Re-build

Hey all, Just wanted to get an economic snapshot if possible.  I have had 6 55W Siemens panels charging a 12V bank of 4 golfcart batteries (220AH @6V) through a 20A Sunsaver Controller and a 800W Modified inverter for over 6 years.  My very remote cabin is wired 120AC, and I have gone through three inverters, which are very inexpensive.  I only average one 3-5 day visit every 6 weeks, and have a 1850 W Coleman genset to power a circular saw or  anything else, but hardly ever use it.  On AC I run CF lighting, a computer, stereo, hand power tools, on DC a small fridge and LED lighting.  I get great production, but I'm going to step up, because I need more amps with a couple of new rooms and a pump.  BTW, I heat with a woodstove, and collect water to a 300 Gallon tank 40 feet above the cabin, where it feeds the system through a filter.  How would you spend $1500?  Thanks very much for taking a minute from your day.

Comments

  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Re-build

    Killing off three inverters is worrisome. You may need to check the loads (hand tools) and see if they overloaded the old inverters. 800 W at 120 VAC is ~6.7 A, or the amount a 5.5 A tool (i.e., a power drill) might draw from an MSW inverter.

    The Sunsaver 20 controller is maxed out with a 330 W array configured for 12 V nominal (16.7 V x ~20 A = ~330 W). You’re probably stuck with a 12 V battery bank (existing DC loads), so that probably rules out “stepping up” to a 24 V system and using the same controller. It sounds like the battery bank has been through a few cycles, so adding batteries to increase capacity probably won’t work particularly well.

    A big, high quality true sine wave inverter might be a place to start. The 12 V Exeltech 1100 costs ~$636. The balance of your budget might go into a bigger and better controller like the MorningStar TriStar 45 ($255 w/ meter and RTS) and a Kyocera 120 PV module (~$540).

    The result would be a well balanced system (450 W STC PV array, 440 Ah battery bank), and the TriStar will do a much better job of properly maintaining the battery bank. The Exeltech inverter should be able to handle some pretty good loads.

    Or, since your cabin use is occasional, stay with the 330 W array and Sunsaver controller and buy a new inverter and a big new AGM battery bank. AGM 8D’s (12 V, 245 Ah) are as low as $260 each, so 3 of ‘em would cost ~$780 and be good for 735 Ah.

    HTH,
    Jim / crewzer
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Re-build

    actually anything you do would be an improvement, but it's just a question as to what's best with $1500 to spend. too bad you don't have more to spend on it. you're adding loads so you need to produce, store, and have available this increase in energy needs. conserving more helps, but i'd definitely go with a sinewave inverter. this may even show a reduction of power consumed because many things run better on sinewave. forget about buying cheap inverters and blowing them out as this is a waste and the $ you spent on them could've been going towards a good inverter. it isn't just the inverter lifespans that suffer as some things do not last with a modified sinewave if they work at all. some things have also been known to blowout as well under mod sinewaves.
    i'd keep your present battery bank as is and add more pvs with a new controller. the batteries you can run into the ground if need be and replace them later with a better battery setup. don't forget that you may want or need to upgrade your wiring too.
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Yep, I'd go for a sinewave inverter as well. However, since you have a generator, I would definately go for a combined inverter/charger model so you can charge the batteries from the generator if needed.

    Personally, I bought an Outback inverter for my off-grid cabin. This way I won't have to fire up the generator for anything but emergency charging. The circular saw, drills, vacuum cleaner, etc. all run fine from the inverter. I don't run anything continously on AC though. All ligthing, refridgeratrion, TV, laptop etc. run directly on DC. This way I can turn off the inverter when it's not needed.

    You can afford an Outback FX2012 but it will devour your complete budget. And you'll need to borrow someones mate if you need to alter the programming...

    On the other hand it will allow you to charge your batteries with up to 120A from the generator although I wouldn't recommend going much higher than 60A with your 440Ah bank.o
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Do not overlook a potential source of cheap true sine-wave inverters.

    Here in Alberta we have a fairly extensive e-recycle program with depots all around the province. This is where I, as well as my brother got our "inverters" for our backwoods solar set-ups. We paid $15 each for some APC RM 1500 UPS's.
    These particular models have the ability to boot from the batteries w/o the need to see grid power first. Simply hook the batteries to the UPS's battery cables and turn on.
    It won't automatically turn on based on load demand but the operating panel can be remotely located in a convenient spot simply by splicing a length of cable into the ribbon cable between the UPS and the operating panel.

    Press and hold the TEST button until the UPS beeps, release the button mid-beep and the unit boots up. It will then sound an alarm protesting the lack of grid power, so hit the test button one more time to acknowledge the alarm and your up and running with true sine wave power for a tiny fraction of what an off the shelf inverter will cost you.

