How to connect a 12v power invertor

Jamie and Kerryn · Veteran Member

How to connect a 12v power invertor

Fastcoach · Senior Member

RE: How to connect a 24v power invertor

The Doo crew · Senior Member

Looks like your set up is 12v by your charger & Ctek & your two batterys will be in parallel not series. We run an inverter for the toaster as NOTHING makes toast as well as the pop up. Wouldn't even think of running a kettle as it would suck far too much power.

Always remember with electronics, once you let the smoke out, there stuffed. A valuable lesson I learnt last night when I fried our 3000w inverter in the middle of the Kimberly's.
Wife is NOT happy as for us no inverter means no aircon to sleep with.

PeterD · Guru

Jamie and Kerryn wrote:
. It's got two standard house batteries another huge green battery thing connected together but I have no idea how this all works..

What is this "huge green battery thing?" Is there anything printed on it? If so please give us the details. A photo or three could assist us to identify it.

As said above, with only two batteries you will not run high power devices for very long. You have to be very careful if you are going to run high power devices on your batteries. Inverter salesmen are a mob of snake oil merchants, they tell you of all the benefits but not the traps and limitations of the devices.

Jamie and Kerryn · Veteran Member

How to connect a 12v power invertor

Aus-Kiwi · Guru

Your better off getting a sparky to fit it .. 240v is dangerous .. Most heating is best done with gas. LPG ..
Best to have DC cables as short as possible with inverter as close to batteries as you can get..
Much less VD ( voltage drop) with 240v.. Breakers and residual device must be fitted..

03_Troopy · Guru

Fastcoach wrote:
Judging by your technical description of the various electrical devices which you have, I'd respectfully suggest you consider using an auto electrician to install your invertor.

Attaching the wrong wire to the "charger thing" just might cause a huge amount of damage to your pride and joy. Just sayin'.

I'll second that biggrin

Jamie and Kerryn · Veteran Member

Thanks for the advice guys, I have a generator in the back but was just thinking about a small power invertor would be easier to make a coffee etc then getting out and starting up the generator.. I might just use the gas cooker and boil the kettle the old fashioned way for now..

03_Troopy · Guru

Jamie and Kerryn wrote:
Thanks for the advice guys, I have a generator in the back but was just thinking about a small power invertor would be easier to make a coffee etc then getting out and starting up the generator.. I might just use the gas cooker and boil the kettle the old fashioned way for now..

The gas cooker would be a whole lot more efficient, and a lot less taxing on your battery.

meggsy · Veteran Member

lets look at the current draw required to run a 1200Watt jug via an inverter. is 100 amps, the jug takes approximately 5 minutes to boil then run a 1000 watt toaster for another 5 minutes it takes a lot out of your battery especially if the inverter idle current is not a low idle current draw --- this does not treat your battery well also remember that the wiring installed to run the inverter needs to be capable of handling 100 amps .... stick to the stiove

Vince · Senior Member

Wiring an inverter is a job if you feel capable of doing can be simple.

If not send it to an auto electrician.

To do it --
Run 6mm B&S twin core wire good up to 1500W inverters (can use 8mm to lower loss but best on higher watt inverters) and up to 3m
Red wire from positive terminal of battery to a fuse (blade or auto trip) close to the battery end and another at the close to the inverter and attached to positive side of inverter
Fuses at both ends are a safe way of the wire if run behind a wall or such not catching fire and burning your pride and joy to the ground

Black wire from negative terminal of battery to negative side of inverter and for extra safety sake a fuse at one end (either). Power runs from negative to positive

As to the items in your pics - 1 is a solar controller the other is a battery charger DON"T connect it directly to either

As for the job you want it to do I agree with Meggsy and 03 Troopy

Cheers
Vince

-- Edited by Vince on Wednesday 14th of October 2015 11:41:14 PM

-- Edited by Vince on Wednesday 14th of October 2015 11:41:55 PM

03_Troopy · Guru

Vince wrote:
Wiring an inverter is a job if you feel capable of doing can be simple.

If not send it to an auto electrician.

