Designing Off-Grid System With Possible Solar Later- Need Design Advice

Scargod
Scargod Registered Users Posts: 15
I have this new cabin in the wilds of British Columbia. My contractor had it pre-wired by a semi-retired electrician. I fired my contractor, so I can't find the electrician... He specified some off-grid power component with the understanding that I wanted it to be expandable. The electrician gave me some cut sheets for Xantrex products and Discover batteries. I have taken this info and run with it. I have done everything from building power supplies to wiring three-phase machinery to adding sub-panels. However, I'm NOT an electrician and I've never done a DC system! I'd like advice and critique of the direction I am going in.

The 650SF main cabin is well insulated and has a wood stove for heat. The three bedrooms equal 500 SF and are disconnected from the main cabin. We do not have plans to heat anything with electricity. We are installing a instant-on propane water heater, washer and propane-fired dryer, a dishwasher (where we won't force dry the dishes), a propane refrigerator and a propane cook stove. All appliances are new, high efficiency mdels. I plan on using LED lighting where practical. We are taking water from the lake with an on-demand water pump and using a small pressurized holding tank. Adding a cistern is possible... Elevating a holding tank would not be an easy task. We have a grinder/pump to move waste up to a septic field 70 feet away.

I have purchased a propane powered Cummins-Onan RV generator, QG 5500 (120/240). I have a table saw, a compressor and am a big DIY JOAT. I am going to finish what is left to do on the cabin. There are usually just two to four people at the cabin right now, but we can accommodate ten or more. The cabin may only be used for a few months out of the year.
I calculated our average watt/hour usage (for 2-4 people) to be 3,500 watts. It is my understanding that the generator would kick in if my usage went over the inverter's output. Also, my goal is to not have a generator running in the evenings or at night. Most all power will go off at night and we would use LED lighting for night-lights, if anything.

Recommended by electrician:
Xantrex XW 6048, 48 volt DC system
865-1050, System control panel
865-1060 Auto generator start
XW-MPPT60 Controller*
Discovery EVL16A-A batteries (AGM type, eight required)

I think I want to add to his list: Midnite Solar E-Panel for Inverter/Charger (175A), instead of the Xantrex panel. I need a separate panel to switch/disconnect all this, don't I?

*I don't see why I need the controller if we are not doing solar (yet). We have a lot of shade and I don't see a decent ROI for it and we would need a lot of arrays and tracking to make it even close to efficient or productive-in the summer months. However, that is when we use the cabin the most. Wind might provide a little bit of power; I am considering it for just keeping the batteries up while we are away.

The AC distribution panel is right above where the pad is for the batteries (underneath the elevated side of the cabin). This is in our laundry/utility room. The distance from panel to batteries is about 8-10 feet. I was going to mount the inverter beside the distribution panel, though it could go underneath, with the batteries in a dog-house. I do have a small concern about theft and was going to put the batteries in a locked, bolted-down metal box. Does this inverter make any noise? I know it will get warm and underneath the cabin would be cooler. Where we are it rarely freezes and temps average 45-65F.
I plan on having the generator about fifty feet away in a raised dog-house. I was going to run #6 gauge wire. I could do 4. I was planning on using a 18 Ga. outdoor rated extension cord to do the generator start circuit with and put the power wires in buried conduit.

This is about as far as I have gotten. I have looked at other batteries, like wet Trojan and Deka. I think I might want 00 battery cables. Do I need additional fused protection for the batteries or anything else if I have the Midnite panel?
OK, ask away or comment!
Thanks
«1

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Welcome to the forum, and to beautiful B(ring) C(ash) Canada. :D

    Not to be harsh, but you're doing the typical beginner's mistake of guessing at components and install.
    First up, an XW 6048 is a good inverter, but because it's a GT hybrid type it's not the best choice for off grid; you're paying for features you'll never use. Do you need 6kW capacity for your electric en toto? Seems most all your appliances will be propane (good, except perhaps for the 'frige).

