A beginner who so so confused .. help?

[SouthPacific]

Hello everyone,

I am very new to solar/wind and trying to plan a proper system for my own needs.  This is for a total off-grid system to run a small house, but filled with lots of electricals.

I have been researching this for months on places like YouTube, these forums and other places.  I am now familiar with several basics, but have a very long way to go. 

My main problem is trying to figure out the best type of setup to meet all my needs, but a solid configuration continues to elude me.

I just purchased a Midnite Solar 6 string combiner and plan to split the load for two controllers.  I have CSUN 305 Poly panels (I bought a pallet, so have many, many extras I will not need, but got a nice price buy buying bulk).  I have 16 Trojan T105 RE's broken into two banks of 8 wired at 24 volts.  I am having a problem finding proper controllers to get, seeing many different ones on places like Amazon, but due to the high watt panels, I can't seem to find a proper controller, nor how many panels would be optimal for my needs.

I also have two 600 watt wind generators (one for each bank), mainly as back-up and for the night breezes to help keep the battery banks charged at all times.  On a side note, can I use this MidNite combiner box with the wind generators, coming off from the DC side on the wind controllers to feed the batteries?

I'm located just south of San Diego, CA, so have a really good amount of sun year around and temperatures extremely mild and constant year around, so weather is not a factor here.

My electricals are all new and Energy Star where possible.  I run 1 large refrigerator about 25 CF and a smaller refrigerator at 10 CF, then a large stand-up freezer at 23 CF.  All new and Energy Star.  I will also be running a in-line water pump on the property, along with a Jacuzzi motor for a whirlpool tub.  The water heater and stove.oven are propane and no "heater" style appliances used, except for the occasional microwave (1,100 watts) and a toaster.  These will be my main draws.  I have other electronics, such as flat screen TV's, stereo receivers, etc. but those are not used a lot.  I have two laptops which one runs 24/7 and the other used randomly, but typically not more than 8 hours a week.

My goal is finding the optimum configuration for my needs and location.

Thanks in advance for any help and if I missed any details, please feel free to ask.

SouthPacific

[Vic]

Hi SP,  welcome to the Forum.

The most successful battery-based power systems begin with a clear knowledge of the LOADs that the system needs to supply,  and when these loads will occur.

Will this be an off-grid system,  or connected to the Grid?

It seems that you might well be starting in the middle,  or the end of a process,  and trying to work backward.

Would suggest that you STOP buying any more hardware,  and concentrate on your loads,  and then do several paper designs to make certain that the system will work on paper,  before buying any more neat things.

Batteries need to be charged,  even while sitting waiting for the rest of the system to come together ...   are you doing this now,  and how?

Parallel strings of batteries can often cause trouble,  with that number of batteries,  you might really want to consider a 48 Volt system.

And,  if you will be off-grid,  with your three refer units,  a 48 V system is probably best.  48 V systems make better use of a Charge Controller's (CC's)  output current  --   the same output current yields twice the power on 48 V vs a 24 V system.

Here is a Link to another Forum,  which has a broad range of topics,  and has fairly good participation,    as does this site:
http://forum.solar-electric.com/

Just to try to get this started,   FWIW,   Vic

[SouthPacific]

Hello Vic,

Thank you for the reply.

Yes, you are correct, I have been buying way too much for my use .. but learning a lot.   

I know I should have done the load test months ago, but just put on the Kill-A-Watt on the line now and will see what 24 hours of regular use gives me.  I just want to make sure at special times, I have the juice to throw a party or just play my music for a few hours at a time.  And that will consist of a couple of 800 watt receivers with 4-400 watt subs, etc. which I know will be a drain, but again, will be maybe once or twice a month.  The majority of the time it will be the basics.

Yes, this will be a total off-grid system.  That is why I added the two wind turbines to hopefully catch some juice at night as well.  I have read that by keeping the battery banks fully charged as much as possible, they will provide many years of good service if maintained well.

I have done everything I can think of to cut usage, but still have my favorite toys (like the music and Jacuzzi bathtub).  I have all LED lighting, most only using 6-8 watts per light and making sure the appliances are as efficient as I could get.

