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> Trying To Go Off The Grid, Solar, wind, etc
BlueVanACD2005
Posted: November 28, 2016 02:11 pm
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I recently bought a house back in June.... and it has been my dream to be off the electric grid ever since. Not that prices are too high, I just like the feeling of being independent.

I have since installed 3600W of solar between two garage roofs (24V systems). I added cables that go underground to bring all the power to a common point.

https://goo.gl/photos/WqXXkGbFX26wBSuR9

Then I added 10Kwh of batteries, configured to 24V also. There are two charge controllers, one for each set of panels. All the batteries are tied into one bank though. The 24V runs to a 24V to 120/240VAC inverter. I ran wires back to the house from there.

https://goo.gl/photos/6h8TmW7vmd93F52r8

I have an electric hot water heater (4500W) and Dryer (5000W) that I never planned on using with batteries. Instead I want to replace them with natural gas appliances. But for now, I put them on their own power distribution panel and kept them powered from the grid. The rest of the house can still be powered from the grid, or ideally, run from my batteries and inverter by opening the main breaker and back-feeding the original distribution panel.

So far it has worked well. Had to revert back to the grid for a bit last week due to lack of sun though. I want to add a wind turbine next year to help with this. Summer shouldn't be a problem with the current setup, but winter months will be challenging (Michigan, USA). The biggest loads I have right now on the inverter are the refrigerator and the furnace blower (about 350W each). I converted all the lighting in the house to LED.

Originally I was going to grid-tie the system, but there were many stipulations for doing this, and a contract needed to be established between me and power company. The power company will never pay me for the power, only offer credits towards future energy use. This is when I decided to splurge on some batteries. I designed it to run everything for two days without any charging.

As a bonus, I picked up one of these from work years ago and fixed it: http://www.redlion.net/sites/default/files/LD4_0.png It has nice big 4" digits. I was using it as a thermometer, but since my batteries are about 100' away in the garage, I converted it into a voltmeter that I can see from inside the house. This way I can tell how much energy I still have left, and revert to the grid if needed.

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gremlinsa
Posted: November 28, 2016 03:13 pm
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Man oh man.. That looks lovely..

I did all the calculations and costings a while back, and kinda put my "Off Grid" into a genny.. Have a look at the thread here where i did all the calculations, checks, and even tried to work out the ROI..

One thing i will suggest is looking at implementing electrically interlocked contactors, heard many stories of how when a non gridlocked system, is out of phase and meets grid power, the Grid always wins.. Seen the effects of an supposed such event once, the genny was well toasted...

Keep us posted on your progress..




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MacFromOK
Posted: November 28, 2016 11:32 pm
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QUOTE (BlueVanACD2005 @ November 28, 2016 08:11 am)
It has nice big 4" digits. I was using it as a thermometer, but since my batteries are about 100' away in the garage, I converted it into a voltmeter that I can see from inside the house. This way I can tell how much energy I still have left, and revert to the grid if needed.

Excellent idea. thumbsup.gif

With windpower, uneven icing (and the resulting imbalance) may a problem in winter. But I'd think some designs may be more ice tolerant than others, so you might look into that. Just a thought.

Sound like you're doing great so far. beer.gif


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deth502
Posted: November 29, 2016 12:31 am
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8 batteries? i would have imagined a system capable of running an entire house would need an array of at least a dozen if not more.

i completely understand wanting to do it JUST to be off grid, but have you done any math on it? im wondering if the cost of setting up everything for the "free" energy will pay itself off before its lifed out. (compared to buying it from the electric co)
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BlueVanACD2005
Posted: November 29, 2016 03:23 am
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I do want to install some type of transfer switch, my worst fear is burning up an inverter.

The 8 batteries are sized to supply two average days of power with no charging (I can always add more). Average use is 5kwh per day. On a good day solar can do about 6-10kwh depending on the season (winter/summer). A bad day is usually cloudy and rainy, resulting in 0.5 to 1 kwh. I anticipate on the batteries lasting about 4-7 years. If you noticed, I used two different brands to see how each one lasts. I looked at the Tesla power wall which has a 10 year warranty, but it also costs about 5x as much as what I paid for these batteries (but does have an inverter too).

Cost is something I have considered. I am not making any money on this setup for another 10 years at best. I just like to do it for fun because I think it's cool to make my own power. When all is said and done, I can put everything back on the grid and take my equipment elsewhere or sell it if I lose interest. There's not too much to undo, it would only take a day or two. My math is as follows: $0.17 per kWh, plus $7.00 per month regardless of use is the grid cost. Over ten years, that's $4000. I see it as pre-paying for electricity by doing this now. And I'm betting on the cost of electricity increasing at least a little over the next ten years as coal is phased out and other plants are built (just a guess though).

