10 watt appliance battery need

SouthAfrica75
SouthAfrica75 Solar Expert Posts: 36 ✭
in General Solar Power Topics #1
If I needed to power 10 watts for lets give or take about 8 hours what type battery should I get ?

A small 6 volt I am thinking
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: 10 watt appliance battery need

    10w * 8hr / 6 volt * 1/50% discharge state = 26 amp*hour 6 volt storage battery minimum...

    That is not a very small battery... about 1/2 or 1/3 the size of a lead acid car battery. Chemistry, type, etc. are probably based on how much you want to pay, if you need to move it around, how long you need it to last, etc...

    The exact voltage probably depends on the device you want to power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36 ✭
    #3
    Re: 10 watt appliance battery need

    Bill... you're always to the rescue.

    As I live in Hurricane country S. Florida I bought 2 years ago a very nice and expensive 5" battery operated TV to replace the one I burned out during the 4 days with no power after Wilma

    Now after Feb 2009 the TV will not get a signal as everything is going digital around the country.

    So I looked into the converter box that I could use, but it needs power. I would only need to power it during a hurricane as I could not power it with my larger set-up outside until after the storm passes.

    It is 7 watts. I would needed it at most to last 8 hours. If we have a storm that lasts that long I and everyone here is in trouble.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: 10 watt appliance battery need

    I am not sure if there are any small portable Digital TVs out there yet (like the little 2"-5" portables that are out there today for analog NTSC)--But, there are a few devices out there that can let your PC/laptop receive over-the-air digital TV... Like this one for $40 or this one for $30 (don't know anything about the vendor/brand/capabilities, etc.).

    At this point, it may pay to wait a bit before spending a lot of cash to "roll your own" portable TV + battery powered DTV receiver.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: 10 watt appliance battery need

    to run your tv at this point with digital coming into play means you have 3 options. 1> go with the converter and it's bound to be needing an inverter as i know of none of the few converters out there that run on 12vdc. 2> buy a new tv with the digital tuner in it and this will probably still need the inverter. or 3> wait for a more conservatively sized 12vdc portable with the digital tuner built into it that currently isn't available to my knowledge.
    this is all extra power that is needed to be able to see that same tv that during those hard times will be more of a pain to produce that same video than it presently is both in terms of power used and equipment needed. do what you feel you must do, but it will no doubt be a 12v battery you'll be needing. 80wh/12v=6.7ah x2(to not go beyond 50% dod)=13.4ah battery. if you'd like to be able to do this for 3 days then it's 13.4ah x 3=40.2ah battery. odds are you'll find a deep cycle battery that can easily meet these requirements.
    do keep in mind that this is only the 8w you specified and a tv and a tv converter combo will without a doubt need more power to run both the tv and the converter.
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  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36 ✭
    #6
    Re: 10 watt appliance battery need

    The TV is already battery powered via "D" cell batteries. I have plenty of those on hand every year for hurricane season. I could probably supply both my neighbors with batteries as well.... LOL

    So all I would need to power is the converter of 8 watts
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #7
    Re: 10 watt appliance battery need

    1) your best purchase option is a Conventional Deep Cycle Marine battery from a local store. About 100AH capacity (50AH useable)

    2) there are some "plug in cig lighter" automotive 12V inverters in the 30 - 75W range, sold as Laptop power adapters. About $40. BUT I think they are the mod-sine wave style of inverter, and your converter box may not like it. You will have to try it out for a week and see if it smokes or not.

    A deep cycle battery charger, automotive charger will generally not top it off properly at 15V
    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 ,

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  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36 ✭
    #8
    Re: 10 watt appliance battery need

    A 100amp battery to run a 7 watt appliance for max 8 hours ?

    Seems like alot of battery for such a small amount of wattage

    I could be less if a hurricane moves over quickly and I can get into the main batteries I have set-up outside.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #9
    Re: 10 watt appliance battery need
    SouthAfrica75 wrote: »
    A 100amp battery to run a 7 watt appliance for max 8 hours ?

    But it is a commonly available size, about $70 here in the US.
    Exide Starting/Deep Cycle Battery:
    http://tinyurl.com/5mzruq or
    http://www.partsamerica.com/ProductDetail.aspx?MfrCode=EXI&MfrPartNumber=NC24&CategoryCode=3583


    You could use a exactly sized 20AH battery, and pay $65 us dollars.
    http://search.digikey.com/scripts/DkSearch/dksus.dll?PName?Name=522-1026-ND

    If I was spending the $, I'd go with the more versatile choice, the Exide deep cycle.
    (which in the fine print is only a 75AH battery, not 100 as my first guess was)
    And there are losses in the power conversion.
    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 ,

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
    Re: 10 watt appliance battery need

    what mike says about the prices on the more available 100ah type batteries is true and you can opt for whatever battery you think will suit you and your wallet, but when going with the higher ah batteries, just be sure you can give them a proper rate of charge with at least 3 stage charging prefered.
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  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36 ✭
    #11
    Re: 10 watt appliance battery need

    Perfect guys.... thanks

    I have 2 x 105 amp batteries in parallel for my after the Hurricane system to power 1 or 2 cf lights, recharge a cell phone, run a portable dvd player for the little guy, a fan or 2 to keep relatively cool and 1 or 2 other items as needed. Unfortunately will not run the refrigerator......

    The condo I live in has a main generator to power elevators, emergency lights and A/C in social hall. I have been given permission to take my batteries down to their work shop and re-charge from their emergency power if needed.

    I will go ahead and get another battery for the 7 watt appliance I need during the hurricane and that will make 3 in total for after.
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