How many 200w pvs?

Foxtrapper

Ok, I just recieved a mppt controller, it's a Tristar 60 amp. How many 200 watt panels can I run on that? My main system is 12v based, but could increase it to 24v, 36, or 48v..I am using 195ah 6v batteries..I also have a 12v and a 3ph turbine that I was hoping to tie in...is that even possible?

BB.

Re: 12v and 24v panel

The numbers I use for "maximum cost effective" array on an MPPT Controller:

• 60 amps * 14.5 volt batt charge * 1/0.77 panel+controller derating = 1,130 Watt Array @ 12 volt bank
• 60 amps * 29.0 volt batt charge * 1/0.77 panel+controller derating = 2,260 Watt Array @ 24 volt bank
• 60 amps * 58.0 volt batt charge * 1/0.77 panel+controller derating = 4,519 Watt Array @ 48 volt bank

Basically, with average conditions/weather/dirty panels/age, the system may clip on occasion (limit to 60 amps maximum output current)...

More clipping in cool/sunny/clear weather.

"Good quality" MPPT controllers are all capable of limiting their output current to "rated" limit--So you can install a large solar array, or even a 24 volt battery bank to MPPT Controller to 12 volt battery bank and use it to run a second low voltage battery bank.

Pick the derating and battery charging voltage for you needs... 0.77 is fairly conservative and many people report 0.82 or a bit higher. If your system is at a higher altitude will give you a bit more solar energy, etc....

Also, if you run power during the middle of the day when the system is floating (pumping well, shop tools, etc.), you can drop the voltage to 13.6 volts for float...

All of these "adjustments" just drop the maximum "cost effective" array size a bit... For the most part, if you are within +/-10% -- That is "about the same" in the world of solar variability.

The equation at the top of this post is "conservative" and is intended towards a bit larger array (and a little bit more clipping of output current on cool/sunny days).

-Bill

niel

Re: How many 200w pvs?

foxtrapper,
firstly know that i put this into its own thread.

a rough way to figure the pvs would be to multiply the battery voltage by the controller's output current rating. for 12v this is 12v x 60a = 720w. dividing that by 200w gives you 3.6 pvs. now you can round that to 4 200w pvs as they don't usually hit their max rating. you will find they also give the max wattage in their instructions, but the controller will hold at 60a output no matter if you go higher than what they state so there's a point you would lose out on power generated.

you will find that going to a higher battery voltage would help your max power to be handled by the controller as it is still going to be able to output the same 60a. this means at 24v for the batteries that it would be 24v x 60a = 1440w. 1440w/200w=7.2 pvs. round it up to 8 pvs if you like.
does this help?

ps- the turbine can go to the same batteries if at the same voltage through its own controller and would need a dump load as well.

Foxtrapper

Re: How many 200w pvs?

Thanks Niel..wasn't sure where to ask my question.

My "1st" idea was to set up a 12v system, as that is what my inverters are, so I bought the windturbines in the 12v configuration. Now I am learning that the higher your battery voltage, ie 24, 36, 48 ect, the more effiencent your power production. The 60 amp tristar mppt controler I bought came from the online store here. So I guess my biggest question is what kind of inverter do I need to do a pvs system in one of the higher voltages that I can get a 240v line feed off of? That confused me just typing it..

If I set up a 48v battery bank to run the pvs system, I still have the 2 12v windturbines to deal with...I still have 2 6v batteries I could set up a seperate bank for them...

BB.

Re: How many 200w pvs?

It really comes down to defining your loads... Do you need 240 VAC to run a well pump a fair distance away? Or do you need split phase 120/240 VAC (normal north American home wiring), etc... What are the power needs (peak watts, average watts, surge current)...

We can point at various products--But sizing your needs will make the job less frustrating for all of us. And for an "optimum" system (i.e., best bang for the buck), the details matter.

