Move to off grid home

Kurt

10 kW
Joined
Apr 21, 2008
Messages
962
Location
South Australia
Some might remember the thread I started then took down from the general discussion section of ES a few months ago regarding our intentions to purchase a off grid home. Anyhow after discussing the thread with my wife she wanted some changes made and was concerned about the information posted jeopardizing the sale to us. Slim chance I know but we really wanted the place so we took the thread down until it was officially ours.

So thanks to the people that took the time to contribute to the 1st thread. Now that we have the keys I am starting this new thread. Basically as a bit of a blog on living off grid.

System basics.
6845750381_98a1ff324b.jpg


Also for emergency back up though it isn't really needed is a Kubota J108 9kva 3cyl diesel generator

Initially I was led to believe the house had 6600w of pv although the sales agent had mixed that up with the continuous output of the inverter. Anyhow 4000w is proving to be way more than wee need.


The system being only two years old looks to be in near new condition. Though I can already see some design faults in the system layout but should be easy to sort out. Things like inverter and batteries housed in the same building (need a dividing wall). Some shading on very back string of panels during the very late afternoon. I am usually fussy about most things but will live with the system for a short while and iron everything out.

Future plans for the home are a home workshop - shed to be built near the home. After not being able to swing a cat in my double garage I use now this is what I am most excited about :D

I need to able to power my modest size lathe, mill , cold saw, Tig welder among other things. Most inductive loads from motors are 1000w motors or less other than my air compressor thats 2400w though I might just convert that to a ICE engine. Will be a little bit of suck it and see regarding starting loads of all the motors. Also my small tig welder taking PF into account needs roughly 5kva when running at max. The workshop isn't being used all the time so I will base my use around available energy at the time.

I was thinking the property could take advantage of pumped hydro to supplement energy storage and make use of excess pv output on sunny days when the battery bank is full early in the day.There is around 1 acre of flat land at the top of a hill Around 6 acres very very steep heading down the mountain for around 250m. There is a medium size spring fed dam up the top. Also a high annual rain fall of around 2000mm. Perhaps even two 20,000 ltr tanks. One fills off the proposed shed/workshop then feeds to the bottom tank down the hill. workshop will be roughly 120m2 roof area or use the dam.

Some pics of the property and system



6769547531_efd97f9f97.jpg


6769549471_e9f594978e.jpg


6769778265_950403bc81.jpg


6769546647_1d5d383474.jpg


6769550891_1f7b9ac3a8.jpg


6780224515_d2f0e22594.jpg


Kurt.
 
Snakes, snakes and more snakes. Given that the house has been unoccupied for a little while it turns out I have a few friends that think the battery storage room is a good home.

1st one was this little guy on the inside of the battery room door. 1/2 asleep and didn't bother me to much.
6924334707_21fb7140ce.jpg


2nd one was a bit more of a fright. I was poking around in the inverter cabinet later at night and discovered a data cable and some spare parts for the system. I could then see what looked to be some 0 gage battery cable tucked into the side of the cabinet along side the inverter. I started pulling at the cable it to discover it wasn't cable but a snake!!! He liked the warmth of the inverter and turned out to just be a harmless tree snake. After getting him out of there with a kayak paddle I did get one pic of him another night when he was investigating my diesel container on the back porch.
6924337253_df598d62bd.jpg


[youtube]bXHPPBTZj2k[/youtube]

3rd snake was a shock to. I hit the button on the auto garage door to go outside . Only to find one tucked under the door and almost stepped on it. Turns out this long skinny one was harmless to. Sniffing around everything looking for frogs.
6778219778_358f0bc5e2.jpg


[youtube]2x8yMV2LXJI[/youtube]

Most of the snakes are harmless but we do have some very nasty ones that will kill you unless you get to hospital very fast so your initial reaction when unexpectedly coming across one is frighting until you work out what kind it is .


To date we have found that the system is doing well. The new 520l refrigerator freezer running,water pump,inverter loss (always on),modem,laptop,tv,stereo,dishwasher all the mod cons we had in our old home. I don't have the data logging software yet (will soon) But every time we have had a big consumption day-night By the time I have my morning Coffey and check the inverter 10am the battery is on float charge :D It works well because the PVs get good morning sun from around 7:30am and the overnight energy is replaced in a hr or two.

managed to get onto the roof and clean out all the levees from under the PV's I dint think the old owner had ever done it. Got me thinking the PVs might be taken off the roof and mounted on trackers later. Easier to clean and more output. Nice view from up there. i also mowed a section for my planed workshop . The location gives me a easy power cable run from the generator room to the workshop only 2m.

small video i took on the roof
[youtube]zCUlCmokqFM[/youtube]


I tried loading the system up one time when my wife was vacuuming 1500w I plugged in a heat gun 2400w and started a few other motors in the garage most likely around 6000w toatal. The funny thing is we get more of a dip in the light output when starting a electric motor in our on grid home than we do in our off grid home. The inverter has some balls 80kg beast :D I haven't try ed welding from it yet but will this weekend. Total continuous output can be as high as 15,0000w as it can share load with generator


I will have the data logging software for the inverter soon so I will be able to show graphs and give more details on how the system is doing.i will run through a listing of total AC loads in the home to. Lighting is something I am working on now is a relatively big home and a lot of lights. It has a mix of CFL and LED.