To do it --
Run 6mm B&S twin core wire good up to 1500W inverters (can use 8mm to lower loss but best on higher watt inverters) and up to 3m
Red wire from positive terminal of battery to a fuse (blade or auto trip) close to the battery end and another at the close to the inverter and attached to positive side of inverter
Fuses at both ends are a safe way of the wire if run behind a wall or such not catching fire and burning your pride and joy to the ground

Black wire from negative terminal of battery to negative side of inverter and for extra safety sake a fuse at one end (either). Power runs from negative to positive
As to the items in your pics - 1 is a solar controller the other is a battery charger DON"T connect it directly to either

As for the job you want it to do I agree with Meggsy and 03 Troopy

Cheers
Vince

-- Edited by Vince on Wednesday 14th of October 2015 11:41:14 PM

-- Edited by Vince on Wednesday 14th of October 2015 11:41:55 PM

I think you made a typo there mate.. 6 B&S not 6mm.. but I'd be happier with 4B&S on a 1500W inverter and 6B&S on smaller. And 8mm? is smaller than 6B&S anyway.

6B&S = approx 13.3mm²

6mm Auto wire = approx 4.2mm²

6mm² is bigger than 6mm auto wire

6B&S is bigger than 8B&S

8B&S = approx 8.3mm²

As far as fuses or Circuit Breakers are concerned, unless you're hooking 2 batteries together, just at the battery end will suffice, in the positive cable. That is to ensure you don't have a live positive lead floating about and arcing against any metal in the event that it comes loose for any reason.

Current runs from NEG to POS for some (Electron Flow Theory), and from POS to NEG for others (Conventional Current Flow Theory)..

-- Edited by 03_Troopy on Thursday 15th of October 2015 09:21:32 AM

Vince · Senior Member

Whoops....thanks 03 Troopy, I don't know why I added mm to wire sizes.... and I thought the 8B&S was about the same as battery lead wire size ??? if not what size is that one?

((Current runs from NEG to POS for some (Electron Flow Theory), and from POS to NEG for others (Conventional Current Flow Theory)..)) I remember having a conversation with the teacher while doing my amateur radio license about these theories.....bought back memories

Cheers

Vince

-- Edited by Vince on Thursday 15th of October 2015 11:24:29 AM

meggsy · Veteran Member

Just as a precaution spend the extra money and get a pure sine wave inverter so you can use it on other electronic devices if you have to and make sure that you purchase one with a low idle current that is unless you are NOT using it, that is switched on and NOT providing a current to an appliance, then the current drew ins a mere few amps. Typically this is perhaps one of the better quality ones with a 12 watt ( 1 amp) idle current http://www.tortech.com.au/pure-sine-wave-inverters/transformer-pure-sinewave-inverter/12v-2000w-6000w-surge-txf-pure-sine-wave-inverter they also have some good info on their web site --- NOTE _ I am not making a recommendation just showing as an example hope this helps

03_Troopy · Guru

Vince wrote:
Whoops....thanks 03 Troopy, I don't know why I added mm to wire sizes.... and I thought the 8B&S was about the same as battery lead wire size ??? if not what size is that one?

((Current runs from NEG to POS for some (Electron Flow Theory), and from POS to NEG for others (Conventional Current Flow Theory)..)) I remember having a conversation with the teacher while doing my amateur radio license about these theories.....bought back memories

Cheers
Vince

-- Edited by Vince on Thursday 15th of October 2015 11:24:29 AM

Vince, "battery cable" can be any size from about 4 B&S (21mm²) to 2/0 B&S (67.4mm²) or even bigger.

Cable Size Chart.png

-- Edited by 03_Troopy on Thursday 15th of October 2015 05:16:14 PM

-- Edited by 03_Troopy on Thursday 15th of October 2015 05:17:04 PM

Vince · Senior Member

Thanks for that...I do get a little confused on the metric mm2 sizes

When I buy it off the net on fleabay it's called 3mm or 6mm or 8mm twin core wire sheathed and it is a good heavy gauge and these are the three sizes I use that were suggested by my cousin the auto elec.

Cheers Vince

Jamie and Kerryn · Veteran Member

Thanks for the advice Meggsy, those are similar to the ones I've been looking at hopefully I'm on the right track..

-- Edited by Jamie and Kerryn on Friday 16th of October 2015 08:52:48 AM

03_Troopy · Guru

Vince wrote:

Thanks for that...I do get a little confused on the metric mm2 sizes

When I buy it off the net on fleabay it's called 3mm or 6mm or 8mm twin core wire sheathed and it is a good heavy gauge and these are the three sizes I use that were suggested by my cousin the auto elec.