    Second, let's start with those loads. 3500 Watt hours per day is not unbelievable, especially for four people. More people will of course use more power. You need to get a firm fix on this as you don't want to run the generator more than necessary. You're looking at roughly 300 Amp hours of battery @ 48 Volts and 25% DOD here.

    Third, get a handle on how you want the system to function. Auto gen starts may be nice, but can be troublesome. Are you going to recharge from the gen alone? Will you add panels later?

    Fourth, before you go buying wire for anything measure the distances. You want to be sure you have the right gauge for each run, regardless of its function, so that V-drop doesn't become a problem. You think you might want 00 battery cables, but as yet you don't know the exact distance they will run or the current you'll be pulling.

    You might go with a 24 Volt system instead, once you get a more definite fix on the power needs.
    Wind is usually a complete waste of money, as few of the commercial units live up to their claims and there usually isn't enough wind to drive them anyway.

    I'm already doing it in the middle of the Cariboo, so you can benefit from my experience! :D
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    I am going by the recommendation of a seasoned electrician who has done many off-grid cabins in BC. Perhaps he was mislead or misunderstood my needs?

    If the generator stops making power I will have lots of propane on hand. That's why the gas fridge. I know that electric would be better in all other aspects.

    Load: that's done with a spreadsheet and is as accurate as I am going to get for four people. I need the headroom for the rare times when the whole fam damily comes. I can't disappoint people who take a float plane to get to us after they fly to Vancouver from Texas.
    Understanding the batteries is my weak point. Wouldn't a bank of 8, 6V batteries (390 AH each @ 20 hour-rating), last a while? Isn't that 3,120 AH's, total (for that capacity)? Is there some trade-off between total battery cycles/frequency of the generator kicking in and depth of draw? I think most of the time our power usage (with only two people at the cabin), will be quite low. I guess I'm thinking the generator will be the equalizer when we have the rare high usage days. BTW, I have purchased the generator. The other components are negotiable. How is auto start troublesome? Isn't the XW inverter/charger completely programmable?

    I am going to say, for now, that the generator will be all I use to feed the batteries. With trees all-round our south side and the sun low in the winter, I don't think it will do us much good. I did some estimates and it's not pretty. I would have to drag an array fifty feet or more out into the lake to get full sun or go 120 feet up!

    Distances I used are fairly exact. I'm not guessing. Calculating the VDI, 6 Gauge is supposed to be fine for the 120V. AC generator supply. At 50 amps and a fifty foot run that would equate to a 1.9 volt drop and if I use 4 Gauge it would be a 1.2 volt drop.
    For the DC I am less certain of myself. If the inverter can do 6000 watts of AC power, that's 50 amps and if I use that and a 12 ft. run of 4 gauge it seems like I would have a .59V. drop @ 48 VDC. Again, this is not my strong suite. I know AC and DC is not apples to apples on losses.
    I hope this helps and that I've got some of it right.
    Thanks
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Try This Jalapeno, Son. It Ain't Hot! As my Nicaraguan friend (lady) always used to say... Eat ONE! SHOW ME you are a real man!!!

    Welcome to BC.. you said that the temps rarely get below freezing. Can you tell us where that place is and still be in ''the wilds'' Not near Coot and I.

    My read is that you need to start from the load analysis and build from there. We are here to help you avoid the READY, FIRE, AIM syndrome...

    3,500W /hr is a BIG load. I am currently building a new system and plan on 6,000 wh for a whole 24 hr. day Max at any time is 600W/hr and that includes the fridge. All AC powered...

    HTH
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    It's on the Sunshine coast. I did my load analysis! I could be way off, but I went over it with the wife. I multiplied the wattage by 1.5 as part of the calculations. This was a year ago and I'm not sure why I used that factor.
    I have a microwave, toaster oven, coffeemaker, etc, figured in. The lake pump is 750 watts of the average watt hours per day and the coffeemaker 675!
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Okay, using 3.5 kW hours as a given ...

