Battery Need / Requirement

SouthAfrica75

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

Kamala

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

Re: Battery Need / Requirement

SouthAfrica75 wrote: »

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.

BB.

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

mike95490

Re: Battery Need / Requirement

SouthAfrica75 wrote: »

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.

SouthAfrica75

Re: Battery Need / Requirement

OOOppppppsssss

My BAD.... it is 8 watts............

BB.

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

SouthAfrica75

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

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.

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

SouthAfrica75

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

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!