Funny thing is I work for the electric company (not the same one supplying my house though).

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dmg
Posted: November 29, 2016 10:08 pm
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if i was nerdy enough i might consider some DIY solar tracking device for the solarpanels, and maybe a nother tracking device for aiming mirrors at the panels.
keep in mind you would need to cool the panels in the hot summer, but unarguably they would give a far higher output.
just something that helps when the sun does not shine as we want it to.

the best would be for real off grid is to somehow store the energy but not in a battery bank. i have no clear idea how well would electrolisis and hydrogen fueled engine setup work, probably the efficiency would be verry low. on the otherhand.. it could be possible to store a lot of energy.
electrolisis is allready quite demanding, and i guess compressing the hdrogen would be required allso. not even sure where to get a compresor suited for that task.
maybe multi-stage compression..
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kellys_eye
Posted: November 30, 2016 09:50 am
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Energy storage can take many forms other than pure electrical. Depending where you live (this works well for me) storing surplus as heat is a good idea. Storage heaters (electrically heated, insulated 'brick' enclosures) can spread a lot of energy over a long period of time and given that heating is one of the most energy 'wasteful' requirements we all (mostly) need then connecting such as part of any off-grid consideration.

Solar water heating panels offer a good return too.

If there was an efficient way to convert heat to electrical energy we'd be laughing.


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gremlinsa
Posted: December 01, 2016 01:22 pm
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QUOTE (kellys_eye @ November 30, 2016 10:50 am)
If there was an efficient way to convert heat to electrical energy we'd be laughing.

Funny how the reverse is piss easy and one of the most efficient energy transfers...

Probably why it's so difficult to do it....


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BlueVanACD2005
Posted: December 01, 2016 01:37 pm
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I have thought about solar trackers, But I have a lot of trees so it makes it difficult. I'm slowly making more room though.

Storage is an interesting subject, batteries are unfortunately the best option for now... I can always upgrade the type of battery at some point though.

I'd like to get two generators:

One would be very small (maybe 5HP, and quiet if possible). It would basically just be a 24V, 100-200 Amp charger. I would make it automatically start once the batteries reached a really low level. Once started it could bring them up to 75% or so and then shut off (leave a little room for solar to charge them too).

The other generator would be much bigger, and have a 120/240V AC output (maybe 10KW). It wouldn't have to be quiet, and I would manually start it. This would be used in a case where I needed to use a big appliance, such as a welder. Or I could feed the house from it instead, and charge the batteries at the same time.
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BlueVanACD2005
Posted: December 05, 2016 01:41 pm
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Just ordered a 850W 24V wind turbine on ebay to add to the mix. It'll be a bit until it arrives, so I can take a little time to figure out where the best location is for it in the mean time.

Also, it has been a very bad week for solar (no sun - this is what prompted a wind turbine purchase), and the batteries do last a solid 2 days without any charging.
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gremlinsa
Posted: December 05, 2016 10:01 pm
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QUOTE (BlueVanACD2005 @ December 05, 2016 02:41 pm)
Also, it has been a very bad week for solar (no sun - this is what prompted a wind turbine purchase), and the batteries do last a solid 2 days without any charging.

LOL... One of the issues with Solar, And it's not easy to calculate these types of problems in, The Turbine will add so much to your system that there's a good chance you could increase your load on the battery's and not notice it a all.

All this talk of off grid and going back to my old thread got us to realize that our genny is over 18 months old and never been serviced.. So today I picked up some SAE 40 oil and a new spark-plug on the way home. Service on it was quick and easy, the oil was quite dark but still OK for a couple more running hours.. Old plug was also in very good condition but the new one went in, old one into storage as a spare for emergency's...

Also was looking at price's for the same genny.. They've almost doubled in price since I bought mine.. shock.gif

Back to the turbine... 850W over 24 hours (if there's a decent wind all day) ~ 20KWh while the 3600W solar with ~5 Hours high sun charge time ~ 18KWh.. So you've more than doubled your power generating ability.. (are you sure about your 10KWh numbers)

And as I calculate and post here, I'm just thinking, check for at what windspeed the turbine generates full power, and what is the max allowable windspeed for the turbine.. then what sort of winds do you have at your place..


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kellys_eye
Posted: December 06, 2016 01:03 am
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Both solar and wind are intermittent and unreliable so a mix of all potential sources is good - shame you don't have a hydro source!

If cost isn't an issue then you're doing all the right things but I'd spend more efforts on finding lower powered units than trying to find the energy to run them. That's a win-win situation.
Btw solar tracking is essentially useless on a cost-energy basis.


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BlueVanACD2005
Posted: December 06, 2016 03:25 pm
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QUOTE
850W over 24 hours (if there's a decent wind all day) ~ 20KWh while the 3600W solar with ~5 Hours high sun charge time ~ 18KWh.. So you've more than doubled your power generating ability..

