Author Topic: Going to be adding on in a major way  (Read 3557 times)

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Mary B

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Going to be adding on in a major way
« on: July 29, 2015, 04:27:29 AM »
Okay I have a $10k budget(has to cover everything, panels, inverter(s), charge controller(s), wire, mounting hardware, batteries thinking a minimum of 2500 watts in panels, maybe 5,000. Solar Blvd has good prices on Amerisolar250 watts panels, pallet of 10 for $1,625. Would like to go high voltage inverter and keep wire costs lower, I see Morningstar has a new one out that is 600 volts in, as does Xantrex. Either will handle 5kw of panels with a 48 volt battery bank. Big question is what inverter for battery backup grid tie? Or stand alone battery only(and I rewire some of my house to run off grid only)?

Looking for ideas of what works, pallet of panels is $1,625, charge controller $1,100(give or take), inverter? I would go to L16's for a battery bank if I go battery at all... straight grid tie might be more cost effective and add a bigger backup generator.

Big question is what inverter would you go with? Rest of the system will be built around that. I am leaning more to straight grid tie, I have a battery backup that can run quite a bit already with the smaller system I already have.

oztules

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Re: Going to be adding on in a major way
« Reply #1 on: July 29, 2015, 06:36:45 PM »
Grid tie will be the best and cheapest.... and 5kw should do all you need for that application.

If you want off grid real living, you need 10kw solar, and that will probably cover you in all weather but the meanest... maybe do poorly for 20 days of the year.

For that and that budget, then 10 kw panels is just over 6000,  6-8kw inverter in the $500 mark if you build your own PJ style, and the charge controller will be about 50 dollars for 100 amps @ 48v  If your panels are 60 cell 6x6 poly or monocells, then mppt is a waste of time. ( good thing.. not bad)

So save the money from the expensive charge controller and inverter and put it toward batteries. If you can get 35kwh for the remainder of money, you will have a full house system, that you may never need to turn over to the grid except for very dark days.

If you want commercial gear, then you will be better to go all out grid tie, as the alternative is a pretty minimalist system, and will require house rewiring as you said. If you go all out, then a change over switch will suffice, and that rewire money goes towards more battery or solar until you run out of budget..... more solar  more solar is the mantra.

I am currently making a 35kwh system for a remote island here, and it will come in at the $10000 AUD mark. It will have 35kwh battery ( trojan) 8kw pure sine inverter, 40x 250 watt panels, 100 amp min solar controller.... it will run a 2500 watt hot water system ( about 4kwh/day) and reverse split system air conditioning.... and desalination unit...... very similar to mine here.
 Very rarely go below 75% charge in the battery system because of the solar array being so big..... every day.... so battery life is extended dramatically >10 years on the trojan  T105-RE

Note: get more panels, but do not point them all  south trying to get the best with or without mppt, you don't want that, you want steady all day solar from all directions when overcast... plenty to the east for morning ( you will be charged up by lunch time probably to 85% or more ) some to the west for late evening top up, and the rest south for main bulk charge... thats the plan I found works best.

If the sun is out, you won't need much array to push the batteries hard, but even thats only for a few hours before it backs off... ie 60-70 amps is all you want for 3 hours to cover last night... the rest of the time will be spent in late absorb and only in the 15-40 amps.... no need to try to pay for mppt at all.... you don't want or need it, it will be a liability.  10kw will be quite  capable of 80-100 amps.... more than we want at any one time... we want less for longer.... don't try to optimise in this case... spread you bets around the sky.

ie 3kw is enough on a sunny day, so plan for the worst days only, and the good ones will be just a joke. If you design for the good days, it is a waste of effort i think.... and solar guru's have not caught on to the fact that solar is cheap now, and their advise is out of date in a lot of cases, trying to get the last drop out of the array, when a bigger array is much cheaper than all the fixes and compromises they come up with... nut then they would be out of a job I suppose.....

Thats how I did it anyway, and it works flawlessly, and the boss does not really even know she is off grid. Does not do housework or anything else with the sun in mind.... just does as she pleases.

