New Member AlfredW

[AlfredW]

Hello Everyone,

I am interested in learning as much as I can, I am interested in having a better understanding of how solar systems work. I am interested in all sorts of applications.
I am a Beekeeper and I have hives located in an area that has bears. What has prompted me to finally join a group and learn more is that I have an off grid battery powered electric fence that I would like to keep charged using solar. I got a battery and solar panel kit. But the panel looks to me to be inadequate. SO I need to have a better understanding of how to put together a reliable system.

THanks,
Alfred

[bcroe]

I would first check that the electric fencer you plan on using will be effective against bears.
I have seen some large animals (horses here) that don't get at all excited about them.

If you expect snow, the effect on panels can be minimized by setting straight up and facing
away from prevailing wind if possible. This could still leave snow blocking for days, which
would require a larger battery bank and panel to cover the gaps. Bruce Roe

[AlfredW]

THank you bcroe,
Yes the charger and fence being effective for bears is certainly an issue. I have covered that as best I can using the advice of the local wildlife management division. Baiting the fence is one way. THat way they get a good mouthfull of charge. Another is to make sure that they cant get their snout past the wire without getting a zap. I have a good charger.

It is the battery and solar that I am less clear on. I could just go out there regularly and switch out batteries but it would be great to be able to leave it on it's own for longer times.
My other objective is that I wanted to use this project as a learning project and begin playing with solar.



PS Is there a different place in the forum that I should be posting this?

[AlfredW]

Charger:

https://www.amazon.com/gp/product/B000BWY6KW/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Current battery and solar kit:

https://www.amazon.com/gp/product/B00O43K24S/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

[AlfredW]

Hmm.... Posted links to the products I am using but I clearly need to read through the forum rules on posting links. I have to run now but will get back to it later.

THanks for the help.

[SunEagle]

Hmm.... Posted links to the products I am using but I clearly need to read through the forum rules on posting links. I have to run now but will get back to it later.

THanks for the help.

I approved your post with those links since they are safe.

[bcroe]

Hmm.... Posted links to the products I am using but I clearly need to read
through the forum rules on posting links. I have to run now but will get back to it later.

To get any help, you will need to know what kind of battery drain (watts) your fencer has. Some minimum
power types just put out a pulse, others a continuous voltage at limited current. The drain may increase
if it is trying to burn through some weeds.

My opinion is that such kits usually have the absolute smallest panel that could keep up for a day under
ideal sun conditions. You might want to think more in terms of a week without decent sun, at the end of
which you might have to go out and change batteries anyway. Generic panels in the 250W range, used
with an MPPT charger, are not that much more expensive than the tiny ones, and when sunlight drops
to 10% under heavy overcast, might still be capable of keeping things going. Bruce Roe

[AlfredW]

I wrote to Parmak regarding the power draw on the fence charger unit.
They wrote back and said:

"The discharge time of the battery is dependent on my things. The type of battery, and the amp/hour rating, are the to biggest. We recommend a marine deep discharge battery(trolling motor battery) for the type and a rating of 80 amp hours. This has been tested and will last 90 days between recharges."

So I calculated that 90 days equals 9024 hours.
80 amp hours divided out into 9024 hours is 0.0088652482269504
0.0089 x 1000 brings us to 8.9 Mamps/hour.

Did I do that correctly?
Because then someone told me that a 3 joule charger (like mine) pulls "350 mAmps/hour so a fully charged 12ampHour battery should last about 34 hours without being challenged." Which is quite a discrepancy from what I got. 350 mA vs 8.9 mA....

I currently have a 12 ah battery with what I think is a 5 watt panel connected directly to the battery without a charge controler.

I have thought that I need a larger (10 or 20 watt) solar panel. But then I wonder about needing a charge controller. The battery and panel kit I purchased has the battery connected directly to the battery. Which then also makes me wonder if the panel itself might be draining the battery at night, which apparently they can do if not properly wired with a diode or something. It does however seem that a larger panel would be a good idea. Which will probably necessitate a charge controller.

Clearly I am on the steep learning curve on all of this.

Definitely appreciate any input.

[bcroe]

My estimate of 90 days is more like 2190 hours. But just to be simple, a 90AH battery lets
say discharged by 60AH to the 30AH level, would amount to 2/3AH discharge per day. The
voltage on my panels drops way down at night, I would expect a blocking diode should be used.

