Expanding existing system question?
Comments
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Re: Expanding existing system question?northerner wrote: »With 2 inverters load sharing, you will minimize overloading and overheating problems.
They're only sharing 240V loads. The 120V loads are powered completely by one inverter or the other, depending on whether they're connected to L1 or L2. -
Re: Expanding existing system question?They're only sharing 240V loads. The 120V loads are powered completely by one inverter or the other, depending on whether they're connected to L1 or L2.
Unless an autotransformer is used to balance the legs. -
Re: Expanding existing system question?Cariboocoot wrote: »Look at it another way:
The purpose of the expansion is;
1). to get 240 VAC?
2). to get additional power capacity?
3). to provide back-up power in the even of an inverter failure?
4). all of the above?
If #1, it's easier and cheaper to just get an autotransformer for the 240 Volt load(s).
If #2, you pretty much have to add the second inverter or else switch out to a bigger unit.
If #3, you could buy a 'reserve' inverter that would handle the essential power needs while the main was down. It would not necessarily have all the abilities but would cost less.
If #4, you're back at doubling up on the Outback.
Purpose of the expansion is to go completely off grid. I'm still on the grid but only for about one more month. It's a no brainer for me to go with the 2nd inverter. That's not the question I was asking in this thread. The real question is dealing with the battery configurations and the fact that my inverter is only 24 volt. As mentioned, I'm kicking myself now for not going with a 48 volt inverter. I may look at the option of selling my existing inverter, and go with (2) 48 volt inverters. -
Re: Expanding existing system question?They're only sharing 240V loads. The 120V loads are powered completely by one inverter or the other, depending on whether they're connected to L1 or L2.
They're sharing the entire load of the house is what I meant, rather than running the entire house load through one inverter. -
Re: Expanding existing system question?northerner wrote: »I'm looking at expanding an existing system which consists of 2 banks of 4, 6v L16 batteries (ie 8 total) giving me 24 volts, a 24 volt Outback inverter, and a Midnite Classic 150 charge controller.
I would like to double the number of batteries, add another inverter in series with the existing, and another charge controller. I could keep the second addition totally separate, except for the linked inverter to give me 2 legs of 120 volt (using an auto transformer).
Another option I was contemplating, was to place the two new battery banks in series to make 48 volts, but run each inverter off the separate banks. The advantage of this would be charging the larger battery bank at 48 volts which is more efficient. Disadvantages I can think of are unbalanced loading on each bank can lead to a slight imbalance with the charging. Also, the negative of only one bank (and corresponding inverter) can be connected to ground. So I'm thinking it's not a good way to go. Thoughts?
The batteries I have are almost a year old, but paralleling them would result in 4 separate strings in parallel. Not good. I'm thinking in hindsight that I should have went with a 48 volt system, but it's too late for that now.
You could have each inverter be in charge of its own battery bank, 2 strings on each inverter, separate, and independent of each other. This would allow you to avoid mixing old and new batteries. This would probably not be advisable if you were having the inverters be in phase-synch with each other (split-phase or 3-phase) as one inverter shutting down due to low DC volts would screw everything up, but if you are all single phase, this should work as one inverter falling out will just be a reduction of output. PDPs and e-panels are designed for multiple inverters to share battery banks so you would need custom electrical if you want to pull that off.
If you want a unified bank you could use a set of busbars to parallel the 4 battery strings. There were two threads that had some creative parallel wiring arrangements to get near current-equality without the use of busbars. -
Re: Expanding existing system question?
I read all your post,s and can,t see why you don,t want to be grid tied. Don,t know what you have to pay for connection fee, but I pay about $10 for the privelige. For $120.00 a year I couldn,t even buy one battery. You could still use all your present wquipment and let the grid make up the difference. solarvic -
Re: Expanding existing system question?YehoshuaAgapao wrote: »You could have each inverter be in charge of its own battery bank, 2 strings on each inverter, separate, and independent of each other. This would allow you to avoid mixing old and new batteries. This would probably not be advisable if you were having the inverters be in phase-synch with each other (split-phase or 3-phase) as one inverter shutting down due to low DC volts would screw everything up, but if you are all single phase, this should work as one inverter falling out will just be a reduction of output. PDPs and e-panels are designed for multiple inverters to share battery banks so you would need custom electrical if you want to pull that off.
If you want a unified bank you could use a set of busbars to parallel the 4 battery strings. There were two threads that had some creative parallel wiring arrangements to get near current-equality without the use of busbars.
I'm thinking of selling the 24 volt inverter I have and switching to 48 volt inverters as other posters recommended. I am still looking at options, however and thanks for the suggestions. -
Re: Expanding existing system question?I read all your post,s and can,t see why you don,t want to be grid tied. Don,t know what you have to pay for connection fee, but I pay about $10 for the privelige. For $120.00 a year I couldn,t even buy one battery. You could still use all your present wquipment and let the grid make up the difference. solarvic
In the area I live, we are paying very high distribution fees for grid power which makes grid tie options not feasible. For example, we are paying roughly 10 cents per kwh for the electric energy use charge. But the final amount we actual pay, including transmission and distribution charges is between 35 and 45 cents per kwh. Makes no sense to grid tie when the distribution and transmission fees are far in excess of the energy usage fees. Other reasons for going off grid, are hopes to eventually make use of the system on an acreage that is not serviced by power. And of course the other big reason is the benefit to the environment in offsetting the burning of coal (and natural gas) used to produce most of the electric power in Alberta. Were it not for the environmental factor, I would not be making this move. -
Re: Expanding existing system question?northerner wrote: »In the area I live, we are paying very high distribution fees for grid power which makes grid tie options not feasible. For example, we are paying roughly 10 cents per kwh for the electric energy use charge. But the final amount we actual pay, including transmission and distribution charges is between 35 and 45 cents per kwh. Makes no sense to grid tie when the distribution and transmission fees are far in excess of the energy usage fees. Other reasons for going off grid, are hopes to eventually make use of the system on an acreage that is not serviced by power. And of course the other big reason is the benefit to the environment in offsetting the burning of coal (and natural gas) used to produce most of the electric power in Alberta. Were it not for the environmental factor, I would not be making this move.
If you grid tie then there would at least be no distribution, transmission or generation charges while the GTI is producing. What does your utility say about net metering? -
Re: Expanding existing system question?solar_dave wrote: »If you grid tie then there would at least be no distribution, transmission or generation charges while the GTI is producing. What does your utility say about net metering?
I have plans to use the system on an acreage not serviced by power, so I haven't investigated net metering. I would think that distribution charges wouldn't be offset if you contributed to their grid, as you're still using the distribution network. It's really the distribution fees that are ridiculously high in this region. -
Re: Expanding existing system question?
Advantages of gridtie. It is a lot more efficient and way less cost. You need no batterrys and all the troubles and maintainance. You don,t have to worry about cloudy days as the grid makes up the difference, A grid tie system is automatic and doesn,t hardly need any maintainance. The way gridtie works. You can make it big enough to supply all your electric. A net metering agreement usually works this way. You design it so it makes a little more than you need for a 24 hour period. When solar is charging in the daytime it will make what you need and some extra which you get back when you need at night and for the days that don,t generate much power. Electric co reads your meter each month and if you have a smart meter like I have it works this way. The meter has a reading of how much electric you generate and another reading of what you used. If you generate a surplus that amount is credited to your account for future use to cover the months you might use more than you generate. AS long as you generate enough power that is needed you only have an account charge for meter reading and sending you the monthly statement. More advantages is you don,t have to worry about overloading your inverters or batterys. You can still practice conservation in order to keep your equipment cost lower. OH AND THERE ARE NO DISTRIBUTION CHARGES UNLESS YOU DEPLETE YOUR CREDITED ACCOUNT. Solarvic -
Re: Expanding existing system question?
