OFF GRID POWER; various thoughts on...

[MountainDon]

That's more or less what I thought the deal in CA was. It does not pay to oversize the PV system when the years use is totaled. That's the way it was here in NM until a few years back. Now the participating power companies will cut a check.

Currently   our cost to buy is about 0.09 (average on December bill) and they pay 0.12 per kWh for any excess

[MountainDon]

In another thread I showed off the LED Christmas lights at our cabin. I also showed that we used 6 strings of LED C6 type white lights mounted down the cabin side and over to the shed for nighttime illumination. That works very well. Even on the darkest night we have plenty of light to see our way from the cabin to the shed and around the immediate area.

I noticed something odd though.

We use an Outback inverter. There are may programmable features. One I use is the search function. This allows the inverter to run in a standby mode when no power is being used. When a load is sensed the inverter turns on. It is adjustable for sensitivity. I have it set down to where a small LED night light will activate the inverter.

However, a single string of the LED Christmas lights or the single LED night light, must be plugged into the receptacle the "proper way". Reversing the plug the light?string will not trip the inverter on. Rather the light(s) pulse on-off in sync with the search signal. Changing the orientation of the plug resolves the issue.   

Just interesting. If at first something doesn't react the way you think it should analyze what changes could be made.

[Windpower]

LED's are

Light Emitting DIODES

a diode passes current in only one direction

so it kinda makes sense depending on how the inverter current sensor works

my 2 cents  $2 worth (inflation you know)

[Windpower]

The BIG RED Batteries are here !!!   

Surrette 6 CS 17 PS     6V 530 Amp Hour

all 1800 pounds of them

Ordered from the Solar Biz (very good people)  shipping was only $120

[MountainDon]

Way cool!  Those are the best batteries anyone on here has ever shown as their own.  There should be many years of great service.

[Windpower]

Thanks Don for the Solar biz tip -- saved me $1600 over the next best deal

they have a 10 year warranty-- hopefully we will be using them well into the next decade -- supposedly individual (dead) cells can be replaced, too


at 50% discharge we should have 10 KW-Hrs of storage

my FIL is going to FL near Miami -- I may ask him to pick up a Xantrex 6048 inverter down at Sunelec to go with these batteries

[MountainDon]

Impressive savings! 

Glad you could benefit

[considerations]

Wow, those look almost like fork lift batteries.  Impressive.

Speaking of which, has anyone ever considered using forklift batteries for their bank?  I've heard of one instance, but never seen any discussion on the possibility, or not.

[AdironDoc]

At home, my two widescreen TV's sit in standby mode most of the time, and, with the added burden of cable box and DVD, add up to nearly 400W/hr or 10KW/day!

I went looking for better options for my off-grid camp and happened upon this nice 32" TV at BJ's. It's an LED by Westinghouse that takes only 54W while on. Add an 8W DVD player and your talking about as much power as a light bulb. Not bad for bringing a couple evening hours of creature comfort to your battery run cabin.

http://www.amazon.com/Westinghouse-LD-3255VX-32-Inch-720p-Black/dp/B003SZRWBO/ref=sr_1_5?s=electronics&ie=UTF8&qid=1296411357&sr=1-5

[MountainDon]

Good, but remember, with any electronic device with a remote control, the main unit (TV, DVD player, etc) will have a constant low power demand. So there will still be a small draw, that will add up. Some like myself who just absolutely don not like to think about that wasted power will use power strips with a switch to really turn off those items. I did it a little different. I installed a wall switch with a pilot light beside the sofa/TV location. It is wired to a half outlet. When we want the TV on we flip the wall switch. The power that the TV wants then trips the inverter standby and powers up the inverter. The remote can then turn on the TV, etc. When we're done we flip the wall switch again and it all goes off. If no other devices are on the inverter goes to sleep.

The standby on the inverter does draw some power but it is far less than the TV or DVD unit.

[AdironDoc]

The standby on the inverter does draw some power but it is far less than the TV or DVD unit.

