System design rev 1

Normok

Hello everyone and thanks in advance for any help/criticisms/advise. I recently bought some property in a very rural location and there isnt any power to the location nor is there any plan to get it there in the near future (I knew this going into it). I figure I can get away with just using 5-6kwh a day but want to be able to expand that. My basic plan is to take my 5th wheel to property and spend time there when not working. Most of the appliances run on propane but can be switched to electricity and my grid allows(frig, water heater, Electric fireplace would be nice too if possible...maybe a long shot). I just finished reading PV design and installation for dummies by Ryan Mayfield but still have some questions. Below is the list of proposed components feel free to say if there are some other options to consider.

Inverter/charger: Xantrex (Schneider) XW6048
Batteries: 16 x Rolls Surrette s530 (2 strings wired at 48v) 800ah
Charge controllers: 2 x Xantrex C40 (1 for each windmax hy2000)
1 x Xantrex XW MPPT 60-150 for solar array
Panels: 24 x Hyundai 250w (Pmax: 250W * Vmp: 30.5V * Imp: 8.2A * Voc: 37.5V * Isc: 8.7A)
Plan on the panels is to run 6 strings of 4
Irradiance at my location will be between 3.7w/m2 and 6.6w/m2
I have a large diesel welding machine to charge the battery bank if necessary aswell

I have 2 basic questions aside from the overall proposed design.
1) Is a dump load required for wind turbines or will they just stop when the battery is charged
2) Are there some different panels I might consider. My choice to select these is pretty arbitrary...these looked nice and priced right.

Let me know if there is any vital information I have omitted.
Thank you again.

Cariboocoot

Re: System design rev 1

Welcome to the forum.

My opinion won't be popular but ... you've picked the wrong equipment.
Using an XW inverter when you have no grid nor likelihood of getting it is not a good idea; why pay for GT ability when you don't need it? And regrettably Xantrex equipment is notoriously 'buggy'.
If you search this site for threads about Surrette you will probably change your mind about them as well.

Your off-grid power requirement is quite high too. Definitely get some real-world numbers on this. Try to cut it in half. No I'm not kidding.

Wind turbines require a constant load to be available, otherwise once the batteries are full the power has no place to go and they can just over-speed and literally fly apart. Reconsider wind; make sure the site is suitable and that the turbines are good ones (unfortunately most aren't) and that the installation is proper (towers tall enough to keep them in good wind). If wind is not needed, don't spend the money. As a rule solar will return more power per dollar.

Panels are pretty much a choice of cost per Watt, as most 'name brand' units are of comparable quality.

inetdog

Re: System design rev 1

Normok wrote: »

I have 2 basic questions aside from the overall proposed design.
1) Is a dump load required for wind turbines or will they just stop when the battery is charged
2) Are there some different panels I might consider. My choice to select these is pretty arbitrary...these looked nice and priced right.

Let me know if there is any vital information I have omitted.
Thank you again.

I can answer the first one:
It depends on the turbine. If the turbine does not have a mechanical brake or pitch change mechanism for the blades, it will rely on a constant minimum load on its output to keep the speed down.
It may have a mechanism to turn the turbine out of the wind for protection (furling), but that will take time and if the load suddenly goes away the furling mechanism may not be able to act in time.
Other turbines just rely on having a minimum load and using a passive design to keep from running away in a higher than normal wind.
There is no way to flip a switch and have the turbine stop spinning. Is some limited cases (it generates a lot of heat in the generator head itself) just short circuiting the output instead of diverting to a dump load may be an option.
In many cases the Charge Controller or AC output box will include these capabilities, or the CC may be fed from a specifically designed Turbine Controller. What you do not want to do is try to use a CC which has settings for PV only in a direct connection to a turbine.
In the case of small hydro, you have the option of bypassing the turbine or closing a shutoff valve. With a wind turbine neither of those options are possible.
With solar PV, the panels will just sit there happily NOT delivering any power and getting just trifling amount warmer instead of being damaged without a load.

Normok

Re: System design rev 1

Cariboocoot wrote: »

Welcome to the forum.

