# Batteries



## T Rice (Oct 6, 2006)

There are a mess of these going to recycling at work.










They came out of some computer UPSs.

Is there an easy way to test them?

Might they be good for a solar storage setup? I don't know anything about this stuff but I sure could use a solar lighting rig for my mobile hen house.

Could I charge a bank of these things with a little panel and get an array of LEDs going for a few hours a night?

Tom


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## Windy in Kansas (Jun 16, 2002)

5 amps rating over 20 hour discharge period. A bank of them should be able to provide you some LED lighting easily without discharging too much. More opinion than anything since I'm not real familiar with LEDs and their ratings. AA battery powered Christmas lights burn for a long time off of two or is it four AA batteries. More lights of course more draw.

Could even hook them to flashlight head if worked right and you didn't buy other lights.


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## byexample (Aug 28, 2009)

Looks like that battery is a sealed, lead-acid battery. Would be considered a 12 volt battery and could indeed be charged via a solar panel with the appropriate charge controller. You could even connect the battery(s) to a small inverter to run 120V AC compact fluorescent lighting. A "40 watt" CF bulb should draw about 9 watts. LED lights can draw way less than that.

To test the battery you'll want to charge it up, take a voltage reading, and then put a test-load on the battery for a period of time. After that you measure the voltage again and take a look at the change.

When full I would expect this battery to read something in the range of 12.8 - 13 volts. If you put a 1 amp load on the battery for an hour it should still read something in the 12.2 - 12.4 volts range after the load is disconnected if the battery has much in the way of life left in it.

These values are all guesses based on my experiences with similar batteries... but every model of battery will behave differently.

For charging 12 volt batteries B&D makes a very affordable line of battery chargers that are commonly available at places like Walmart. I think we paid $75 for a 40 amp charger. Supports gel, flooded and AGM battery types. I think as far as these batteries are concerned I'd treat them like AGMs since they are sealed.

Here's another tip: those UPS devices that you pulled those batteries out of are really just a cabinet for a battery, 120V AC battery charger, and pure sine wave inverter. For those of you out there looking for a junk-yard solution to providing pure sine wave power it is possible to use the electronics in these devices with larger batteries... you just have to find a way to disable the beep, beep, beep that is broadcast when the inverter is producing power from the battery(s).


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## T Rice (Oct 6, 2006)

Patrick,

I'm only looking to power a single 12V LED spot light bulb, 4W. for a couple of hours a day.

Can you advise what might be required in terms of a panel to run this?

I guess the issue would be one of getting the voltage up since as I understand it a single solar cell will only produce ~0.5V so a 24-cell array would be required. I really am not familiar with how these things are packaged etc.

Thanks

Tom


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## mightybooboo (Feb 10, 2004)

If Im not mistaken only SOME UPS put out pure sine wave,I think we had a big ole thread on that one time.But I could be wrong,memory isnt all that great for things I dont have to remember.


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## scatyb (Jan 20, 2009)

HOLY CRAP! If those produced pure sine.....:banana02: But yeah, I thought they just did modified. Still any info on that would be great.

Now on to these little batteries. They are sealed in a sense, but on the top there are going to be a series of little flat caps that can be popped off. INside is a rubber plug that can be pulled so they can be refilled if necessary. I have done this with a bunch of em and used one of those reconditioner to bring em back. Worked good.


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## Jim-mi (May 15, 2002)

A goodly number of those UPS units are mod sine.
depends on the price tag.
The really good units are pricy.

Be gentle with the charge \ discharge rate of those small bats


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## T Rice (Oct 6, 2006)

OK here's the plan.

I got one of these from Home Depot:










Pretty expensive bulb ($20) but its supposed to last 35000 hours. I should be dead by then!

And one of these from Northern Tool:










And I'm going to build a little CMOS timer to cycle it on/off. Only will run a few hours each night in the hen house.

Anybody see any holes in this plan?

Thanks for the input.

Tom


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## wy_white_wolf (Oct 14, 2004)

T Rice

By the time you calculate in for winter insolation hours and system ineffiecency you will be *lucky* to get 1 hour use a day out of that system.


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## T Rice (Oct 6, 2006)

wy_white_wolf said:


> T Rice
> 
> By the time you calculate in for winter insolation hours and system ineffiecency you will be *lucky* to get 1 hour use a day out of that system.


Can you give me any more specific information in about how you are figuring this?

I really don't know much about how this stuff works but it just seems like if there if ~2W in for ~6-7 hours and 4W out for 2 hours things would be somewhat balanced. I could definately be way off base with that line of thinking.

At any rate if you have any specific suggestions on how this might be improved I'd really like to hear them.


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## byexample (Aug 28, 2009)

You might consider adding a 12 volt voltage regulator to your lighting fixture. A 12 volt solar power system doesn't always put out 12 volts. It could vary from 11.5 - 15 volts. When I first started working with LED lights on our 12 volt system they all died an early death -- less than a year. So I wired a small 12 volt voltage regulator into our RV lights to shield the LED bulbs from the higher voltages and provide a fixed voltage of 12 volts to the lights.

Haven't lost an LED bulb since. They also flicker a lot less when other loads are placed on the 12 volt system.

Since your bulb is fairly expensive you might want to consider something similar.


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## T Rice (Oct 6, 2006)

Thanks Patrick,

Can you just use a regulator like used to be used on cars back before they had computers?

I think you can get those at a parts store for ~$20.


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## Jim-mi (May 15, 2002)

Do the math
1.8 X 4hours of solar window = 7.2 
Means you can only run that lamp for 1.5 hours this is assuming that all conditions are right; full sun etc.
You need lots more PV and a small charge controller . . . . .other wise your bat is soon dead.


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## byexample (Aug 28, 2009)

I purchased my regulators at RadioShack. They are electronic components that are commonly placed on circuit boards. They are small in the amount of power you can run through them... but for one LED light they seem to work just fine. Costs about $1.50 I think.

I've never tried working with the type you mention... but anything that stabilizes the voltage at or around 12 volts should do the job just fine.


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## Jim-mi (May 15, 2002)

No you do not use a "car type regulator"

Look at a Solar Insolation map . . .you will find Atlanta listed at 4.74 average hours.


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## idahodave (Jan 20, 2005)

I'd use a low drop out regulator. The typical 7812 needs a couple of volts to work and isn't a good choice for this application. 

The LM2940-12 series would be a better part and is available from Digi-Key for under $2.00.


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## 12vman (Feb 17, 2004)

Those batteries shouldn't have a bulk charge over 13.6 - 13.8 volts. A charge controller between the panel and the battery is necessary.

The lamp usually won't be used until dark I figure and the battery should settle down to 12.2 - 12.4 volts. I believe the lamp should handle that. I don't see any need to regulate the voltage to the lamp.

I would suggest a larger panel, around 5 watts, and a charge controller to protect the battery. I use this controller on my outdoor lighting system. It ramps up to around 14 volts and regulates to 13.2 volts. That should be OK for those batteries.


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## wy_white_wolf (Oct 14, 2004)

T Rice said:


> ...I really don't know much about how this stuff works but it just seems like if there if ~2W in for ~6-7 hours and 4W out for 2 hours things would be somewhat balanced. I could definately be way off base with that line of thinking.....


Your 6-7 hours is off. Off-grid or stand-alone systems need to be designed for worst case.

I don't now the specific location other the N. Georgia. So we'll use Atlanta. If you visit this site you will see Atlanta has a December low of 2.10 hours average insolation.

So that little 1.8 watt panel will average (1.8*2.10) 3.78WH production in December. Now we need to addjust that figure for net energy loss's from ineffiecencies. so ruduce that by 1/3 (3.78*.66) and you get ~2.5WH net or usable power. 2.5WH divided by that 4 watt load times 60 minutes means it will provide enough power on average to light the bulb for 37.5 minutes daily.

The proper way to design a system is to start with the load and work the other way. First off I would test one of those lights to see if it will provide adequate (sp?) light.

So he wants to light his chicken coop for 2 hours a day.

4 watts times 2 hours = 8WH daily need 
(if more lights are needed muliply by #)
(adjust hours if you want it longer or shorter)

add in for ineffiecency 8WH times 1.5 = 12WH needed for production

12WH divided by 2.1 hours (Dec. low) = *5.7w panel minimum*
(adjust for location and if you have any shading of the panel)

12WH divided by 12v (system voltage) times 5 days storage = *5 AH minimum battery* at 12v

2amp charge controller and a timer to turn it on/off would round out the basic requirements for the system.


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## T Rice (Oct 6, 2006)

Thanks guys,

If I keep hanging around here I'm liable to learn something.

TR


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## no1cowboy (May 2, 2004)

I use a similar one to that, I have a 50 watt panel hooked to a sunlite Controller hooked to the battery that runs a dozen or so led lights through out my house used as night lights. the Controller turns the lights on at dusk off at dawn.


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