You Americans crack me up.
Northerner lives in Alberta, Canada. Most utilities up here don't know solar from a hole in the ground and no, there are no laws which say they have to accept it much less buy it. True, Ontario has a program (which pays more for solar generated power than it sells it for and so now the utility needs a massive rate increase to make up the difference) but out here in the part of the country that Ottawa sees only as a source of revenue ...
Technically BC Hydro (a Crown corporation) allows GT systems. They pay what they sell for: $0.10 kW hour. Your GT system will lose you money faster than you can say "What happened to the penny?"
It all costs more to begin with too.
That said, I think he's going to find it extremely difficult and expensive to try and meet power needs in northern Alberta entirely off grid 365 days per year. The daylight gets pretty short along about December.
We have got one forum member even further North, in Yellow Knife. I don't know how his system is fairing just now, but I expect there's a lot of generator run time accumulating.
Canada: it ain't sunny Spain. :-) -
Re: Expanding existing system question?
Thats why the " Snow Birds " head south for the winter. No pun intended, I do the same thing, I abandon my off-grid in November and go back in March - April. I tried one year to live year round and gave it up as unsustainable. I spent 4 years just getting ready to give it a try and many $$$ and in the end it just didn't make sense. I ended up putting 8.2 KW of grid tie on my city house and use it's revenue to offset my off grid adventure.Cariboocoot wrote: »You Americans crack me up.
Northerner lives in Alberta, Canada. Most utilities up here don't know solar from a hole in the ground and no, there are no laws which say they have to accept it much less buy it. True, Ontario has a program (which pays more for solar generated power than it sells it for and so now the utility needs a massive rate increase to make up the difference) but out here in the part of the country that Ottawa sees only as a source of revenue ...
Technically BC Hydro (a Crown corporation) allows GT systems. They pay what they sell for: $0.10 kW hour. Your GT system will lose you money faster than you can say "What happened to the penny?"
It all costs more to begin with too.
That said, I think he's going to find it extremely difficult and expensive to try and meet power needs in northern Alberta entirely off grid 365 days per year. The daylight gets pretty short along about December.
We have got one forum member even further North, in Yellow Knife. I don't know how his system is fairing just now, but I expect there's a lot of generator run time accumulating.
Canada: it ain't sunny Spain. :-)
I guess Chris Olsen is has about best set up and I am sure it's a 24 hour a day quest for him to keep it all functioning. Not everyone has the skills necessary to pull it off. -
Re: Expanding existing system question?Cariboocoot wrote: »You Americans crack me up.
Northerner lives in Alberta, Canada. Most utilities up here don't know solar from a hole in the ground and no, there are no laws which say they have to accept it much less buy it. True, Ontario has a program (which pays more for solar generated power than it sells it for and so now the utility needs a massive rate increase to make up the difference) but out here in the part of the country that Ottawa sees only as a source of revenue ...
Technically BC Hydro (a Crown corporation) allows GT systems. They pay what they sell for: $0.10 kW hour. Your GT system will lose you money faster than you can say "What happened to the penny?"
It all costs more to begin with too.
That said, I think he's going to find it extremely difficult and expensive to try and meet power needs in northern Alberta entirely off grid 365 days per year. The daylight gets pretty short along about December.
We have got one forum member even further North, in Yellow Knife. I don't know how his system is fairing just now, but I expect there's a lot of generator run time accumulating.
Canada: it ain't sunny Spain. :-)
I absolutely agree. We do get plenty of sunshine here, however. In winter, there will be a few months of generator dependency, but the cost of natural gas is really cheap here. I can generate my own electric power using a natural gas generator for less than the electric utility sells it! :cool: And really only needed to any extent as I mention for a short period in the winter. I'm already close to par with my power use, and will be tripling my solar network.