I figured I wouldn't need as much wind, because it can be 24/7 as opposed to sun. Right now is about the shortest amount of sun we will have, (but it is very low in the sky, and has been very cloudy). So cloudy yesterday, the panel voltage never overcame the battery voltage to charge them at all.

QUOTE
(are you sure about your 10KWh numbers)

You mean about the battery capacity or my usage? I calculated battery capacity based on voltage and Ah. Usage I got from my electric bill before going somewhat off the grid. I may add another (4) batteries after the wind turbine is installed to give me a capacity of 15KWh on my battery bank, or about 3 days of energy with zero charging.

QUOTE
And as I calculate and post here, I'm just thinking, check for at what windspeed the turbine generates full power, and what is the max allowable windspeed for the turbine.. then what sort of winds do you have at your place.

I tried to pick a turbine with a low starting speed, and a medium working speed. We don't get very high winds around my area usually.

QUOTE
I'd spend more efforts on finding lower powered units than trying to find the energy to run them.

I have everything converted to LEDs, and besides lighting, the only thing I have hogging all my power is the refrigerator (about 350W) and furnace blower (1/5HP or about 300W). The fridge and furnace both run about every 45 minutes... We were a little heavy on use this weekend too (Coffee machine draws 1500W, Toaster draws 1500W).

QUOTE
Both solar and wind are intermittent and unreliable so a mix of all potential sources is good - shame you don't have a hydro source

I would love a nice flowing river in my back yard to set up a hydro turbine! My goal is a mix of solar (50%), wind (45%), and gas-powered (5%) generation when all is said and done.

QUOTE
Btw solar tracking is essentially useless on a cost-energy basis.

I have read this before... Only if I had a lot of time and got bored would I build such a device lol.
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deth502
Posted: December 06, 2016 11:34 pm
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QUOTE (kellys_eye @ December 06, 2016 01:03 am)
Both solar and wind are intermittent and unreliable so a mix of all potential sources is good - shame you don't have a hydro source!


ive often thought this myself. im not a big fan of solar or wind yet, for reasons stated (not consistent) and the cost/benefits seem to be marginal during the expected lifespan, from what ive seen, but ive often wished i had a running water source on my property to generate power. i could make a water wheel and hook it up diy for pennies!! and have a consistent source of free power. unfortunately, unless we have some end-of-the-world type plate tectonics happen, thats not in the cards for me.
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BlueVanACD2005
Posted: December 21, 2016 02:33 pm
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I was wondering something about my battery bank...

Would there be any advantage of tying the between-bank-voltage together?

i.e. tying the blue wires together in the picture below.

user posted image

I would lean towards no, there wouldn't be any reason to do this. But maybe it would help keep all the cells balanced? May cause bigger issues if there were a problem with one particular cell though.
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kellys_eye
Posted: December 21, 2016 09:38 pm
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You could do that and fit cell monitoring to alert on cell differences....

Similar to what they do with Lithiums....

Higher voltages mean more reasonable (thinner) cable requirements plus longer runs. You can also make the best of cell volt drop if the powered equipment has a wide input range for operation - much of the 24V stuff I used in marine work had operating input voltage range of 10-32V DC meaning a 24V battery arrangement could fall significantly before the equipment stopped working.

A 48V system wouldn't be unreasonable either.


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BlueVanACD2005
Posted: December 22, 2016 04:30 am
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Well noted, I created a 24v system and kind of wish I would have gone 48v at times because of high current situations.

I basically have the setup above, except I used 6v batteries instead. So if there were a reason to tie the intermediate voltages together, I would end up tying the 6v, 12v and 18v sets of cells together. But again, I didn't think there would be much reason to do this besides trying to keep everything equally charged. Seems like it would just be a waste of wire.

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phin
Posted: December 22, 2016 10:27 pm
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Just a couple of comments:

1) Ma Bell used 48 volts for many reasons and I think it is really smart.

2) In your batty schematic, I have wondered at times if each battery should have it own electronics for charge, discharge and protection. Since the circuitry would only handle one battery, the currents would not be too high. The isolation of batteries allows for individual, personalized charge management. It may actually allow for much higher output voltages OR direct to AC at each battery.