So I will report back in about 24 hours with the watt usage and we can go from there.

Thanks again and hope you are having a wonderful Thanksgiving holiday with family and friends.   

SouthPacific

[Vic]

Hello SouthPacific,

Regarding the MNPV6 Combiner and the wind turbines,     the Combiner,  generally would not be used as a connection point for a turbine,  in most systems.

If you live in a very windy location,  a turbine might be able to contribute some power to your system.   There are a number of turbines that have very optimistic specifications on power output.    Hope that your turbines are among the ones that have honest specs.   Often turbines need to be mounted fairly high off of the ground to get clean air.

AND,  as before,  how is it that you are charging the batteries that you already have?

Batteries that sit,  off of charge,  still have a self-discharge,   and will Sulfate after a month,  or so.

Regarding your PV modules and CCs,  the design approach would depend on what will be your system voltage,   and some other details.

More later,   Vic

[mike90045]

You are going to need a backup generator for the times that there is no solar, and you can use the jacuzzi to keep it exercised  The pumps & heaters will quickly drain even a large battery bank.

[SouthPacific]

Hello SouthPacific,

Regarding the MNPV6 Combiner and the wind turbines,     the Combiner,  generally would not be used as a connection point for a turbine,  in most systems.

If you live in a very windy location,  a turbine might be able to contribute some power to your system.   There are a number of turbines that have very optimistic specifications on power output.    Hope that your turbines are among the ones that have honest specs.   Often turbines need to be mounted fairly high off of the ground to get clean air.

AND,  as before,  how is it that you are charging the batteries that you already have?

Batteries that sit,  off of charge,  still have a self-discharge,   and will Sulfate after a month,  or so.

Regarding your PV modules and CCs,  the design approach would depend on what will be your system voltage,   and some other details.

More later,   Vic

Hi Vic,

Thanks again for the reply.  I'll try to make sure I read and answer all questions and my apologies for missing some already.

First, I am very much a beginner here, so most of my lines of thought come from research on YouTube and many other sources, then a bit of general electrical knowledge from regular style house wiring (still not an expert, but have done regular style panels in many homes).

On the wind generators, I got those in an attempt to compensate for electrical power during night time ours to help charge the batteries even at night when we have some wind.  So my line of thought (and only thought) was to hook the DC side of the wind controller to the combiner panel to minimize wiring issues.  I understand that the "ratings" on these are not going to be very accurate and given it is wind generated will vary greatly.

Luckily, my area of the world is extremely predictable the huge amount of time.  I live just south of San Diego CA on the Mexico side of the border (I can see downtown San Diego from here) and I live on a hillside about 1/3 mile away from the waters edge, so the ocean keeps things extremely temperate all year around.  Typical winter is high of about 70 and low of about 50 with very few exceptions.  Summer, high of 80 and low of 60 with very few exceptions.  Lots of sun the huge majority of time (hence the solar) and not a lot of wind, typical breezey days of 7-12 mph, making the wind generator not great, but at least something to possibly compensate over night hours.

I have built good towers for the wind generators.  They are up about 40 ft with perfectly clear clean wind when it is blowing

As to the battery banks, I purchased the batteries about 5 months ago and have custom wired them for now at 12 volt banks and keep them charged with the land power and 12 volt chargers.  I understand this is important not to let them just sit, so I put a charger on them about once a week to 10 days, which the banks then meter out around 87% and I make sure the banks get fully charged each time to keep them active.  I just transferred one bank over to the 24 volt configuration and have begun testing the solar panels and wind generation on that bank.  That is why I started researching on the controllers.  I have some 12/24 volt 30 amp basic controllers, then tried another "cheap" MPPT 60 amp controller, only to find it was not an real MPPT and a POS.      Then I found the MidNite solar site and began using the calculator tools and seeing the real stats for the panels I have (they are CSUN 305's) and now trying to find proper controllers to run these panels and the best configuration for my setup.

