.
Bears do not rationalize electrical shock, as you might suspect, and fight or flight enters into the equation. Flight.
I have been shocked through my hand, through my hand when wet, through my hand when wet not wearing shoes, holding hands with another person, holding hands with 15 people and through my hand with my feet far apart- sans shoes (hurts the most).
I do not fully understand the rational behind this, but rest assured a good bit of D-cell juice has entered my hand. If it were dangerous, I would have only done it once.
TO BE CLEAR= THIS WAS A PORTABLE BACKPACKING BEAR FENCE, not a hard wired cattle fence.
THAT would be stupid!
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