maybe a stupid idea...looking for opinions

[defed]

i've got a 4' Piggott (24v) which is a test model before i leap into a 10'.  my plan is to fly it for the rest of the summer and thru winter to see how it goes.

i have read that the doc wattson type meters don't handle the cold very well.  while testing the turbine, the batteries will remain outside under the tower.  since i can't really leave the meter out in the 0F temps for months, is it feasible to house the batteries, rectifier and meter, in an insulated box that is heated directly from the batteries (dc heater of some sort), and via dump load, should i have them fully charged?  the box would be small, so it wouldn't seem that it would take too much to keep it at, let's say 50F.  it would have to be vented somehow i guess for letting any battery gases out.

if this is a stupid, impractical, or even impossible idea, please tell me what else could be done.  i'm open to an ideas.

Dave

[luv2weld]

Dave
Not enough info to even start an argument.
Where are you?
What kind of winds do you get??
Tower height??
Tower sheltered or in the middle of an open field?
How many batteries and what type? How old?
An insulated ice chest (cooler) might be an idea.
But if you use a plastic ice chest, make sure the dump load doesn't touch the plastic.


Ralph

[SparWeb]

Cold batteries:  The only relevant question is:  Will you leave them for long periods in a discharged state?  If you answer yes, then warming the batteries will prevent the ion-depleted electrolyte water from freezing.  Fully charged batteries won't freeze in -50, partly discharged ones only slightly different.

But then you have to ask yourself: are you using the WT power to charge the batteries, or heat them?  It stops making sense very quickly!  I think I asked the same question a couple of years ago.

My batteries are in an insulated cabinet outside.  When there's lots of wind, and the batts are full, the dump load often heats the cabinet by 10-15 degrees.

My charge controller has a temperature compensation sensor, so it adjusts the voltage when it's cold.

If you're like me, you'll find yourself investing in the "infrastructure" for a while, and by the time you get your 10-footer done, you'll be better equipped to use the wind energy than you are now.

[Seekscore]

Since you seem to have a plan for your testing and your question is about the Doc Watson meter...

Mine was outside this last winter in a non insulated box with my dump load, rectifier and controller. Batteries were external to the box. We had some really cold days with very little wind. I didn't experience any problems leaving the Doc outside in cold temps but it wasn't exposed to moisture. I am sure if it got wet, it would have had problems. I didn't experience any problems with the Doc Watson being in the cold.

Mike

[defed]

Where are you?
What kind of winds do you get??
Tower height??
Tower sheltered or in the middle of an open field?
How many batteries and what type? How old?
An insulated ice chest (cooler) might be an idea.
But if you use a plastic ice chest, make sure the dump load doesn't touch the plastic.

i'm near buffalo, ny, so it gets cold here.

my location, especially in winter, gets alot of localized wind.  the west side is open to field, and the house gets trim ripped off almost every year.  i am getting some anemometer stuff to get concrete data.

the test tower, i hope to get it close to 20'.  i've already had the turbine charging at about 12', so if i can push it up a bit, it should help.  final tower will be 50', but may never get it ready until the 10' mill is done....but the progress of that depends on permits and test results of the 4'.  i figure if it works fair at 20', that is a good indication that 50' can only be x times better.

the batteries...just using some older ones that i have around.  they are 'marine deep cycle', at 100ah i think.  so 2 in parallel for 24v at 100ah.  i can add another set for 200ah, but i have to calculate what the potential charge of the 4' mill is...200ah is probably too much.

i thought about a cooler for the box.  the main reason i want some heat in it is for the turnigy meter (got this one instead of the wattson) and, while the batteries might not NEED heat, it helps.

i would run some sort of heater directly from the batteries and have something (another heater?) on dump.  that's fine for winter, but i wouldn't want the box cooking in the summer.

maybe even a solar heater?  but i would still need something to run w/ the batts and dump.  this is just a test for a year or so, to gather data and make observations, and the power will probably be small for the 4', so a self contained 'waste' of the power is fine for the testing.

[Ungrounded Lightning Rod]

Batteries are heated by resistive losses when they're charging or discharging, have a lot of thermal mass, and the sulfuric acid acts as very good antifreeze when they're charged.

So it's usually adequate, even for extremely cold climates, to just insulate the box and keep the ventilation down to where it adequately prevents accumulation of an explosive mixture from outgassing during charge.  The batteries will normally stay warm unless you don't pull any significant amount of power for hours while there's no charging (calm days, overnight on solar systems).  If you keep 'em at least partly charged the worst that happens even if they get cold is that you're limited, at first, in how much current you can draw when you start using some power.

