Small off grid solar system ... I'm taking the solar plunge

Small off grid solar system ... I'm taking the solar plunge

PostBy: lsayre On: Fri May 22, 2015 6:29 pm

So far I've purchased 4 x 260 Watt panels, an MPPT charge controller, and a 1500W 24V inverter. I still need to bag 4 x ~350 AH 6V deep cycle batteries, and all of the necessary racking, wires, junction boxes, and fuses to put this tiny system together. Will probably also need a 40 Amp rectifier and a generator. This system will not be grid tied. Hoping to get (on average) about 80 KWH per month from it. About 20% of our overall electrical demand (as long as we don't run the AC). Using it purely as a learning experience, but it may come in handy in a power outage.

Anyone know how to put one of these puppies together properly?
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)


Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: Lightning On: Fri May 22, 2015 6:40 pm

Wow. That's pretty neat :D
How much you got into it cost wise?
Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: Rob R. On: Fri May 22, 2015 6:43 pm

what do you plan to power with it?
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: lsayre On: Fri May 22, 2015 7:27 pm

Rob R. wrote:what do you plan to power with it?


I'm mainly hoping it will be sufficient to power both our refrigerator/freezer and our deep freezer if/when called upon. Both of our refrigeration units are new and combined they draw only half of the current of the older units they replaced. Realistically it won't power much more than that and a couple 10 Watt LED light bulbs (60 Watt equivalent). But after that, whatever roughly 2.6 KWH of on average daily output (after factoring in all of the inefficiencies of the system that I can think of) will permit. For comparison, we run our entire house on only about 8 to 10 KWH per day when the clothes dryer and the AC unit are not factored in.

Lightning wrote:Wow. That's pretty neat :D
How much you got into it cost wise?


Hoping to keep it at around $3K total (not including a generator). I'm in for $1,605 so far. That includes the 4 panels, the inverter, and the MPPT (maximum power point tracking) battery charge controller. Definitely doing this on the cheap. I just located a new 24V 40A battery charger (rectifier) that runs on 120 VAC single phase for only $206 delivered.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: McGiever On: Fri May 22, 2015 7:43 pm

Red = Positive
Black = Negative

Black (AC) = Hot
White (AC) = Neutral
Green = Earth Ground

Series connect the batteries for additive voltage.

You most likely know this already. :)
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Coal Size/Type: PEA / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: coalnewbie On: Fri May 22, 2015 7:43 pm

I wish you well as I have tried this sort of system and failed miserably, perhaps you will do better.
coalnewbie
 
Hot Air Coal Stoker Stove: LL AnthraKing 180K, Pocono110K,KStokr 90K, DVC
Hand Fed Coal Stove: Invader 2
Baseburners & Antiques: Wings Best, Glenwood #8(x2) Herald 116x
Coal Size/Type: Rice,
Other Heating: Heating Oil CH, Toyotomi OM 22

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: lsayre On: Fri May 22, 2015 7:50 pm

In case you were wondering, the 24V 40A battery charger would only come into play when there isn't enough sunlight to charge the battery bank with the solar panels. This rectifier can use either grid or generator sourced 120 VAC as its power source.

It's not good to leave a battery bank at half charge for any period of time. It's more than not good to take a FLA battery bank below the 50% charge level.

A 24V FLA (flooded lead acid) battery bank has exhausted 50% of its charge capacity when it voltage has dropped to 24.2V. You never want to go below that level.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: lsayre On: Fri May 22, 2015 8:04 pm

coalnewbie wrote:I wish you well as I have tried this sort of system and failed miserably, perhaps you will do better.


What problems did you encounter?
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)



Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: davidmcbeth3 On: Sat May 23, 2015 1:50 am

coalnewbie wrote:I wish you well as I have tried this sort of system and failed miserably, perhaps you will do better.


I have looked at 10 folks who went through a PV state rebate program ... they are generally happy with their system but also noted that the ROI is about 20 yrs.

I would need a ROI of 5 yrs before getting any type of system - its all about the $$$ with me. Currently, the technology isn't making it -- solar is just not viable in my latitude and weather cycles. Not yet anyway.

Wind is also a no-go, not enough wind.
davidmcbeth3
 
Coal Size/Type: nut/pea/anthra
Stove/Furnace Make: Hitzer
Stove/Furnace Model: 503

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: lsayre On: Sat May 23, 2015 3:36 am

grumpy wrote:This might help with the battery's..

http://www.smartgauge.co.uk/batt_con.html


That looks like excellent advice for parallel connected batteries, but to achieve 24V from 4 x 6V batteries I must wire mine in series. Your diagram shows the difficulty in balancing the charges properly in a parallel battery system.

The difference between series and parallel is that in series the voltages add up but the amps remain the same, whereas in parallel the amps add up but the voltage remains the same.

For me, it will be 4 x 6V and 350 AH batteries wired in series = 24V and 350 AH.

To keep from frying my MPPT charge controller my 4 solar panels must be wired in a 2 x 2 combination of the two methods known as 'series/parallel'.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: Freddy On: Sat May 23, 2015 5:26 am

I've got solar & skipped the batteries. I grid tied and so far love it. I'm 4 years into a 9 0r 10 year payback. If I have time I'll come back & explain why I prefer grid tie..... in one breath I can tell you now..... it's cheaper & you get more power.
Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: lsayre On: Sat May 23, 2015 7:07 am

Freddy wrote:I've got solar & skipped the batteries. I grid tied and so far love it. I'm 4 years into a 9 0r 10 year payback. If I have time I'll come back & explain why I prefer grid tie..... in one breath I can tell you now..... it's cheaper & you get more power.


There is no doubt that a battery based off-grid type system costs fully twice as much (or more) as grid tied. That plus the FLA battery bank lasting only somewhere between 5 and 10 years. But it all depends upon your goals, and mine are not suited to grid tied. From what I've learned when the grid goes down a grid tied system goes down right with it. That means no power during an outage. My entire 'initial' aim is to have at least enough power to keep our frig and deep freezer up and running in an outage (without having to run an expensive generator, at least for 1 full day or less of outage, which is mostly what we see around here when we experience one). And mainly I want to learn its capabilities and have fun with it running other stuff during the 99% of the time when there are no outages. Sort of a hobby toy. You have to exercise the batteries on occasion anyway to my understanding, so why not have fun with it.

But with your electric car a grid tied system is perfect for you and a battery based system big enough to accomplish your goals would cost perhaps as much as your house.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: McGiever On: Sat May 23, 2015 7:17 am

Larry, Where will the excess power generated by solar go during those time periods after the batteries have become fully charged?
Must you manually switch the load(s) upon loss of utility power?
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Coal Size/Type: PEA / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Small off grid solar system ... I'm taking the solar plunge

PostBy: johnjoseph On: Sat May 23, 2015 7:21 am

This is really interesting I like it! Keep us posted on this venture once it's complete and in use. I like he specifics your are able to pull from your coal use and if eventually you can apply those same types of specifics with your new electric system that would be beneficial for some that are looking at trying the same! Good luck with this venture! Great post Thanks!
johnjoseph
 
Stoker Coal Boiler: Keystoker KA-6
Other Heating: pellet stove, oil boiler