    Caution: Do not attempt to use a generator & the UPS's charger circuit to recharge a large array of batteries or you will let all the smoke out of the unit

    If anyone has any experience with or knowledge of other models of UPS's that boot from battery only I would encourage them to share it with the world. These appliances have an incredible amount of embodied energy in their manufacture and it is a waste and a shame to see operable "inverters" crushed and melted to recover a few mg of precious metals.
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Bunzo, I have tested the APC Smart 1000 UPS and Smart 700 UPS and they boot-up without being plugged in as you describe. I am planning to use them in my off grid setup to be built this fall. Any info you could share of what devices you have successfully used with your 1500's would be appreciated.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Re-build

    be carefull guys as these things weren't meant for constant use. they may not last as long in a constant use environment so consider looking at them as being rated 1/2 of what they are and they may give a bit more life.
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Thanks Neil, good advice.
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Hello all

    I am new to this site, and I like to start out by reading all the older messages first to get familiar with a site. This thread hit home with me, as I shall explain below.

    I use a pair of APC SmartUPS SU2200XLNET units on my PV system as true sinewave inverters. The XL series are an extended run design. These are fairly new units for me, as I had upgraded several months ago. My prior setup used a pair of SU1200XL, and I had run them for months at a time. These quality APC UPS units can be found on the government surplus market for pennies on the dollar as agencies upgrade or replace them. These particular units are nominal 48 VDC, and have an external battery connection on the rear. They work like a charm as true sinewave inverters, and keep track of loads of operational parameters which can be polled via RS-232.

    I have hacked out serial cable wiring, and communications protocols, to allow custom programming of settings from my laptop using HyperTerminal. In my application (partial grid/partial PV) I use heat sink mounted 400 amp blocking diodes to prevent them from charging the battery bank when I switch to total grid power (batteries low/extended cloudy weather, ect). The onboard charger charge rate is programmable for the battery bank size (the XL series are designed to charge/maintain a large external battery bank), and the time duration of bulk vs float charge is programmable as well.

    Startup without grid power is as simple as pressing the power-on button until it beeps, then releasing. Setting up automated operation is pretty simple with the aux function in my Outback MX60. I sense that to switch a 240 VAC relay that kills grid power into the units to force them online/offline based on a programmable trigger, like battery bank voltage.

    One last thing, the chassis of these SU2200XL series are the same as the SU3000XL series, just minus 12 of the FETs (3 per heat sink), and the associated capacitors/resistors, so they are very easy to upgrade yourself to SU3000XL if you have the electronics experience. All of the holes are there on the heat sinks, and the mainboard, for adding the missing components.

    Bob
  • System2System2 Posts: 6,290 admin
    Re: Re-build
    Hey all, Just wanted to get an economic snapshot if possible. I have had 6 55W Siemens panels charging a 12V bank of 4 golfcart batteries (220AH @6V) through a 20A Sunsaver Controller and a 800W Modified inverter for over 6 years. My very remote cabin is wired 120AC, and I have gone through three inverters, which are very inexpensive. I only average one 3-5 day visit every 6 weeks, and have a 1850 W Coleman genset to power a circular saw or anything else, but hardly ever use it. On AC I run CF lighting, a computer, stereo, hand power tools, on DC a small fridge and LED lighting. I get great production, but I'm going to step up, because I need more amps with a couple of new rooms and a pump. BTW, I heat with a woodstove, and collect water to a 300 Gallon tank 40 feet above the cabin, where it feeds the system through a filter. How would you spend $1500? Thanks very much for taking a minute from your day.


    A couple of things just struck me.
    First, regarding your blown out inverters, you mention only visiting a few days every 6 weeks. Do you leave them connected to their normal wiring when you're not there? If so, the failures COULD be lightening induced. I've been using them for about 15 years, with the 150 watt unit for the CF's on 24/7 for about 3 years now, and the only failures have been lightening, except for the one I reversed polarity. :-P
    Second, to conserve power, I would only use the 800 watt inverter for those big loads, like the saw. I would suggest a smaller one for the small loads of CF L's and computer, save on idle current, perhaps a still smaller one just for the Cf's, which do not require true sine. Note that if your hand power tools do not have variable speed, they don't need pure sine either, as they have universal motors, not induction motors. The variable speed circuits tend to mis-behave on MSW.
    All the best
    Wayne

  • SolarJohnSolarJohn Solar Expert Posts: 202 ✭✭✭✭✭
    Re: Re-build

    I'll just echo what others have said. I've been using an Exeltech 1100-watt sine wave inverter and I love it. I've only had it for a few months, but I used it continuously for a week when a storm knocked out grid power. It didn't even heat up. When I purposly overloaded it, the voltage just sagged a little, but it went right back to normal when I removed the overload.

    I would also invest in lightning protection. A $35.00 lightning arestor and some wire, and I would make sure the system is properly grounded.

    You might use the remaining part of your budget for batteries, as was previously suggested. I would also make sure that the wiring is heavy enough to handle the current when the loads are large. A DVM is a good investment (if you don't already have one). I use a data logger to monitor array output and battery voltage over time.

    John
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    "One last thing, the chassis of these SU2200XL series are the same as the SU3000XL series, just minus 12 of the FETs (3 per heat sink), and the associated capacitors/resistors, so they are very easy to upgrade yourself to SU3000XL if you have the electronics experience. All of the holes are there on the heat sinks, and the mainboard, for adding the missing components."

