Planning a System, please review.

klrskiesklrskies Solar Expert Posts: 30
I'm beginning to become familiar with what's involved with installing /using an off grid solar power system and would appreciate experienced thoughts.

I started learning with a harbor freight 12v, 45 watt, 3 panel amorphous cell system. It has a controller with some d.c. outputs and a volt meter. I added a single marine deep cycle battery that I dont discharge below 12.1v and I added a 400 watt modified sine wave inverter to run limited a/c applications on. I was given a crappy chinese controller that claims to be an mppt type controller. I added an analog volt meter to the panel output and digital volt and amp meters to the battery side to monitor activity.

The controller is not behaving as an mppt controller. Panel voltage seems to be coupled to battery voltage unless:

panels become shaded and then controller pulses seemingly trying to elevate and send pulsed power to the battery, or

when battery is full, it pulses to float charge, or it hits the input voltage limit of 17v and pulses..I don't think its even a good pmw controller, let alone mppt.

I never see panel voltage operate at a sustained, higher voltage than battery voltage whenever charging...to bad, as the panels put out around 24v no load voltage.
The amperage to the battery is about the same, maybe a bit less than the controller that came with the harbor freight kit.

I've aquired (4) 235 watt, 24v panels, a xantrex c35 controller, eight 6v, 325 ah batteries, and a 1800 watt modified sine wave inverter. I don't plan on keeping the controller or inverter. I'd like to aquire a hi quality mppt controller. As my system may double in size to 2kw in the future, I want to size the controller accordingly. I was looking at midnite solar's classic mppt controllers, and see they size them by maximum volts coming in from the panels, yes? If I double the array size, which controller size should I get? (

regards,
Ken

Comments

  • icarusicarus Solar Expert Posts: 5,399 ✭✭✭✭
    Re: Planning a System, please review.

    Not much time to write right now, but I suggest you read the following,,

    12.1 is a fairly deep discharge.

    http://www.batteryfaq.org/

    http://www.windsun.com/Batteries/Battery_FAQ.htm#Lifespan%20of%20Batteries

    Tony
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Planning a System, please review.

    Welcome to the forum, Ken.

    Can't say anyone will be surprised at the performance of your existing equipment. The HF panels are notoriously low quality, we've seen so-called "MPPT" controllers here (from China) that obviously aren't, and marine/RV batteries aren't the best choice for RE nor are MSW inverters. The up side is that you haven't spent a ton of money on stuff that doesn't work right; you're learning on the cheap. Or as cheap as solar gets, which isn't very. It could be worse; you could have tried making our own panels and gone through that nightmare. :roll:

    BTW, the "24 Volts" you see on the HF panels is Voc, not Vmp; you couldn't actually charge a 24 Volt system with them. For that you need a Vmp around 35. What the heck am I talking about? :D Glossary of terms: http://forum.solar-electric.com/showthread.php?t=6136

    Another good "starting point" read, The Battery FAQ's: http://www.windsun.com/Batteries/Battery_FAQ.htm

    Before you go acquiring or buying any more stuff, let's reflect on the right way to design an off-grid system:
    1). Determine your loads. It's a lot easier to figure out how much power you need and then how to supply it rather than figure out how much power you've got and what you can do with it. In that vein, it is also important to know what the system is for: off-grid living, RVing, emergency back-up power, experimentation, et cetera.
    2). After you determine your loads, see how much you can reduce them. Money spent on conservation always gives a better return than money spent on generation.
    3). The size & type of inverter will be based on the maximum Watts you expect to use at any one time. The size of the battery bank will be based on the total Watt hours used between charge intervals (preferably daily). The size of the array & charge controller will be based on how large the battery bank is.