My opinion won't be popular but ... you've picked the wrong equipment.
Using an XW inverter when you have no grid nor likelihood of getting it is not a good idea; why pay for GT ability when you don't need it? And regrettably Xantrex equipment is notoriously 'buggy'.
If you search this site for threads about Surrette you will probably change your mind about them as well.

Can you suggest some other inverters to consider - I liked the expandable aspect to the XW inverters plus Im pretty sure I want only a sine wave inverter. As far as the batteries go I just picked them based on price. They seem to be pretty proud of them and I figured it was for a reason. Plus I noticed a few guys had them on one of the show and tell threads. Any different ideas on batteries?

Thanks

icarus

Re: System design rev 1

Electric fireplace? FYI, any resistant electric heating device is really a no-no for an battery based PV system. In short, if you wish to get heat from solar, do it directly, (solar hot water, solar space heat etc) as it is way cheaper, and way more efficient. Also running a absorption fridge on electricity is very inefficient. A propane fridge is reasonably efficient use of BTUs, but to get those BTUs from elecricity is not a good way to go,, unless you are using the electricity from opportunity load when the batteries are near full.

The singel biggest (read most expensive! ) mistake that beginners make is,, Ready, Fire, Aim!

All design considerations and hardware choices stem from a complete understanding of the load. The loads drive all choices. A simple calc to make regarding off grid is my quick rule of thumb. That is,, take the name plate rating of the PV, divide that in half to account for ALL system loses, then take that number and multiply that by 4 to account for a reasonable daily average hours of GOOD sun one can expect, per day. Most people at once and the same time over estimate thier solar potential, and under estimate thier loads,, leading to heart ache.

So, for example a 1000 watt PV system might look like this, 1000/2=500*4=2000wh/day. So you can easily see that if you are looking to produce 6 kwh/day reliably, you are going to need. At least a 3 kw system. One soon realizes that conservation is your cheapest energy dollar.

As one more FYI, we live off grid, with 400 watts of PV. On a daily basis we use 5-800 WH/day.

Welcome to the forum, keep in touch. There are some very sharp folks here who have proverbially forgotten more of out PV than most of the rest of us will knew. Ask your quests ions freely, people are more than willing to help, and if you generally follow thier advice, you will design and build a good workable system.

Tony

Normok

Re: System design rev 1

icarus wrote: »

Electric fireplace? FYI, any resistant electric heating device is really a no-no for an battery based PV system. In short, if you wish to get heat from solar, do it directly, (solar hot water, solar space heat etc) as it is way cheaper, and way more efficient.

So, for example a 1000 watt PV system might look like this, 1000/2=500*4=2000wh/day. So you can easily see that if you are looking to produce 6 kwh/day reliably, you are going to need. At least a 3 kw system. One soon realizes that conservation is your cheapest energy dollar.

As one more FYI, we live off grid, with 400 watts of PV. On a daily basis we use 5-800 WH/day.

The fireplace idea was ...lets say more of a dream.
The plan for the array was 6kw (24 x hyundai 250w). not including wind - which looks like something to reconsider.
As far as 5-800w/ day I really dont know if I could do that. At least not right away(I might start twitching from withdraws).

Cariboocoot

Re: System design rev 1

Normok wrote: »

Can you suggest some other inverters to consider - I liked the expandable aspect to the XW inverters plus Im pretty sure I want only a sine wave inverter. As far as the batteries go I just picked them based on price. They seem to be pretty proud of them and I figured it was for a reason. Plus I noticed a few guys had them on one of the show and tell threads. Any different ideas on batteries?

Thanks

A couple of questions:
Do you need 240 VAC? Think carefully because most things that use 240 VAC are things you try to do without off-grid (heavy motors, heaters).
Do you need 6kW of power at any given time? Again think carefully; you'd be amazed at how low all-at-once loads might really be. They generally increase in relation to the number of people in the household, as one person can really only use 'so much' power at any given time.