      APC makes different variations within the same capacity UPS, it's not simply a matter of adding heat sinks and FET's.  I have an SU2200 and SU3000, neither are the XL models.  The SU2200 is a 3U rack mount and the SU3000 is a 5U rack  mount.  The SU3000 has much larger transformers than the SU2200.

      I would also recommend using the XL models as they are designed for extended runtimes at their maximum capacity.  The Anderson type connectors on the back make DC connectons a snap.  I should note that my SU2200 has one NEMA L5-20R outlet that is powered by both transformers for built in load balancing.   The NEMA 5-15R outlets are each driven by a single transformer so I wouldn't recommend powering large loads from these outlets for long periods of time, the associated transformer may overheat.  Also, to the best of my knowledge, all Smart UPS models are true sine wave except for the Smart UPS 650.  I'm not sure but I think all of the Back UPS models are modified sine wave.

      A SmartUPS 1000XL powers my 5000 BTU window unit (about 550 watts) for hours at a time in the summer.   It's single transformer gets pretty hot but it is running at near capacity.

      Use this information at your own risk.

    Cheers,

    Bad Apple
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    I do not have any of the APC rack mount units. You are quite correct about being cautious, not all of these are the same. I do have several variants of the APC tower XL models, ranging from a lone SU700, up to a lone SU3000XLNET. Of these, both the SU2200XLNET and the SU3000XLNET are the same inside. Even the transformers are the same size in these particular units. Since I only had a single SU3000XLNET unit, and I had 4 of the SU2200XLNET units, I chose to use a pair of those for my system.

    My intent for adding the "missing" FETs was not to increase total capacity, because firmware and limit settings in these units are still at factory defaults. I chose to add the FETs so that the existing FETs do not have to work as hard, especially when running at or near limit. This equates to longer operational life when operated within the factory specs for that model. I had one SU2200XLNET fail during operation at about 50% load. Since I had to order FETs to repair that one anyways, I ordered extras for all. For the modest price of the parts, it was good insurance.

    While these UPSs work fine individually, they are not syncronized when paired up for 240 VAC operation. So using a pair of these together to operate 240 VAC loads is not recommended. I would rather have a pair of grid tie Outback or similar units set up for syncronized 240 VAC operation, but currently I cannot afford that sort of investment. I have had goood luck aquiring these "higher end" APC units from govt auctions dirt cheap however, so I make do.

    Bob
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Total newbee here,

    hi i have an su2200r3u i received it dead. Any suggestions on how to best determine the status. I dont want to purchase new batteries if the unit is toast. Here are some observations:

    1. it doesnt smell burnt inside.
    2. the 2 30 amp fuses appear to be intact.
    3. 120v power seems to make it to the main board
    4. the batteries aren't bulging and i am attempting to charge them on my backups pro 1000
    5. i thought that you could plug it in and it would charge up the batteries to a threshold then the unit would turn on, but in testing the output in the of position i get 0 volts on the battery plugs (ups side)

    thanks
    j
  • BB.BB. Super Moderators, Administrators Posts: 30,733 admin
    Re: Re-build

    The various manuals are here (if I got the right unit)...

    If the batteries are dead, you might be able to connect a couple car batteries temporarily and see if you can get it running again.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Re-build

    unless specified as new batteries inside i would always consider the batteries as toasted and i would insist on subtracting the cost of said new batteries from the used purchase price or at least understood that would be an expense to be expected. i purchased 3 ups last year and they all had new batteries installed which made the purchase price i paid for them to be more reasonable to me.
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    ok thank you for your answers. i'll try the car batteries. i just figured the unit would do something when i plugged it in even with dead batteries.
  • BB.BB. Super Moderators, Administrators Posts: 30,733 admin
    Re: Re-build

    I worked with these types of stand-a-lone UPS a few years ago (most where not APC brand)... And many of them required you to push a button to turn them on--or even some sort of long or multiple button press to turn on with dead batteries...

    Also, they may give errors if not connected to a properly grounded (including a grounded neutral if 120 VAC) wall outlet.

    Read through the manual and see check that you have the starting sequence and wiring right too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Re-build
    If the batteries are dead, you might be able to connect a couple car batteries temporarily and see if you can get it running again.

    SmartUPS 2200's are 48v, you'll need four x 12v batteries to test it. To test, take one of the Anderson connectors off the dead battery pack and connect it to four series connected 12v batteries. Reconnect the Anderson connector inside the battery compartment. The UPS should cold start without AC power and should charge the batteries with AC.

    Just in case you aren't aware, the "on battery waveform" on your BackUPS Pro 1000 is modified sine wave (square wave).

    Cheers,

    Bad Apple
  • System2System2 Posts: 6,290 admin
    Re: Re-build

    Great it works! I used some old batteries which hold a charge for about 15 seconds. I guess the unit wont start unless it has some amount of charge in it. So Here is my new question... which i will start a new post bc its a new topic..

    http://forum.solar-electric.com/showthread.php?p=19038#post19038
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