Small off grid solar lighting system advice

[jsp]

I am after some advice on wether to put in a small off grid solar lighting system, or if its not worth it and just connect the mains. I have bought an old place in mid north SA for a weekender.

I am saving about $250 a year in supply charge alone - not including the cost of what power I might use. Eventually I will connect mains, to run hot water and spend more time there etc, but for now its occasional camping.

I have thought of a deep cycle car battery, something like a N70T should provide enough storage, charged from a 5 or 10 watt panel through a cheap solar charge controller, running a few 12v flouro or led lamps.

I am looking to run upto 3-4 lights for upto 4 hours. Mainly just at least two lights in one big room and a light in the loo. Also possibly charge a laptop and mobile phone. About once a fortnight, once a week at absolute most.

I have a small inverter which has been charging tools/phones/laptops for the past 5 plus years without issue from my second battery in the car, so can use that on the system as well.

Is it worth the hassle? Or is it not really worth it for the few $ it may save? I have looked at using some cheap stuff from ebay - or is that too much trouble in itself? What's potentially the best battery option?

EG:
charge regulator
(http://www.ebay.com.au/itm/5A-10A-15A-20A-30A-PWM-Solar-Panel-Battery-Regulator-Charge-Controller-12V-24V-/310834631943?pt=AU_Home_Outdoor_Lighting&var=&hash=item485f301507)
solar panel (http://www.ebay.com.au/itm/10-watt-12V-solar-panel-PV-solar-module-battery-charger-for-RV-boat-camping-/231004622949?pt=AU_Solar&hash=item35c8f2d065)
Globes (http://www.ebay.com.au/itm/12V-Compact-Fluorescent-Light-Bulb-DC-Lamp-12-Volt-globe-wiring-terminal-clips-/261318091922?pt=AU_Car_Parts_Accessories&hash=item3cd7c5a492)

[bee utey]

Is the mains feed still connected to the outside of the house? If so I'd consider wiring a complete 12V lighting system around the house, totally separate from the mains circuit. Run the newest LED downlights and you'll never miss the mains lights. CFL globes are sooo yesterday. You can then charge the battery if needed from your vehicle via jumper leads if you're in the middle of an overcast week. Panel wise I'd go for a minimum of 80W but you'd be wise to go bigger again. 12V lights can also be controlled by simple PIR sensors, they are really cheap on ebay from china. That way no-one can drain the battery by leaving the loo/passage/bath light on. I've got 4 around my place in critical locations, I can get in and up the stairs without needing a torch. My kitchen is well lit by 6 5W down lights.

globes (http://www.ebay.com.au/itm/10X-MR16-LED-LIGHT-GLOBE-12V-9W-WARM-WHITE-DOWNLIGHT-DIMMABLE-50W-HALOGEN-BULB-/321082059954?pt=AU_Lighting_Fans&hash=item4ac1fb6cb2)

sensors (http://www.ebay.com.au/itm/TAD-T28AD-12V-Infrared-Sensor-Switch-PIR-Auto-lighting-Switch-/181059022042?pt=AU_Building_Materials&hash=item2a27f56cda)

Keep your eyes peeled on gumtree and ebay for solar hot water panels, you can now get a 12V circulating pump that runs off a 20W panel installed next to the HWS panels. A simple over-temp switch can shut off the circulation to not cook your tank.

Once you get the mains back on you can run the 12V system off the same battery with an automatic battery charger as well. No power failure will ever bother you again.

[Safari]

Hi I have a bush weekender that I have developed over the last 10 years. The differance in 12 volt LEDs over the last few years is amazing. I am now about to convert my normal house to a solar only 12 volt lighting system with 240 battery charger back up. At my bush block I have 12 volt lights, 12 volt pressure pump and inverter. I have an instaneous gas hot water system, gas fridge and gas cooker. I also have an engel fridge. We turn up to a fully charged house battery and can turn lights on on arrival. We stay at the shack for up to 10 days at a time but usaually just for weekends. I have a generator that I use for workshop chores that is usally used for a short time every second night at shower time to run the pump and to top up the batteries if needed. I have thought about spending more money on solar cells and batteries but realised it was false econony for my needs as the generator covers this need. PM if you want some ideas as I think I have a pretty good system that is fairly cheap compared to the systems they want to sell you. Cheers Rob

[Vern]

Jsp, you panel size is way to small, I'd try for 2x100+ watt panels, 2 deep cycle batteries (100a/h) and a 30a charge controller. As for lighting, led is definitely the way to go.

[Blknight.aus]

LED lighting is the go.

depending on what you need the lights for (reading, general illumination, brain surgery) strip led lights are a good easy option for basic general illumination if with spot lighting for the more detailed requirements.

I've setup what you're asking about a few times for people (usually for long duration tenters and camper vans) and generally go with a 40A panel, cheap 5-10A regulator and an N70Z size battery.

