12V Car battery as emergency power

[Moose]

Anyone like to take a guess as to how much listening time I could expect, powering about
4 analog scanners off of a fully charged car battery? Rough ballpark? Thanks

...in the path.

 

[homeinva]

whats the amp hours on the battery

 

[Moose]

Haven't bought it yet. Let's say something in the middle?

 

[Alliance01TX]

Battery

Howdy

Depends on the following, at minimum:

1. Size (amp hours) of the battery
2. Condition of the battery (meaning old-new, etc..)
3. Current draw of the devices in amps (mA) with lights and speakers going (peaks)
4. Will the current drawn be consistant
5. Would you have a charger running (maint type) on the batteries to keep them charged up

All this said, I would guess the 'range' might be ~ 4-12 hours, which is a large margin of error and the above factors could still sway the numbers widely...

Hope this helps....

Bill

 

[homeinva]

i agree also how many time the that the radio breaks sq. and the audio comes through

 

[pjtnascar]

If you're buying it just for the radios, get a deep cycle battery, the are better suited for discharge and recharge.

 

[Moose]

Thanks to everyone who responded. If the hurricane does cut power here in NJ
I hope to keep at least 1 to 4 scanners running for at least a day or two. I've
never been in a situation where the power has been out for more than just a
few hours. (pretty lucky for my advanced years. lol). This hurricane has the
potential to change that and I want to keep aware of my surroundings.

 

[pjtnascar]

I didn't realize you were here in NJ. I am getting prepared today, even though I live in Northern NJ. A few years back, we had a freak snowstorm the week before Halloween. Because of the weight of the ice/snow on the leaves of the trees, powerlines went down and I lost power for almost three days. Not fun. After that, I bought a generator, so now I'm better prepared. We seem to lose power here pretty often, but outages don't last that long.

We will be watching the storm closely. Make sure you have your flashlights, etc. ready in addition to your scanners.

 

[Rob_K]

If you're buying it just for the radios, get a deep cycle battery, the are better suited for discharge and recharge.

I may buy an Optima battery for this storm.

Take a look at KB0NLY's setup for some awesome power ideas:
Shack!

 

[Moose]

Other than backup power for the scanners I'm all set. Flashlights, candles, solar powered lights, water, canned goods, etc.

 

[Moose]

Deep cycle batteries

Checked several stores in the area. All the deep cycle batteries run $209 +. I was hoping to spend less than $100.00 for something. Since this may just be a one time event, I plan on getting a regular car battery and hope the power doesn't go out.

 

[pjtnascar]

You can get a marine battery at Walmart for trolling motors. It is a deep cycle, for about $79.00. That's what I have used and it works well. Unless you are planning to upgrade your car battery anyway, I'd get the marine one. Don't bother with those Optima deals fofr a one time deal. If there are any junkyards by you, they may sell reconditioned batteries. There is one in Roxbury that sells them for $35.

 

[Moose]

Okay, sounds like a plan. Leaving work now, headed to Wal-Mart.

 

[K9WG]

You can get a marine battery at Walmart for trolling motors. It is a deep cycle, for about $79.00. That's what I have used and it works well. Unless you are planning to upgrade your car battery anyway, I'd get the marine one. Don't bother with those Optima deals fofr a one time deal. If there are any junkyards by you, they may sell reconditioned batteries. There is one in Roxbury that sells them for $35.

^^^^ What he said ^^^^ Marine batteries are designed for long time output and recharging. Car batteries while working will not last as well.

 

[kb0nly]

I may buy an Optima battery for this storm.

Take a look at KB0NLY's setup for some awesome power ideas:
Shack!

Thanks for linking to me Rob!

If this was long term i would say spend the money on a good battery but for short term, get something cheap. You could get a simple float charger from your local Wal-Mart and a $50-60 car battery and even with all four scanners receiving audio your looking at what 4-5a draw? You should put an ammeter inline and see what they actually draw with squelch open and receiving, set all four to NOAA weather radio, adjust volume level to your normal setting and measure the current consumption.

Take a typical car battery, say 50Ah for some of the cheapos, its going to go at least 5 hours with a 5a draw. I know the math doesn't seem right, but only figure 50% of capacity to be safe, when the battery voltage starts dropping off the scanners won't wanna run anyway, my Uniden's get flaky below 11 and at 10-10.5v they shut off.

If your expecting a longer outage i would go to a salvage yard, buy up some cheap used batteries and make cables to put them all in parallel to make a bank of batteries, get a good charger on them and make sure everything is fully charged and keep the charger on there to maintain them til power goes out. Being this outage is weather related i won't even bother suggesting solar to extend your run time, as it won't be sunny enough anyway!

A small generator might be a good investment, then you could also run the tv, fridge, some lights and a fan, etc. I know a lot of people bought little 1kw units when the tornado hit us July 1st. I was the only one in my area of town that had power thanks to my 6500w gen.

Best of luck to you, hope you weather the storm ok!

 

[kb0nly]

Heck even a DC generator would help you out now that i think of it. A junk yard alternator and a small gas engine off a lawn mower! Connect the output of the alternator to the battery and there you go.

 

[slicerwizard]

I would guess the 'range' might be ~ 4-12 hours

Estimates like this are ridiculously low. A 12V car battery or deep cycle battery will have a capacity of 70 to 90+ Ah (a couple of $50 deep cycle batteries I bought last year at Costco have capacities of 95 and 125 Ah). Four receivers will pull 2 amps TOPS, so you're looking at DAYS of run time.

 

[kb0nly]

Estimates like this are ridiculously low. A 12V car battery or deep cycle battery will have a capacity of 70 to 90+ Ah (a couple of $50 deep cycle batteries I bought last year at Costco have capacities of 95 and 125 Ah). Four receivers will pull 2 amps TOPS, so you're looking at DAYS of run time.

True but your not compensating for voltage drop off!

Just because a battery has say 70Ah doesnt mean it will run a 12v device using 1a for 70 hours.

My Optima YellowTop fully charged will run my shack on receive a couple days depending on transmit time, but thats not continuous, i shut off radios that i am not using, turn them on when i need them, etc. The two scanners will run for about two days here on battery before the voltage drops to the point they won't stay on.

Four receivers will draw MORE than 2 amps. Even my Uniden's pull more than that. Scanning they pull less than an amp each yes, but when unsquelched and producing audio they pull almost 2a each due to the audio amp taking power. Why do you think they put 3a fuses in the power cords?

I would like to see four scanners producing satisfying audio levels at the same time and drawing 2a or less.

 

[Moose]

Ok. Finally got my marine deep cycle battery from Autozone. I called one of the Autozone's near where I live. They said they had three in stock but were not selling them. They said they wanted to keep them for themselves. Finally found one on the other side of the county. Anyway, should the power go out I most likely will just power one scanner. The hurricane is still hours away from NJ. Hopefully it won't be as
bad as they are saying.

 

[pjtnascar]

Let's hope for the best, Moose!