    48 Volt system: roughly 75 Amp hours. 25% DOD = 300 Amp hour battery bank.

    So 390 Amp hours @ 48 Volts would seem more than enough.

    However, the Xantrex XW 6048 isn't a good choice here. Like I said, grid-tie features you will not use. It also appears you won't need a 6kW maximum power capacity either. Since the solar seems "iffy" device integration won't be an issue either. I suggest you consider this Magnum inverter: http://www.solar-electric.com/maenms4444wa.html
    It's about $1,000 less than the XW 6048 and very easy to install. Its built-in charger has a very good power factor too, which helps with economical generator charging.

    Keep the DC lines short, as their current level is higher. Inverter close to the batteries is a good idea, and don't leave out the breaker/fuse. With a 4kW inverter on 48 Volts you're looking at 84 Amps at maximum power, not including surge. This calls for a minimum of 2 AWG wire. Most of the time you won't be running anyplace near that current. I don't ever max my 3.5 kW Outback, even with water pump, 'frige, sump, and everything else running.

    The Magnum, like most inverters, can be hard-wired to a standard breaker box. The generator will feed the AC IN on the inverter, which will switch loads over and start charging whenever it senses power.

    DC isn't much different than AC, really. The biggest problem is getting proper DC rated switches/circuit protection.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    the 1.5 is probably to account for losses in conversion, better to use the real standby Inverter figures, range from 5 to 40w depending on make.

    Hey , this is a CABIN, to live the back-to-simpler -times experience, where else can they make toast on the top of the wood cookstove?


    Deep 6 the Coffee maker and use the propane stove, a kettle, French Press and a thermos bottle, better coffee anyways.
    Use the Microwave as an anchor, they are real power hogs. Toaster oven too...

    Pump is probably about right , on average, mine is 9A @ 120V AC = 1080W, but it only needs to run ~ 10 minutes at a time. Use a larger pressure tank as it lessens the total run time substantially, say at least 50 gals of supply not total volume.
    The macerator pump will be a killer best powered by the genset.

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice
    westbranch wrote: »
    Pump is probably about right , on average, mine is 9A @ 120V AC = 1080W, but it only needs to run ~ 10 minutes at a time. Use a larger pressure tank as it lessens the total run time substantially, say at least 50 gals of supply not total volume.

    Ha! Gotcha beat! 875 Watts for 6 minutes. :D
    When that one goes however ...

    I have a septic pump too. Draws nasty 1200 Watts, but only runs 30 seconds a day so it isn't a big concern. I just make sure it only comes on midday when the batteries are full up.

    The microwave? Occasional use only. 600 Watts "cooking power" eats over 1 kW in real electricity.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Yup for us 2 per householders, that short macerator pump run time is OK, but it sounds like he could end up with a houseful of cityfied types and the toilet will be flushed constantly.... and there goes that pump again, OOPS... not even taking hot jalpen'os into consideration, oh ya, and more water too...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Thanks!:D
    I feel like I'm making progress thanks to the input! This is making sense instead of NOT. I am willing to ditch the Xantrex stuff (though I hear it is a good product). I'm into KISS. Does the Magnum have as clean a sine wave? We have computers... Once I had a dirty generator kill a microwave oven.:grr

    Other questions: I have a few neighbors and most have inverters under their cabins. It is quite humid on the coast. I can put it in a sealed environment (AKA known as theft-proof), and/or ventilate it as needed with DC fans and a thermostat. I can certainly keep any electrical equipment dry, except for the humidity aspect. Any suggestions?

    I can have two foot runs from the batteries to the inverter. ;) "0" wire sounds like a good idea since I won't need much.
    Will I want a remote (meaning 12 feet away, inside the cabin), monitoring display or control panel?
    The only other thing I can think of at the moment is how I should size the battery to battery cables. Should they get progressively bigger? I'm sure this is absurd and that I can pick a common gauge to link them with...
    Thanks to all! Especially you Canucks! Monday I am crossing into BC with a van-load of appliances and the generator.:p
    G'nite!
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Why would you up TTY inverter under the house?

