Running LED lighting off a car battery Ideas needed

[truckster]

Situation: A remote cabin with no mains supply available. Customer has bought a generator to supply small power (2 no. 2 gang sockets) but wants to use the genny to charge a car battery(ies) to run some lighting. I think LEDs so if anyone has any ideas of how I can achieve this I would be grateful.

The lights would need to provide sufficient lighting for 8 hours a day as the cabin is being used as some sort of therapy room with paying customers.

 

[Spoon]

Don't know much about charging up car batteries, but you will need to know what lighting the customer requires. What's the total wattage? Will they be 230VAC LED lights? This will also let you know who many car batteries you will need. You will also need an inverter to change the 24VDC to 230VAC if using 230VAC lights.

 

[Richard Burns]

This is working on adding inefficiency to inefficiency!
The generator will be costly to run, though probably the easiest short term method for power.
The charging of the batteries will be inefficient and waste more power.

However it is possible but to run lighting for 8 hours may mean a large battery supply depending on the required lighting level.

A basic, simple, not very accurate approach is to say
15W of 12V LED lighting may take up to 30W of power to run depending on the efficiency of the lights.
This would equate to 2.5 A over 8 hours = 20Ahr, this would be fairly reasonable for a battery to supply that current over that time.
You would not want to drain your batteries to more than 50% so a 40Ahr battery might be required,or larger if you may need the battery to supply the lights for more than a day.

Then you need to consider charging time which will be about say 4 hours to replace the lost charge at trickle charge.
So you might need to have two batteries and take one home to charge each day rather than running the generator for four hours, but if you did run the generator then you could charge one battery for four hours and also light the lights for four hours and then switch off the generator and the other battery could then be used for the next four hours and then next day swap over.
You would also need a decent charger that will provide a good quality charge to maintain the batteries in their best state. The charge current will also need to be within the capacity of the generator (unless the battery is taken home) though this should not be a problem.

 

[ruston]

Consider if ELV would be suitable for the sockets , and your total power requirement for the day.
Then consider if a typical caravan type charging arrangement could be utilized using off site charging, solar, and/or Genny.
Use gas for any heating and hot water requirements .

Ps. Gas generators are available too.

 

[Lucien Nunes]

Aim to use 12V or 24V LED lighting. Until we know how much lighting is required, nothing else can be specced.

I wouldn't bother with any battery less than say a 679 110Ah leisure battery, i.e. don't use a car battery for cyclic charge/discharge. The key to the process is the charger, a 3-step unit is almost essential here for max charge rate, and still the biggest limitation will be the length of time the genny must run to complete the charge. A lead-acid can charge quickly to about 75% full but the last 25% takes as long or longer, but if you don't complete the charge fairly regularly, the battery will sulphate and lose capacity.

Li-Ion can charge faster, hence probably fully charge while the genny is in use for other things, but many times the price.

 

[Davisonp]

Have a look at “Search results for: 'Led Strip Cool White Per Cut Length 14.4 Watts'

This LED strip should run directly from a 12V car battery and 2 or three meters will produce quite a few lumens.
You will need formers with diffusers as well as the strip.

 

[Marvo]

Therapy room is a well known euphemism for a knocking shop

Using the genny just to charge a battery for the LED lights is going to work out helluva expensive, also the genny will be running for most of the time with almost no load which is one of the worst things you can do to a genny.

Maybe look at a caravan/camping type solar kit with a couple of PV panels, a charge controller and a deep cycle battery.

 

[PEG]

If it needs the generator anyway,this needs to be the main source of lighting power,with an intermittent back-up,of battery lighting,only.

The best way i could see this being achieved,with only a relatively small power requirement on the sockets,would be with auto modulating generator.

These are used by the motorhome/horsebox builders,and are essentially,a small,petrol geny,2-4Kw,which modulates its' engine speed,according to load.

They also contain an internal control system,which allows them to start automatically,when a load is detected,or storage battery capacity drops,below a predetermined level.

They come in a fancy stainless housing,and are VERY expensive,but seem the ideal way around this requirement,as cost has not been flagged as a restriction :mickey:

Just came to me,who makes that unit,it is Dometic,impressive gear,but hold your breath for the retail...