Need Help with Solar setup

[davenok]

Hi all. We are building a small offgrid home that will have low power requirements. I have good general understanding of wiring and DC circuitry but after I read some bad stuff about a particular unnamed company (not gonna smear anyone on hearsay), I am a bit uncomfortable with spending my money with them. They offered a hybrid charge controller that would accept direct input from my panel array as well as from my wind turbine. Long short, decided I'd rather go with a MidNite Classic 150 but am a bit confused as to the "extra" components that seem to be introduced in all the implementations I've seen.

My big questions are:
1. I know that Classic 150 takes wind, solar and hydro, but will it accept input from them all, or do you have to choose which source you are using? (ie, Do I need 2 controllers to do wind and solar?)
2. The combiner box serves as a break as well as a cutoff for your array(s)
3. Like I mentioned, this will be a rather minimal 24v system with an array of around 800w solar and a 1600w turbine. I want to do the minimal possible installation while still staying safe.

Any advice is appreciated immensely!

[Westbranch]

Dave you said 1.  Classic 150 takes wind, solar and hydro,

that should read Classic 150 takes wind, solar and OR hydro, choose 1, any 1...

2.  yes it can be used as a disconnect as well as a combiner if necessary

3. You have not mentioned batteries yet... nor the loads you want to power?

[davenok]

OK, That answers one of my questions... as I assumed, it's OR, not AND.

As far as batteries, was looking at Trojan golf cart batteries. We are going to start out very minimal and then add panels to grow the array and batteries to the bank as we can afford.

As far as load, we want to power lights , a desktop PC, a few various chargers (phones, etc), and a few kitchen appliances for starter system. Eventually as the system grows, we'll incorporate washer/dryer and a few other appliances, but our effort here is two fold... First, stop giving money to the electric company, and second, to actually learn to reduce our energy usage.

The mobile home we own will remain grid connected and will function as our laundromat until we can grow the system enough to run the dryer and the other high energy devices. Not an ideal transition but we make due with what we can afford

[ClassicCrazy]

Davenok
There are a couple ways to consider sizing your batteries.
If you have or are going to have an inverter on it you need to size them to be able to handle the largest surge you put on it.
So if that is going to be the inductive load surge from your washing machine motor size for that. Of course you will need an inverter that can handle that too.
Best way to size your lead acid battery pack for long life is to size it so you only use 20 % of its capacity before you recharge ( either from wind, solar , or generator ) .
Which gets to the point of adding on batteries later - you want lead acid batteries to all be the same type and age. So you can't just add on a few more batteries in a few  years.  You can do that with PV panels ( if they are similiar) but not suggested for batteries.
So in the long run you may be better off going with L16 size batteries ( or larger)  now instead of golf cart batteries.
The other thing to keep in mind is that it is better to have fewer larger batteries in series , than to have two series strings of smaller cells paralleled . 

If your batteries are full and the sun is shining or the wind is blowing you have lots of extra power to use for washing or drying or whatever - that is the time to use it if you can.

Is the turbine water powered ?

Larry

[davenok]

Wind, but turbine is probably out of budget for "phase 1" as I don't have the budget for 2 Classic 150s right now... especially with misc hardware (combiner panels, bus bars, etc). Trying to get started on a shoe string. I have $3k allocated to off grid power in the build.

We will live with whatever function that gives us beyond lights for now and use utility power in the trailer as needed to supplement. I'll look into the recommended batteries and post specific details of my build before purchase.

Something like crown-cr430-6v-flooded-l16-battery (not sure if legit to post links to external sites?)

430ah @ 20 Hr. rate. 6v battery, so 4 of those make a 24v system. I don't exactly understand the "430ah @ 20 hr rate"... does this mean that it can deliver 430amps per hour for 20 hrs sustained? or 430 amps over 20 hours?

[Robin]

Very good advice given here.
The Crown is basically an L16 from the 430 amp hours at 6 volts. Here is the sanity check. Amp hours goes like this:
You can run a 430 amp load for one hour or a 1 amp load for 430 hours. Or anything in between. The battery doesn't like to be discharged in one hour, so that is why they came up with a 20 hour rate, but you do not get to discharge 430 amps for 20 hours.
Choose your batteries carefully. Like was stated, you cannot come back in a few years and add more batteries to your existing bank. The bank will have changed capacity and will not be compatible with new batteries.
Be aware that most off-grid folks do not try to run a dryer from Solar. You can certainly do it, but you will have about 5000 watts of load for an hour. That is a very big load and since you cannot afford unlimited batteries, panels and inverters, go with gas.