Magnum inverters are quite a value for off-grid, and can be "stacked" if more power is needed: http://www.solar-electric.com/maensiwainac.html

Regrettably Surrette has had a lot of trouble lately, and their operating Voltages tend to be on the high side which is difficult to deal with. Look at Crown batteries http://www.solar-electric.com/crdecyinba1.html or whatever brands are available near you. For a first battery set it's best to buy the least expensive you can because of the increased probability of premature damage. Sometimes 'warehouse' brand golf cart batteries are your best bargain.

For charge controller, there is none better than the MidNite Classic: http://www.solar-electric.com/misoclchco.html

Just some things to consider.

Cariboocoot

Re: System design rev 1

Normok wrote: »

The fireplace idea was ...lets say more of a dream.
The plan for the array was 6kw (24 x hyundai 250w). not including wind - which looks like something to reconsider.
As far as 5-800w/ day I really dont know if I could do that. At least not right away(I might start twitching from withdraws).

We run our cabin on <3kW hours per day.
With a 48 Volt system, 100 Amp hours is roughly 4.8 kW hours (not including system losses). This would be in keeping with the golf cart battery idea as they are about 220 Amp hours.

At 6kW hours per day you'd need at least 275 Amp hours @ 48 Volts, and 550 Amp hours would be better.
For that minimal battery bank you'd need about a 2kW array (about 4kW hours per day end-to-end), 4kW for the larger of course.

A 6kW array could yield over 12kW hours per day on a good day (AC Watt hours, all system losses included).

icarus

Re: System design rev 1

Believe me, I am not suggestion that anyone can live with 5-800 WH/day. I cite that simply as an example of the calc. We live with so little, because we came to it from living with no power at all except genny power a few hours a night. we have no TV, no heating or A\C loads, have a simple water system with low powe draw etc.

It used to be that our lighting was the big load, and we were pretty stingy with them, but now with CFs and LEDs the lighting is almost incidental. Or biggest draws are the ISP modem that now is on ~18 hours/day, the radio and the Internet radio that goes with it, and lap to/iPad charging.

we also use the genny for the shops.

Tony

Our use also mirrors the second it's important rule of off grid living... That is the loads ALWAYS grow with time. Use a reasonable growth estimate in your design calcs so you can grow into your system (within reason) (we strted with a car battery, and a reading light!

Normok

Re: System design rev 1

Cariboocoot wrote: »

A couple of questions:
Do you need 240 VAC? Think carefully because most things that use 240 VAC are things you try to do without off-grid (heavy motors, heaters).
Do you need 6kW of power at any given time? Again think carefully; you'd be amazed at how low all-at-once loads might really be. They generally increase in relation to the number of people in the household, as one person can really only use 'so much' power at any given time.

Magnum inverters are quite a value for off-grid, and can be "stacked" if more power is needed: http://www.solar-electric.com/maensiwainac.html

Regrettably Surrette has had a lot of trouble lately, and their operating Voltages tend to be on the high side which is difficult to deal with. Look at Crown batteries http://www.solar-electric.com/crdecyinba1.html or whatever brands are available near you. For a first battery set it's best to buy the least expensive you can because of the increased probability of premature damage. Sometimes 'warehouse' brand golf cart batteries are your best bargain.

Ok so as far as the 240v question goes - I want to just plug my 5th wheel into the distribution panel. The plug for the 5th wheel is a 50a 120/240v.

As far as using the 6kw all at once I dont really see that happening initially but as the systems grows it would be nice to be able to. My primary goal isnt to make my money back its primarily to just get away from everything and still have some of the conveniences.

Now your idea about the batteries is great...I have read several instances on this forum of new guys wrecking their battery bank. Awesome piece of advise thanks.

Cariboocoot

Re: System design rev 1

Okay, you really need some concrete power requirement numbers or else you're just going to go 'round and 'round and never get any system at all.