Post more over the weekend.

Kurt
 
Man Kurt congrats to you and your wife.. I can see now why she was not willing to take any chances.

That place looks pretty ideal and wow what a view.. I am jealous.. please keep us posted.
 
Beautiful! I love it! I like your fun snake buddies too. :)


One tiny error in the picture of the printed materials list is the battery name. If folks are trying to find them, it's an "Exide 4RP1330", not "Exide 4PR 1330"


48v 1330Ah pack. At a semi-reasonable SOC, you've got about 30kw-hrs available in that pack. That's a lot! :) Shouldn't have any issues charging a fleet of ebikes or running a hot water heater and dryer etc. (though, you wouldn't want to run a dryer more than about 6x in a day, but who does that?)

Welders draw heavy power while running, but use surprisingly little energy overall due to the low duty cycle.

Sounds like a really fantastic place. I'm jealous! I would love to one day live in a similarly beautiful and amazing home.

Great choice!

-Luke
 
liveforphysics said:
One tiny error in the picture of the printed materials list is the battery name. If folks are trying to find them, it's an "Exide 4RP1330", not "Exide 4PR 1330"-Luke

Yes this is a pic of the specs sticker on the side of each battery.
6778567344_bfabaea30c_z.jpg



The battery's use tubes rather than plates of lead. Each terminal on each battery has a air tight membrane (not just a rubber cover) to totally seal the conection apparently all corrosion on the terminals is eliminated as long as the seal is maintained. They are old school tec I guess but from what I have read about them they are very robust and some of the big company's use them to power remote power stations for communications networks . The life when not given a hard time is around 15 years or potentially longer. My inverter is set to never discharge the pack below 80% state of charge before the activating the generator.To date the generator hasn't started. So I am using under 20% capacity :D I want to try and get a good life out of the pack as its around $15,000 RRP to replace.

Something funny I got a junk mail slip in the mail from a energy company claiming they could save me 10% on my next power bill :D I was thinking i should call them and ask them how they planed to do this LOL

Kurt.
 
Just Wow.
Living the Dream.
Picturesque.
A vacation spot for a snow bound(Not this year.) Canuck :wink:
Congrats.

So, when are you going to build the dirt track/proving ground?
Looks a real nice spot to test/ride Dirt Ebikes.

All the best to ya. :mrgreen:
 
My ebike is a trike and I haven't used it up here yet but there is a nice smooth dirt road for a couple of KM leading out to the sealed road then around 8km ride to the local town. My trike was setup for city riding so i might have to rethink my e bikes. I feel the need for a dual suspension MTB to ride to town on. Perhaps build my own frame when I get my workshop built. Its i nice feeling being able to build the bike on solar then charge the bike on solar.The local community is very supportive of e bikes as there is a very big green living drive. The guy next door to me is actually the the builder architect that built my house. His business workshop at home is all solar powered and he runs some big power hungry machines like wood thickness.

Its funny when guests come to the house and they know its not connected to the grid they are expecting lanterns,candles and a battery radio LOL They get a shock when they come inside at night and you have a 40" tv going and the dishwasher on and about 30 lights on in and around the home . There like this cant all come from the sun each day :? . We don't try and wast power but you really don't have to compromise over on grid.

Kurt.
 
+1 to a new DirtEbike.
Might be stretching it, having just bought the dream.
But, looks like a Stealth Bombers job :twisted:

I take pictures of many of the solar installations around my area.
Our northern local, requires solar tracking for best results.
Largest Premium PV array in my area.within 20kms.

View attachment 1
96 in total..JPG


Thats alot juice. You like a' the juice/. eh?

Welding from solar power, just seems right. :mrgreen:
 
That would have to be 20kw or more!! just one hr of sun would do the average family home each day LOL. The issue for off grid is storing that energy.Battery's have a limited life and get expensive though PV are relatively cheap. With losses I a 20,000l tank feeding into another with around 80m head over 250m and pumped hydro is about the same as a 5kwh battery that lasts for ever as its just water.When my battery's are full at 10am I have 4kw of charge going to wast every hr until the sun is down. Thats the trouble with off grid unlike grid fed systems that just load the inverter to suck all that the PV's can produce when the suns up.