    Follow the advice of others,, start with the loads, and work backwards from there. For those of us who live off grid, conservation is the name of the game. Using batteries comes with its own set of complications and ergo it's own learning curve. Most newbies kill at least one set of batteries before they figure out how to make them last.

    Welcome, and god luck! Where on the coast are you?

    Tony
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    IMHO:
    Magnum is one of the top 3 brands out there for good large inverters. Outback and X are the others.

    Yes to the monitor, there are several out there that will do a good job. More later

    Possibly put the inverter inside the house and the batteries outside in a lockup.

    Batt cables should be all of one size and as short as possible. There is a thread on cables but I can not place it right now.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    An Outback choice you may want to look at: http://www.solar-electric.com/vfx3648.html
    Although it does require a "MATE" for programming: http://www.solar-electric.com/mate.html

    Xantrex, Magnum, Outback ... and "name brand" sine wave inverter has a clean wave form. Often better than the local utility. Incidentally, it isn't computers that suffer from poor waveform; they usually have really good power supplies that can clean up just about anything you plug them in to. A/V equipment, however ... And generators are a whole 'nother situation. "Fixed" RPM gens often suffer from Voltage and frequency drift as the RPM changes according to load demand. They can be rough on some things. Inverter-gens have as clean an output as anything.

    It is indeed humid on the coast. I used to live in the GVRD and green slime can grow on everything, not to mention the mould. You probably get the salty sea air there, known for corroding everything metal. Outback makes sealed units like this: http://www.solar-electric.com/fx3048t.html Fairly resistant to most foul weather conditions. Personally I'd keep it located somewhere that is easily accessible so that you can look at it every now and then and see if corrosion is creeping in.

    Battery cables should be sized to handle the maximum current expected. As with 4000 Watts / 48 Volts = 84 Amps. ALL the cables should be the same size, including between the batteries, because the current is equal throughout a circuit. For two feet of wire 2 AWG would actually do the job, but bigger can't hurt (except your wallet). And be sure to have some circuit protection on it. This is one example of a nice breaker/disconnect: http://www.solar-electric.com/mr60ampdccib.html

    Remotes can be useful. Outback's MATE is a remote, and Magnum offers remotes for their inverters as well: http://www.solar-electric.com/recoandotac.html Both of these inverters have a standby mode which reduces their power consumption considerably while waiting for a load to be present. There is a minimum amount of load required to "wake" them.
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice
    Scargod wrote: »
    *I don't see why I need the controller if we are not doing solar (yet). We have a lot of shade and I don't see a decent ROI for it and we would need a lot of arrays and tracking to make it even close to efficient or productive-in the summer months. However, that is when we use the cabin the most. Wind might provide a little bit of power; I am considering it for just keeping the batteries up while we are away.
    I highly recommend you install some array.


    You said the cabin will be unused for many months and charged only with the generator. If you are gone for months on end you need to make a critical assesment of what (if anything) will remain on when you are gone. A system with an inverter in "search mode" can easily consume >100 Watt/hours a day.

    Think of how the battery will be charged and discharged. (assuming your system components are properly proportionally sized)
    It is likely that you will run the generator sometimes manually, and sometimes automatically.

    If you only do it manually, when you first arrive at the cabin, the system will have been slowly discharging since the last time someone ran the generator. If the system is to be unattended for several months it should be completely turned off. Any device which is attached without a hard disconnect will be drawing some level of current. When you arrive at the cabin and make yourself at home you will draw energy from your batteries which can only be replaced by generator run time. You could stay for several days or you could leave later the same afternoon, but in the end, if you do not want to leave your batteries at some degree of discharge, you will need to run the generator as the last thing you do before you turn off all of the breakers and leave. You will have to plan what time you start the generator in order to leave if you are on a schedule.

