Discuss What size dc isolator needed in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Reaction score
0
Just a quick question. We have a yard with no electric up there so using a 12v car battery connected to an invertor to power 230v lights. I'm wanting to connect a dc isolator from the battery to inverter so we don't have to keep connecting the clips to the battery and can use turn the isolator on. I know that the amps are alot more for 12v but what size dc rotatory isolotir would it need. 80amps
 
Why not use 12 volt lamps and a standard light switch?

Edit: Infact LED tape gives off plenty of light for little current draw.
 
Why not use 12 volt lamps and a standard light switch?

Edit: Infact LED tape gives off plenty of light for little current draw.
Because we only recently purchased this and it already prewired lights and fuse board etc. Just need a simple way of switching the supply on and off instead of connecting the battery clips as I think if left on over night the inverter would slowly drain the battery
 
Err on side of caution, 1000w at 12v is 83A

So may as well be a 100A isolator.
What is it fused at?
 
Any AC switch or isolator is fine for 12V DC at the same current rating. A 100A main switch would suit here. Anything using 100A from a car battery will soon kill the battery though!

Note, the same is not true for higher DC voltages above say 24V, because of the arc. A normal 100A 400V rated AC switch carrying even 20A at 400V DC would probably turn into a fireball when someone tried to switch it off as the contact separation would not be great enough to extinguish the arc.
 
Just seems to be very inefficient to run it through an inverter if all your doing is powering some lights.
 
Any AC switch or isolator is fine for 12V DC at the same current rating. A 100A main switch would suit here. Anything using 100A from a car battery will soon kill the battery though!

Note, the same is not true for higher DC voltages above say 24V, because of the arc. A 100A 400V rated AC switch used to interrupt even 10A at 400V DC would probably turn into a fireball when someone tried to switch it off.
Thanks. Won't be using anything like 100amp. Led laps about 10 so probably like 60w max. Just looking for something to turn battery off and on without having to remove and re attach the battery clips
 
Hi,can you not leave the clips on the battery,and switch off at the inverter?
 
Those ELV flag key switches are OK but very basic, and the cheap ones are rubbish. As you don't need the short term peak current capacity for starter duty, a regular 100A main switch is a better device cheaper than a good one. But, yes, doesn't the inverter have a soft switch or do you not trust it?
 
If it's using a car battery you shouldn't drain it more than about 20%, cycling it any deeper will result in it failing in a few weeks or months.

To be honest, if this setup is a couple of lamps running from a camping type inverter in a domestic setup you could get away with using a recovered circuit breaker as an isolator even on the DC side. DC isolators are generally expensive and this doesn't sound like it's a critical application so it won't be a safety issue even on the off-chance the circuit breaker fails prematurely with the DC load....although I doubt it will. Also a 100A switch from an old CU as Lucien suggests or an engine kill switch mentioned above by Bill would all work great.
 

Reply to What size dc isolator needed in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock