How long with a T105 battery last if its never used?

[Murby]

What kind of life expectancy could I expect from a Trojan 6V style battery if its always kept fully charged and almost never used?

I want to install a battery backup system for my home but don't plan to actually use it very often. We lose grid power maybe three to five times a year for maybe four or five hours each time and I'd like to still be able to watch TV or run the computers.

So I'm wondering, if I put in a couple of the Trojan batteries but hardly ever discharge them, how long will they last just sitting there with a smart charger maintaining them?

[Sunking]

Well you are talking about Float Service and that basically means your batteries are on Calendar life. Expect 3 to 5 years service life. You do know solar is not needed, required, or even wanted in this application right?

For this type application you would be better served using a different kind of battery made for Float Service. T--105 is not the best option for Float Service.

[Murby]

Well you are talking about Float Service and that basically means your batteries are on Calendar life. Expect 3 to 5 years service life. You do know solar is not needed, required, or even wanted in this application right?

For this type application you would be better served using a different kind of battery made for Float Service. T--105 is not the best option for Float Service.

I'm listening.. please continue.

And how is it that a car battery can last for a decade being bounced around and used all the time where a deep cycle dies in less than half that time? 3 to 5 years service life for a battery that is only used three to five times a year??? HUH??

[max2k]

I'm listening.. please continue.

And how is it that a car battery can last for a decade being bounced around and used all the time where a deep cycle dies in less than half that time? 3 to 5 years service life for a battery that is only used three to five times a year??? HUH??

car battery is not really 'used' - it returns stored energy during start, the rest of the time it floats. Start lasts 5-10 sec and that happens 2 times a day so over 7 years you get it working for 7x365x2x10 = 51,100 sec or approx 14 hrs. Deep cycle work back and forth 24x7.

[Sunking]

And how is it that a car battery can last for a decade being bounced around and used all the time where a deep cycle dies in less than half that time? 3 to 5 years service life for a battery that is only used three to five times a year??? HUH??

No car battery last 10 years. It might still work, but capacity is gone.

The answer is two fold.

1. A Car aka SLI battery (starting lighting & ignition) is made from Lead Calcium alloy which is made to be Float Charged. Car batteries are never discharged or I should say cycled and deeply discharged. You would destroy them if you cycled a car battery. If cycled will only last maybe 100 discharges. A SLI or Cranking Battery is designed for a short brief burst of high current, then immediately recharged at a very high rate.

2. A deep cycle battery is a lead antimony alloy. Has much thicker plates and designed to be deeply discharged. They do not do well in Float Service for long periods of time.

What is in play here is charge voltages. Car batteries, or our Alternators Voltage Regulator uses a Higher Voltage of roughly 14.2 volts. This is done to recharge as fast as possible because we typically do not drive for 8 hours to fully saturate a battery. It is a controlled Over Charge to prevent Sulfation on the battery plates. Deep Cycle batteries use a 2 or 3 stage charging algorithm. Starts at 14.4 to 14.8 volts, but folds back to 13.6 volts when charged.

Bottom Line i son a SLI battery you only use the top 2% of energy, and deep cycle you use as much as 80%. So which should you use? Depends on what you want to do. You sound like you want Emergency Power in Float Service.

Now you can use a pair of golf cart deep cycle batteries to do this. To make them last you will need to cycle them from time to time, and apply an EQ charge time from time. They need to be exercised. There is a down side to using Deep Cycle batteries in your application. They cannot deliver the very high current demands. I cannot count how many times folks come here with a pair of golf cart batteries wondering why they will not operate a 1500 watt Inverter. Answer is because they cannot supply more than 40 to 50 amps of current without excessive voltage sag. The internal resistance is to high. 500 watt OK, 1000 is out of the question.

For you, look for a Telecom Version of a VRLA which is going to be a AGM battery with Lead Calcium plates. These batteries like a car battery only have 50 to 100 cycles in them, but can last 10 to 15 years in Float Service. More Importantly can easily handle 1C discharge currents and work best using a inexpensive Float Charger. That means from the same 12 volt 200 AH golf cart battery can handle that 1000 or 2000 watt Inverter when called upon.