    Keep in mind that finish charging is the slowest part of the charging process. It also is the least efficient use of generator fuel.

    If you stay for weeks or longer you can cycle your battery SOC (state of charge) between 60% and 90% for several days and do a finish charge once a week or so. If you start your generator at 60% SOC your batteries should be able to take in your charger's full capacity. If your charger is sized for 15% of your battery's C20 rated Ah capacity, you would run your generator for two hours and be close to 90% SOC. As charging voltage reaches the bulk voltage setting, the charging current begins to decrease (otherwise voltage would continue to rise). It will take longer to charge above 90% because the batteries can no longer absorb as much current.


    Most AGS (auto gen start) systems are designed to start your generator once your battery voltage falls below a voltage set point for a set amount of time. The battery voltage of a system in use will be pulled down depending on SOC and size of the load. A larger load will pull the voltage down more than a lighter load. An unattended system can self-discharge slowly without pulling the voltage down enough to trigger the AGS. This can leave your batteries below 90% SOC for long periods of time. Making fine tuning adjustments can be "an exact art and a subtle science" and very difficult to monitor if you are not around to monitor it and have everything turned off at the breakers.

    Some AGS's also have SOC% start and stop settings. Be careful. If your charger is multi-stage it has to be involved in the "AGS SOC decission" process, otherwise your AGS may still be calling for your generator when you charger has gone into float mode. Also, SOC meters are notorious for getting off track.

    You can sometimes set an "exercise" time in your AGS which can start the generator for a short run every 30 days or so. (lots of variations of this)

    If you can put in some panels, go for it. Even if it will not keep up with your usage while your are there. Even if you just add 4 old 50 watt pv panels through a PWM charge controller it can really have an effect. You may even have enough to set your Inverter on "Search" with a high LBCO (Low Battery Cut Out) setting. It may even be able to turn the lights on for you if you arrive late at night.



    Alex Aragon
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    BTW:

    A small wind turbine can also be worthwhile as a trickle charger while you are away. It really depends on your site. Remember, though, that many things can go wrong with moving parts. It's usually best to keep it simple. PV arrays can easily provide enough current to overcome battery self-discharging even with bad weather or even if you have some serious shade issues. If theft is really an issue you may want to look at doing a small unisolar type peel-and-stick to the metal roof of a shed.

    Alex

    Alex
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Here are pictures of what I am dealing with: Attachment not found.Attachment not found.Attachment not found.
    The yellowish and green boat is pointing almost due north.
    I have looked at sun charts and the sun azimuth/elevation for our area and today we have five hours where the sun is at a 40-50 degrees elevation. This won't clear the trees due east, south or west if the array is near the ground. If I put an array on my roof (near the vantage point of the photo of the trees and sun), I would have an arc of almost 90 degrees of sun during summer months. I calculate I have to elevate the array by 40 feet to clear the treetops, even if the sun is high enough. From November through February, I might get 1-1/2 to 2 hours of sun IF I have it elevated.
    How much would 2 to four panels weight? My roof peak is 15 feet. I would have to go 25 feet higher. Or trim limbs away and mount it on the side of one of my biggest trees.
    I've actually thought about suspending an array by cables between trees. My electrical run might get to 80 feet.
    Just read about "micro-inverters and how they can be more efficient with shade and ambient light.

    BTW, we are not going to clear a bunch of trees to give us minimally more sun.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Hmmmm, with out running any specific panel numbers, those batteries need ~ 4 amps per 12 v set to get a 1% charge rate, a 120W 12v panel makes ~7a per, so you would need 4 panels for all 8 cells to trickle charge them, if they get good winter light for at least 1 hour you might just scratch the batt needs. You need NO SHADOWS to get rated production, the shade froma single branch of a leafless tree can drop output to 50% or less.

    120W 12v panels weigh ~25 pounds.