Also, I am looking forward to emerging battery technology, and a cost effective and efficient replacement for lead acid batteries. I'm hoping there will be a better alternative after my current batteries are finished. Longer life batteries, that are efficient and non toxic will make off grid systems even more feasible! -
Re: Expanding existing system question?Cariboocoot wrote: »That said, I think he's going to find it extremely difficult and expensive to try and meet power needs in northern Alberta entirely off grid 365 days per year. The daylight gets pretty short along about December.
That's feasible. I'm going to do that too. Worse yet, I've got trees that shade my panels pretty bad during Christmas, and I've got batteries that require charging voltage 10% higher than they should. That's quite a bit of headwind, bit I'll be switching off the grid in April or May. I think I could even do that with the current setup, but it would be real hard in winter. So, my current plan is to get more panels.Cariboocoot wrote: »Canada: it ain't sunny Spain.
There are some really sunny places in Alberta, especially south parts around Lethbridge, which gets 300+ sunny days a year. In the North, it's getting worse because the Sun is too low and days are too short in winter. -
Re: Expanding existing system question?There are some really sunny places in Alberta, especially south parts around Lethbridge, which gets 300+ sunny days a year. In the North, it's getting worse because the Sun is too low and days are too short in winter.
There are some really sunny places in BC too, but that doesn't stop the days from getting shorter. If we could store up the "eight surplus hours" in Summer for use in Winter it would work, but it's not feasible. Expect batteries to sit for six months holding a charge? No way. So again you come down to having to build a system that can supply needs when there's only 6 hours of daylight and that ends up being huge for the other extreme; when there's 16.
Spain, and any other place closer to the equator than those of us above the 49th parallel, has the advantage not in sheer number of sunny days but in the consistency of daylight hours. It makes it easier to plan a system even if the days aren't all sunny. -
Re: Expanding existing system question?
I currently have a 1.4 kw solar grid. In the past month I have generated close to 140 kwh through my charge controller and made use of close to 100 kwh of 120 volt power. That is mainly through the month of February when days are relatively short. I plan to triple my solar network to 4.2 kw. I don't expect to have any problem at all! -
Re: Expanding existing system question?
Well, no one ever expects to have problems till the Gremlins come out and get ya. It's always a good idea to have a plan, B, C & D. One Hail Storm can put you out of business in about 30 seconds, how I know.northerner wrote: »I currently have a 1.4 kw solar grid. In the past month I have generated close to 140 kwh through my charge controller and made use of close to 100 kwh of 120 volt power. That is mainly through the month of February when days are relatively short. I plan to triple my solar network to 4.2 kw. I don't expect to have any problem at all! -
Re: Expanding existing system question?
Let's see ... 140 kW hours in a month is about 4.6 kW hours per day, divided by 1400 Watt array = 3.2 hours equivalent good sun with zero losses.
Neat trick. How do you do it?
What could be expected from that array:
1400 * 0.84 (efficiency assuming good elevation and nice, cold temps + MPPT controller) = 1148 Watts * 2 hours equivalent good sun on Dec 21st = 2296 Watt hours DC.
You must have elevation and cold temps working for you, as your figures indicate an extremely high efficiency ration which not to be expected. I can get almost that at my cabin (2.4 kW hours from 700 Watts of panel) but that is on the long days of the year, not the short ones.
Got tracker? Mind you, they have trouble with our Winters and there's not much tracking goes on when the sun is down on the horizon line and only pops up a little ways for a few hours a day.
The days are already noticeably longer, though. That's one good thing; the shift may be drastic but its also quick. Those poor Equator-dwellers are actually losing daylight now! Why, by the Summer solstice they'll be down an hour! -
Re: Expanding existing system question?Blackcherry04 wrote: »Well, no one ever expects to have problems till the Gremlins come out and get ya. It's always a good idea to have a plan, B, C & D. One Hail Storm can put you out of business in about 30 seconds, how I know.