A problem for electronics in the box, though, is corrosion from acid fumes if they're flooded rather than sealed cells.

[defed]

A problem for electronics in the box, though, is corrosion from acid fumes if they're flooded rather than sealed cells.

true...i was thinking of how to keep them in a separate compartment to avoid this while still have them heated.  if i don't heat the box, what else can i use the power for...assuming there is any?  i mean, i need SOMETHING to power, can't just charge w/o using.  i would like to have some lights, at least thru the dump circuit, so i can tell from a distance the 'state of charge'...ie, if X light is on, the dump is on...if no light is on, the bank is below Y voltage.

been awhile since i read up on ghurd's controller....you can set it to activate at different voltages...like dump at 14+ volts.  can you set it to do things the opposite way?  like supply voltage to a light until the voltage drops below 11v, then shut off?
 

[kurt]

ok just taking the simple aproach here but if you are not going to be using the power for anything just get a ghurd controller and a proper dump load for the max output of your turbine then set the ghurd controller for a proper float voltage for the batteries that way whenever you have wind your batteries will get a nice slow maintenance charge and be in good shape when you decide to use the power for something. just top up the battery water now and then should be fine. doing most anything else is just going to be putting undue wear on your batteries. when your not doing anything useful.   

[ghurd]

"can you set it to do things the opposite way?  like supply voltage to a light until the voltage drops below 11v, then shut off?"

Actually, it is the same.
The load is On if the battery is above the set point. 

11V is a dead as a door nail battery, which increases the chance it will freeze, and will very quickly ruin the battery.

In a standard dump load configuration, the controller is fast.
An incandescent bulb may not even be on long enough to glow with a low charging current.
A few LEDs in parallel with the dump load would show up because they are "Instant On".

G-

[defed]

thanks Ghurd.  i was only using 11v as an example, not necessarily a goal!

i will probably be sending in an order for at least one controller here shortly...and see if i can't mess it up!

thanks.

[ghurd]

It is basically the same.
The load turns on at the calibrated voltage, and stays on until it drops below that voltage minus the hysteresis voltage.
The hysteresis is the only difference between a dump load controller and an LVD.
G-

[freejuice]

ok just taking the simple aproach here but if you are not going to be using the power for anything just get a ghurd controller and a proper dump load for the max output of your turbine then set the ghurd controller for a proper float voltage for the batteries that way whenever you have wind your batteries will get a nice slow maintenance charge and be in good shape when you decide to use the power for something. just top up the battery water now and then should be fine. doing most anything else is just going to be putting undue wear on your batteries. when your not doing anything useful.   

Yea, that is the setup I have currently for my 11 footer.
 Also you cant go wrong with those controllers....I had a little trouble putting mine together at first, but is was all ME and not his kit!....What i was really needing the whole time was a good magnifying glass!

[defed]

do you have any pics of your setup, freejuice?  would like to see how you did your electrical and battery box stuff.

[freejuice]

Hi Defend,
 Some of this stuff I have already posted in these fourms. But let's see.
 If I violate the picture size, I hope Tom, Ghurd or other moderators will delelte it and I will repost it as smaller pics.
 I'm assuming these photos have bee reduced before I posted them on photobucket.
 Anyway here goes:
First I dont have a battery box, I have the batteries on a solid 2x 12  plank of wood elevated with a few 8 inch cinderblocks...I want air to move all around them...they are located in my garage.
However I have seen some neat battery box designs on this forum.
 Ok here is the front of my rectifer/heat sink box, when she was pushing about 30 amps, to the right is the shut down switch....dont mind the mess it still needs a good paint job...this idea was taken from VoloFarmers hinged box. Inside you will see the basic Dan's setup for the rectifier and Amp meter...below it are two green wires they lead to one negative terminal and one positive terminal on the batteries

Here is the box opened:
I dont like the fuses to the right which lead to the batteries, I had one to blow when another thunder storm blew in yesterday....thus it took any load off the mill, the turbine was reving t the point of blowing up...winds were at 50-60 miles an hour in spurts...tower shook a bit and the whole mill was folded up, I was able to get to the shut down switch...whew.
 The wire coming in from the right are the turbine wires, I used about 3 strands of #12 ga wire for each phase, thats why you see the large wire nuts tying these phases together before they go to the rectifier....I guesss I could have eliminated the terminal block here.

 More close ups: