Emergency lighting...LEDs and batteries

EAdamsEAdams Solar Expert Posts: 34
I am planning to put together some emergency lighting for my house for when we lose power say in a storm, etc. I am having difficulty deciding what batteries to use to power a small quantity of LED lights. I will probably have 3 sets of X-RE 3.6v@350ma LED lights and will most likely run them 8hrs at a time. My current thought on batteries had been reg deep cycle types that you have to fill with water OR 2 6v golf cart batteries OR 1-2 of the Optima brand AGM be it blue, red, or yellow.

What I need to know is:

1) What kind and how many batteries would you recommend?

2) What guage wire do I need for the runs to the LEDs (50-75ft)?

3) Is there a better way to do this?

thanks guys!:D

Comments

  • EcnerwalEcnerwal Solar Expert Posts: 101 ✭✭✭✭
    Re: Emergency lighting...LEDs adn batteries

    The quick questions are wadda ya want, and how often do you need it?

    Depending on the answers to that, this might be an answer to "3", and it might not.

    On the low end, requiring very little expense and no wiring, I've been extremely impressed with the combination of a good "smart" LED replacement bulb in a Mag-lite flashlight and NiMH rechargeable batteries, with a good "smart" charger (for which read fast, really fast - meaning it actually has the smarts to monitor the battery properly, not like those "fast" 8 hour chargers). It's not a system built into the house, but directed at the ceiling it lights up the room better than an oil lamp, and directed at the page you can read a book with it quite easily - and I'm talking a 2x AA light here - the C&D size lights are presumably brighter, etc, though finding good rechargeables in those sizes (that are not just an AA cell glued into something to bulk it up) is a more difficult task.

    I try to cycle all my sets (and I keep sets as sets) of rechargeables though the charger every month, whether they have been used or not. With a brick of 20, and getting at least 6 hours for a pair, that will cover a pretty long outage - but it's not automatic. The sum total cost is well under $100, though, even with a few more flashlights.

    Going back to the route you think you are headed down, if this is going to be a grid-charged (or even solar charged but only used for backup) light system, AGM would probably be the best bet, because maintenance is likely to be forgotten about when it's no longer shiny and new. You have, however, left off an important component - how are you going to charge these batteries up? You need a charger that won't cook the batteries.

    Size of battery depends on how long you expect power to be out (or plan to have light for, anyway), and a little bit how often. The more often you use it, the less you'd want to draw it down, in seeking long life for the battery. If it only gets used 3 times a year, you can (IMO) happily discharge it 80%, because it will die of old age before it dies from cycling.

    If you are going to stack 3 3.6V lights and run from 12 V (are these self regulating, or are you planning to put in a regulator or resistor, at least?), you'll be running 350mA down the wire - which doesn't take much of a wire, even for 75 feet. If you parallel them, a shade over an amp. 16 or 18 gauge would be fine for series, and series gets you the same light for less power. 16 gauge would be fine for parallel. Don't forget to put a fuse or DC circuit breaker at the battery.

    Say you are running in series, 8 hours per day, and want a week, with 50% depth of discharge on the battery. .35A * 8hours*7days = 19.6AH used, so a 40AH battery would supply it. If running in parallel, triple that and get a 120AH battery. Only want 3-1/2 days - half those sizes....etc.

    It's possible that code minimum might be 14 gauge. I don't recall for sure - I think I know it is for 110V wall wiring, I don't know if that also applies to low power DC if it's run in the walls and/or conduit.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Emergency lighting...LEDs adn batteries

    i had done this in a section of stairs for my home and i used the smaller white leds. (rated 30ma and kept under 15ma with resistors) this is better in that they can be aimed with more than one being used at a location and will draw significantly less current. this took away all of my concerns about what gauge to use and even if i left it on, my battery would certainly not go dead from its small draw. i do suggest putting in fuses and switches as your battery and wiring will suffer in shorts and i would assume you want to turn it off.
    that brings up the subject of the switches as i use standard 110vac light switches due to their cheapness and being i'm keeping the current low. ac switches won't handle large dc currents for very long as they aren't made to handle the large arc created from dc, but under or arround an amp should be fine.
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: Emergency lighting...LEDs adn batteries

    I started out like you did about 4 years ago. Started with a 12V 17AH gelcell battery and five 1156 white LED lamps. I got 5 RV lights to place the 1156 lamps in. Wired it all using 18AWG lamp cord. This setup would power for about 10-20 hours. I was using old handme down batteries. They lasted less than 12 months each before dieing.

    I would go the AGM battery, cost more, but worth it. Also would go with 12V automotive LED's also. The reason is 12V stuff is easier to get.

    Need to pick your loads( LED's) first, then we can get you size of battery to meet to backup time.
  • EcnerwalEcnerwal Solar Expert Posts: 101 ✭✭✭✭
    Re: Emergency lighting...LEDs adn batteries
    niel wrote: »
    i had done this in a section of stairs for my home and i used the smaller white leds. (rated 30ma and kept under 15ma with resistors) this is better in that they can be aimed with more than one being used at a location and will draw significantly less current.

    For that type of application (individual LEDs), particularly if off-grid, a Supertex CL2 or CL25 is better than a resistor - takes a 5V drop for the device (so, like a lot of things it works nicer on 24 & 48V systems, but it does work on 12V) and feeds a constant current out - the trick being, you can put 2 white or 3 red in series on a 12V system, thus getting 2-3 times the light out for the same current you'd be putting into a resistor + LED. On 24V you can get 6-8X the light for the same power, and 13-20X for 48V. They work all the way to 90V.

    You can stack LEDs and use a smaller resistor, but then you'll get variation in brightness with system voltage, and need to take steps not to fry things when you equalize. With a CL2, you get 20 mA out, a CL25 puts out 25mA - about 44 cents each from Mouser in non-surface mount packages that are easier to wire up by hand. I didn't do extensive shopping around, so there may (or may not) be a better price on them somewhere else.

    http://www.supertex.com/pdf/datasheets/CL2.pdf

    Can do the same thing with an LM317 and a resistor, with the resistor value allowing you to pick a particular current value - but that's less robust with 48V, for instance, (can work, but the device can only have 37V across it - so long as there's plenty of load on the far side this should be true, but it's not like having a device rated to take 90V across the device itself...) and probably ends up costing slightly more. The good side is that it only needs about 3V for itself, so you can run 4 red or 3 white (well, maybe - depends on the white) from 12V.
  • EAdamsEAdams Solar Expert Posts: 34
    Re: Emergency lighting...LEDs adn batteries

    For charging I have 60w of solar panels (4 - 15w panels @1amp each) and a 7amp charge controller. I'll probably charge the batteries with a reg charger the first charge. All came from Northern tool. they were running a sale adn my brother lived close so no shipping. :)

    Anyone know the ah of the optima batteries? I think the red, blue, yellow each have a diff rating. Wonder which would be best for my application. I like the idea of the AGM because of the non-gassing of H gas.

    I am starting to be swayed to the using of 12v auto LEDs. Which would work best? Dome? I'd need a good reflector to mount it in, preferably a Autozone product as I have one of those stores close.


    Thanks for all the good ideas!
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Emergency lighting...LEDs adn batteries

    ecnerwal,
    that is a nice option for current regulation as the current does vary on the leds with using just a resistor depending on the led junction temp as you are most likely aware of and is the reason for my designing for an even lower base current design of about 15ma. i may have to get some of them if i remember to do so.

    EAdams,
    if you actually get 4a from the pvs i would say the highest ah rating for the battery may be 80ah as this would be representative of having the pvs give a 5% charge (20hr)rate to the battery. the min capacity using generic lead acid batteries would be about 31ah for the 13% rate of charge and you can expect increased maintenance in going with the higher percentages. the typical 100ah battery that are usually commonplace and cheaper would have a 4% charge rate to the battery and the lower this is, the longer it takes to charge the battery and it will get to a point of not even keeping up with the normal idle charge losses. the best range for the battery may be around 40-60ah, but you can go the outer edge range we often say can be used and go between 31 and 80ah. upping your charging power would allow a better charge percentage and charge time on a common 100ah battery.
    the leds for car use are another easy option for many as autoparts stores down the road are easier to deal with than sending through the mail and you won't have to wait as long.
  • EAdamsEAdams Solar Expert Posts: 34
    Re: Emergency lighting...LEDs adn batteries

    Assuming I get a 80ah battery, what could I expect to get for safe continuous run time on a single standard 12v LED dome light between charges?