I did finally get a true base reading on my usage.  The Kill-O-Watt meter for 24 hours sits at 7.1 kw for 24 hours.  This is an average style day with only the very basics running.  When I say basics, it is the usual things that will be running in the 24 hour period.  This does NOT include things like the Jacuzzi motor or other extras like stereo receivers, powered subs,etc.  But it does include the two refrigerators, freezer, laptops, TV, etc. (typical things used everyday).

To summarize again, I have 16 of the Trojan T105 RE's.  I have them custom length cabled with 2/0 wire and proper copper lugs (I got the good crimping tool, knowing I would have to do lots of connections) with most battery to battery connections being the same length with almost all under 1 ft each.  Also, I configured distance from solar panels to controller to a minimum, which is 30 feet max and controller to battery bank around 6-8 feet.  So I have tried to think of all the best configurations to maximize the efficiency of the entire system.  The run from the wind generators to the controllers is less than 100' using 10 gauge wire and 10 gauge wire from controller to batteries in under a 10' run.

My plans were to use 2 banks of 8 batteries in series/parallel combinations using 24 volt settings and inverters.  Using one bank to run all the small items and the other for the big items, like the refrigerators.  But I am totally open to any and all suggestions/recommendations...that's why I am here..I need expert advise.   

So based on this information, what would you suggest?  Or if you need more information, please let me know in detail and I will answer any questions and provide all the specific information I can.

Thanks again!
SouthPacific

You are going to need a backup generator for the times that there is no solar, and you can use the jacuzzi to keep it exercised  The pumps & heaters will quickly drain even a large battery bank.

Hello Mike,

Thanks very much for the reply.

Based on my battery bank sizes and configurations, would the Jacuzzi motor run a bank down when used for say 30 minutes?  I understand that such things as electric heating elements take huge amounts of usage, so I have tried to stay away from any of those.  My stove/oven and water heater are propane.  Also, I am learning with the wind generators, I have seen things on YouTube regarding "dump loads" for those.  I would like to get your opinion on an idea I had.  Instead of getting a dump load resistor, getting a water heating element as the "dump load" drop-off which would activate the heating element and could be used for additional hot water supply???  Is this something that would work?

Again, thanks for the reply and any and all suggestions/recommendations is greatly appreciated.   

SouthPacific

[mike90045]

A wind turbine dump load,  must be an ultra-reliable "Must Function" sort of load.   It has to be rated to absorb the full hurricane power the wind turbine can output, and when that happens, I'd have it trigger an alarm so you can throw a rope net into the turbine and tie it down at a full stop.   Spinning un-restained, they self-destruct.  There are several terrifying videos on youtube of wind turbines, on fire, spinning to death, throwing blades enormous distances as they grenade themselves.   You don't want to be that person.

A water heater tank of some hundred gallons, with NO thermostat could be used, as long as the element does not boil dry.

"Every month on average 10 wind turbines are destroyed"
http://notrickszone.com/2014/07/28/engineering-magazine-underestimated-danger-every-month-ten-wind-turbines-destroyed-by-fire/
"Only one conclusion can be drawn on the wind turbine concept: the contraptions are impractical. It’s tantamount to using 500 laborers to do the job of a single Caterpillar excavator."

[SouthPacific]

A wind turbine dump load,  must be an ultra-reliable "Must Function" sort of load.   It has to be rated to absorb the full hurricane power the wind turbine can output, and when that happens, I'd have it trigger an alarm so you can throw a rope net into the turbine and tie it down at a full stop.   Spinning un-restained, they self-destruct.  There are several terrifying videos on youtube of wind turbines, on fire, spinning to death, throwing blades enormous distances as they grenade themselves.   You don't want to be that person.

A water heater tank of some hundred gallons, with NO thermostat could be used, as long as the element does not boil dry.

"Every month on average 10 wind turbines are destroyed"
http://notrickszone.com/2014/07/28/engineering-magazine-underestimated-danger-every-month-ten-wind-turbines-destroyed-by-fire/
"Only one conclusion can be drawn on the wind turbine concept: the contraptions are impractical. It’s tantamount to using 500 laborers to do the job of a single Caterpillar excavator."