-Bill

niel

Re: How many 200w pvs?

i feel i must clarify that the controller will hold itself at its rated output current, but it does not have an infinite ability for higher input voltage ratings and my reference to higher voltage was to up the battery voltage. it would also go without saying that a higher pv voltage is needed to charge a 24v or 48v battery bank. after you've already purchased a turbine and inverters rated at 12v then you've already locked yourself into a 12v battery configuration unless you plan on replacing the turbine and inverters to go to a higher battery voltage. if your loads dictate more power to be inputted onto a 12v battery setup then another controller can be bought with more pvs feeding it, but expanding the battery bank into many 12v sections can cause an imbalance if not properly done and it does get more difficult to achieve this the paralleled battery strings there are and we generally discourage too many. (like more than 2 in parallel)

you did not indicate the number of 6v batteries you have being used in a 12v configuration.

this could be a case where it would've been better to ask us our opinions before you had bought anything.

Foxtrapper

Re: How many 200w pvs?

Well lets see:

'Frige @ 3.9amps
4 freezers @ 5amps each
Dishwasher @ 12.6 amps
clothes washer 10amps
Electric dryer 5400watts
32inch tv @ 160watts hr * 6 = 960 watts
15 energy efficient bulbs @ 60 watts each
Outbuildings:
20 energy efficiant bulbs @ 15 watts
Outside wood furance: 2 water pumps at3amps
1 blower @ 3.5amps


Sorry about the mixed amps and watts, some of the appliances only listed amps..

Photowhit

Re: How many 200w pvs?

Sounds like your on the grid currently, If you want to off set costs why not do a grid tie system. If you want an off grid back up, look at a charged from the grid battery bank or cheaper an auto start gennerator.

If you want to go off grid look at your electric bill and tell us your KWhours used, but your looking at some very big numbers.

Cariboocoot

Re: How many 200w pvs?

Foxtrapper wrote: »

Well lets see:
Sorry about the mixed amps and watts, some of the appliances only listed amps..

Do not trust any of those numbers. Go buy a Kill-A-Watt (or similar) meter and take real world readings. Inevitably they will be different. Sometimes better, sometimes worse.

Some CFL's, for instance, are "13 Watts" except they have lousy PF and actually consume almost twice that. The refrigerator will do a bzang! start-up surge over 1kW. The electric dryer is an absolute no-no on an off-grid system. You would need a huge system at 48 Volts just to run that power-sucking monster.

Foxtrapper

Re: How many 200w pvs?

"this could be a case where it would've been better to ask us our opinions before you had bought anything"

Definetely...:D...Now onto salavaging what I can out of what I already bought..

"you did not indicate the number of 6v batteries you have being used in a 12v configuration"

The batteries are on order, this is or will be a new hookup...I have the turbines, towers, 12v charge controller for them, and the 60 amp mppt controller, (I got that because of the large number of higher voltage panels that are available, vs the number available for 12v systems), also because I have an 80watt panel that is also 12v...nothing has been hooked up yet..so, other than the money spent on the towers and turbines and 12v inverters (I had one inverter that I bought some years ago for a road trip), i'm not out too much..

It has been hard to get any of the people selling stuff to answer any questions..I have a chance to get 20 200w 27.5Vmp sv solar panels locally at $250 each..would like to know if that is a good deal or not? Here is a link to the panels..the other thing is these are 2nds, so may not have a warrenty with them...

http://shop.windandsolarsupplies.com/SV-Solar-Panel-200-Watts-2750-Vmp-SV-T-200-HV.htm

Foxtrapper

Re: How many 200w pvs?

Photowhit wrote: »

Sounds like your on the grid currently, If you want to off set costs why not do a grid tie system. If you want an off grid back up, look at a charged from the grid battery bank or cheaper an auto start gennerator.

If you want to go off grid look at your electric bill and tell us your KWhours used, but your looking at some very big numbers.

I would like to be indepentant of the grid, or at least mostly indepentant...KW hours used avearge 800 month..I would settle for getting outside furance on solar or wind energy, simiply because if the grid goes out, we don't have a good source of heat...

Cariboocoot

Re: How many 200w pvs?

Divide $250 by 200 Watts and you get $1.25 per Watt, which is really cheap. The 27.5 Vmp indicates they are "grid tie" panels and will not work properly with a battery system unless an MPPT type controller is used.

Be advised a 12 Volt system will not work well for powering many of the items on your list. It will handle the lights, but above that the current demands go into the realm of the absurd. Collectively it would be impossible for a 12 Volt system to handle the loads without major problems (even leaving out the dryer).