    Looks like Powell lake . could you place a pole right near the lake shore? Regulations?
    How deep is it just off shore? Could you anchor a raft with panels on it? How secure (theft) would they be?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    The best case scenerio would be to have enough pv and enough sun to provide finish charging current. That would make it so you would only need to bring your batteries back up to 90% SOC before you left. It sounds like this is not going to happen.

    A few small panels in the best roof spot you have can keep your batteries from self discharging (1-2%/month) even in winter with quite a bit of shade.
    Other installers and tecs will think I'm crazy and jump all over me about this but I have tried it and found it to work. When the sky is overcast, the light is non-directional and there are few hard shadows. I first tested this on a small system which was installed on a cabin before the trees got too tall. This 110 watt pv array puts out nowhere near the panel rating but it keeps the batteries from discharging while sitting unattended. Confirmed by SG readings after three months which were slightly better with the tiny array than without. (Admittedly it is difficult to get a truely accurate measure of this.) The array actually puts out more in winter than in summer because of denser summer foilage and more non-directional winter light.

    I do not suggest that you spend much on this small array. Four cheap old panels (48 volts) into a PWM can do the trick.

    I know I'm "gonna get it" for this but I doubt it will be from anyone who has tried it.:roll:

    Alex
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Well,
    I'm off grid, and decided to go with the XW6048, because it is so versatile, and it's large surge capacity.
    I'm really hoping I can get by with only one of them, for a family of 2. But I do have the space, if I need to add a 2nd one.

    Not much chance of the Grid making it to my property, but if it ever did, I would have the option of the whole house on a UPS.

    It has a robust battery charger, and internal transfer switch for generator use too. And the charger is a .9PF if I recall correctly. And if you have any 240VAC gear, a single inverter produces that, I use it for the well pump.

    And it's system control panel , cost less than the outback Mates & Hubs. Firmware updates are a little tricky, but your installer should update it at the time of install for you.

    So there are lots of factors to consider about it.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    I concur with SR that a minimum amount of PV is better than none and that you will have to bulk charge the batts first, just before you leave. since it is a test you could go cheap on the PV, even amorphous would tell you if it is working... BUT be warned , if you get the PV solar bug you will expand the array, this is a given, as it can be infectious... so if you expand you will need to match the panels output..

    ps this is the time to buy PV as they are as cheap as they will probably go..

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice
    mike90045 wrote: »
    Well,
    I'm off grid, and decided to go with the XW6048,And it's system control panel , cost less than the outback Mates & Hubs. Firmware updates are a little tricky, but your installer should update it at the time of install for you.

    So there are lots of factors to consider about it.

    IMHO, The AGS for the XW is a much easier (KISS) install than the Outback or Magnum.

    Alex
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    If it's all about money then I don't want to split those hairs. I am building a cabin that has and will continue to get passed down through generations. It may see high usage at varying times. I cannot predict the future, but I can plan for it.
    I know my architect wants to bring people out this summer to help me finish the project. That would be four city-slickers and two old farts, at least.

    I am back on the bandwagon for a solar component. Even if it is just for battery sustenance. Long ago, I had a scheme for running a cable from one tree to another and hoisting the array up to it. I would anchor the bottom corners with guy-wires. I would then have a three-point harness where I could pivot or tilt the array. I just need a tree climber.:roll:
    Also consider that I intend to do this install myself. If you go back to my original post, I said that I have done many things electrical in my 50 years of working. I feel capable of doing anything and improvising. However, a good plug-n-play system, like the Xantrex, is appealing. It is also very versatile and upgradable.
    We have a "stage" left from part of the floor of the original '60's cabin. I haven't torn it down yet. I have a tarp roof over it. I might need serious power for a rock band one day...:p

    I DO appreciate all the input I have received!
    Cheers!
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Here is something to look at http://www.midnitesolar.com/productPhoto.php?product_ID=242&productCatName=Factory%20Pre-Wired%20Systems&productCat_ID=20&sortOrder=3
    that will simplify things a lot for you. Inverter CC etc in one package. Our sponsor carries Midnite products too.

    with 48V system you will need several panels in series so any shadow on one panel will bring the whole array down... is your chainsaw sharp?

    Just thinking, how do you get all that propane across the lake?

    good travels
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    I thought there were arrays, and/or micro-controllers, that prevented shadows from killing a panel's power output.
    I do have an open area about 40 X 50. It is the space where the old cabin stood. If I get high enough I shouldn't have shadows.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    An MPPT controller will HELP with shading issues. Also panel wire schemes (series, parallel, series/parallel ) can also make a huge difference. It would be important to look carefully at the al world shading issues, and discuss and consult with folks about wht the best design would be.


    It would also be important to try to design for the time of year that you are intending to occupy the place. It is one design consideration to allow float charge in the winter and fullest use in the summer for example, as opposed to designing for 365.
    Tony
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Whatever panels you use you need 58V or more feeding the MPPT Controller to recharge that 48v batt. How you get it is one $64 question, there are lots of different panels to use.
    This year I would run the gen in the morning and evening to keep the SoC up on the batt. If you can get some panels up all the better.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice
    westbranch wrote: »
    with 48V system you will need several panels in series so any shadow on one panel will bring the whole array down... is your chainsaw sharp?

    You might want to seriously consider Unisolar PV modules.

    The amorphous laminate panels are less effected by shade, less visable, harder to steal and less susceptible to damage.

    The output of mono and poly chrystalline PV modules is greatly reduced with even small amounts of shade. Unisolar style amorphous modules have their cells running the full length of the module. It is less likely to shade an entire cell. The decrease in output is not as drastic. It is more proportional to the amount of shaded area.

    They have no frames and do not reflect much light. I often do a double take before I realize there are peel-and stick panels on some roofs. The only way to take them is to remove the roofing panel.

    They are the only panel I would put next to a baseball park.
    I have seen Unisolars with bullet holes in them still doing their job. (do not try this at home:-))

    Alex
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    48V... the more I think about this little wrinkle, the more I think an analysis of the suitability of a 24V system is needed.
    Total watts could stay the same (2 parallel banks) but the winter charge Voltage needed (+-29V) could be a bit more easily attained with fewer panels in series (2 vs 4) considering shade issues, but more arrays to get the same total watts.
    Alternatively run more appliances directly off the gen and have only 1 24V batt bank. Lots of options.

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    I hope nobody minds an update after 2-1/2 years and can lend some advice regarding my current dilemma.
    I went with a 24 volt system that consists of eight six-volt.. well, I'l just list it out:
    Magnum MS4024PAE inverter/charger with FN60 NPPT regulator, ME-ARC (50?) remote control panel, BMK battery monitor kit and ME AGS auto generator start with networking,
    Outback Flexmax 60 controller,
    Cummins Onan HGJAE, 5.5KW, propane generator,
    Eight, USL16HCXC, wet batteries, 420 AH @ six volts each. Two banks wired in parallel to give me 24 volts,
    Sharp solar panels: SH-230 BLK (230 watts) X five,
    Panel tracker mounted on flat roof with tripod mount.
    I power a dishwasher, washer and dryer (propane), on-demand water pump, Navien, on-demand hot water heater, power-flush toilet, septic pump, small microwave, fancy grinder/coffee-maker and Wilson phone/internet amplifier and Sierra Wi-Fi hotspot. We use laptps and have LED or CFL light bulbs and are very conscious of our energy usages, in that respect.