Try looking at DEKA Unigy 12AVR series. They are Telecom 12 volt batteries from 30 to 170 AH batteries.

[Murby]

I wonder if Lithium Ion would be better... Or maybe just suck it up like a man and get the nickle iron batteries???

What works best in my situation??

[Mike90250]

I wonder if Lithium Ion would be better... Or maybe just suck it up like a man and get the nickle iron batteries???

What works best in my situation??

NiFe has their own set of issues

[azdave]

We lose grid power maybe three to five times a year for maybe four or five hours each time and I'd like to still be able to watch TV or run the computers.

Get a small portable generator and an extension cord. Much smarter way to have temporary power for those items.

[Murby]

Get a small portable generator and an extension cord. Much smarter way to have temporary power for those items.

I have a 5000 watt portable generator that I converted to run on our natural gas.. We're out in a semi-rural area surrounded by farmland and 5 to 10 acre plots.. A lot of times, when the power goes out, its only for three or four hours.. (this is what I'm trying to look for a solution for).. When a big storm hits, we know the power is going to be out for days and I just pull out the 5000 watt unit and run it continuously on natural gas for days on end. I do shut it off at night however and it would be really cool to have a battery backup system to keep the sump pump running and maybe charge phones and stuff..
A small portable generator might be an idea to consider.. have to find something really quiet because I don't want to hear it when I'm trying to sleep.

[SunEagle]

I have a 5000 watt portable generator that I converted to run on our natural gas.. We're out in a semi-rural area surrounded by farmland and 5 to 10 acre plots.. A lot of times, when the power goes out, its only for three or four hours.. (this is what I'm trying to look for a solution for).. When a big storm hits, we know the power is going to be out for days and I just pull out the 5000 watt unit and run it continuously on natural gas for days on end. I do shut it off at night however and it would be really cool to have a battery backup system to keep the sump pump running and maybe charge phones and stuff..
A small portable generator might be an idea to consider.. have to find something really quiet because I don't want to hear it when I'm trying to sleep.

There are a couple of inverter type generators that are relatively quiet and can be enclosed to reduce the noise even more. Sure a battery supplying power to critical loads at night is nice but at what cost?

Is it worth spending a lot of money on a solar / battery system for emergency power or finding a way to get a lot more power quietly by using small generators?

[Mike90250]

A small generator can charge a small battery bank for quiet night time illumination. Might be able to run a fridge off it too, just spend more $ for more batteries , but much less than a field of solar PV panels.

[Murby]

Generators are not a renewable source of energy.. Since they depend on infrastructure to provide them with fuel, they are not a consideration for a long term solution.

[J.P.M.]

Generators are not a renewable source of energy.. Since they depend on infrastructure to provide them with fuel, they are not a consideration for a long term solution.

Define long term.

Off grid relies on infrastructure as well. Think batteries and the infrastructure required to make, maintain and dispose of them. It's all relative.

[max2k]

Define long term.

Off grid relies on infrastructure as well. Think batteries and the infrastructure required to make, maintain and dispose of them. It's all relative.

I think OP keeps referring to SHTF situation when no infrastructure will be available. IMO at that point electricity as a concept will be gone too and whoever survives will have to start from scratch. You can get by for 2-5 years with everything gone but then things will start to break and there won't be replacements available. Nature will take over so most useful items will be firearms and ammo and even them will be gone too in 50 years or so. The data storage as we know it today won't last long so the books kept in oxygen free enclosure would probably be the best source of info.

[SunEagle]

Generators are not a renewable source of energy.. Since they depend on infrastructure to provide them with fuel, they are not a consideration for a long term solution.

My opinion is that batteries have a shorter life span then any type of fossil fuel generator. But then again your opinion may be different.

Since the 2004 hurricane season I have never run out of gasoline or propane during any power outage in my area of Florida.