Hello Mike,

Thanks again for the reply and the article.  I read the article and the comments on it.  The wind portion is very small and was only seen as a night-time style backup solution to produce some power to the battery banks when the solar is not running.  The cost is very minimal, at less than $400 per unit setup (about $240 per wind generator w/controller and then $87 for a 100' 10 gauge 3 wire industrial style extension cord as the wire run and then the misc. parts).  These are not large turbines, with the blade spans being only around 5' diameter.   I also took into consideration the area wind speeds, which are not a lot here.  I can't remember the exacts, but I think the average wind speed for my location is around 8-12 mph.  We just had a storm system pass through yesterday afternoon and had gusts to maybe 20 mph here at the coast.  So I certainly understand the many factors that can play in this arena.  Luckily, I am in a location where weather factors are extremely stable .. that's why I chose here to live.  Especially the temperature factors, with typical year around temps only vary about 10 degrees.  Typical winter temps (like now) sit around high of about 70 and low about 50 with few exceptions and summer highs about 80 and low around 60 with few exceptions.   Not only is it very predictable for things like solar and wind, its very easy on an old body.   

Wind was the only thing I could find as an alternative for night time power generation.  Would you have any other recommendations?

Also, you had mentioned a backup generator, which I do have.  I fire it up about once a month for about 30 minutes, just to keep it running.  I have had it about 2+ years now and it still fires up by the second or third pull.  its only a small 3500 watt unit and portable.  I got it on sale for about $180.   But you had mentioned using it for the Jacuzzi motor.  I have not fired up the Jacuzzi motor on the battery banks yet, but wondered if you knew what kind of draw I can expect on this portion, since you had brought that up? 

I'm still wondering the best style setup, having the two main battery banks (right now two sets of 8 Trojan T105 RE's) and was thinking of having one bank for the big items, like refrigerators/freezer, water pump (which is a small 1/2 hp but have a pressure tank in-line as well to reduce usage and don't run much, a typical shower per day and plan the occasional Jacuzzi bath) and the other bank for all the small things, like TV, stereo, LED lighting, etc.

Your thoughts?   

Thanks again,
SouthPacific

[mike90045]

First, what is the inverter you are using ?   Can it supply the large loads like the jacuzzi and it's heaters,  and your water pumps ?

The more sophisticated inverters can also double as battery chargers.  Some can even assist a generator if the loads are too much for the programmed size of the generator.

Battery banks.   Generally, hook-up and use all the batteries, all the time. Trying to "reserve" some only increases the wear and tear on the others.

Alternative charging.   There is wind, hydro and solar thermal.  Not much else unless you build a steam engine and generator for it to spin.    if your winds are generally under 20mph, there's not much energy there to bother to harvest.

[SouthPacific]

First, what is the inverter you are using ?   Can it supply the large loads like the jacuzzi and it's heaters,  and your water pumps ?

The more sophisticated inverters can also double as battery chargers.  Some can even assist a generator if the loads are too much for the programmed size of the generator.

Battery banks.   Generally, hook-up and use all the batteries, all the time. Trying to "reserve" some only increases the wear and tear on the others.

Alternative charging.   There is wind, hydro and solar thermal.  Not much else unless you build a steam engine and generator for it to spin.    if your winds are generally under 20mph, there's not much energy there to bother to harvest.

Hello Mike,

Thanks again for the replies.

I have two inverters at present, both identical.  24v 3500/7000 units.    My two battery banks are 24 volt (one in use, other about to be hooked in) with 8 Trojan T105 Re's in each.  Wired with 2/0 copper, proper lugs and custom cut lengths almost all under 12" long.  The 8 batteries are in 24 volt series with a single parallel setup, giving more amp hours.  Both banks will be in constant use.  My plan was to have all the light loads on one bank (TV's, laptops, LED lights, etc., plus the quick heavier loads, like the microwave (which is rarely used and when used only a few minutes at a time).  The second bank I planned to dedicate for the constant heavy loads, like the refrigerators/freezer, water pump (a single 1/2 hp pump that does not get much work).  So both banks will be in constant use.  I also have 4 12 volt gel batteries I plan to use as a very light load extra, with a small controller and a single panel as a very small 12 volt setup with a 12 volt inverter I have had for a year or so, but all in perfect shape.