One idea I had was just to build Electric car and have it set up to start charging when the house battery pack reaches float charging.

Kurt
 
The province of Ontario was/is? offering 20 year grid tied-in contracts.
@ get this 80+ cents a Kwh :shock: (@ the cost of tax payers of course)
Most of the systems that took advantage of this "Offer/Contract" pay off @ year ten.
Earning you money from there on out. Gravy.

Solar installs are all over my area now.
I imagine the rest of Ontario took "advantage".

Cynical me sees it a a cash grab/safe guarding of the wealthy.
Those that had the land, cash/financing, connections & know how.
To take advantage of a program that appears "green".
Fiscally irresponsible program, that we all will be paying for 20 years from now.

Dont get me wrong.
I want to see as much advanced renewable tech as the next,
Responsible, Apocalypse/Zombie fearing, greenie, hippie fella. :roll:

This was a bad program.
Introduced green tech @ a high cost.
Peace :mrgreen:
 
Kurt said:
... The issue for off grid is storing that energy.Battery's have a limited life and get expensive though PV are relatively cheap. ...
One idea I had was just to build Electric car and have it set up to start charging when the house battery pack reaches float charging.

Kurt

In case you are unaware or for others, Consider.
http://www.nickel-iron-battery.com/
Potentially will outlast you. Thats all ya can do :wink:

A local, for us North Americans. Out of Montana. (no affiliation)
http://www.zappworks.com/
There are others.

I think a 25kwh car or 50kwh truck, would make an Ideal mobile powerplant :mrgreen:
 
We had the same thing in Australia. Every state was different. Basically you got a 1000w gid tied system for free after you got your rebate and then sold your renewable energy certificates at market trading rate. The rebates became less and less as the system size got bigger. 1500w was the sweet spot before the rebates drooped off. On top of this every state was offering a kwh buy back rate some as high as 60c kwh mine is around 50c kwh. The funny thing is people in the state that was offering 60c kwh went mental but then they axed the buy back rate an made a lot of people upset. My house in the city has a 1.5kw system and that was about $2000 out of pocket fully installed. The take up rate isn't that bad in the suburb our city house is in. As soon as one person gets it next door wants a bit of the action and so on. I just looked at a 2011 satellite pic of the block and I could count 9 homes with solar there would most likely be 12 or more by now.

The new house would have got some heavy rebates under a different system for off grid system. It would have qualified due to its location and distance from grid power.

Kurt
 
As far as covering the fear of a large home battery pack wearing out in 7 years,...and then the cost of lead has gone up 10X...and the money has inflated (diluted?) 2 or three times...

You can order a spare set of identical batteries now, just special-order them from the factory as dry/never-filled units. With the electrolyte in sealed drums. I've heard they can last over 20 years that way. Then they work just fine once you pour in the electrolyte...
 
spinningmagnets said:
As far as covering the fear of a large home battery pack wearing out in 7 years,...and then the cost of lead has gone up 10X...and the money has inflated (diluted?) 2 or three times...

You can order a spare set of identical batteries now, just special-order them from the factory as dry/never-filled units. With the electrolyte in sealed drums. I've heard they can last over 20 years that way. Then they work just fine once you pour in the electrolyte...


That is something to think about but at $15,000 to just have them sitting there for 10 years even at 6% interest I think that money would be better in the bank and would grow to over $30,000 by then. There is then hope that new tec and battery's are available in 10 years are better. Its a gamble if price will go up or down . If only we all could read the future.

At this stage I just got the quota last week for the proposed workshop at $38,000 so I need to put cash towards that.

Time will tell how long the pack lasts It's had a very easy life over the last 2 years as the old owners were not there full time. Spec sheet said something like 4500 cycles at 10% DOC and thats about what they see now .10% is around 6kwh and to be using that from the pack I would have to consume that 6kwh from 4pm -6am I am lucky to use 4kwh over that time period. So they should have another 10 years in them at least. When you think about it most people are more than happy to pay 15k or more for a new car every 10 years so its not that bad.

Kurt
 
Man, 4kw on the roof is all you should ever need. Sweet!
 
Over the weekend we had about 100mm of rain on sat then Sunday was overcast and light rain all day. I checked the battery's 9:30 am and they were at 96%. Even on a crappy day the pv are still feeding 10 - 20amps hitting float charge before 10:30am.

A small video from the weekend
[youtube]D1yrSJ4J-oo[/youtube]

Kurt
 
I have been thinking about this a lot and i keep not understanding why people doesn´t use LIFEPO4... just an example:
http://offgridnz.livejournal.com/
and token from here the numbers http://www.solarpaneltalk.com/showthread.php?2214-LiFePO4-The-future-for-off-grid-battery-banks
So I'm comparing the cost of AGM deep cycle batteries with LiFePO4 batteries, and it seems that LiFePO4 will win out.