Photowhit is spot on here: you've got grid, you've got 4kW of panels for cheap, add a grid tie inverter with the proper permits and permissions and you'll be far ahead over trying to rig up a battery-based system.

Photowhit

Re: How many 200w pvs?

I'm shooting for a system that will do 330 Kw hours a month. I've been off grid for 10 years and am comfortable doing the setup my self, and have gotten bargains on many of the componets and I'm major heavy use time is summer (cheaper smaller system since there is 2x the sun in summer) I figure I'll have close to $10,000 and likely most others doing it the cost would be above $15,000. If my heavy use was in winter add 5-7K...

Solar isn't a cheap alternative...

Foxtrapper

Re: How many 200w pvs?

"Solar isn't a cheap alternative"

If the grid goes down, it might be the only choice available..It is not about saving money, because even with cheaper panels, (sharp 230 watt grade B panels are at .87watt before shipping), it costs more for a solar system than you'd use in elect from the grid..it's more about the freedom that comes with not relieing on anyone else to make your energy for you..I see this more as a must get done, than a want to get done...our grid is old..even the "experts" are starting to warn about it's continued viability....the storms that hit Washington DC recently and cause power outages for days are just a reminder that it can happen at anytime...

I think you will see rising interest in solar and wind energy...demand will out strip production and costs will go up..

Photowhit

Re: How many 200w pvs?

Foxtrapper wrote: »

..It is not about saving money,...
...a reminder that it can happen at anytime...
..

If you want to be completely reliant on solar, no back up genny, For 900KWhours a month, in NY winter with average 2 hours of daily sun, I don't even want to think about the numbers, quick guess your looking at $100,000+.

And if the SHTF the guy with the biggest gun will enjoy it.

Seriously, you might first look at conservation, next a solar hot water heater (if you don't already have one), are you using a wood stove for heat? How well insulated is your home? a clothes line would be a good start as well...

Cariboocoot

Re: How many 200w pvs?

I happen to know the fellow who has designed the grid control system for most of North America (yes, one guy is largely responsible for it all). He has warned for 40+ years about the inevitability of catastrophic grid failure. It has happened, in areas, from time to time. But it's never quite as catastrophic as the doomsdayers would have you believe. There's too much profit in keeping it working. Ironically the main reason it is in jeopardy is the same thing: the profit comes from operating it, not upgrading it. :roll:

inetdog

Re: How many 200w pvs?

Cariboocoot wrote: »

I happen to know the fellow who has designed the grid control system for most of North America (yes, one guy is largely responsible for it all). He has warned for 40+ years about the inevitability of catastrophic grid failure. It has happened, in areas, from time to time. But it's never quite as catastrophic as the doomsdayers would have you believe. There's too much profit in keeping it working. Ironically the main reason it is in jeopardy is the same thing: the profit comes from operating it, not upgrading it. :roll:

Another major contributor to catastrophic failure of a large network, as shown by studies in the telecom industry, is uniformity of hardware and software design. If everybody is using exactly the same technology, the chance that one flaw or one attack can take the whole system down is increased. I do not have any idea how uniform the control software tools used in the power industry are, but a variety of types of power sources, from coal through hydro to PV would have to increase the survivability of that part of the system.
The interties are whole 'nother question! :-)

Foxtrapper

Re: How many 200w pvs?

Basic system would provide heat in the winter(wood stove), cold in the summer (freezers)..would also like to be able to pump water(could hand pump as the well is only 85 feet deep)...not too worried about the dryer..combination of solar and wind would be perfect..as far as the bigger gun, that would hopefully be me..

Foxtrapper

Re: How many 200w pvs?

"But it's never quite as catastrophic as the doomsdayers would have you believe."

It's only a catastroph if your the one in it..lose of power here for 2-3 days would wipe out $1000 plus of food that are in the freezers..if offgrid solar can do nothing more than run my freezers, then that would be good enough..

icarus

Re: How many 200w pvs?

Buy a $1200 genny, $25 worth of fuel, and you can certainy run the freezers for any outage far, far cheaper than you can build, install and maintain an battery backed up PV system. Not to put to fine a point on it, but we have said this over and over again, and it is a fact based in reality.