    To look at what you've got:
    Four 235 Watt panels = 940 Watt array. That's good a size. About 1.8 kW hours AC "out the door" under typical conditions. Enough power there for a large (500 Amp hour) 12V system or a small 24V one. This big of an array would show the benefit from an MPPT controller.
    C35 charge controller = 35 Amps @ system Voltage. That won't do for 12V with that array, but would work for a 24V system (35 Amps * 29.6 charging Volts = roughly 1000 Watts max).
    325 Amp hour 6 Volt batteries. You'd need two for 12V, or four for 24V. Again the 24 Volt system configuration works nicely here as the array should make about 24 Amps which would be a charge rate of about 7%. Maximum power potential around 3.9 kW hours. Since these are probably L16 type "tall case" batteries you'll need to equalize them more often because the actual charge current is shy of the 10% minimum recommended for those.
    1800 Watt MSW inverter. Oh well, can't have everything perfect. :p

    In short, you've almost got a completely viable system as is. You're right to want to change out the controller and inverter, and possibly add a bit more panel (around 1250 Watts would be good for 325 Amp hours @ 24 Volts).

    MidNite controllers are very nice, but not necessarily what you need. Their high V input capacity is good for installs where long wire runs are necessary so you want to keep the array Voltage up. With the batteries mentioned above, you only need to be able to handle 32.5 Amps output. Most MPPT controllers from the Morningstar 45 on up would work for that.
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    Thanks for the responses! I'll read-up on the linked information.

    I have eight 325ah, FLA, tall 6v deep cycle batteries at this time.

    I've been using a kill-o-watt meter to get some perspective on watt useage. If going off grid, with a small honda 2000w generator for back-up, it looks like conservation of power makes it possible to operate an effecient 800 sq. ft living space with energy effecient appliances on 3~4 kwh/day without any air conditioning in the summer...that's a problem, as I'd like to add 10,000 btu of air conditioning capability to the system...about 300~400 watts/hr. or another 8~10kwh /day. although air conditoner energy consumption diminishes at night time.. still a cosiderably larger system! Yet... living in this area of the country requires air conditioning/de-humidification in the 4 summer months... maybe a compromise where the system is sized to handle the summer air conditioner loads with some assistance from the generator? During hot, sunny days I would think 4 more panels would carry the air conditioner load, but what about when the sun isn't out...demand goes down as well...I'm thinking I'd run the generator alot to assist with air conditoning load during the hottest months...and increase my battery bank capacity considerably. Air conditioning is such a big load.

    I looked into grid tied with our local remc...not too favorable, and requires $1,000,000 worth of liability insurance, ability for them to lock out the system, $20 minimumum monthly fee, credit of 1/2 the retail kwh cost that's only carried thru the next monthly billing cycle.

    regards,
    Ken
  • icarusicarus Solar Expert Posts: 5,399 ✭✭✭✭
    Re: Planning a System, please review.

    If you have the grid available,, use it! Any battery based system comes at twice the price with about h alf the efficiency. The grid is ones best asset, and best "battery" bank.

    Tony
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    Appreciate what your saying.

    I dislike the idea of remc getting my electricity for 1/2 of what they sell it back to me for...and paying for a millon dollars worth of insurance,plus another $20/month for a connection fee. their instalation costs are amortised over a 5 year span onto the monthly bill too. Indiana isn't too friendly in regard to energy co-generation...but our cost/kwh is relatively low....10~.11 / kwh.
  • BB.BB. Super Moderators, Administrators Posts: 29,883 admin
    Re: Planning a System, please review.

    Yea, it is tough... Our (Northern California) rates peak out at $0.52 for summer afternoon rates >~900 kWH per month... But we have great Net Metering (no extra charges, home owner's insurance is "good enough") we get paid back retail for power costs and have a 1 year period to break even (yes, if you use a lot of power, you can get $0.52 per kWH--although, practically for my TOU plan, summer afternoons is $0.32 per kWH and we buy our off-peak power at $0.09 per kWH.

    Now, I just need to wait some weeks/months to get a new/replacement GT inverter before the summer ends... :roll:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    why do batteries have to cost so much!? seems to be the stumbling block for all things alternative in energy. how hard is it to make a huge battery? i cant imagine energy becoming any cheaper or our grid getting any smarter.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Planning a System, please review.

    How hard is it to make a huge battery? Very. For one thing almost all the "ingredients" are classified as hazardous material.