I've got to get around to using the new power strips I bought last week. My bill is outrageous considering I'm home only at night, keep all the lights (CFL) off and have gas stove/heat/water. I used the Kill-a-watt meter and noted my refrigerator (normally the largest household draw) uses only 1.5 KW/day. My bill says I'm using 15Kw/day. Other than refrigerator, I've got a 65" LCD TV, and a 50" LCT TV, 2 PCs, one of which is usually always on, and a hot tub. Sometimes I scratch my head and think it just doesn't add up. My pals have homes twice this size and half the bill. I've noticed I can keep my TV's off, but my cable box if turned off, takes some 5 mins to reprogram itself. Not worth the aggravation. I'll run everything through power strip except cable boxes.

My 5KW cabin inverter is on order and draws 0.9A at a rated efficiency of 90% and 95% at 1/3 load. I will turn it off unless we're using something electric. Figured if something doesn't run properly, I'll add a pure sine wave unit for that appliance alone. Can't see spending for filet mignon when most of my appliances will gladly eat leftovers.

[glenn kangiser]

Sounds like you have a plan there, Doc.

We have built our system up to where about 90% of the time it handles our parasite loads too, so we just pretty much run like a normal house.

You might want to contact your power company and complain or have them do an energy audit.  They had been making a mistake on reading our old meter for years.

[Cowboy Billy]

Wow, those look almost like fork lift batteries.  Impressive.

Speaking of which, has anyone ever considered using forklift batteries for their bank?  I've heard of one instance, but never seen any discussion on the possibility, or not.

My Dad Brother and I have 120 acres in Michigan's eastern UP. We got a used smaller 24v forklift battery 1100lbs. We have a 26' travel trailer with a 12'x20' room on it. We run the lights tv microwave ect for about 3 days on it before we have to charge it back up. Which usually takes 5 hrs with our home built chingfa diesel generator. We do have two small solar pannels on it but they are in the woods and generally just make up for battery losses while we are not there.

The biggest problem we are running into is that we have two cells that self discharge faster than the others. So when we use it our battery voltage drops off faster than it should and we have to charge it more often. Also the low cells are more likely to freeze and cause further damage. We have been trying to find a single cell battery charger but haven't had any luck yet. And trying to charge up the low cells and not over charge the good cells isn't working.



The box on the 4x4 is the charge controller for the solar pannel and the 750 watt wind-generator which we haven't put up yet. On the back wall is our 5000 watt inverter.  Once I get the the tower up for the wind-generator I want to make a underground root cellar that will hold the generator and battery near the tower and help keep it from freezing.

Billy

[MountainDon]

Have you tried a desulfator?  Or thought about a chemical additive?   At this point there's little to be lost.

[Windpower]

These chargers are expensive but I have heard good reports about them rejuvinating batteries

http://www.r-charge.com/RC-15A24-2412VDC-Industrial-Charger-Rejuvenator_p_99.html#

[Cowboy Billy]

Thanks Don

Just looked up the desulfater. Looking at the plans I think my brother can figure out how to set it up to charge/desulfate 1 cell as well as the whole battery. Even as it is its not bad as we usually just go up for the weekend and we can run it friday nite to sunday and recharge it before we go home. But we would like to bring it back up as far as possible so we are not taking more life out of the battery than possible. Dad and I were up 10 days over new years. And only used four gallons of diesel to run the 10 days and leave the battery fully charged. For the $750 we paid for the battery 2/12 years ago it has just about paid for itself in fuel cost and not having to listen to the generator run.

Thanks Windpower

Nice looking unit but not cost effective for our use level. We are only at the farm once or twice a month for the weekend and a few weeks a year. If we were there full time it might be a different story.

Billy

[AdironDoc]

Ok, I had promised myself to exercise at a least a modicum of fiscal restraint going forward but seeing the liquidation on sunelec.com, I took the plunge. My off-grid collection now includes 2 Sun panels, 200W, and a 30A MPPT charge controller. $1.68/Watt. Not bad. At 3 peak hours minus various losses, I figure in the order of a kilowatt daily. Added to the wind turbine it should be all I need. If not, there's always the Yamaha 2300 Inverter. Now I suppose I'll be needing to buy a shed to mount the panels on and store all the goodies in. Thanks guys for pointing me to what seems to be the most inexpensive solar site around. Now, is there a reallycheapsheds.com? 