................oztules

.................oztules
« Last Edit: July 29, 2015, 06:45:06 PM by oztules »
Flinders Island Australia

Mary B

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Re: Going to be adding on in a major way
« Reply #2 on: July 29, 2015, 07:49:59 PM »
Unfortunately the control freaks have passed ordinances, everything I install has to meet electrical code and be UL approved. It will all have to be inspected, approved, signed off on... And after reading the hoops I have to jump through to grid tie, the fees and expenses I am better off going with an off grid system. Off grid I can get away with some shortcuts but to be insured everything still needs UL approval.

My biggest electrical use is the hot water heater. I am replacing that with on demand gas in a month, I may put some solar preheat in front of it to save on the gas bill. Fridge was recently replaced with a chest freezer that is only using .4kwh a day instead of 3.4kwh the upright fridge used. Air conditioning this time of year is another big user and I will leave that on grid. But lighting, the freezers, etc can easily go off grid because my usage is low there. I am building some 24 volt lights to put in that will be motion controlled(PIR) to save power. TV is getting replaced too with an LED backlit instead of the CFL backlit I have now that is a power hog. I am tired of repairing that TV too! I really don't use all that much power. 2 loads of laundry a week, been drying stuff outside and for winter I am getting an indoor clothesline. 2 computer monitors will also be replaced with energy efficient LED instead of CLF backlit(each one draws 200 watts, they run hot!).

Mary B

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Re: Going to be adding on in a major way
« Reply #3 on: July 29, 2015, 07:53:02 PM »
I forgot to add, I already have 2400 watts of off grid solar and a 928 amp hour battery bank(24 volt system) that is running my ham gear, computer system, and the freezer to fridge conversion. add another 5kw off grid and I will have plenty for most of my needs.

DamonHD

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Re: Going to be adding on in a major way
« Reply #4 on: July 30, 2015, 02:57:48 AM »
One thing that helps us is MHRV (mechanical heat recovery ventilation) in the kitchen (which lets us dry clothes on the clothes horse inside in winter; we never need a dryer) and the bathroom.  The fans only use a couple of watts each (and run at 24V internally).

http://www.earth.org.uk/MHRV-mechanical-heat-recovery-ventilation.html

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

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clockmanFRA

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Re: Going to be adding on in a major way
« Reply #5 on: July 30, 2015, 08:14:26 AM »
Hi Mary B,

Its a fairly big step to go totally Off Grid. But we have been slowly shifting for the past 10 years.

We here have Grid Utilities but use it as a standby generator when there's no wind and no sun. We are not Grid tied to the main Utilities so we do not need to jump through any hoops, but I still install to the appropriate safety standards, I have 3 young boys !.

We have 63kW of batteries, 8kw of PV with 5kW on trackers, and 3off Hugh Piggot 3.7m (12 footers) wind turbines, at present but another 9kw of roof mounted PV planned/happening.

Over the years as our RE has increased, I have fitted more Change over switches, see pic.

9011-0

I am tight with money so most of my stuff, ancillary's, is used/second hand, carefully chosen.

 AC coupling, using used second hand GTI's, is very cost effective in feeding into my created Mini Grid as my buildings with the PV etc can be up to 500 ft away from each other.
 AC coupling Is something I am very seriously moving into. However the Inverters on the market at present are a little flaky, so some signal Powerline switching is going to be required to calm down the PV GTI's when NO power is being used at the buildings. (I will ask the forum members for ideas/concepts when I have tested the GTI's actual parameters).

So instead of the PV on the roof power going to a controller and then to batteries I am directly feeding the PV into my Mini Grid when the Mini Grid requires power, like Mrs holiday maker in our No 1 Gite decides to dry her hair and use the electric kettle, and My Inverter with batteries starts to supply then the GTI is switched on and takes over.

Step by step, then I recommend Change over switches, and yes they are Positive and Negative with Centre position Off.

 
Everything is possible, just give me time.

