solar panel directly with inverter

barkat
barkat Registered Users Posts: 1
hi..
i have a 150watt solar panel and 90AH battery i want to run two fans (a.c) with it now how many watts inverter do i need and what else will be required...
my secnd question is can we used inverter directly with solar panel without battery in between them to directly convert solarpanel dc into ac for fans? if yes how ?
my third question is in how much time a 100watt solar panel will charge a 100AH battery ?
thanks..

Comments

  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: solar panel directly with inverter
    barkat wrote: »
    hi..
    i have a 150watt solar panel and 90AH battery i want to run two fans (a.c) with it now how many watts inverter do i need and what else will be required...
    my secnd question is can we used inverter directly with solar panel without battery in between them to directly convert solarpanel dc into ac for fans? if yes how ?
    my third question is in how much time a 100watt solar panel will charge a 100AH battery ?
    thanks..
    Welcome to the forum,

    We can't begin to answer your questions until we understand your loads better. How many watts do the fans draw? How many hours per day do you want to run the fans?

    DC fans tend to be more efficient than AC fans, and they can be run without the losses of an inverter. They can be run without a battery with the addition of a linear current booster.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: solar panel directly with inverter
    barkat wrote: »
    hi..
    i have a 150watt solar panel and 90AH battery i want to run two fans (a.c) with it now how many watts inverter do i need and what else will be required...

    The size of the inverter depends on the amount of the loads, all measured in Watts. The 90 Amp hour will limit the amount of run time (up to perhaps 400 Watt hours AC) and that 150 Watt panel will just be enough to recharge it. This assumes a 12 Volt system and a fairly efficient inverter like the Morningstar 300. You will also need a small (10 Amp) charge controller to regulate the charging from the panel, plus appropriate wiring to handle the current and fuse protection on the charge controller's output and inverter's input.
    my secnd question is can we used inverter directly with solar panel without battery in between them to directly convert solarpanel dc into ac for fans? if yes how ?

    No. There is no way to do this as the power output from a solar panel will vary and not in accordance with the demands of the load. You can run some DC loads such as a fan directly from a panel but since the panel's output varies according to the amount of sun it gets the load will only run when the panel produces enough power to operate it, not whenever you want.
    my third question is in how much time a 100watt solar panel will charge a 100AH battery ?
    thanks..

    That depends on a number of factors, mainly how deeply discharged the battery is and how good the insolation on the panel is. The other big factor is the Peukart curve of the battery; the initial charging goes rapidly, but as the battery nears full charge the rate slows so it takes longer to recharge the last 20% or so than the first 80% (for example - not precise numbers). It is not simply a matter of "a 100 Watt panel puts out 5 Amps and so will replace 50% of the battery capacity in 10 hours".

    Hope that helped.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: solar panel directly with inverter

    since your 150W panel may be just able to recharge that battery I would seriously look at having 2 - 150w panels, which would need a 20Amp charge controller. this is to account for cloudy days that lower PV output. There is more but first you need to give us more details on the inverter, battery and the fans.

    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
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: solar panel directly with inverter
    barkat wrote: »
    hi..
    my second question is can we used inverter directly with solar panel without battery in between them to directly convert solarpanel dc into ac for fans? if yes how ?
    thanks..

    It is possible to build an inverter which is capable of running directly off a PV input without batteries (SMA is doing that) but as far as I know they are the only ones. It is an additional feature of a GTI model and it will not be able to make use of the full output of the panels. The two types of inverter which are usually seen are ones which deliver the full panel output to stable utility grid connection (Grid Tied Inverter or GTI) and ones which can deliver AC in variable quantities from a battery source, with the battery charged or supplemented by PV (off-grid or hybrid inverter.)
    SMA SB 3000, old BP panels.
  • colocarl
    colocarl Registered Users Posts: 1
    who is SMA ? how can i contact them as i want a no battery no grid small system.  panels and inverter to run 6 cf  freezer during sunny hrs as it will stay cold at night
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    colocarl said:
    who is SMA ? how can i contact them as i want a no battery no grid small system.  panels and inverter to run 6 cf  freezer during sunny hrs as it will stay cold at night
    It's basically for a grid tied system, good like trying to kick over a compressor with high startup current...

    ...but to answer your question, here's a link to the company;

    SMA America | SMA Solar (sma-america.com)
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    In general, mfg like SMA do not work with individuals directly. They use their distributors/retailers to provide pre and post sale support.