0.35A draw is going to amount to .35AH per hour, or 8.4 AH per day. That is only 7 days on
the 60AH discharge plan, I suspect the average drain might be a lot less.

A larger panel with a charge controller will take care of the blocking diode, and allow operation
even under clouds and shorter days. If snow is an issue, putting the panel straight up will help
a lot, at the loss of some efficiency. Bruce Roe

[Sunking]

We recommend a marine deep discharge battery(trolling motor battery) for the type and a rating of 80 amp hours. This has been tested and will last 90 days between recharges."

So I calculated that 90 days equals 9024 hours.
80 amp hours divided out into 9024 hours is 0.0088652482269504
0.0089 x 1000 brings us to 8.9 Mamps/hour.

Did I do that correctly?.

Almost except for your Scientific Notation.

M = Mega = 1000 = 1 x 10^{3
m = milli =} 1/1000 = 0.001 = 1 x 10<sup>-3

So you missed it by a factor of 1,000,000. Your charger uses 9 ma @ 12 volts or 0.1 watts. What it really means is your fence charger works with almost no power only requiring 0.1 watts. A 10 watt panel and 10 AH battery would be a lot of overkill. As far as a bear goes, I doubt it would even react or notice a shock from your fence charger. 0.1 watts would not even kill a bug. Your cell phone uses 10 times that much power when talking and most of your cell phone power is absorbed by your head cooking your brains with microwave energy. Kind of explains why people under 30 today do not not have common sense. Their brains have been fried by microwave energy their whole life while being Socially Engineered in public schools.</sup>

[Mike90250]

Bears are after the bee larva, not the honey.
They need a special configuration of fence wire, hot ground hot ground. so their arm gets shocked between the 2 wires. Hot to earth does not phase them, feet do not make good earth connection

https://www.beesource.com/forums/showthread.php?296317-Solar-fence-charger-for-bears

[AlfredW]

THanks for the replies,

I see that I used the wrong notation. M mega, m milli....... So I meant that it comes to 8.9 milliamps per hour.
It does actually put out a GOOD shock I accidentally got myself with it yesterday, It about made me jump out of my socks.

Mike90250 Yup the bears like the larvae and the honey as well even the comb has some calories. So it is a meal complete with desert for them.
I have not yet taken a picture of the fence to post but the way I have it set up the bear cannot get even a toe through without touching wire. It is a 4"x2" galvanized wire mesh fence mounted on PVC pipe over metal fence T bars, with an additional ground mat of chicken wire all around the base.

Then the fence is baited with small pieces of foil that have peanut butter on them. This way any bear is sure to touch the fence with it's nose or tongue.

The charger that I have is the one that they are discussing in that thread from Beesource the Parmak 12.

The issue that I have is that instead of purchasing the solar model I purchased the unsolar model and so now I am trying to pair it with an appropriate battery and solar panel.

Today I went out and bought a 12 105ah battery for it. So that at least I know it will operate for a little while without trouble as I figure out how to add a solar charger to keep it juiced up.

Now my limitation may be battery fluid maintenance as it is not a maintenance free battery.

Still need to figure out how much solar I will need to replace what the fencer draws.

THanks for the help. and for any further input.

[bcroe]

You could try measuring the charger current with a meter. But if it draws power in pulses, that
will not work. In that case one method would be connect it to a capacitor large enough to supply
half a dozen or more pulses. Charge it to 14V, connect it to the fence unit, and note how long
it takes to drain it down to 12V. Now you can calculate the coulombs and with time the average
current, your PV panels must replace this completely in the time the sun shines.

Note, grass on the fence might increase drain. Bruce Roe

[AlfredW]

Just got this back from the folks I got the charger from.

Power (max): ................630 mW (0.63 W)
Voltage Voc: ..................9V
Current (Max) Isc: .........70mA
Current (Min) Isc: ..........60mA
Voltage (Peak) ..............8.5V
Cell Size ........................0.67 in 17mm x 0.67 (17mm)
Cells in series ...............18 pcs
Panel Size .....................3.54 in (90mm) x 5.90 in (150mm) x 0.67 in (17mm)

[Mike90250]

How does a 9v charger work on a 12v battery ?

a 20 or 30w panel would be enough, with a small quality charge controller (Morningstar Solar makes good ones, fleabay, not so sure)

https://www.morningstarcorp.com/products/productssunsaver-gen-3/