Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Off grid light in small shed

azaxev

New Member
I am looking for a way to install light in a shed, approx 6m2.

Have 5m 2W/m LED strip that will be stapled to rafters, they are exposed.

For the battery, I am thinking convenient Ryobi set of 18V/2Ah battery with charger that sells here rather inexpensively. Battery would be pernamently in charger, stepped down to 12V for LED strip.

Charger's DC adapter would be removed and replaced with solar panel + boost regulator.

Expecting one inconvenience, charger is too fast, charging 36Wh battery in 40min, that is 54W, so solar panel would need to be about that size as well, which seems rather ineffective, since the battery can be topped during entire daylight I would prefer if it took 4-6hrs to recharge that battery. Not sure how difficult would it be to fiddle with chargers internals to slow it down.
 
Last edited:

Diver300

Well-Known Member
Most Helpful Member
You need to find what is used to charge the battery. Your link doesn't work for me.

The power tool chargers that I have generally don't have separate mains adaptors and chargers. There may be a charge control IC that can be made to reduce its charge rate. Some charge ICs are happy to be fed from a low current supply, and they will just let the battery charge as fast as the available current will charge it until the battery is full.
 

Pommie

Well-Known Member
Most Helpful Member
It might be much simpler if you use a 12V SLA (sealed lead acid) battery. Note, your LEDs are going to take ~830mA so to last 12 hours would require a (12x0.8) 10Ah battery - however, a 20Ah would be better as you never want to fully discharge a lead acid battery. Also, your 18V 2Ah battery only contains 36W of energy so assuming 100% efficiency it will last ~3.5 hours. A single 12V LED downlight only uses 6W and will (probably) be much brighter than your strip lights.

Mike.
 

azaxev

New Member
You need to find what is used to charge the battery. Your link doesn't work for me.

The power tool chargers that I have generally don't have separate mains adaptors and chargers. There may be a charge control IC that can be made to reduce its charge rate. Some charge ICs are happy to be fed from a low current supply, and they will just let the battery charge as fast as the available current will charge it until the battery is full.

Thanks, that is great to know about chargers. This one seems to have external wall adapter.


It might be much simpler if you use a 12V SLA (sealed lead acid) battery. Note, your LEDs are going to take ~830mA so to last 12 hours would require a (12x0.8) 10Ah battery - however, a 20Ah would be better as you never want to fully discharge a lead acid battery. Also, your 18V 2Ah battery only contains 36W of energy so assuming 100% efficiency it will last ~3.5 hours. A single 12V LED downlight only uses 6W and will (probably) be much brighter than your strip lights.

Mike.

I really do not need that much from it, the shed is used as storage, nobody ever stays there longer than 5 minutes.

Also considered SLA battery and I would be fine with even 1Ah one but they are not that much more cost effective. The small ones cost $1-$2/Wh here and I could not find any on the second hand website within 30km radius. Power tools batteries have become uniquitous, often come on promotion for less than $1/Wh or in BOGOF deals. I own a small Ryobi, Dewalt battery powered tool lineup, several chargers and battery packs. Tools and batteries are also heavily traded on second hand markets.
 

Pommie

Well-Known Member
Most Helpful Member
Is a battery charger available that can be powered from 12V I.E. a car lighter socket.

Mike.
 

Latest threads

EE World Online Articles

Loading
Top