Hear me out...

Goal - Provide 1 kW of power.

Assuming 80% DoD for LiFePO4 and 20%DoD for AGM (Which will give us approximately 5 years for each type of battery), we will need:

x24 3.2V, 16AH of Headway LiFePO4 batteries for a 12.8V, 96AH pack (1.28kW) and

x2 12V, 255AH, Concorde AGM Groupe 8D batteries for 12V, 510AH pack (6.12 kW).

since 80% DoD of 1.28 kW = 1.0 kW and
20% DoD of 6.12 kW = 1.2 kW

Price for x2 Groupe 8D Concorde batteries ~ $1,200
Price for x24 Headway LiFePO4 batteries ~ $600

.. not to mention x24 LiFePO4 batteries only weighs about 30lbs.

I guess the price of the Battery Management System for the LiFePO4 cells and the complexity of the system far exceeds that of the AGM batteries for now. Perhaps the technology is still immature.

Are there any technical barriers from preventing the use of LiFePO4 batteries as solar battery banks? Maybe the discharge rate (100A)?

For me it makes perfectly sense
 
Lifepo4 isn't out of the question but .....

Using my system as an example the pack is around 63kw 100% DOC or 30kw at 50% DOC 6.3kw at 10% DOC and so on .There are Large lifepo4 cells out there But that would take a lot of 16ah headway cells .

Lets use your 30% DOC for led and 80% DOC for life . Using 16ah headways you would need 400 cells to give 30% of my 1330ah 48v led pack. Not to mention if you really needed the capacity you could take the pack down double that on the lead and that would take 800 headway cells.

400 cells is one big BMS and a lot of balance wire's. :D


Now you can fix this issue with some big life cells . I have googled some 400ah 3,2v cells
imgp1838a.jpg



This is the cycle life of a 400ah lifepo4 I found
2000 cycles 80% DOD
3000 cycles 70% DOD


This is the cycle life of my exide led battery's
1500 cycles to 80% DOD
2500 cycles to 50% DOD
3300 cycles to 30% DOD
4500 cycles to 10% DO
D

So at the 80% DOC the lifepo4 is only 25% better than the led on the cycle life. There is a big difference between golf cart led battery s and large RAPS battery's. Not to mention a 5 year warranty on the Exide battery's and only 12 months on the lifepo4

Weight isn't a issue when your powering your home as the battery's just sit in a bunker on a concrete floor and get shifted once ever 15 years. Mine are are around 120kg each 1.4 ton but I can easily slip a trolley under one cell and move it around.

Yes the future isn't led but for now the advantages of lifepo4 for powering your home are not the same as a EV. Weight,C rating are not a issue.

As it stands in my 48v 1330ah pack using 12 cells is around $15,000 retail. it would be interesting what you could get for that in large life cells.

Kurt
 
Hillhater said:
Certainly there are 1000Ahr Lifepo4 cells available at ?? $$'s
...but also these 100Ahr , 48v LIFepo4 packs at $240 each !!
http://www.alibaba.com/product-gs/510024456/48V100AH_LiFePO4_Lithium_Battery_For_Telecom.html


Most likely there is larger lifepo4 I haven't done much searching. $240 for 100ah 48v would only be $3200 for a 1300ah 48v pack that sounds very good. Not sure how reliable they would be at that price point.

To me the criteria is..reliability, service life, safety then price . the last thing I would want is to be eating by candle or generator because a BMS or Chinese cell had a fit.

Its just going to be a learning experience with the battery's i have now as to how long they last and how they perform overall. I might do some research into large life example's.

kurt
 
Not sure if you've already considered it or not, but Ironcore does NiFe batteries. These things has amazing cycle life - like 5000+ and counting. They work out to be as expensive as LiFePO4, but will probably last far, far longer. Google Edison batteries.
 
jonescg said:
Not sure if you've already considered it or not, but Ironcore does NiFe batteries. These things has amazing cycle life - like 5000+ and counting. They work out to be as expensive as LiFePO4, but will probably last far, far longer. Google Edison batteries.

Interesting learn something new about battery's every day . Nickel is expensive and like you say they are about the same price as Life.

I am happy with my lead and they are ticking along nice considering they are absorbed into the purchase price of the house and only two years old unless something bad or unforeseen happens I would be looking at battery's for many years.

I will be looking into using excess solar output to drive a mono pump. Then have two water tanks and setting up a pumped hydro down the hill. this will be setup to drain back late at night to recover a few kw charge extending the battery s life.

Kurt.
 
Back
Top