    niel wrote: »
    ecnerwal,
    EAdams,
    if you actually get 4a from the pvs i would say the highest ah rating for the battery may be 80ah as this would be representative of having the pvs give a 5% charge (20hr)rate to the battery. the min capacity using generic lead acid batteries would be about 31ah for the 13% rate of charge and you can expect increased maintenance in going with the higher percentages. the typical 100ah battery that are usually commonplace and cheaper would have a 4% charge rate to the battery and the lower this is, the longer it takes to charge the battery and it will get to a point of not even keeping up with the normal idle charge losses. the best range for the battery may be around 40-60ah, but you can go the outer edge range we often say can be used and go between 31 and 80ah. upping your charging power would allow a better charge percentage and charge time on a common 100ah battery.
    the leds for car use are another easy option for many as autoparts stores down the road are easier to deal with than sending through the mail and you won't have to wait as long.
  • BB.BB. Super Moderators Posts: 26,837 admin
    Re: Emergency lighting...LEDs adn batteries

    All depends on how "big" the dome light is... Here are some for sail boats... 180 mAmps (0.18 amps).

    Assume 80 AH battery, fully charged. Discharge to 50% maximum:

    80 AH * 50% = 40 AH

    40 AH / 0.18 amps = 222 hours (22 days at 10 hours per night).

    A better way, or at least a backup, would be to get a good quality LED flashlight with variable output that runs CR123 lithium batteries. It will run for ~65 hours (on low--but plenty of light for around the house use) on 2xCR123 batteries--and the lithium batteries will store for 10+ years. Oh darn--I see that this has just been discontinued... I have this guy for a few years now and have been very happy with it for everyday carry on my belt.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 7,281 ✭✭✭✭
    Re: Emergency lighting...LEDs adn batteries

    When you loose power, is it for a day, or a week at a time - where are you located ?

    Since you are indicating this is mostly standby usage, for 2 or 3 times a year, I'd use a low maintainance battery, either an AGM or Optima style, Deep Cycle format, not a starter battery, not a combo starter/deep battery.

    You would need a reliable 4 stage charger to keep the expensive battery topped off on standby usage.

    Your 3 sets of lights will draw just about an amp. For 75 feet, @ 1 amp, 16ga household lamp cord would work pretty well. Are all 3 lamps going to be at the far end of the cord, or will some be mid-point?

    If you anticipate multi-day outages, you might look into a solar PV panel for fun, to recharge daily. If in winter, you run the light 12 hours, you only consume 12AH, and could go for 3 or 4 days on 1 battery, before it gets critical and needs recharge. A 100W panel, on a sunny day, should easily replace 12AH, but it's a slow charge, because you are just topping off the battery.


    Your mileage may vary. I'm working on a loaner computer, and don't have all my caculators to check wire sizes.

    Mike
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • EAdamsEAdams Solar Expert Posts: 34
    Re: Emergency lighting...LEDs adn batteries

    Most of the time it is overnight but we had 1 real bad 1-week outage over a icestorm.

    4-stage? I have cheap trickle charger and a Craftsman 5,10,50 amp charger. Prob use Solar cells to keep it topped off. See above post on what I have.

    Probably be used 2-4 times a year. Located in West Ky.

    Probably go with 12v dome lights from Autozone or Advance auto and the draw will be alot less than the 3.6v X-RE bulbs.

    I'll be using some solar panels to keep them topped off. Would like a cheap USB interface device that would log input from the cells. It'd be a neat way to get into that logging aspect of Solar. Not sure what to get there.


    mike90045 wrote: »
    When you loose power, is it for a day, or a week at a time - where are you located ?

    Since you are indicating this is mostly standby usage, for 2 or 3 times a year, I'd use a low maintainance battery, either an AGM or Optima style, Deep Cycle format, not a starter battery, not a combo starter/deep battery.

    You would need a reliable 4 stage charger to keep the expensive battery topped off on standby usage.

    Your 3 sets of lights will draw just about an amp. For 75 feet, @ 1 amp, 16ga household lamp cord would work pretty well. Are all 3 lamps going to be at the far end of the cord, or will some be mid-point?

    If you anticipate multi-day outages, you might look into a solar PV panel for fun, to recharge daily. If in winter, you run the light 12 hours, you only consume 12AH, and could go for 3 or 4 days on 1 battery, before it gets critical and needs recharge. A 100W panel, on a sunny day, should easily replace 12AH, but it's a slow charge, because you are just topping off the battery.


    Your mileage may vary. I'm working on a loaner computer, and don't have all my caculators to check wire sizes.

