Outdoor security lighting, can it be fed via battery?

[MEDWARD]

Hi, I have a spare 210 Watt panel and was wondering if I could somehow use it to charge a battery which could run a security light, is this possible?  If so what would I need?  Does the battery need to be kept indoors?

[northern installer]

easy job really,if you stick to 12 volts.  A small charge controller will prevent the battery from overcharging,battery will be fine outside if rain is kept off it,and perhaps lagged against frost;you can use a 12 volt cfl lamp in an ordinary fitting,or caravan type 8w or 21 w flourescent fittings.

[MEDWARD]

What sort of costs would I be looking at for the battery + charge controller.  Is there a specific type of battery you could reccommend?

The panel specs are

Maximum power (Pmax) 210
Max. power voltage (Vpm) 41.3
Max. power current (Ipm) 5.09
Open circuit voltage (Voc) 50.9
Short circuit current (Isc) 5.57

[dhaslam]

Are you sure the maximum voltage figure is correct?

Looking at the figures again the  current  and voltage do roughly match the output.     

[MEDWARD]

I cut and pasted direct from Sanyo Hip-210NHE1 data sheet.

[MEDWARD]

Practically how many outdoor lights could be run off the battery?  I was thinking of security lights, but would be useful to be able to keep them switched on to light the decked area incase I wanted to have a bit of a garden party.

[tony.]

you need to start with your load and work backwards.

so decide on the type of lights you have, power rating of these lights.

thats the first step.

tony

[dhaslam]

That size panel should give you about  .5 kwh per day average which would quarter charge a  24V 100 amp battery every day and  run  five  10 watt bulbs for ten hours, but that is an average, much less in winter and dull days and more in summer and sunny days.  It needs a charge controller.   If security lights are intermittent you wouldn't need anything like that size of panel.

Note that solar panels themselves need to be in a secure place.     

[billi]

Hello

This chargecontroller perhaps and if you go for 24 volt Battery the 10 A version should do fine  (think i found it in the UK for about 80 pounds its an MPPT so makes better use of the high voltage panel
If you stay with a 12 volt batterie you need the 20 A model

http://english.ivt-hirschau.de/content.php?parent_id=CAT_64&doc_id=DOC_220

Regards Billi

[MEDWARD]

Would the charge controller need to be housed inside?

To feed the lights from the battery can I use normal flex?

Is there any maintenance required with the battery?

[MEDWARD]

Someone told me flood lights might be the best thing for a 17' x 17' area, how long would they stay lit assuming a battery was full of charge?

[northern installer]

floodlights? well divide the number of kilowatts consumed by your floodlights into the number of kilowatt-hours stored in the battery,result in hours is how long they will last in theory,but in practice,use 40% of this figure to avoid over discharging your battery.

[desperate]

Medward

Floodlights? security lights?............bah, mutter mutter, moan, grumble, bloomin lights, Astronomer, gripe gritch, dark sky  gasp..........must remember the old apoplexy desp

Desperate

[MEDWARD]

So can anybody recommend a battery as I've got NO experience what so ever and an idea of cost for the battery.

Also if anybody has got any experience of Flood/Security lights that would be suitable for the 17'x 17' area.  Will I need CFL or LEDs???

[Outtasight]

If you don't want to have to mess about with putting water in the battery now and then get a sealed type of battery.  The cheapest ones at caravan shops are the "wet" kind with tops that open and so you have to put water in them once in a few months or they dry up.

A 100Ah AGM battery is about £200 and a gel one is about £212 plus about £20 for delivery. 

Cheapo wet batteries from a caravan shop are about £75 for 110Ah but AGM and gel batts last at least 3-4x as many charge/discharge cycles.  On the other hand, AGM and especially gel batteries are quite easy to kill through poor charging control (using cheap chargers) so it's best to play with cheap batteries until you get used to looking after them!

If you just want to mess around with some really cheap second hand batteries, you can find some ex-telecoms 100Ah gel sealed ones on fleabay for about £35-40 but you take a chance on them being duff.  Just do a search on "leisure battery" and it will turn up loads.  There's a guy always selling big old 2V, 6V and 12V batteries that have come out of data centre power backup units.  Most people won't or can't post them though.  They are too heavy and the wet ones can't be posted at all (as they leak acid everywhere if you don't keep them upright!)

The problem with using low voltage outdoor lights may be that you can't get PIR motion sensor ones that turn on and off.  Most PIR ones are mains voltage only and although you could fit a 12V ES screw CFL bulb in some mains fittings, the PIR sensor won't work as that was meant to work on mains voltage.  If you don't need PIR then that makes it easier.

Whatever you do, don't try to run regular 150W-300W tube halogen flood lamps.  Consumes way too much power and I think you can only get mains ones.  For instance, a 150W halogen flood will use up half of a 100Ah battery (through a mains inverter) in about 3.5 hours.  You don't want to discharge any lead acid battery by more than 50% on a regular basis or it will die more quickly.  If you used a PIR lamp and had it set on very short timers then you might get away with it though.  You'd need to turn the inverter off manually though to stop it draining the battery slowly even when the lamp was off during the day.