OzInverter man. Normandy France.
http://www.bryanhorology.com/renewable-energy-creation.php

3 Hugh P's 3.7m Wind T's (12 years) .. 5kW PV on 3 Trackers, (8 yrs) .. 9kW PV AC coupled to OzInverter MINI Grid, back charging AC Coupling to 48v 1300ah battery

oztules

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Re: Going to be adding on in a major way
« Reply #6 on: July 30, 2015, 03:44:47 PM »
If you can get credits for excess generation, then there is only one way forward.
A hybrid system is a non starter, as you have all the expenses of off grid, and the expenses of on grid, and your living like a pixie... there should be no compromise if your spending decent money.

I use 700 and 1000 liter freezers, twin door fridges ( with in door ice maker etc etc), proper lighting where ever I want, hot water and air conditioning..60"tv 24/7 ( don't talk about it.. it is mandatory) all easy to achieve.. it takes panels and more panels, but no compromise.

Unless your gas is town gas, it is expensive and annoying to have gas bottles. Solar hot water is expensive and unnecessary if you have plenty of power.... if you really have to compromise, then perhaps a heat pump hot water system)

The best advice if you are allowed to rack up credits with the grid feed.... is go through the hoops, and get as big a grid tie system as is possible, and live like a king... you already have emergency power.... even a 5kw grid tie system will give you near neutral operation in grid tie format.. ......in off grid... 5kw.....not so  good in dark times unless you skimp on power.

The big advantage over here ( this island) is the grid feed is unity priced.... ie 28 cents for use and 28 cents for feed nett. Diesel power plant allows us to keep these tariffs.. on the mainland it is more like 25c use, and 8 cents feedback... still very good if you put in enough panels to pay no power bills at all ( I'm $300 or more in front at the moment... so no bills at all )


Do as you will, but I think your heading the wrong way... as we get older we should have no need to compromise life style, and we need less things to fail... gas hot water, solar pre heat, small off grid system, grid system... what could possibly go wrong??

I can understand gas stove, but a decent gas hot water demand unit will burn up 30- 60 hp of energy...( normal ones here are 54kw) if you enjoy a hot shower for any length of time, that means gas bottle changes every 2 months or so i would guess Over here thats over $120/ 90 lb bottle every few months.....hope it is cheaper there at the moment. Town gas would be a different matter I guess.... but still good money after bad.


..............oztules
« Last Edit: July 30, 2015, 03:49:07 PM by oztules »
Flinders Island Australia

thirteen

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Re: Going to be adding on in a major way
« Reply #7 on: July 30, 2015, 04:57:26 PM »
Mary B as a suggestion and if you have room take off the insulation off of you water heater and the plumb it in front of your on demand water heater and let the warm air inside the house warm up the tank, (ground temp is around 50 degrees so even 15 helps) room temp is 70. A friend of mine has his old water tank mounted on his ceiling. Then he  lets the on demand water heater make up the difference. Just an idea to think about. 13
MntMnROY 13

Mary B

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Re: Going to be adding on in a major way
« Reply #8 on: July 30, 2015, 09:03:05 PM »
I can't meet their requirement for grid tie. I need perfect south and 60 degrees on either side of that that are clear of obstructions. Not going to happen here. Plus a $300k liability insurance policy, plus a monthly connect fee on top of what I pay already, plus pay for a second meter,... to big of a headache for little return.

And I see 20-50 power outages a year, some lasting 20+ hours so my solar is my backup generator. So adding more batteries makes sense to give me more backup power. I already use minimal power, always have. Water heater is my biggest user and as I said it is getting replaced because it is getting to the age where it is going to start leaking anyway(water here eats tanks, anodes don't last more than 4 months). I could put a heck of a big water preheat coil in the ceiling of the kitchen, it has a drop ceiling and a false space, my bedroom is above it so it stays warm. That room is 18x16 feet, forced air furnace is in that room along with ducting to other rooms so the space between the ceiling and the floor above stays very warm(love my warm bedroom floor in winter!). I could even run a loop and a tank in front of the on demand gas heater and keep 30+ gallons of water at room temp.