    I have good news and bad news. I chuckled when I re-read the posts. I went from an initial three PV panels to five. This is about all I can do on this location without running into things. I trimmed branches and only have a couple of tree-tops that provide shade during a brief period. During peak summer I can have about six hours of good sun and when it's just the two of us, we can go days without the generator if there's sun.
    The first winter the batteries went flat. Can't remember exactly why. The second winter they were fine from September through May. A caretaker guy said the system was fine. When we got here, six weeks later, I only had eight volts. I found a light on when I got the system powered up. This leads me to believe that he turned the inverter on and turned on lights and then left... forgetting to turn the last light off and the inverter off.
    I also found a couple of battery cells with plates that weren't 100% covered. I spent many hours charging the batteries @ 80 amps and now the system is averaging about 25 volts and the electrolyte is reading 1250. I have 240 hours on the generator and a rocker stud just came loose. That was re-tightened and the system seems stable.
    I welcome any and all comments. I have questions...

    I would like to charge batteries I use for my trolling motor with the Cummins Onan generator. Instructions seems to say it can do 10 amps of DC charging. Yet when I hook up a second battery in parallel to the starting battery it does very meager trickle charging.

    The MAIN THING that I hope to find and answer to is whether I can get the generator to shut off in an automatic fashion. When we leave the cabin it will be unoccupied for months. Though we are on the "Sunshine Coast", believe me it gets dark in the winter. A mountain blocks the low arching sun. We only get 3-4 hours of sun, when there's sun. It is rainy and damp most of the winter from October to June.
    I have five, forty pound bottles of propane tied in to my system. I lug these across the lake, through the woods, onto two boats, etc., etc. Lots of schlepping involved. And, I'm 68. Fortunately, very healthy. Lots of activity and lots of trout in my diet.
    So far, I have done the "generator off" manually. I have the system programmed to come on at 6:30AM and off at 8PM. I have it set to "silent mode" when it is done working. That is usually when I shut it off, especially if we have sun.
    I cannot find any setting that will allow me to shut off the generator and not have it idling in the background. I think I can do an "exercise" routine for when we're gone, but I really don't know how to handle this. Seems the system might have been fine this spring had the caretaker not turned on the inverter and left it on. I don't feel I have a baseline I can trust and I hope for some experienced, off-grid advice.
    Thanks. I look forward to everyone's input.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Always nice to hear how things work out--In your case--Oops, care taker issues. Perhaps some 24 VDC LED lamps directly from the battery bank--Possibly with a mechanical timer (twist for 1 hour of lights). May save the issues of running the AC inverter for occasional off-season lighting.

    To charge the trolling motor battery--Use a 120 VAC battery charger or a 24 to 12 VDC charger (several options here).

    The DC battery charger on the genset is really not going to cut charging a deep cycle battery.

    I am not sure about the auto-shutdown--Is your question how to shut down when charging from the 12 volt aux alternator/generator--Or charging you main bank?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Scargod
    Scargod Registered Users Posts: 15
    Re: Designing Off-Grid System With Possible Solar Later- Need Design Advice

    Thanks, Bill.
    I'm talking my main battery banks. When we left the cabin last fall I turned off the generator at the ME-ARC and shut off the propane. I also turned off the inverter. I thought the PV array would be all the batteries would need to stay alive. I have the batteries in an insulated doghouse, in a tight cluster and it's perhaps ten feet above water level. My main water filter (in the compartment next to the batteries) did not burst during the winter like the ones in the cabin ;( so temps get down to or near freezing, but the lake's water keeps things near it a little warmer. Perhaps I'm digressing.
    Perhaps it was a workable solution, but I'd like one where the genny could step in if required. I know there's an exercise option.
    I have not found an "auto turn off" other than a fixed time range like "Generator Run Time" or "Quiet Time". Is there any solution to relying on solar to maintain the batteries and the controller only running the generator if there is no sun for too long a period? Does the "AC In-VDC" setting play into this beyond the obvious?
    Also, FYI, the array is almost directly above the controller and batteries. That run is about 35 feet and the generator is 50 feet away. I oversized the wiring on both. The PVA is putting out as much as 7 amps@ 60 volts. Perhaps could stand a cleaning. I have three panels and two panels in parallel. I have wondered if I could add any more PV panels in static positions for morning sun, before it goes behind the mountain in the winter months.