I source all of my gear (when its not provided and Im just doing the hook ups) from jaycar unless its a really big job in which case I still get the primary components from jaycar (regulator, panel, strip lights) but source the wire from major electrical retailers as its cheaper by the roll.

[jsp]

Jsp, you panel size is way to small, I'd try for 2x100+ watt panels, 2 deep cycle batteries (100a/h) and a 30a charge controller. As for lighting, led is definitely the way to go.

I would love a setup like this, but the cost of it defeats the purpose of not just reconnecting the mains.


I was thinking of fluoro's to try and get reasonable spread light in a large room, and the experience I have had with leds is great but a bit more directional, maybe the latest ones are far better?

unfortunately downlights are not an option in this building, but I would like fairly bright - its a 20x30 foot room with 12-16 foot ceilings. The outdoor thunderbox is the easy bit.

[Blknight.aus]

led strip lights in a round tube with a bad polish job...

you can now get led strips in fluro tube format.

[Vern]

What about just getting a fold out solar panel kit with built in charge controller and a deep cycle battery, when your finished with it you can always use it for camping.:)

[jsp]

well a 40watt panel should fall into my lap and I just bought a cheapo 30a 2 stage charge controller from fleabay, and found a local seller who might be able to sell me 12v standard bayonet fitting led globes for about 10-15 bucks each depending on wattage, so looks like I just need to find a battery.

Given I don't need too much power and if need be can simply get a bigger battery in future, whats the most cost effective way of doing it?

[Vern]

No point getting to big a battery if your solar panel is to small to charge it.

[Blknight.aus]

given that the battery will take charge from anything that can push a higher voltage than whats in the battery.

I suggest starting with an N70 type battery or one thats the same as the one thats in your vehicle.

head to somewhere like super cheap and pick up somethign thats between N55 (just a mite smaller than the orignal D1 battery) and an N70 (the original series/defender battery)

hell head to a wreckers and try your luck their too if you want to do it on the cheap.

Just make sure that the first thing you do when you turn up and the last thing you do before you leave is to make sure that the cells are topped up and that the battery isnt copping direct sunlight or sitting in the damp and its top is clean.

[jsp]

fantastic, didn't even think of the wreckers.

A 45ah deep cycle is about $100, which should run 60w of stuff for about 4 hours before it starts getting low if I have done the calculations correct (probably not).

I am not too fussed about the panel size given it will have on average at least 5 days to charge and realistically 2 weeks to charge. And if it proves to be reasonable I might go the whole hog in the future.

Half the project is tinkering and learning half is having some lights without connecting the mains.

Monday is a public holiday so I guess supercheapauto might have 20% off so that will make batteries reasonable too.

[Bush65]

For $15 you can buy a 5m strip with 300 LED's on ebay. The strips can be cut and used as multiple shorter strips if you want.

Just something to consider vs $10 to $15 for a singe bayonet globe.

[slug_burner]

60W at 12V needs 5A.

45Ah will be achieved at approx 2.25 A discharge (C/20).

At 5 amp discharge rate you may get half to 1/3 of the capacity. You should get your 4 hours but you will be running the battery very flat and therefore reducing it's life. Give it a go with as many batteries as you want to afford. The less discharge of the battery the longer it will last in terms of cycles. Starting batteries don't do well with deep discharge so if you go batteries of that type you may need a couple.

Worth giving it a go for the learning experience. Go the strip LEDs, order them directly from China for a few bucks and free postage costs.

[jsp]

I have been VERY happy with my budget solar light setup, have even run a small 300w modified sine wave inverter to charge a few batteries, and a 12v stereo.

I have decided to upgrade, keeping the current small setup just for the lights and adding a separate system for 240v inverter usage.

At this stage I just want to run a fan, some power tools, a small tv and an electric keyboard with usage only being one or two days a fortnight, with the car fridge thrown in occasionaly.

So far I have acquired a 1500w pure sine wave inverter, and a 600w pure sine wave inverter, a pair of 80watt solar panels with a 30amp charge controller, and I have come across 6x 12v 65 AH deep cycle batteries. They aren't the best batteries for the application but the price was way too good to pass up. They are rated to 280 cycles at 100% usage or 950 cycles at 30% usage, so I should get a few years out of them in my scenario. They are fully sealed.

What's the easiest best battery box/cupboard? they shouldn't vent too much, I would like them to be inside. Apart from ensuring everything is insulated, is a metal cabinet the best?

[brettphillips43]

G'day cobber. If you only have a smallish solar panel and would like heaps of power on tap with a VERY short recharge time... mere minutes versus hours/days.... check out how to make a 12 Volt battery using "Capacitors". Redily found in dicarded micro-wave ovens. Its easy to do, and you have more power on tap than you would need. If i can be of further help, dont hesitate to contact me. Cheers, Brett