Use deep discharge marine battery as emergency power source?

[clare]

LKots of places the noise and fumes make use of a fuel-powered generator impossible or impractical.

[Tegger]

[e-mail] wrote in news: [e-mail]:

Why not simply purchase a computer Uninterruptible Power Supply (UPS)?

It will probably cost you less than trying to cobble up something from bits here and there. And it will come with USB and 120VDC outlets, so you can charge your iPod as well as power ordinary light bulbs to see the iPod by.

UPSs are available at many price-points with many different runtimes.

APC is a major manufacturer of good-quality UPSs.

I've got two APC UPSs: a Back-UPS RS 1500, and Back-UPS ES 550. I often work from home, and I NEED stuff to stay up in the face of the flaky power in my area.

[Mark]

I know this will start a flame war, and I'm not going to respond to it but...

if you want this battery only for EMERGENCY power meaning that you are going to deep discharge it once or twice a year, then you are better off cost wise buying a standard car battery not a deep discharge battery. Deep discharge batterys ARE needed for applications where they will be deeply discharged over and over. A regular car battery will survive just fine a few dozen deep discharges. Since there is a large cost savings, you can probably buy two regular car batteries for the price of one deep discharge.

In any case, as was said, the important thing is not to over or under charge it. Even a small unregulated charger if left on long enough will overcharge the battery and shorten it's life.

Mark

[me]

Yeah thought of that

But do they come in capacities capable of running a week with small to moderate loads for lighting and such?

[gfretwell]

One thing you can do is to recharge your battery from the car. I did that after hurricane Charley to run a few inverters off of my golf cart. I used the batteries and charged them from the car 2 at a time. Now I have this gadget.

[me]

Actually I am now thinking abt FORGETTING a deep discharge battery... and instead basing some kind of system off portable rechargeable drill batteries that are LI-ON

[Percival P. Cassidy]

Where are such caps available? Google turned up just a few references to such things but no links to vendors.

Perce

[Tegger]

[e-mail] wrote in news: [e-mail]:

A whole week? I think a marine battery won't last two days with what you plan to do with it. Think of what happens when you leave your 55W car headlights on overnight.

A generator is probably a better bet for you.

[jamesgangnc]

You ae not going to run anything for a week off of a battery you can carry. Batteries as a backup power source are very limited. Enough lithium batteries to be of any use will cost a small fortune.

If you need a week you need a generator.

[Jim Elbrecht]

That's a whole nuther ball game. Lead acid cells do what they do very well. LI-ion cells do what *they* do very well. I don't think there is a whole lot of overlap in what they are both suited for.

There are reasons that cars use lead acid and drills use li-ion.

What are proposing to power? How long are you guessing the emergency will last? How often will you need to supply emergency power? Will you see it coming?

Jim

[Caesar Romano]

On Mon, 31 Jan 2011 21:31:35 -0600, [e-mail] wrote Re Re: Use deep discharge marine battery as emergency power source?:

Yes, but they get expensive:

[Robert Green]

Yesterday, when I checked the condition of both my car batteries in anticipation of the coming big freeze. Perhaps things are different in the Great White Way. My battery kit contains a small bottle of sulfuric acid, a larger bottle of distilled water, a voltmeter and a "turkey baster" hydrometer to test the specific gravity of the battery fluid.

-- Bobby G.

[trader4]

Exactly. I have a Bosch car battery in my car, installed last year, that has caps on the cells too.

The other thing that just isn't so is this:

"The common high output deap cycle lead acid cell today is the starved eletrolyte AGM battery, which can be shipped by air and is not considered as "hazardous material" when it comes to transporting or handling."

True AGM are one type that is available, but this implies they are the whole market or that it would be uncommon to find a deep cycle that isn't AGM. In the marine market there are flooded cell deep cycle marine batteries that are widely used. They are less expensive than AGM and I would expect there are lots of other applications they are used in for similar reasons.

[Robert Green]

Exactly. I have a Bosch car battery in my car, installed last year, that has caps on the cells too.

The other thing that just isn't so is this:

"The common high output deap cycle lead acid cell today is the starved eletrolyte AGM battery, which can be shipped by air and is not considered as "hazardous material" when it comes to transporting or handling."

True AGM are one type that is available, but this implies they are the whole market or that it would be uncommon to find a deep cycle that isn't AGM. In the marine market there are flooded cell deep cycle marine batteries that are widely used. They are less expensive than AGM and I would expect there are lots of other applications they are used in for similar reasons.

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I have a deep discharge marine battery that's got caps and liquid electrolyte. From what I understand the plates are thicker and have less total surface area than a car battery. The car battery is designed primarily to provide maximum amperage for cold cranking and thus needs much more electrode surface area than one meant to provide moderate current continuously, as in a marine trolling application. Batteries with access caps are almost always meant to be used in one position whereas the SLA batteries can usually operate in any position without danger of sulfuric acid leaking out.

If I recall correctly, the problem with deep discharging car batteries is that lead will drop off the plates and start to build up at the bottom of each cell, eventually bridging the electrodes and shorting that cell out. Depending on what site you're reading from, that can happen either after a few deep discharges or 30 or more.

-- Bobby G.

[trader4]

I tend to agree. But, it all depends on what his definition of "small to moderate loads" is. If it's lighting a small 12V lamp for 10 mins at a time a few times a day and charging his cell phone via USB, then it could last more than a week. On the other hand, for most emergency power for home use, you'd want to also run more, like the refrigerator, more lights, possibly the furnace, etc.

I can tell you with my cabin cruiser it had two dual purpose marine batteries and you could pretty much drain them in less than 24 hours of reasonable use. That included just lighting, running the refrigerator bathoom fan, radio, water pump, etc.

He should start by putting together by determining the running current for all the loads and how long they each will be used. Then he'll know the required AmpHours and what size battery range he needs.

[hallerb]

Battery MUST be forever on a charger, like a trickle charger but after a few years it will go bad.....

Marine batteries have short lives and short warranties.

Your probably better off to buy a new battery for your vehicle and use the old vehicle battery for your back up needs. this costs less and works well.

[me]

Last maybe 4 days

Use for LED lighting MAINLY

and powering small electronic devices and recharging those devices such as cell phones, netbook etc

I realize it would be impossible to do much more than that with batteries

[me]

lighting would be very high efficiency type... CFL based or LED based only

[jamesgangnc]

Get a car battery and try it but I still think you will be disapointed. I've seen things as simple as leaving an interior light on overnight drain a battery to where it would no longer start the car. I have a group 29 dual purpose bvattery in my boat just to deal with sitting and running the radio. And I still limit that to a few hours. A group 29 battery weighs about 60lbs.

[Tony Miklos]

Hmmmm? Funny, the car battery I put in my garden tractor has a strap. It's not a marine battery.