And just a note, the Jacuzzi I have is a tub, not a big multi-person unit.  Its a 3'x5' tub, with, I think, a 1 hp motor.  It does have 10 jets however, which I really like over the standard 4-6 jets.  So you may have been thinking of one of the big units.  I know that can be a huge factor in draw.

Yes, the wind is not much here.  The turbines I have are "rated" (which we know those can be very far off) for peak efficiency at 12 mph and claim 600 watts peak), so I figure is I can get 400 watts during the night, its better than nothing.  No hydro for here as well.

Your thoughts from here?   

Thanks again,
SouthPacific

[dgd]

It looks like there is not really much advice anyone can give you as you are already comitted to two 24volt battery banks and each is multiple parallel battery strings, you have invested in 24volt inverters and you have decided on loads applied to each 'system'.
I agree with Vic's previous comments and advice.
If doing this design again then 48V single battery bank, single string of cells, would have been the best solution, bigger 48v inverter and Midnite 150 MPPT controller pluse epanel and solar combiners
Also one 1Kw wind turbine.

So since you have decided on your basic configuration the only useful advice I can think of is to use Midnite Classics for each battery bank, with WBjr battery current monitor. Each of the turbines should be direct wired to the DC distribution on Epanel but before the WBjr so that the current provided by the turbine can be monitored. The turbines are so small that you are unlikely to need any load diversion or Clipper hardware. They are still useful for those bad weather but windy days to get something into each battery bank.
I see they are 3phase output AC turbines so forget their controllers, just wire via a 3 pole shutdown switch then 40 amp 3phase rectifier then rectifier DC outputs to Epanel DC in terminals (where Classics connect to). I think MN have a turbine shutdown switch.

Using the Local App you should be able to monitor what is happening on each system, or better still use Graham's app on an Android tablet.

dgd

[SouthPacific]

It looks like there is not really much advice anyone can give you as you are already comitted to two 24volt battery banks and each is multiple parallel battery strings, you have invested in 24volt inverters and you have decided on loads applied to each 'system'.
I agree with Vic's previous comments and advice.
If doing this design again then 48V single battery bank, single string of cells, would have been the best solution, bigger 48v inverter and Midnite 150 MPPT controller pluse epanel and solar combiners
Also one 1Kw wind turbine.

So since you have decided on your basic configuration the only useful advice I can think of is to use Midnite Classics for each battery bank, with WBjr battery current monitor. Each of the turbines should be direct wired to the DC distribution on Epanel but before the WBjr so that the current provided by the turbine can be monitored. The turbines are so small that you are unlikely to need any load diversion or Clipper hardware. They are still useful for those bad weather but windy days to get something into each battery bank.
I see they are 3phase output AC turbines so forget their controllers, just wire via a 3 pole shutdown switch then 40 amp 3phase rectifier then rectifier DC outputs to Epanel DC in terminals (where Classics connect to). I think MN have a turbine shutdown switch.

Using the Local App you should be able to monitor what is happening on each system, or better still use Graham's app on an Android tablet.

dgd

Hello dgd,

Thanks very much for the reply.   

Honestly, I'm not truly committed to much.  That's why I am here.  Even though I have the equipment, I can change things out without much problem.  Luckily I have the resources to simply buy something else.  When I started all this, I picked up the batteries first, finding what was a good local deal on the Trojans.  Now, after much more research, I wish I would have gone with the larger battery configuration of the same line, but figure I can still get decent use out of what I already have for several years.

All the extras I have I can easily re-sell locally, because there are a lot of people nearby with little to no power.  I already have people interested in the extra panels and I will actually be making a profit there, since I bought a full pallet (24) and got a good price at only .52/watt.

I have an array of 12v and 24v inverters and controllers as well, so getting rid of those for what I paid for them is not a big concern.

So I am basically still open for change and finding out the best design for the solar setup.  The wind situation is not a priority, since I got those very cheap and those are nothing more than a night time solution to get even a little power during the night, with the main concern of keeping the battery banks in the best condition possible.

Luckily, we have a huge amount of sun here.  Very little rain and very temperate climate year around, so that takes care of many factors most people have to consider.