    Imagine melting lead, mixing in the right amount on antimony & whatever else you've determined is necessary for the right plate consistency, pouring it into moulds the right shape, testing the result, finishing them off, connecting them together the right way with spacers in between, moulding a plastic case to hold them and the right amount of liquid, sealing the top on, mixing up electrolyte with the right % of sulphuric acid, filling the cells, electrically 'forming' the plates, testing the result, starting over if it isn't right, the half-dozen steps I've forgotten ...

    Not exactly a DIY project. :roll:
  • icarusicarus Solar Expert Posts: 5,399 ✭✭✭✭
    Re: Planning a System, please review.

    Batteries are expensive because they use vast quantities of metals that are expensive. Couple that with transportation costs etc and there you go.

    When it gets right down to it, your grid power at $.10 per kwh is really cheap. PV is going to have very hard time competing. You certainly won't do it with batteries. It is also very important to realize that batteries (all batteries) have finite life span, regardless of usage.

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 29,883 admin
    Re: Planning a System, please review.

    Think of what your Great Grandfather used to do:
    BB. wrote: »
    Eric/Westbranch posted a link to a 1922 battery repair manual. A very interesting read and look back almost 90 years at technology and mass production (near the end are some factory photographs).
    Antique battery info (1922) (thread)

    And here is the direct link to the table of contents:

    THE AUTOMOBILE STORAGE BATTERY ITS CARE AND REPAIR

    Despite the title, also includes information on storage batteries too (Farm Lighting Batteries).

    Still very similar technology today for the "cheap and durable" lead acid batteries we use today.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,044 ✭✭✭✭
    Re: Planning a System, please review.

    It sounds like you have picked up a complete 24v system. The C35 charge controller is a good reliable unit that I believe will work as a backup for even a 48 volt system I think. It would be good to have it as a spare. Likely the inverter is a 24v if it came with this system and it was up and running. I use a PWM charge controller very similar to the with my 24 volt system, My heavy use is in the summer when MPPT CC'c are less effective.

    If the batteries are good, why not set up what you have and divert some loads to it. You might change out the inverter for a pure sine wave inverter. If the system hasn't been running for a while you should check the batteries to see that the cells have enough water to cover the plates then do an equalizing charge and evaluate your batteries.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    Yes, I picked up up a complete 24v system from an Amish familyabout 100 miles away(off of craigs list) that ran two freezers to store deer meat in. After letting the meat spoil twice, they decided to go on the grid! 6 months old...

    I'm thinking about going off the grid...personal reasons mostly I guess...would like to keep one foot in reality however. If consevation is good, seems possible on 3~4kwh/day. We're so used to cheap energy, it requires some effort to quit being an energy hog! I'm used to useng over 1000kwh a month...You guys have probably faced the same truth?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Planning a System, please review.
    klrskies wrote: »
    Yes, I picked up up a complete 24v system from an Amish familyabout 100 miles away(off of craigs list) that ran two freezers to store deer meat in. After letting the meat spoil twice, they decided to go on the grid! 6 months old...

    I'm thinking about going off the grid...personal reasons mostly I guess...would like to keep one foot in reality however!

    I'm not surprised they gave up: that system would not power two freezers. One good one, maybe. But the MSW and AC induction motors don't get along; meaning the freezers would use even more power than they would normally.
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    I would like to consider useing D/C where possible...seems simple ands efficient...what really has to have pure sinewave inversion? perhaps best use dc where possible and pure sine wave everywhere else?

    My GE side by side "energy Star" fridge uses 2.9 kwh per day!That doesn't seem very "starrish" to me!

    I wondered what it was like if both compressors tried to start at the same time by chance on the amish set-up...I understand your probably refeing to the poor quality of the sine wave for the refigerations compressor motor, yes?
  • bsolarbsolar Solar Expert Posts: 103 ✭✭✭
    Re: Planning a System, please review.

    well, pure sine is probably best, i got a 2500watt sunforce and i like the thing, theyve actually come down in price since i got mine, saw one for 416 i think it was .. fridges and freezers can be put on a timer so they arnt popping on every time you grab a beer ..
    .. i would say double your panels and you would be fine offgrid with alittle feeling things out and planning. Your not going to be running ac imo you might as well forget that .. get a quality all-metal 20" floor fan or two and you'll survive ..
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Planning a System, please review.