Even though the connector is rated at 50 Amps maximum that doesn't mean you'll ever come close to that, which is good. 50A @ 240 VAC is 12 kW. At 120 VAC it's 6 kW. Chances are the maximum current on that circuit is 40 Amps. If the feed is 120 that's 4.8 kW, and 9.6 if 240. So first up is determine how much power actually goes through that connection: Amps and Volts. It will save you a lot of grief. Then you can say you need to supply 'X' Amps at 'Y' Volts which is 'Z' Watts. That becomes numbers you can deal with.

Normok

Re: System design rev 1

Cariboocoot wrote: »

Okay, you really need some concrete power requirement numbers or else you're just going to go 'round and 'round and never get any system at all.

Even though the connector is rated at 50 Amps maximum that doesn't mean you'll ever come close to that, which is good. 50A @ 240 VAC is 12 kW. At 120 VAC it's 6 kW. Chances are the maximum current on that circuit is 40 Amps. If the feed is 120 that's 4.8 kW, and 9.6 if 240. So first up is determine how much power actually goes through that connection: Amps and Volts. It will save you a lot of grief. Then you can say you need to supply 'X' Amps at 'Y' Volts which is 'Z' Watts. That becomes numbers you can deal with.

I bought a kill a watt meter and checked all the various outlets and did calculation on the water pump and converter separately. I have changed every light bulb in the trailer to led and figure I could get away with 5-6kw/d (I run a lot of electronics) but that would be "roughing it". Eventually I would expand the system to accomodate this addition power use. Later plans include building a shop that will hopefully be 100% RE. I guess I should have restated my initial question to: are the components I have selected good and will they work well together?

Cariboocoot

Re: System design rev 1

Normok wrote: »

I guess I should have restated my initial question to: are the components I have selected good and will they work well together?

In my opinion, they would work together but are not a good choice. You'd be better off with a Magnum MS4448PAE powered by two parallel string of eight 6 Volt golf cart batteries (for starters) recharged by about 3kW of array through a MidNite Classic 150. Such a layout would be expandable as you can parallel four of those inverters (16 kW of output power!) and the battery bank could be upgraded to higher capacity if needed, to say nothing of the array. Also the MidNite controllers can be paralleled and they will 'talk' to one another. MidNite also makes some very nice equipment for putting it all together: http://www.solar-electric.com/midnite.html

Since I'm starting to sound like a commercial I'll reiterate that none of us moderators work for NAWS or MidNite or any of the other solar product companies. We don't get any sort of compensation or incentive to mention or recommend products. I will also say that there are other ways of achieving the same ends; the above is simply how I would go about it.

icarus

Re: System design rev 1

A shop is a whole other dimension. The problem is not just the total KWH loads, but the peak loads of lighting, and most particularly strarting loads of power tools. There are many here who do it, but for a part time or hobby shop, a genny installation might be much more cost effective. Due to happenstance, I hve a selection of generators, and can run only the one that is big enough for what I am doing. Most of the time these days I run most of the shop tools off a 2800 watt Mitsubishi genny that came into my lap. My biggest draw is the surface planer and it runs fine on that genny. Running multiple tools gets to be an issue with battery based systems as well, due to starting currents.

Bottom line is, you re going to need a big battery bank and big inverter (relatively) for a shop. That may not BR a good solution for the house, as large inverters powering small(ish) house loads are not real efficient. A system with multiple inverters may be in order.

Tony

Normok

Re: System design rev 1

Cariboocoot wrote: »

Also the MidNite controllers can be paralleled and they will 'talk' to one another. MidNite also makes some very nice equipment for putting it all together: http://www.solar-electric.com/midnite.html

Is it important for the inverter and the charge controller to be of the same brand or "talk" to eachother. If not then that changes things being a rookie I assumed there would be compatabity/settings issues to deal with - issues a rookie would rather not deal with. Just so I understand your previous statement - If I were to get lets say 10 of those midnight charge controllers and have 4 of them attached to wind turbines and 6 to solar arrays they would each "talk" to each other to keep the batteries charged without any communication necessary from the inverter.