I have designed my solar array on a tilt style platform.  I live on a pretty steep incline, with the sun coming over the hill in the am.  I can make the solar platform almost flat to begin catching the morning sun, then tilt from flat to the west (towards the ocean) to maximize the direct line of the sun, even down to sunset. It will also pitch at the north end to better track the sun within the seasons.  I am hoping between a good MPPT controller and the use of direct angle to the sun, I can maximize the power (again, just a thought, I am an extreme novice here).  So this is more of a "science project" for me, but appreciate and encourage all the  suggestions/advise from those like you who know a LOT more about all this than I.   

One question would be is if I go to a 48v setup, will two banks of 8 T105 RE's be sufficient to run everything I have listed?  Or should I run the 16 I have now as a 48v in series with a single parrele between those and get another bank of the larger Trojans as my second bank?  Or is there a better storage array that is still cost effective?

Thanks again!
SouthPacific

[TomW]

SouthPacific;

Not to jump on you but after seeing your post that nothing is set in stone hardware wise and drawing from personal experience:

Just go 48 volts to start and you will not regret it! The old, often cited,  reasons to not go to 48 volts are no longer valid.

Stay away from batteries in parallel if at all possible. Many reasons for this but mostly connection resistance and hard to keep them in balance.

Use one battery bank unless you have very good reasons to use multiple banks like distance from point of use or something like that.

Maybe sit down and do some calculations on your needs. A Kill-a-watt can help if used wisely, especially on things like refrigerators / freezers that run intermittently. Use the nameplate rating on appliances and hours of use to come up with your consumption on items you know your use hours like  TV, music & computers.

Careful design considerations will make the difference between a sweet system that does what you need and expensive paperweights in your yard and basement.

My best advice is to slow down and ease into things rather than go fast and loose.

Just my opinions, apparently shared by some in this thread.

Tom

[Westbranch]

Instead of doing a lot of playing with the panel angles and direction, I suggest you research 'Virtual Arrays'

Here is an example:
http://kb1uas.com/mnsforum/index.php?topic=2321.msg21910#msg21910

or do a more global search.  then you can use some of those extra PV's

[SouthPacific]

SouthPacific;

Not to jump on you but after seeing your post that nothing is set in stone hardware wise and drawing from personal experience:

Just go 48 volts to start and you will not regret it! The old, often cited,  reasons to not go to 48 volts are no longer valid.

Stay away from batteries in parallel if at all possible. Many reasons for this but mostly connection resistance and hard to keep them in balance.

Use one battery bank unless you have very good reasons to use multiple banks like distance from point of use or something like that.

Maybe sit down and do some calculations on your needs. A Kill-a-watt can help if used wisely, especially on things like refrigerators / freezers that run intermittently. Use the nameplate rating on appliances and hours of use to come up with your consumption on items you know your use hours like  TV, music & computers.

Careful design considerations will make the difference between a sweet system that does what you need and expensive paperweights in your yard and basement.

My best advice is to slow down and ease into things rather than go fast and loose.

Just my opinions, apparently shared by some in this thread.

Tom

Hello Tom,

Thanks for the reply.   

I had placed a Kill-O-Watt meter on my line and I use a base of 7.1 kw in 24 hours.  This includes all my basics, including 2 refrigerators and a stand up freezer.  I ran my typical things during that time, like TV, lights, etc.  this does NOT include things like running the Jacuzzi tub (it is an actual bathtub, not a big multi person unit) or my music equipment (which when ran can take up some juice, because a single receiver can be 800 watts and add in dual subs at 400 watts each can be like running a big microwave for an hour or two).

So that is where my needs get a little more complicated.  My base things are no problem.  It's when I want to run all my "extras", I want enough juice to run those at any given time as well.

You mentioned not using parallels, but with my battery banks, I have a total of 16 Trojan T105 RE's, which placing 8 in series will give me a single 48v bank.  Would you recommend I then run a single parallel between those to keep it all at the 48v?  Or simply make two banks?  And with such banks, will my 2/0 cabling work or will I need larger than that?

Thanks again,
SouthPacific