    Using DC where possible is efficient. Especially as opposed to converting to AC only to run a power supply that converts back to DC. There is a drawback, however; your system Voltage is 24. AC output is 120. The longer the wire run, the more Voltage drop you get. Unless the DC lines can be kept short and fat you may find you run out of V for what you want to run. The higher the current requirement the worse this becomes.

    I know what you mean about the 'friges. An Energy Star 14 cu. ft. unit I just tested uses more power than a non Energy Star 16 cu. ft. I use at the cabin. The start-up surge on these things can easily be 5 times the running current, or more. And yes the motors do not like MSW; the waveform is not good at creating the right electromagnetic field in the windings. It's like trying to run it on low Voltage. Some motors won't run at all on MSW, but those are usually the large frame high-torque units. Which MSW inverter you have makes a difference too; the more "steps" to the waveform the closer it is to pure sine. Technically the "pure sine" inverters are just a lot more steps and a lot better smoothing so that their output more closely resembles the sine wave you'd get from grid or gen power.
  • BB.BB. Super Moderators, Administrators Posts: 29,883 admin
    Re: Planning a System, please review.

    I just bought a "cheap" 18 cuft frost free Fridge/freezer from Mega Depot--Energy Star rating of 311 kWH per year (less than 1kWH per day).

    If you never go with grid tied or off grid solar, researching and spending on conservation (including other appliances, laptop computers, insulated ceilings/windows/walls) will still be a big win for you and your family.

    Once you get your power usage documented and as low as possible, then you can look at GT or Off Grid Solar power to save money and/or go to an off-grid location (where the power lines are too expensive/not available).

    A good way to look at consveration... Figure off-grid power will cost you around $1-$2+ per kWH--Or ~10x the cost of your grid power today.

    All of a sudden that refrigerator that costs your 2.9 kWH per day:
    • 2.9 kWH per day * 365 days = 1,059 kWH per year
    Or $105.90 per year on $0.10 per kWH grid power would cost you around $1,059 to $2,000+ per year on Off Grid power... A new ~$700-$1,000 Energy Star Fridge could save you huge mounts of money when building/maintaining and off grid system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    how efficient are the newer pure sine wave inverters? seems pricy to put in huge pure sine inverter to cover everthing.
  • BB.BB. Super Moderators, Administrators Posts: 29,883 admin
    Re: Planning a System, please review.

    It is more their effect on your loads... About 80% of your gear will run OK, and about 10% will fail or not work correctly.

    Somethings do not work well (wall mount transformers, smaller induction motors, sometimes refrigeration compressors, some battery chargers, etc.). But it is difficult to give an exact list. And it is diffcult to "know" which will fail within minutes or run for years on MSW.

    All About Inverters
    Choosing an inverter for water pumping

    Some people pay the big $$$ for a small true sine wave inverters for computers, tv/radios, battery chargers, etc...

    And get a cheap/large MSW for running large motors/power tools. MSW tends to be less efficient powering motors--as the MSW will waste around 20% of the power going to the motor as heat (and why motors tend to get hot on MSW inverters).

    If you are in the middle of nowhere, you would be better off (usually) to get a TSW inverter to run most of your loads. Reliability is usually better for your loads.

    Of course there are many folks here with only MSW inverters and are very happy with them.

    -Bill

    And TSW inverters tend to use 2x as much power when running with no loads (can be pretty significant power wasting if you need power 24x7 for computers, DVR's, refrigerators, etc.).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.
    Photowhit wrote: »
    It sounds like you have picked up a complete 24v system. The C35 charge controller is a good reliable unit that I believe will work as a backup for even a 48 volt system I think. It would be good to have it as a spare. Likely the inverter is a 24v if it came with this system and it was up and running. I use a PWM charge controller very similar to the with my 24 volt system, My heavy use is in the summer when MPPT CC'c are less effective.