Just some ramblings of an envious observer.
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dmg
Posted: December 23, 2016 12:40 am
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i'm not sure i would go with battery solution at all to be honest.
charging them is wastefull, and powering stuff from them is allso wastefull.
and batteris do not last for a life.
grid tie is a better option in this case, but it really depends on your goal..

and about your battery setup..
if you have batteries in series you should use a battery equaliser.
in trucks that have full 24 v system they are used for a good reason.
you don't want the to be any different by voltage, and the equaliser will do just that.
and paralelling different voltage sources is not a good idea eighter, it would bring stuff closer to eatch other.
and most probably you SHOULD tie the blue wires to a star point.
it make sure the banks get in paralell first, meaning you will have to bank of paralell batteries connected in series.
it mathers, as if you paralell them first, then you will make sure that pack will be equipotentional. and the secund too. if you connect them in series afterwards the difference in voltage will be less between the series connected packs thisway.
it can get you a bit more battery life.
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MacFromOK
Posted: December 23, 2016 02:57 am
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QUOTE (dmg @ December 22, 2016 05:40 pm)
i'm not sure i would go with battery solution at all to be honest.
charging them is wastefull, and powering stuff from them is allso wastefull.
and batteris do not last for a life.
grid tie is a better option in this case, but it really depends on your goal..

"Depends on your goal" is a big part of the equation here.

Since he lives up north, grid power failure for several days may be quite common in his area. In that case, LA batteries are still the best method of storage for the money AFAIK. beer.gif


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BlueVanACD2005
Posted: December 23, 2016 03:30 am
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I didn't like the stipulations the power company used for grid tie. They will never pay me, and if the power goes out I still don't have electricity. Though the grid is pretty reliable.

As for the balancing, I think it is less critical on flooded cells? They aren't lithiums. I have a truck with a 24v system and it treats two 12v batteries as one. The electric forklifts I have seen treat an entire pack as one. We have 130vdc banks at work with 56 cells in series, no balancing (charger has an 'equalize' setting that brings up the voltage a little temporarily though).

And to go beyond the connection of individual batteries, each battery consists of (3) 2v cells that I wouldn't be able to monitor separately.

Not trying to negate any comments, I appreciate the discussion. I'm not sure I have seen a flooded cell bank with balancing, but always on lithiums.
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Sch3mat1c
Posted: December 23, 2016 11:55 pm
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Lead acid batteries top up nicely. The downside is excess electrolysis of water. Which, if you're keeping them balanced and topped up (in terms of water level), you're fine. The plates do wear a bit, I think, but not as quickly as with other chemistries.

Sealed technologies (like NiMH) electrolyze water on overcharge, recombining the gas with a catalyst. But overcharge is bad for other reasons (physical changes in the plates), so you want to avoid that.

High voltage chemistries (lithium whatever) use solvents other than water, that physically break down on overcharge and don't recombine. Hence gas buildup and explosion.

For sealed tech, it's better to have a per-cell balancing circuit, or to cycle the pack regularly (which tends to bring all cells towards the average charge level, except for the bum ones that don't charge at all).

Tim


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kellys_eye
Posted: December 24, 2016 04:42 pm
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AGM deep cycle batteries are obviously the best choice on a cost-per basis and given I've seen them used across the marine industry for many years and that they operate effectively, efficiently and reliably you can't do better imho.

If used properly, standard lead acid batteries are nearly as reliable. Many boat users seem to forget that such batteries are fitted and used in their own cars and they are essentially fit-and-forget for at least 5 years (my car has the same battery for 8+ years now and is still in very good condition) so can be used reliably if USED PROPERLY!

Others have tried silver chloride and other esoteric technologies but I've yet to see any distinct benefit from them - seemingly their cost-return has yet to be realised in most cases!

Until either the price of lithium/ni-cad etc comes down considerably for most applications you can't beat the simple lead-acid (or AGM) unless you have a very specific power density requirement.


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BlueVanACD2005
Posted: December 31, 2016 02:24 am
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Added four more batteries: https://goo.gl/photos/eoCod5cuVByQoQi29
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dmg
Posted: December 31, 2016 03:55 am
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QUOTE (BlueVanACD2005 @ December 23, 2016 03:30 am)
I didn't like the stipulations the power company used for grid tie. They will never pay me, and if the power goes out I still don't have electricity. Though the grid is pretty reliable.

As for the balancing, I think it is less critical on flooded cells? They aren't lithiums. I have a truck with a 24v system and it treats two 12v batteries as one. The electric forklifts I have seen treat an entire pack as one. We have 130vdc banks at work with 56 cells in series, no balancing (charger has an 'equalize' setting that brings up the voltage a little temporarily though).

And to go beyond the connection of individual batteries, each battery consists of (3) 2v cells that I wouldn't be able to monitor separately.

Not trying to negate any comments, I appreciate the discussion. I'm not sure I have seen a flooded cell bank with balancing, but always on lithiums.

that is mighty interesting for sure,
some of my machines do have 24 volt system, consisting of 2 lead acid battery connected in series, but... they all use an equaliser, that is allways connected.
the forklift example however does indeed rasies the question, but i guess it has something to do with them being usually deep cycle batteries, those don't care that mutch i guess..
or i don't know.
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