    Our host, Northern Arizona Wind & Sun is one such sales and support company (and they pay for and adm this forum):

    https://www.solar-electric.com/search/?q=sma

    The other way of doing this is to go with a DC Danfoss refrigeration compressor based freezer. For examplehttps://images.homedepot-static.com/catalog/pdfImages/a6/a6ee540e-69ac-4fd1-80fc-95b7d959538b.pdf:

    https://www.homedepot.com/p/Unique-9-3-cu-ft-265-l-Solar-DC-Chest-Freezer-Danfoss-Secop-Compressor-in-White-UGP-265L-W/306705286?NCNI-5

    This unit looks to run on a 12 or 24 volt battery bank... But I believe the actual compressor (or some models) can run directly from solar panels.

    Here are links to Danfoss DC compressors (various types/sizes) and some reviews/support information:

    https://duckduckgo.com/?q=danfoss+dc+compressor&atb=v122-1__&ia=web

    In theory, you could have a refrigeration technician pull the old AC compressor on your freezer, and replace it with a DC Danfoss unit to meet your needs...

    Or you can get the HomeDepot (or similar) DC Freezer off the showroom floor, and setup a sola power system (12 or 24 volts) with a X00 Watts of panels, maybe 4x golf cart batteries and away you go (choose 12 or 24 volt if you have other DC loads you would like to run).

    One big issue with running a freezer during daylight hours only--Depends on how cold you want to keep the food (?) and how sensitive to temperature variations you may be. The "standard" is Zero Fahrenheit and don't have the temperature cycle above that (i.e., rise to +0F during night and then brought to zero or below during the day)--That can accelerate freezer burn (evaporating/sublimation of the water ice from food and condensing it on the packaging). A bigger issue if you plan on long term freezing of product then a "warmer freezer/freezer burn" is a bigger issue).

    There are lots of DC freezers out there--And they generally are not cheap--But but setting up a Solar array + AC inverter (no battery) is not going to be easy--Although people have done it.

    Missori Wind and Sun (no connection with anyone here) has done some Solar Panels -> AC inverter systems configurations... You might want to talk with them about their options. The ones they list on their website (just a quick search) seemed to be 300 Watts or less.

    https://mwands.com/suntaqe-inverter-charger

    One issue with standard AC Compressor refrigeration systems... Is that they generally have pretty high starting surge Watts/VA--And you need a 1,200-1,500 Watt array to provide for those few seconds of starting surge. Sort of "cost inefficient" (>~1,200 Watt array to run a 120 Watt 120 VAC compressor).

    The DC compressors are really nice--They are "soft start", can run on solar panels directly (need to pick correct model?). And are very efficient.

    Also, our host has a good varaity of DC freezers too:

    https://www.solar-electric.com/search/?q=freezer

    They tend not to be cheap--But the savings on larger system+battery bank+solar array vs DC panels (or DC panels+a couple of batteries and a charge controller)--May work for you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,039 ✭✭✭✭✭
    edited December 2020 #9
    Quote,  BB said,
    One big issue with running a freezer during daylight hours only--Depends on how cold you want to keep the food (?) and how sensitive to temperature variations you may be. The "standard" is Zero Fahrenheit and don't have the temperature cycle above that (i.e., rise to +0F during night and then brought to zero or below during the day)--That can accelerate freezer burn (evaporating/sublimation of the water ice from food and condensing it on the packaging). A bigger issue if you plan on long term freezing of product then a "warmer freezer/freezer burn" is a bigger issue).


    Being that the Sundanzer DC freezers don't have a fan running in the compartment I THINK they are less likely to cause freezer burn. Seems that way after about two years with mine. I may be wrong here but regardless I really love this freezer.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    In early experimentation, I attempted to use a freezer as a refrigerator primarily using day time power albeit  with a battery to keep a charge controller operational with dismal results, the temperature was uncontrollable, however having said that, the ambient temperature was high, perhaps better results would be different  in cooler climates than tropical. The unpredictability of sunlight would also play a part in the attempt to power solely with solar which in my opinion would result in dissapointment at some stage.

    Even the thought of series connecting panels to achieve 230VDC (native voltage being 230VAC) and feeding that into an inverter type refrigerator crossed my mind , since AC is rectified anyway in such appliances,, but I came to the realization it's vastly simpler to build according to needs using existing technology, rather than trying to reinvent the wheel, my consideration was based on full time offgrid so others milage may vary. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.