Battery Need / Requirement

SouthAfrica75
SouthAfrica75 Solar Expert Posts: 36
I need a battery to power an 8 amp dtv converter box to use in the event of a power outage from a Hurricane

Would need to run it about 5 to max 8 hours a day for probably 3 to 4 day max.

I don't want a battery that is heavy or bulky....

Any suggestions as to what type battery I could get and from where

Thanks

Comments

  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    Re: Battery Need / Requirement

    Any battery able to meet your need, as stated, will be heavy and large. Other helpful people on this forum can explain why this is so. BTW, welcome.

    Bulky, to me, means large volume/small weight.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Battery Need / Requirement
    I don't want a battery that is heavy or bulky....

    You want the Harry Potter "Infi-spell" Generally, stores are sold out.

    You could look into Lithium laptop batteries, but they are very expensive.


    So looking at a typical DTV converter box, draws about 30 watts @ 120VAC
    8 hours x 4 days = 32 hours Run time (max)
    30 w x 115% to allow for inverter losses (Morningstar SureSine @90% eff)
    = 35 w consumed @ 12.5V = 2.8A
    x 32 hours = 89.6 AH consumed (90Ah)

    A typical group 27 deep cycle battery holds 100 AH.
    You never want to remove more than 50% of the charge, so you would need
    2 , group 27 size, deep cycle batteries (not marine)
    These weigh in at about 50 pounds (US) each.

    Gives you 200 A storage, 100A useable, and would run a 30W, 120V load for 32 hours, just meeting your spec.

    Then you need a way to keep the battery properly charged, and a car battery charger will not do it.
    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 ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: Battery Need / Requirement

    If that is 8 amps at 12 volts and 50% maximum discharge:

    Flooded Cell Lead Acid:

    8 amps * 8 hours * 4 days * 1/50% = 512 Amps*Hours @ 12 volts

    Crown 6volt 225 AH batteries $125 x 64 lbs:

    4 batteries => $500; 256 lbs; 450 AH

    If you use an AGM battery, you can discharge to 20% state of charge, and if you assume the minimum power needs (this is a smaller system assuming less hours and days of use):

    8 amps * 5 hours * 3 days * 1/80% = 150 Amps*Hours @ 12 volts

    Concord AGM batteries PVX-2120L => 1 battery; 212 A*H 138 lbs $483

    Or, you can get a small Honda Genset...

    eu1000i:
    Engine: 1.8 HP, Single Cylinder,
    Overhead Valve, Air Cooled
    Displacement: 50 cc
    AC Output: 120V
    1000W max.(8.3A)
    900W rated (7.5A)
    Receptacles: 15A 125V Duplex
    NEMA Plug Number: 5-15P
    DC Output: 12V, 96W (8A)
    Starting System: Recoil
    Fuel Tank Capacity: 0.6 gallons
    Run Time on One Tankful: 3.8 hrs. @ rated
    load--8.3 hrs. @ 1/4 load
    Dimensions (L x W x H): 17.7" x 9.4" x 15.0"
    Noise Level: 59 dB @ rated load
    53 dB @ 1/4 load
    Dry Weight: 29 lbs.

    Assuming 8 hours * 5 days of generator use:

    25% load * 900 watts = 225 watts (vs 8 amps*12 volts = 96 watts)

    8 hours * 4 days / 8.3 hours per 0.6 gallons = 2.3 gallons of gasoline

    30 lbs for the genset + 2.3 gallons * 6 lb/gal gas = 44 lbs for kit

    ~$700 USD + $6 of fuel = $706 for kit.

    And the generator will provide 2.3x more power (225 watts for 32 hours) vs the biggest system above (96 watts for 32 hours).

    You can run a small fridge, and some CFL lighting too in the emergency.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Battery Need / Requirement
    I need a battery to power an 8 amp dtv converter box

    dtv = Dish T V or Digital TV set top converter box (USA new standard)?

    8A is a LOT of power. 8 watt is more believable.
    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 ,

  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36
    Re: Battery Need / Requirement

    OOOppppppsssss

    My BAD.... it is 8 watts............
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: Battery Need / Requirement

    Take my 8 amp numbers and divide by 12 ( ;) ).

    I assumed that you where including powering a TV and such too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36
    Re: Battery Need / Requirement
    BB. wrote: »
    Take my 8 amp numbers and divide by 12 ( ;) ).

    I assumed that you where including powering a TV and such too.

    -Bill

    Bill... Thanks

    Actually I only need to power the 8 watt converter box... My portable TV I will run as I have in past Hurricanes with "C" batteries.... I have boxes of those
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Battery Need / Requirement

    You're portable TV may run on batteries,,, but if it is getting signal off the air,, after mid June '09 it won't get a usable signal. If it is off the satellite dish or cable it still will.

    I suppose that there are some small DTV portables made nowdays,,, how expensive I don't know.

    Tony
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: Battery Need / Requirement

    Tony,

    They sell $40-$80 DTV converter boxes to allow analog TV's to continue to be operated (don't know if they use channel 3 or require the AV inputs).

    I looked around a bit for portable TV's with digital tunners--and they are done in the $200-$110 range now (~7" wide screen or so).

    But not a lot of them out there yet--and the digital reception is still a bit of a question. Many users need to use an external whip or amplified "house" antenna for good reception. However--I believe that many TV stations where broadcasting on reduced power for their digital signals until the analog switchover is performed.

    I have an older (bigger) converter--is kind of flaky (software needed work, has an issue with the HDMI failing to initialize if the HDTV monitor is not turned on first)--but with a cheap amplified antenna I pickup all my local DTV stations very nicely (have to "rotate" the antenna very accurately--have it sitting on a dresser in our second floor bedroom). Even get one or two that analog is not worth watching on.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SouthAfrica75
    SouthAfrica75 Solar Expert Posts: 36
    Re: Battery Need / Requirement
    icarus wrote: »
    You're portable TV may run on batteries,,, but if it is getting signal off the air,, after mid June '09 it won't get a usable signal. If it is off the satellite dish or cable it still will.

    I suppose that there are some small DTV portables made nowdays,,, how expensive I don't know.

    Tony

    Tony...... Thanks

    I have a DTV converter box that I've connected to the portable TV, it works great..... That's my reason why I'm looking for a battery to run the converter box.....
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Battery Need / Requirement

    You're right,,, I omitted that without a cable connection, or a satellite OR a dtv conversion box,,, analog tv will go dark. Thanks for the clarification,

    Tony

    PS One more phantom load to power 24/7!