If one wished to build a battery based system because me wants to, then go for I t, but don't be lulled into the notion that it is going to be cheaper.

Tony

Cariboocoot

Re: How many 200w pvs?

Yes, it can run your freezers.
Freezers tend to stay cold enough for a day or two without power on their own. Add $1000 worth of generator & fuel and you're good, for a lot less money than the equivalent solar power would cost.

That is the thing and the whole of the thing: you have to weigh the probability of an outage combined with its likely duration in order to determine which is the most cost-effective back-up system for you.

In some places where the grid is psychotically unreliable having your own solar power system just makes sense. But since any good off-grid system inevitably includes a back-up generator (Dave is going to disagree with that! ) you might as well try the generator route first; less money, and you'll probably need it anyway.

A typical refrigerator or freezer will use around 1 kW hour per day on average (more in Summer or with kids) and have a start-up surge a bit over 1000 Watts. A 12 Volt back-up system can be built to handle one. Two, you might prefer 24 Volts to run them.

I am so glad you didn't say the essential thing to run when the power is out is the telly! Yes, that's is the first thing a lot of people say when asked!

Foxtrapper

Re: How many 200w pvs?

No, hasn't got much to do with cost...more to do with workability..I want an independant source of power. Generators are cheaper, but they relie on gas..gas doesn't store all that well..you can run out of gas, you can spend alot of money on gas....

inetdog

Re: How many 200w pvs?

Foxtrapper wrote: »

No, hasn't got much to do with cost...more to do with workability..I want an independant source of power. Generators are cheaper, but they relie on gas..gas doesn't store all that well..you can run out of gas, you can spend alot of money on gas....

On the other side of that argument, batteries don't store that well either, and if you are looking at the really long haul, you can run out of batteries....

Foxtrapper

Re: How many 200w pvs?

I do have a generator, in fact I got 2..3500 and a 5000w...

I just want to do solar cause I want to..:D...You guys are a tough crowd...:D

Going solar is like moving into your first apartment...the feeling of total freedom from the parents!:cool:

Cariboocoot

Re: How many 200w pvs?

What sort of gasoline is it people buy that doesn't store well? I've been using the stuff for decades and never had any trouble storing the stuff in sealed containers. Even without stabilizer it'll keep a couple of years - at least well enough to run a utility engine.

Before anyone starts to argue with me about this, read what I said: I have done it and it works.
Even gasoline left over Winter in open-vented fuel tanks will still burn the next year. I've done that too.
Most of us can "turn over" the gasoline stocks every year no problem; the same gas that goes in my generators goes in my snow blower, log splitter, lawn mower, chain saw, grass trimmer, 4Runner, and van.
This probably explains why I have about twenty jerry cans. :roll:

inetdog

Re: How many 200w pvs?

Cariboocoot wrote: »

What sort of gasoline is it people buy that doesn't store well? I've been using the stuff for decades and never had any trouble storing the stuff in sealed containers. Even without stabilizer it'll keep a couple of years - at least well enough to run a utility engine.

But do you use stabilizer anyway? How about 2-cycle premix, does that keep well for you too or do you mix it on demand?

Foxtrapper

Re: How many 200w pvs?

The enthol kind..doesn't store worth a crap....it is recommanded that you roatate your stock every 6 months....besides, maybe I want to store gas for other things like my truck, car, fourwheelers..ect....putting all your eggs in one basket can cause problems...why not have a power source you don't have to think too much about...

inetdog

Re: How many 200w pvs?

Foxtrapper wrote: »

why not have a power source you don't have to think too much about...

A lot to be said for that! For PV you have to do most of your thinking in advance instead, planning your system.
And please don't just forget about your batteries. :-)

Foxtrapper

Re: How many 200w pvs?

Well, the other good thing about pv's are they are quite....it doesn't announce to the whole world that someone is around..that might come in handy someday..:D

inetdog

Re: How many 200w pvs?

Foxtrapper wrote: »

Well, the other good thing about pv's are they are quite....it doesn't announce to the whole world that someone is around..that might come in handy someday..:D

Yep, as long as you don't leave your lights on at night with the blackout curtains open. :-)

Foxtrapper

Re: How many 200w pvs?

My thoughts exactly:cool:.

Anyway, back to the solar part of this thread...:-)