# Wire loss questions



## Farmerwilly2 (Oct 14, 2006)

I would like to install an electric gate closer at the top of our drive (about a 400' wire run) and I'm working on different posiblilities. 

1) Probably one of the easiest would be to use a solar/battery charger at the gate, but I don't really want to keep a panel close to the road for someone to snag.

2) Running a 12g ac line from the house, but to avoid excessive voltage loss (20-25%) I'd need seriously big (and expensive) gauge wire.

3) Running the ac line and installing a voltage compensator to boost the voltage back up, but that seems to be another cost prohibitive alternative.

4) Maybe the solar option with a longer conductor to take it further from the road

I'm not sure I could find a transformer that would step up a voltage from say 70-80v back to 120v. Seems all the transformers I've found were 110 to 220 or step down the same way. 

So those are the options I am kicking around and wondering if the wizzards of wattage can offer direction.


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## 12vman (Feb 17, 2004)

Does it operate on A.C. or D.C.?

How about a secure battery box at the gate and 2 batteries that you can swap out. Charge one at the house and when the one at the gate gets low, swap it out with a fresh one..


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## wy_white_wolf (Oct 14, 2004)

Solar panels mounted on a 20'-30' tall pole/drill pipe are harder to steal.

why not run 220 from the house and step it down at the gate?


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## fishhead (Jul 19, 2006)

How many amps can a gate motor use? I wouldn't think you would need to run too many amps to run it.

I ran overhead 220 volt wire about 300 ft to a 1 hp motor. It was a few years ago and the wire cost $1/ft. The price of aluminum has dropped since then.


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## TnAndy (Sep 15, 2005)

Since what you seem to be looking at will run off a solar panel, such as that "Mighty Mule" brand opener, it's most likely a DC actuator that does the work. All you really need is a battery, then run a 12ga wire to a trickle charger to keep the battery up, and the battery delivers the DC power to the opener.

400' isn't THAT far a run, believe it or not. You start looking a the runs in a lot of houses, and you'll come close to that by the time you leave the panel and get to the end of the circuit.

I have a run up to the top of my mountain, which is 2300' in length. We used #8 wire....all that is at the other end is the power supply for a couple of 50w radios, so it's plenty. But I was curious: a voltage loss calculation ( using a table I found on the internet ) says the 120v in ought to be about 90 volts on that end. Nope....no load at all, it's 111v. So I hooked a small 4 1/2" grinder up doing some work, and measured the voltage when I turned it on.....it would drop to 104v when you first hit the switch, then back up to 109v when running, not grinding. Grinding, it would vary between those two. The motor on the grinder is probably small, don't remember, but I'd guess not over 8-9amp. But it did the job, and didn't heat up ( a sign you're drawing over amperage at low voltage )

My conclusion is voltage calculators are way conservative.

My own gate opener: Two 1/2hp (750w total ) motors 950' from the house panel, + a motion detector type light at the gate.....another 200w. I ran #6 wire, and it's been fine for many years.


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## SolarGary (Sep 8, 2005)

12vman said:


> Does it operate on A.C. or D.C.?
> 
> How about a secure battery box at the gate and 2 batteries that you can swap out. Charge one at the house and when the one at the gate gets low, swap it out with a fresh one..



Or, have the batteries at the gate, and run a low power AC line to the gate that powers a charger that charges the battery?

Gary


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## donewithcity (Sep 9, 2010)

I have a GTO/PRO 4000, and it has an internal battery (great if the power goes out). It is fed using a low voltage transformer (wall wart) and the documentation says you can run the low vloltage with 16 gauge direct burial cable up to 1000' It can also utilize small (15 to 30 watt) solar panel to charge the battery. 
http://www.gtopro.com/index.htm


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## Harry Chickpea (Dec 19, 2008)

feh. A gate opener that uses a motor may not need much at all. Motors just slow down with low voltage. I use two hundret foot orange extension cords to run a couple water pumps by the creek. They pump the water up about 100' through 300' of pipe. A properly balanced gate should use MUCH less power.

I might do something different. Check online for gate designs. Back in the 20s or 30s, Pop Mechanics had designs for a few that were gravity operated gates. You pushed them open and they swung back into position on their own. That means all you would need is a solenoid to unlock the gate from your car with a remote or a push switch, or just a rope or lever to open the lock.


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## Farmerwilly2 (Oct 14, 2006)

Once again HT folks come up with the answers. Thanks again for tips.


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## artificer (Feb 26, 2007)

Its amazing the amount of power you can put through a small or long wire with AC. 1/2 amp is still 50 watts if the line droops to 100v. Thats 24hrs a day. If you compare it with a solar panel, you would need at least 240 watts of pannel to make the same power. 400' of 12ga burial wire is going to be a whole lot cheaper. (could even use 16 ga... 2V droop with 1/2amp load for 400' run)

The one thing to make sure of is that the charger can run with the reduced voltage at the end of the wire. Some simple transformer chargers will not provide adequate voltage unless you feed it the proper 115V power. If you only have volt or two of drop, it shouldn't matter.

Michael


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## Farmerwilly2 (Oct 14, 2006)

I checked the GTO site, they provide an 18v~ transformer that can feed their gate controller, up to 1000' run. My next stop is to price the 16ga. feed.


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