Again thanks for your patience with my questions.

westbranch

Re: System design rev 1

there,is another dimension to the loads you quote, and that is the 'timing' of each load in relation to the other loads, ie how many of the loads er simultaneous and which occur independently. In periods where you may have several loads occurring together you need to plan for the total load at that time not just 5 Kwh over the whole day.

hth

Normok

Re: System design rev 1

westbranch wrote: »

there,is another dimension to the loads you quote, and that is the 'timing' of each load in relation to the other loads, ie how many of the loads er simultaneous and which occur independently. In periods where you may have several loads occurring together you need to plan for the total load at that time not just 5 Kwh over the whole day.
hth

I see your point there. It is something I have considered but have been unable to quantify it accurately or meaningfuly. I guess thats the reason I went with the 6048 as that seemed to exceed my immediate needs plus I really liked the ability to expand to 18kw. My ultimate goal is use 100%RE and no fuel. I understand the size of battery bank will have to be massive but its a price Im willing to pay.

Cariboocoot

Re: System design rev 1

Normok wrote: »

Is it important for the inverter and the charge controller to be of the same brand or "talk" to eachother. If not then that changes things being a rookie I assumed there would be compatabity/settings issues to deal with - issues a rookie would rather not deal with. Just so I understand your previous statement - If I were to get lets say 10 of those midnight charge controllers and have 4 of them attached to wind turbines and 6 to solar arrays they would each "talk" to each other to keep the batteries charged without any communication necessary from the inverter.

Again thanks for your patience with my questions.

Not a problem. You can basically use any brand charge controller with any brand inverter. Even though some (like Outback and Xantrex) do have the ability to communicate between them most do not. It isn't strictly necessary as the two units function independently most of the time. The exception to this is inverter-chargers where it is nice, but not essential, to have the solar charge controller and inverter 'agree' on things like battery temp and Voltage.

I have an Outback MX60 charge controller and a VFX3524 inverter. They can 'talk' to each other but I don't have them connected (requires a 'HUB'). It has never been a problem.

How extensive the MidNite controller's communications are I don't know. Ten talking to each other? Maybe. Certainly two can! I do know they make the best controllers for both solar and wind. ChrisOlsen has such a set-up with both PV and turbines and is quite pleased with the MidNite controllers.

There are many companies that make charge controllers that do not make inverters, and vice-versa. Most of the time the 'communication' comes down to reading the battery Voltage and acting accordingly. There are sometimes issues with multiple charge sources allowing too much total current, but this is not a common thing (which explains why there's no industry solution for it yet).

Normok

Re: System design rev 1

Cariboocoot wrote: »

Not a problem. You can basically use any brand charge controller with any brand inverter. Even though some (like Outback and Xantrex) do have the ability to communicate between them most do not. It isn't strictly necessary as the two units function independently most of the time. The exception to this is inverter-chargers where it is nice, but not essential, to have the solar charge controller and inverter 'agree' on things like battery temp and Voltage.

Yes, this is a problem I read about on this forum. A guy had some wind turbine dump loads along with a solar array and for some reason (I think it had to do with charging calibration/settings or something) the charge controllers were dumping the load but the inverter/charger was kicking on the generator. I assume this was because the controllers were happy with the voltage but the charger wasnt. Is this is a common problem in wind/solar hybrid systems?

westbranch

Re: System design rev 1

Normok wrote: »

I see your point there. It is something I have considered but have been unable to quantify it accurately or meaningfuly. .

My solution was an EXCEL spreadsheet divided into one hour increments from 07:00 to 23:00 hrs, with a best guess of on/off times to the 1/4 hr.

hth

Cariboocoot

Re: System design rev 1

Normok wrote: »

Yes, this is a problem I read about on this forum. A guy had some wind turbine dump loads along with a solar array and for some reason (I think it had to do with charging calibration/settings or something) the charge controllers were dumping the load but the inverter/charger was kicking on the generator. I assume this was because the controllers were happy with the voltage but the charger wasnt. Is this is a common problem in wind/solar hybrid systems?