    If the batteries are good, why not set up what you have and divert some loads to it. You might change out the inverter for a pure sine wave inverter. If the system hasn't been running for a while you should check the batteries to see that the cells have enough water to cover the plates then do an equalizing charge and evaluate your batteries.

    Perhaps I could use it for some existing loads...120 v stuff, or maybe some D/C...If I put the 8 batteries in the basement, I'll need to vent the hydrogen gas outside while charging though. Would be difficult to switch back and forth with my current 120v a/c house wireing...maybe run cords to what I want to power...much to consider regarding how to utilize the system.

    I'm single now, children are on their own, I own 10 acres with a rejuvenated farm house, dettached garage, barn, pasture, and pole barn. I would prefer to rent my house, garage, barn, and pasture out, leaving it on the grid, and move myself into an efficent 600~800 sq. ft living space inside my pole barn/machine shop...like an apartment inside my polebarn. It would be set up for off the grid functionality...wired appropriately, well insulated and sealed up tight with foam, natural lighting, D/C and/or propane or natural gas appliances...then I'm not trying to be convert to dual power systems as I would in my 1500 sq. foot conventional house space...central air and furnace, wired for normal grid service. and I would have some rent income, and less property to maintain. time is becoming more valuable as I get older!

    I have thought about living in a large 5th wheel or travel trailer too, seems already set up for D/C or alternative power sources...If my pv system were mounted on/in an enclosed trailer I could be mobil as well...or take it with me easily if I ever re-locate without loosing much on my pv investment. Living in a large rv, I would not give up shop space in my pole barn either. As most rv's aren't insulated to well, it would help to get it out of the weather as much as possible...under a carport at least, preferably out of the wind too. My nosey neighbors dont always like seeing them, raising possible zoneing and property tax issues. Would be something to consider though...I see some nice larger 5th wheels and travel trailers with generators selling pretty low these days. probably much less than building an apartment inside my pole barn / shop.

    I appreciate all the helpful information being provided on this forum. many thanks to you all for taking time to provide insight and share your experience.

    regards,
    Ken
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    As I look at the suns path, it occurs to me that an array that can be manually rotated to possibly track, and be away from shading would be best located 75`~100' away from my batteries. As my 4 panels are sharp 24v, I'd consider going 48 or 96v from the panels to an mppt controller and then step down the voltage at my [8] 350ah, 6v, L16 batteries to something workable.

    My question is: If one is off grid and wants to utilize dc power as much as possible to minimize losses, it seems 24v is a good choice for dc circuits to minimize wire size. and lighting and refrigeration appliance are available for 24v, although perhaps not as much as 12v. I'd think I'd want a pure sinewave inverter for some 120v a/c appliances, and induction motors, but use dc for refrigeration, lights, and where possible. Am I thinking straight?
    regards,
    Ken
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Planning a System, please review.

    You could do a 48 Volt array. 96 Volt could be a problem. The reason being the Voc on the panels is something around 44 Volts. All four in series would be 176 Voc and you'd have to use the MidNite Classic 200 for a controller.

    On 48 Volts across 100' you'll need some hefty wire to reduce the Voltage drop to acceptable levels. We're talking 6 AWG here. If you were to run the higher Voltage array it would be probably 10 AWG or 8 AWG. Wire price vs. controller price; what can you get it for?

    As for whether to use 120 AC or 24 DC for most things there are a couple of aspects to consider. One is the length of wire runs from the power source to the device. As in the example above, lower Voltage suffers more from V-drop. Another thing to think about is if you are going to need the AC anyway, how much AC are you going to need? A 300 Watt inverter or a 3000 Watt inverter? It can be a lot simpler to just run AC wiring as per standard household equipment if the one inverter you need to buy will handle everything anyway.

    I have this sense of déjà vu here; how many times have I answered this same question? Must be a popular topic! :D
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.