Cheers Vince

Yes, it is particularly confusing when we have such a ridiculous system as auto wire sizes, that use the overall wire size including the insulation. This gives no idea of the actual conductor size.

for example:

Auto Wire____ mm² (CCA)

3mm _________ 1.1mm²

4mm _________ 1.8mm²

6mm _________ 4.2mm²

And they are only rough equivalents because the tolerances on insulation thickness to actual conductor size of auto wire is pretty rough. The chart from Redarc shows 6mm auto wire as 4.56mm²

PeterD · Guru

Vince wrote:
1.. Red wire from positive terminal of battery to a fuse (blade or auto trip) close to the battery end and another at the close to the inverter and attached to positive side of inverter

2.. Fuses at both ends are a safe way of the wire if run behind a wall or such not catching fire and burning your pride and joy to the ground

1.. Blade fuses are way too small, you need heavy fusible links. Your suggested 1500 W inverter may require up to 150 A of current. The power rating of an inverter is its output power. To allow for the power lost in cables and the inverter itself you divide the output power by 10 (and not by 12) to determine the maximum current input.

2.. Every fuse has a little voltage drop across it and is also the source of potential future problems (apart from blowing.) Fuses are there just to protect the wiring, they are only need close to a current source that will provide enough current to overheat the wire/cable. Cables from a battery certainly need fusing. Power supplies and chargers only need fuse protection if the wire from them or any other device connected to the wire is capable of overheating and causing problems. Solar panels only need fuses at the battery end of the cable, if you are using cable that is heavy enough to prevent a large voltage loss there is no chance of the panels overheating the cable.

oldtrack123 · Guru

Jamie and Kerryn wrote:
I would like to get a power invertor so we can run a 240v kettle, toaster etc when we are on the road. I'm not sure how I would connect it to the batteries and any help would be great.. It's got two standard house batteries another huge green battery thing connected together but I have no idea how this all works.. It has two charger things connected to them as in the attached photos.. The silver charger thing turns on when I connect mains power and the other black charger thing runs constant from the solar panels I think?

-- Edited by Jamie and Kerryn on Monday 12th of October 2015 07:19:16 PM

Hi

Perhaps you should also be made aware of the fact that the 240v from any inverter can kill, just like mains power

The SAFETY recommendation is to only have ONE class 1 appliance /devise CONNECTED at any time!

YOUR kettle , toaster ARE class 1 !!

Class1 devices will always have a 3pin plug.

Aus-Kiwi · Guru

Yep two supplies can be way higher voltage than 240 .. There are isolation switches etc that approved electricians install..
Keep in mind of the 12v amperage from batteries to feed inverter..

justme · Member

Hi, I have a hi-ace van with 2x 120 agm batteries in the back.
I can re-charge them by plugging into 240 and have a ctek charger to go with it.
I also have 160 watt foldable solar panels to use if camped for a while.
The batteries mostly re-charge as I drive along exploring.
However, I was recently camped for 4 days and only used the batteries.
They had no trouble running my engel fridge (very cold); led lights; radio; laptop; cordless kettle and toaster.
I have a 1500 / 3000 w pure sine wave inverter bought online for $240 (on sale) and fitted by the auto electrician for $40.
Didn't take long, screwed it on to a frame and wired it up with heavy duty wire. all good.
Cheap investment to be able to flick on the kettle and toaster in the morning (not at once though), or later at night.
The toaster is a $7.50 one from kmart and the cordless kettle is a 1 litre sunbeam bought online for $30.
I only put in half a litre though as that's heaps for a cuppa and top up.
I have had no problems or issues with any of the gear i have. All works well.

Jamie and Kerryn · Veteran Member

justme wrote:
Hi, I have a hi-ace van with 2x 120 agm batteries in the back.
I can re-charge them by plugging into 240 and have a ctek charger to go with it.
I also have 160 watt foldable solar panels to use if camped for a while.
The batteries mostly re-charge as I drive along exploring.
However, I was recently camped for 4 days and only used the batteries.
They had no trouble running my engel fridge (very cold); led lights; radio; laptop; cordless kettle and toaster.
I have a 1500 / 3000 w pure sine wave inverter bought online for $240 (on sale) and fitted by the auto electrician for $40.
Didn't take long, screwed it on to a frame and wired it up with heavy duty wire. all good.
Cheap investment to be able to flick on the kettle and toaster in the morning (not at once though), or later at night.
The toaster is a $7.50 one from kmart and the cordless kettle is a 1 litre sunbeam bought online for $30.
I only put in half a litre though as that's heaps for a cuppa and top up.
I have had no problems or issues with any of the gear i have. All works well.

Thanks mate, I'm getting some great advice which is all very helpful and will take it all into account when I buy my inverter..

Aus-Kiwi · Guru

150 amp DC from memory would require 50mm cable from batteries.. The fuse / breaker also protects the cable ..

03_Troopy · Guru

Aus-Kiwi wrote:
150 amp DC from memory would require 50mm² cable from batteries.. The fuse / breaker also protects the cable ..