Not really. Every now and then you get a system where the parameters are off. This is usually caused by different charge controllers that lack the ability to agree on Voltage settings, let alone Voltage. When you get into multiple controller systems it pays to go for the high end ones that can be programmed in 1/10 Volt increments, et cetera. Trying to get some of the less-expensive ones to work ... they tend to have fixed Voltage set points or maybe two choices.

mtdoc

Re: System design rev 1

I agree with the others. My 2 Midnite CCs talk to each other and work well with my Outback inverter. Small differences in voltage readings between CC and inverter can easily be offset adjusted to agree and prevent any charging conflicts.

You might want to consider an Outback inverter as well since they can also be "stacked" in many multiples to expand your system.

Either the Magnums or Outbacks would be good choices. With either one I would recommend using Midnite Classic CCs and buying a prewired ePanel. For example THIS Midnite prewired epanel with a dual stack of Outback GVFX 3648s will give you a 7200 watt system complete with 2 Classic CC and all the appropriate breakers wired in a nice enclosure and ready for PV and/or wind power input for a street price of about $7K.

That's a good sized system that would handle over 10kVA peak loads which I would think would suffice for most home shops. If not you could always expand to a quad stack! It's only money, right!:cool:

Normok

Re: System design rev 1

Ok I just checked out the the midnight CCs and I am a bit confused what makes them better. I assume my problem is I am only looking at capacities instead of features - most of which I dont fully understand.

The classic 150 has a max wattage input of 4500 - price $610
The XW MPPT 60-150 has a max watt input 9000 - price $479
So thats double the capacity at $140 cheaper. I am sure Im missing something just not sure what.

This is turning out to be a lot more than I anticipated. I sure appreciate all the advice.

Edit - Stike this whole comment. I just figured out my numbers are wrong. I better digest what Ive figured out today and begin new another day.
Thanks everyone

icarus

Re: System design rev 1

As a general rule, don't buy hardware JUST on the basis of price.

Remember,, avoid the ready, fire, aim.

T

SolarMusher

Re: System design rev 1

Normok wrote: »

Ok I just checked out the the midnight CCs and I am a bit confused what makes them better. I assume my problem is I am only looking at capacities instead of features - most of which I dont fully understand.

The classic 150 has a max wattage input of 4500 - price $610
The XW MPPT 60-150 has a max watt input 9000 - price $479
So thats double the capacity at $140 cheaper. I am sure Im missing something just not sure what.

This is turning out to be a lot more than I anticipated. I sure appreciate all the advice.

Edit - Stike this whole comment. I just figured out my numbers are wrong. I better digest what Ive figured out today and begin new another day.
Thanks everyone

60A x 58.4V = 3500W for a XW60/150 CC and not 9000W.
96A x 58.4V = up to 5000W for a Classic 150 CC.
As Coot said, a Classic is your best choice for solar or wind.
Erik

Normok

Re: System design rev 1

Alright after spending the majority of my weekend researching and a huge amount of customer feedback on forums I have decided to go with the Classic 150. I bought 2 of them from solar-electric.com and also purchased my solar panels. Still havent made up my mind on the inverter or batteries yet- still have to read up on my choices a bit more. Thanks to everyone for their input. Ill keep you all posted as I piece this thing together.

niel

Re: System design rev 1

norm,
you can opt to go with this,
http://www.solar-electric.com/maenms4444wa.html
and if you need more power than this you need to revisit conservation efforts in my opinion. if on the outer chance that more than this is necessary you could run another inverter plus this one, but into its own distribution panel as this you can't combine to the same main panel. what you could do is opt for one inverter to take on continuous everyday stuff like lights, ac wall adapters, clocks, refrig, sat tv, and other little things that won't require big power (except maybe the refrig), but needs to be available 24/7. the other to handle more high power intermittent loads on its own separate breaker box. you can decide how you will best need it laid out, but i think you get the idea.

edit to add-note that you could use more than one of the ms4448 inverters paralleled as per their spec sheet,
http://lib.store.yahoo.net/lib/wind-sun/Magnum-MS-PAE-datasheet.pdf
but there are further things that need to be done for parallel stacking.

now you could still opt for the xw inverter due to its higher power handling capabilities and the generator could be run if need be through the normal ac1 for grid power. that is 6kw and i don't see why you might need this much power, but yes, you can opt for more inverter power beyond this too.

there are other high power inverters out there too like the sunny island and the outback radian, but at a higher price.

note that the classic is said to do an excellent job on the hy turbines as well. i think keyturbocars ran one, but you can read up on that stuff over at the midnite solar forum.