[davenok]

OK, Thanks. I'll post details of what I intend to buy. As far as not being able to add batteries, it is possible to start a separate bank of batteries with addition of what, just an additional charge controller and some breakers/wiring and a few other misc components? Not ideal and we are well aware we are going to have pretty limited power in the house at first, but baby steps, right? The trailer is killing us on HVAC system energy... very inefficient trailer. The house is underground eco home that will forgo HVAC totally or at least very substantially (summer may need a window unit to cool whole house).

[Westbranch]

well the standard advice is to start with GC golf cart batteries as they are durable and cost effective... Fact - most batteries are killed vs dying a 'natural' death... if they survive you can re-purpose and replace with 2 V cells , available in much higher Amphrs like up to 1000 and more Ah

[ClassicCrazy]

Have you studied up on wind energy ?
The wind generators are expensive and take maintenance which is not so simple when they up at their ideal 80 to 100 foot height.
Solar is a lot easier .
Anyway good thing you are starting with the solar part first !
I will just throw some number out for the heck of it
1000 watts PV   $1000 ( $1 a watt )
rack for PV unless you are making you own can cost almost as much .
Classic , breakers , boxes wiring ,  etc $1000 or so
Golf cart batteries maybe $100 each ( not sure what lead prices are now - think they may be high )
L16 batteries are probably at least $1000 for 4 of them .
Since you will have grid power there you could do without a generator and get a good inverter/charger to keep the batteries happy .
Samlex has decent lower cost  ones, Outback is quality step up , Midnite inverters of  small size won't be on market for awhile from the sounds of it.
That is my rough estimate .
But you can get 30% back if you can take the federal income tax credit.
I think it is a good investment - nothing like having your own power source !
Larry

[TomW]

As Larry said, solar is pretty much plug and play. As in install it and forget about it.

Batteries need looking after either way so, unless you like the effort involved in a turbine you might be better off leaving the wind out of the equation.

Turbines are more fun to watch than boring old solar panels, of course.

Views perhaps not shared by everyone.

Tom

[mike90045]

1 problem with wind turbines:  Wind.   You either have too much, or never enough.  99% of home sites are not suited for wind.  Where there is enough wind for power, it's too windy to live.
Or, you have a big storm, the batteries fill up and and the turbine brakes fail, and burn your dump load, and boil your batteries - Yow!!

[davenok]

So, one last, silly question. I can feed an array of matched panels into the Classic 150 at some higher voltage combination, such as 48v, 96v, etc VOC, then have the Classic 150 charge a smaller voltage battery bank at say 12 or 24v?

[TomW]

So, one last, silly question. I can feed an array of matched panels into the Classic 150 at some higher voltage combination, such as 48v, 96v, etc VOC, then have the Classic 150 charge a smaller voltage battery bank at say 12 or 24v?

Absolutely!

That is the beauty of MPPT, it transforms higher voltage to lower voltage so long wire runs can be used without crazy large cables.

Probably want to be closer to 2X battery voltage but higher is doable with some losses from the wide spread from input to output.

Best of luck with it.

Tom

[ClassicCrazy]

So, one last, silly question. I can feed an array of matched panels into the Classic 150 at some higher voltage combination, such as 48v, 96v, etc VOC, then have the Classic 150 charge a smaller voltage battery bank at say 12 or 24v?

Yes that is what it is all about !
Run series strings of higher voltage so you can use smaller wire size  to Classic and then charge lower voltage batteries.
But in practice it is best to try and keep battery voltage and string voltage sort of close for best efficiency .  But you can go to the limits if you need to - the Classic will just be running hotter .
You can use the string calculator on Midnite site to plug numbers in to see what works.

Larry

[davenok]

So, does this look like a decent startup build? And am I missing anything crucial? (wiring, cabinet fittings, batteries, etc not listed)

Aims 1500 Watt pure sine inverter                                      $279.00   1   $279.00
Canadian Solar 320 Watt Poly Solar Panel                      $185.97   4   $743.88
100 Foot Black & Red 10 Gauge MC4 cbls                        $84.99   1        $84.99
Midnite Solar Battery Capacity Meter, Model# MNBCM        $63.00   1     $63.00
150vdc breaker 60 amp                                                        $20.00   2     $40.00
combiner box - Midnite Solar MNPV2-MC4                      $149.00   1   $149.00
charge controller - Midnite Solar Classic 150                      $568.00   1   $568.00
TOTAL                                                     $1,927.87