[AdironDoc]

Ok guys. Let's say I've got a couple of SUN panels, 200W each. I run them through my MPPT Controller and into my 12V bank.  I know there are always losses, I just don't know how big those losses usually are. My solar map shows 3.5hrs average peak. What kind of actual power output should I expect? How large a difference between a sunny day and raining?

[Squirl]

Is that in the winter or summer?  I have found many solar maps to be unreliable because the average 365 days a year.  Some average by month and some by season.  I once found a site with the raw data of average sun hours in a given day.  This gave me the best perspective of how they came to that number. This also gave me the difference based on weather conditions.  I think the best charts are broken down by month.  Sorry, I can't find the site.  I assume that 3.5 hours is peak summer sun. I have researched the Catskill area and in the winter the sun hours are far below that.  Although I believe you said your place was seasonal anyway.

[MountainDon]

Links to monthly solar maps are available in ther first message in the Off Grid PV Sizing Tool topic.

Inefficiencies in lead acid batteries can be as much as 20% of what the PV modules were putting through into the batteries. That figure includes the losses that occur when the energy is withdrawn and used to light a lamp, turn a motor, etc.

Have you run your projected use, etc through the PV calculator?  Two biggest errors made with owner designed PV systems are:
1.  insufficient storage or withdrawing too much energy and
2.  insufficient wattage from PV modules.

[AdironDoc]

Closest city to me shows 2.5hrs by winter, and 4 in summertime, avg 3.55. I'm assuming being there in all but winter. Just wondering what a "200W" panel would be expected to put out under real world conditions, assuming direct sun, peak hour, and in rain.

I've done a energy budget and it appears I will be using on the order of 1-2Kw/day depending on how often the pumps run. I've assembled 8 220AH batteries for 1760AH at 12V. I wanted to have a discharge depth of 50% to last a 3 day weekend, so figure I have now have 10KW to spend over a three day period. To lengthen the discharge period (or shorten the recharge period), I have the wind unit, and now the 400W of PV. It seems to me I have more than enough to cover extending my stay by a few days or using a bit more than I originally figured. I've toyed with adding another two panels if need be. My MPPT handles 1200W max.

Although the rated watts on all the panels out there look impressive, I still wonder what I'll be generating each day while I sit on my porch and enjoy a cold one.

[MountainDon]

What will 200 W panels do in the real world?  


Pretty good if the sun shines brightly!   In winter cold weather they do even better as long as the sun shines and as long as the modules are correctly tilted. Modules are generally rated at 25 C (77 F) degrees. When the temperatures rise the output falls and the opposite happens when temperatures fall. Voltages can spike quite high when the modules are first illuminated on a deep freeze day. That only lasts for a moment, just long enough to fry charge controller electronics if their over-volt point is reached. Our panels Voc is 36.1, the theoretical maximum. I've seen it as high as 42.6.

Our modules are rated at 208 watts each; three modules for 624 watts. In bright summer sun, even with elevated temperatures, our modules perform above their rating.

This past weekend we had some rather low temperatures at the cabin. Yesterday with the sun bright it was still only 15 F outside. The Outback recorded a maximum power of 701 watts at one point.    I observed 665 to 678 watts myself over a period of a half hour.

Cloudy weather does drop the output, but on all but the blackest of cloudy days they still put out.

At least that's what our Sharps are doing. YMMV

[AdironDoc]

What will 200 W panels do in the real world?  


Our panels Voc is 36.1, the theoretical maximum. I've seen it as high as 42.6.

Our modules are rated at 208 watts each; three modules for 624 watts.The Outback recorded a maximum power of 701 watts at one point.    I observed 665 to 678 watts myself over a period of a half hour.

Cloudy weather does drop the output, but on all but the blackest of cloudy days they still put out.

Thanks Don, that's awesome! I expected disappointing results but it's nice to know the claimed rating is close to the real rating. My MPPT can handle up to 40W panels, and my VOC is 33.2V. Hopefully not an issue. I'm looking forward!

[Windpower]

Ordered the Xantrex XW6048 Thursday




from Sunelec -- good price --  $2900

http://sunelec.com/index.php?main_page=product_info&cPath=6_38&products_id=54

The FIL is going to pick it up when he is down in Miami and drive it back for me

saved almost $400 shipping 

[glenn kangiser]

Will you be able to use it either on or off grid or is it grid tie only, Windpower?  Nice inverter.