Normok

Re: System design rev 1

niel wrote: »

norm,
you can opt to go with this,
http://www.solar-electric.com/maenms4444wa.html
and if you need more power than this you need to revisit conservation efforts in my opinion. if on the outer chance that more than this is necessary you could run another inverter plus this one, but into its own distribution panel as this you can't combine to the same main panel. what you could do is opt for one inverter to take on continuous everyday stuff like lights, ac wall adapters, clocks, refrig, sat tv, and other little things that won't require big power (except maybe the refrig), but needs to be available 24/7. the other to handle more high power intermittent loads on its own separate breaker box. you can decide how you will best need it laid out, but i think you get the idea.

Actually I dont think I get the idea. First question - On the description for the magnum inverter it says they are able to run in parallel, up to 4 units. Can these all be run to the same distribution panel? Second question when you mention using 2 different inverters is this when a second distribution panel would be necessary? And what would be the advantage of using different inverters assuming 4 of the magnums(if I ever get that far) would provide enough power.

Thanks.

Cariboocoot

Re: System design rev 1

Normok wrote: »

Actually I dont think I get the idea. First question - On the description for the magnum inverter it says they are able to run in parallel, up to 4 units. Can these all be run to the same distribution panel? Second question when you mention using 2 different inverters is this when a second distribution panel would be necessary? And what would be the advantage of using different inverters assuming 4 of the magnums(if I ever get that far) would provide enough power.

Thanks.

With the Magnums (or Outbacks or Xantrex's) in parallel they act like a larger inverter: four would be the equivalent of one 16kW inverter. They all feed the same distribution panel.
You cannot do this with inverters that aren't designed to be connected this way.

bbbuddy

Re: System design rev 1

Normok, we are in the same situation as you are...off grid in a 5th wheeel...

We have a Classic 150, a Magnum PAE2024, 4 Crown 395 AH batteries, 2200 watts PV, and a 240v trailer connection.

We run a 120v refrigerator and freezer, a satellite tv and internet, and right now during the day I also use a 400/800 watt quartz radiant heater. At night our loads mostly consist of several lights, the tv, and the internet.
I use a 120 washer during the day, and can also use a 120v dryer during the day too.

I'm trying to wring every watt out of the system for grins right now, and yesterday was able to hit 10kw [I think 10 kWatt*Hours == Bill B.]. That's watts out from the PV, not watts available for use. It also includes the batteries being full and in float for 3 hours.. That's in NE AZ, lat ~34...

Posted just to give you an idea of what can be done. You DO have to monitor loads, and load shift. It's NOT a mindless system like on-grid.

No matter WHAT you do, invest in a good battery monitor, like the Trimetric...can't live without it. It always tells you how many watts are left over for battery charging, while you are running loads...and never skimp on wiring.

niel

Re: System design rev 1

sorry to be confusing to you, but i was thinking not just of different inverters, but also a cheaper (gt or non gt as it matters not) inverter to run the smaller loads separately from the main higher power inverter that may only be needed at certain times and can be shut down to save on idle losses.

i did see that what i was saying could've gave the wrong impression of the magnum not being able to stack for higher power levels so i added the note and yes, that would be to the same main panel in the case of the stacked magnums. i have no experience with stacking them as i don't have a large setup myself, but i have found that i could get by just fine on 4kw from a generator (without my wife taxing things to high as many here have heard me complain of her electric use abuse from me) and that included and air conditioner. as i also said the xw i believe to be stackable as well and there are other inverters of higher wattages from other inverter manufacturers too. i just have trouble wrapping my head around needing to have 2 or more of them stacked. in the interest of clarity forget about my mentioning the use of differing inverters to separate distribution panels.