3000watt inverter cable size?

[Hollando23]

Hi guys.
I have had a search through some threads but have trouble finding any clear reference to cable sizes for running inverters.
I got a 3000watt pure sign wave 12v to 240v inverter to run a kick ass juicer and a blender and also the chickies hair dryer and straighteners. In know these seem like messed up things to take but will will be on the road for about 6 months any help on this would be awesome.

[Steveyb]

3000 aye! What batteries you running for that ? At full tilt you will pulling a couple of hundred amps. How long will the run be? I would be going no less than 70mm sq. Maybe even 95.

[ktm300]

Get a Generator

[skirex]

Yeah at least 70mm. And keep the cable short!

[Stu.wrf450]

I'm gonna run a 2000watt. How long you gonna be running it for? I'm just gonna run the car while I'm using men using something big. I've been told a 5 or6 gauge will be fine. What is 70mm? Shorly that can't be thinkness?
That's a huge cable. Haha

[Hollando23]

Wow. I was going to run a 0 awg maybe even two from my second battery to a sub board set up in the canopy and have the lux running when I use it. I would take a genny but space is at a premium. But I'll need to get one massive fuse/circuit breaker on it to and then fuse each circuit out of the sub board

[Steveyb]

Here is a conversion page for awg to mm

http://www.engineeringtoolbox.com/awg-w ... d_731.html

Do the math chaps. Watts don't change, they stay the same.
So, lets say your running the car for this. 2000/13 = 150amps (roughly)
At a 3 metre length 5 awg is good for about 60 amps.... That's quite a way short from your full load current.

[VMN]

I was advised recently to use the supplied cable and not extend it! However if you do need to, you need to aim for no less than 0.5 volt drop which can be calculated by
Voltage drop = (length(m) x current(A) x0.017) / cross section(mm2)

Length of earth wire must be counted so earth return via the chassis is a good idea!

So check the inverter efficiency. Say it is 85%. Divide you 3000 w output by 85% to calculate input watts and add say 20% for headroom. Now divide watts by volts to get amps and at 12 volts you'll come up with about 354 amps.

From the formula, 2m of cable run requires 0B&S cable (well 48mm2 when the 0 cable is 49.2mm2)

Phew! Glad I only ordered a 1500 w inverter!

[Rocket55]

So my 6mm won't cut it

It's one thing to buy a huge inverter, it's another thing to try and power it up without burning your car down

Some excellent advice above.

For those that don't fully understand, I seriously recommend seeking professional advice here from people who DO understand, as opposed to people who THINK they understand, as the price you will pay for getting it wrong will be extreme.

[Hollando23]

It sounds like parallel 1 awg or 0 awg will be the go. But I think I'll talk o a auto sparky first to triple check so i don't waste my time running pricey cable and fuses that wont work.
Cheers boys lot of great info and advise

[ktm300]

The batery wont last two seconds running something like that

[Hollando23]

Yeah ktm300 i thought it would...I'll have the lux running while we use the inverter which has a bcdc 25 charger set up on the dual battery I hope this will be sweet. We shouldn't get anywhere near 3000 watts while using it, only got that size because it was a great price and I'll have reactive load running off it which have a higher start up current.

[VMN]

Yeah ktm300 i thought it would...I'll have the lux running while we use the inverter which has a bcdc 25 charger set up on the dual battery I hope this will be sweet. We shouldn't get anywhere near 3000 watts while using it, only got that size because it was a great price and I'll have reactive load running off it which have a higher start up current.

A couple of extra things to think about.
1. You need a fuse (300-350 amp) as close to the battery as you can.

2. Make sure you keep it turned off when not in use. Check the idle power consumption with no load. It could be 2 amps or so on a big inverter. If you can't easily reach the inverter console once installed, consider opening the case and extending the wiring to the on/off switch. The alternative is to put a relay on the 12 volt input which is the path I took in my car with a small inverter but a relay to switch 300 amps or so with will be very expensive.

[Bullzye]

The batery wont last two seconds running something like that

My old mans work utes all have fairly big inverters and hell run drills with inch auger drill bits and even a 5inch angle grinder. You just have to keep the ute running.

[VMN]

The batery wont last two seconds running something like that

My old mans work utes all have fairly big inverters and hell run drills with inch auger drill bits and even a 5inch angle grinder. You just have to keep the ute running.

All of these use a lot less than 3000 watts. I bought a drill on the weekend rated to drill holes up to 13mm in steel and it is only 850 watts. An angle grinder would be not much different.

The drill replaced one that finally died 30 years after my father gave it to me for my birthday in 1983. It may come as no surprise that I bought another Bosch.

[Bullzye]

The batery wont last two seconds running something like that

My old mans work utes all have fairly big inverters and hell run drills with inch auger drill bits and even a 5inch angle grinder. You just have to keep the ute running.

All of these use a lot less than 3000 watts. I bought a drill on the weekend rated to drill holes up to 13mm in steel and it is only 850 watts. An angle grinder would be not much different.

The drill replaced one that finally died 30 years after my father gave it to me for my birthday in 1983. It may come as no surprise that I bought another Bosch.

The grinder is 1800watts and in some of the trucks they have 2400watt microwaves so it is possible

[Stu.wrf450]

I have got a 6 gauge raining to my fridge and this auto elec reakons it would be fine to go of that. I haven't got an invertor yet and it's something I won't do my self as I want it done properly!

[Hollando23]

So far so good...
I've got my Bcdc and aux battery in the back charging off the cranking battery. Off the the aux battery I have run about a ft of 0 awg through a 200A ANL fuse, out of the fuse through a 275A DC isolator then to my 3000watt inverter all in 0 AWG. It's limited to 200A and so far haven't blown the fuse and been using it daily for a month. I have a volt meter wired to the battery to keep an eye on it and always have the luxy on when using it. Getting a 120 watt panel today so won't have to drive so much to charge the battery for the fridge and lights...
Banging!

[martynvella]

You wont blow the fuse till you demand about 2000 watts from the inverter, then the draw will be approaching 200 amps. It is a very big inverter to be running off one battery, be interested to hear what type of battery you are running and how well it copes with high current demands. A lot of batteries cant cope with prolonged hi discharges simply because the hydrogen ion transfer into the outer layers of the plates faster than they can be absorbed into the inner parts of the plate thus saturating the plate and output drops off, a short rest allows the ions to move deeper into the plate and the battery will recover if it isn't fully discharged at this stage. Deep cycle had fewer plates but thicker because they were designed for smaller but longer discharges compared to the short hi current of the starting battery.

Please let us know how the system is performing under different load conditions and what battery you are using.

[mattwhite]

What size bcdc you running?