Around here, with witer tilts and predominant NW winds, the hail is very unlikely to cause a damage!
We had huge hail the size of peaches few years ago. Totalled two cars. We had do re-do all the shingles on the roofs and all the gutters. Our neighbor lost all his windows on the west side, but our windows were new and none of them broke. I guess solar panels have high quality glass that will survive too. -
Re: Expanding existing system question?Cariboocoot wrote: »Let's see ... 140 kW hours in a month is about 4.6 kW hours per day, divided by 1400 Watt array = 3.2 hours equivalent good sun with zero losses.
Neat trick. How do you do it?
What could be expected from that array:
1400 * 0.84 (efficiency assuming good elevation and nice, cold temps + MPPT controller) = 1148 Watts * 2 hours equivalent good sun on Dec 21st = 2296 Watt hours DC.
You must have elevation and cold temps working for you, as your figures indicate an extremely high efficiency ration which not to be expected. I can get almost that at my cabin (2.4 kW hours from 700 Watts of panel) but that is on the long days of the year, not the short ones.
Got tracker? Mind you, they have trouble with our Winters and there's not much tracking goes on when the sun is down on the horizon line and only pops up a little ways for a few hours a day.
The days are already noticeably longer, though. That's one good thing; the shift may be drastic but its also quick. Those poor Equator-dwellers are actually losing daylight now! Why, by the Summer solstice they'll be down an hour!
I think it's largely due to colder temps and the MPPT charger that allow the panels to produce even more than the rated output. On one occasion it popped a 63 amp breaker from the charge controller output. I have seen well over 1800 watts production from the panels after the sun comes through a cloud. But now they are often producing more than the rated output, as the sun is higher and is still cold. And no I don't use a tracker, but can tilt the arrays to match the suns angle seasonally. -
Re: Expanding existing system question?Around here, with witer tilts and predominant NW winds, the hail is very unlikely to cause a damage!
We had huge hail the size of peaches few years ago. Totalled two cars. We had do re-do all the shingles on the roofs and all the gutters. Our neighbor lost all his windows on the west side, but our windows were new and none of them broke. I guess solar panels have high quality glass that will survive too.
Big hail is not very common here as well, but yes anything can happen. At least it would be in summer when losing power wouldn't be so critical as it would in winter. -
Re: Expanding existing system question?
Panels are usually rated for around golf ball sized hail...
Solar panel damage from hail storm
Golf Ball Protection
-BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset -
Re: Expanding existing system question?
here is another link, my panels survived.
http://forum.solar-electric.com/showthread.php?9426-What-the-hail-is-going-on!&highlight=hail -
Re: Expanding existing system question?solar_dave wrote: »here is another link, my panels survived.
I thought I would post these -
Re: Expanding existing system question?I thought I would post these
That looks like one big hail stone in the car. Just think how many times it must have been uplifted in the storm before it grew big enough to fall out and how high and strong a storm that must have been. -
Re: Expanding existing system question?
Here is a bunch. I probably worry about wind more than hail. I think the point is PV's can be compromised, best to have a plan. The only time I really was from a Ice storm that made them useless for 8-9 days. Fuel became a issue because the computerized pumps would not work and the 30 mile trip back and forth to town became a problem.
https://www.google.com/search?q=hail+solar+panels+damage+picture&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=BdU3UYP_PIiNyAHFsYD4BQ&ved=0CDAQsAQ&biw=1165&bih=550 -
Re: Expanding existing system question?I thought I would post these
The old cliche of golf-ball-sized hail, in the flesh, as it were.SMA SB 3000, old BP panels. -
Re: Expanding existing system question?The old cliche of golf-ball-sized hail, in the flesh, as it were.
Just like that
Attachment not found. -
Re: Expanding existing system question?Just like that
It cheated, having grown by the agglutination of smaller hailstones! Respectable size nontheless, but it did not spend as much time growing as it could have to get to that size.SMA SB 3000, old BP panels.
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