    Mike
  • EAdamsEAdams Solar Expert Posts: 34
    Re: Emergency lighting...LEDs adn batteries

    This is interesting...


    http://www.tractorsupply.com/webapp/wcs/stores/servlet/ProductDisplay_10551_10001_134698_-1______?rFlag=true&cFlag=1

    A solar shed light
  • BrockBrock Solar Expert Posts: 629 ✭✭✭
    Re: Emergency lighting...LEDs adn batteries

    I would agree with Bill I would just get a good LED light (or lights) and go that route. Although the 123 battery version is brighter and smaller I bought my dad the 2 AA version of the same light

    https://www.4sevens.com/product_info.php?cPath=22_69_71&products_id=195

    I also have bought way to many lights from "4sevens" and the Fenix line are really hard to beat for price, performance and quality. There are some more expensive lights, but they get really expensive really fast.

    My personal favorite right now is
    https://www.4sevens.com/product_info.php?cPath=22_69_49&products_id=639
    A single AAA light that is honestly brighter then a 2 D cell Mag and the size of an AA battery, easily pocketable and if you really want to go crazy you can put a 3v LiIon AAA sized cell (10440) in it and it puts out over 120 lumens in high, granted it only runs 10 minutes at that level, but talk about a pocket blaster :)

    Getting back to the flashlights, the 2 AA version runs 55 hours on low or 20 hours in medium, more then enough light to light up a room if set on a table pointed up at the ceiling. Again using common AA cells easy to find or use NiMH rechargeable cells.
    3kw solar PV, 8 L16's, xw 5548, Honda eu2000i, iota DLS-54-13, Leaf EV, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Emergency lighting...LEDs adn batteries

    sometimes lights like that don't last long if you have need of it enough.

    btw brock, i just bought another flashlight recently. it is a 3w led maglight fed with 3 aa batteries. it was on sale wallmart for $20.
  • BB.BB. Super Moderators Posts: 26,837 admin
    Re: Emergency lighting...LEDs and batteries

    I see the P3D has just been upgraded by a somewhat more expensive and brighter LED.

    The AA and AAA type lights are great too... I have an older AAA LED (another mfg.) that I keep in my wallet with an extra battery or two... Hardly know it there, but I have many hours of light in an emergency.

    I may have to follow Brock's links for some upgrades.

    Another option is a head lamp... They look dorky (un-cool), but they are really great to have when you need your hands free... Just about as good as having a room lamp (the light from the head lamp is always where you are looking).

    The new "ZebraLight" head lamps (1x AA or 1x CR123) look very nice too.

    For emergency use, it is surprising how little light you need (or sometimes even want).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ron17571ron17571 Registered Users Posts: 19
    Re: Emergency lighting...LEDs and batteries

    Ive kind of been thinking about this lately,mabe recharging batterys and using portable led lights would be easier than hard wireing.how about those round lights you push in a little to turn on,ive also seen led lanterns.i keep trying to learn more about how much draw you have with various things.there are some preety powerful flashlights out there now.i saw light strings with a box for batterys on ebay.
  • ron17571ron17571 Registered Users Posts: 19
    Re: Emergency lighting...LEDs and batteries

    Also saw security motion sensor lights with 5 watt panels on ebay.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Emergency lighting...LEDs and batteries

    ron,
    as i stated some of these solar outdoor lights won't work well if needed often. they design them for only an occasional short triggering. if you have any prolonged activity or even a tree branch swaying in the wind, it will kill the batteries and the pv is usually not large enough to bring up depleted batteries if of the proper capacity for heavy use. the depleted batteries in the store bought outdoor solar lights may have their lifespan shortened when allowed to be drained that far and often. and let's face it, when the batteries are dead the light doesn't work when you need it.
    to my knowledge, none of the commercial solar lights have been designed for good reliable long-term use. somebody know of some that are?
  • lamplightlamplight Solar Expert Posts: 368 ✭✭✭✭✭✭
    Re: Emergency lighting...LEDs and batteries

    lots of good flashlight info here. i think im due.

    for a home night light system i bought some 12v edison (your regular screw in type in AC fixture) LEDS. i cant remember exactly but they are very low wattage and the advantage thus being you can use cheaper AC light fixtures and thin/cheaper wire if its low voltage. mine are 3-4 regular (old style) led's running at less than 1w per fixture. use a xantrex c12 lighting controller and a couple cheap sealed batteries from radio shack (about 13ah i think). working flawlessly for a few years. but for more output you could look at smething like http://www.theledlight.com/12volt-led-bulb.html

    id agree with neil and others the all in one lights with there own solar panels tend to disapoint, although places like backwoods soar carry some good motion lights with their own battery and panel, its usually more effective to build something with better components , its no that hard (and look at all the help you get here :D
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