running appliances without batteries

baja1baja1 Registered Users Posts: 13
heres my question. I have 820 watts of solar(8 75watt panels on the outback and 2 110 panels on a sun saver. I have (had) a battery bank,4 245AH 8D AGM's that are all dead.
can I run my chest fridge during peak sunlight hours with batteries disconnected just solar thru controllers thru inverter? or is this bad on the controller???
(until I can afford a new battery bank) thanks

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: running appliances without batteries

    Nope. Won't work. No batteries = inverter doesn't run. They can not be powered off the hugely varying Voltage and Amperage of raw panels. The charge controller doesn't do anything for that without a battery bank to reference.

    You might want to read through this thread: http://forum.solar-electric.com/showthread.php?t=11689
  • VicVic Solar Expert Posts: 3,112 ✭✭✭✭
    Re: running appliances without batteries

    AND, particularly page three of that thread:

    http://forum.solar-electric.com/showthread.php?t=11689&page=3

    Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • rgk1rgk1 Solar Expert Posts: 132 ✭✭✭
    Re: running appliances without batteries

    Just out of sheer curiosity, could you put just a small inexpensive battery in to make it work?
    4-Risen 320 watt in series/parallel, 8-215ah 6 volt GC2 batteries in series, Exeltech 1100 watt/48 volt inverter, Tristar 45 MPPT controller.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: running appliances without batteries
    rgk1 wrote: »
    Just out of sheer curiosity, could you put just a small inexpensive battery in to make it work?

    Depending on your definitions of "small, inexpensive battery" and "make it work", yes.
    Too small an Amp hour battery will cause severe Voltage drop if the current required at any point overwhelms it. And of course it won't last long with less than ideal capacity. You might also have to reset some charging parameters, depending on the system.
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: running appliances without batteries
    rgk1 wrote: »
    Just out of sheer curiosity, could you put just a small inexpensive battery in to make it work?

    yes. It may not last as long, since all starting peak power will be coming from only 1 battery. I'm assuming this is 12V,and 1 sam's club deep cycle battery
    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 ,

  • RCinFLARCinFLA Solar Expert Posts: 1,393 ✭✭✭✭
    Re: running appliances without batteries

    There are two situation in this case on a small battery.

    First is if a period of cloud overcast goes by dropping out much of your PV power. Most of the power will then be coming from battery.

    Second is the filtering of the inverter ripple current provided by batteries. Too small a battery may have too high internal resistance. You may get too much ripple on the inverter supply that will cause it to shut down or act irratic.

    If the battery is capable of running your loads, by itself, for about 30 minutes you stand a fair chance of it working.
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