    Thanks for responding.
    I feel there is so much infomation and considerations that us new people are somewhat overwhelmed with the possibilities and consequences. Please know your help is appreciated!

    It would simplify set up to do all a/c thru a quality inverter, but don't they consume quite a bit of power...especially when inverting small loads with a large inverter...or is that not a big consideration?

    regards,
    Ken
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Planning a System, please review.

    Ken;

    That is a very good question.
    Consider my situation. I have a 3.5 kW Outback inverter. It uses 20 Watts all the time, even when doing nothing. That's 480 Watt hours per day just to run the inverter.
    The inverter is that large because it needs to power a couple of sizable pumps to handle water in and out. There was no choice in this due to the configuration of the site. The 'option' of moving the 60-year-old lodge or rebuilding in a location more suited to water handling (up the hill; gravity flow in and out!) was not practical: tens of thousands of dollars. Most of the time this inverter has to supply less than 300 Watts! A little 12 Volt Morningstar could do the job (uses 450 mA while idle - about 6 Watts). The refrigerator would be troublesome for start-up, but it's possible that could be arranged too. But when the big power is needed, it's needed. No sense having dual systems when you have to pay for the big unit anyway.
    Some would argue the savings on Amp hours. Indeed the Outback has a 'search' mode which reduces consumption to 6 Watts. I did the calculations; the mount of time the inverter is on in 24 hours the 14 Watt difference comes to 10 Amp hours. That's "margin of error" territory. Then there is the trouble that some low Wattage lighting may not provide enough draw to bring the inverter out of 'search'.
    Add to that the fact the kids (30+ years old) are left on their own there and have difficulty enough running the system as it is. I couldn't see trying to explain a split 120 VAC system much less an AC & DC system. Our Chris is a civil engineer, but he doesn't grasp electrical concepts.:roll:
    So all those factors combined led me to use the one big inverter and leave it running all the time. Not the most efficient, but it is the most practical in this situation.
    They still use the water pump "off hours" and run the batteries down dead. Last year they did it every night for a week before calling to ask what was wrong. To off-set that kind of use I'd need a bigger battery bank and more panels, just in case someone ran the pump after 'Float' was gone. That's not as practical as teaching them to start the Honda and boost the batteries back up before night.

    Note the Morningstar 300 Watt inverter uses 6 Watts running (less than 1 in 'standby') and the Outback uses 6 Watts in 'search' mode. Inverter consumption is an issue, and it comes down too how much power you use how often? Does it justify the bigger inverter? Buying both (assuming the same system Voltage so they'd run off the same bank) would be an additional expense. Maybe the money would be better spent on more battery/panel capacity.

    There' no one answer for any situation, much less all of them. Unfortunately that means you have to wade through all the possible solutions and at some point decide "this is what I'm going to do", knowing there will be downsides to that choice.

    Then the circumstances of the site change and you'll wish you'd done it differently. Don't second-guess yourself until you make no choice at all. You could wait forever to find that perfect answer. In the meantime you'd have no power.
  • klrskiesklrskies Solar Expert Posts: 30
    Re: Planning a System, please review.
    Photowhit wrote: »
    It sounds like you have picked up a complete 24v system. The C35 charge controller is a good reliable unit that I believe will work as a backup for even a 48 volt system I think. It would be good to have it as a spare. Likely the inverter is a 24v if it came with this system and it was up and running. I use a PWM charge controller very similar to the with my 24 volt system, My heavy use is in the summer when MPPT CC'c are less effective.

    If the batteries are good, why not set up what you have and divert some loads to it. You might change out the inverter for a pure sine wave inverter. If the system hasn't been running for a while you should check the batteries to see that the cells have enough water to cover the plates then do an equalizing charge and evaluate your batteries.

    Yes, it is a complete system. It ran 2 small meat freezers in a remote area for an almish family for 6 months. The c35 just handles 12 & 24v though, so 48v is out with this controller, I think the 40 handles 48v? Batteries were still at 12.8v but I did a charge cycle. to freshen them up. I'm learning alot of valuable info on this forum. Really great!
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