Inverters US vs NZ

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BushRat

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#283836 15-Mar-2021 08:48

Hi All,

Looking at purchasing a 2000w 12V Pure Sine wave battery converter from the US. Awesome unit with everything I need at a fraction of the price for the units available locally. Only problem is that the AC voltage output is 115V being a unit designed for the US. I have an understanding of step down transformers for taking 220V to 110V, but need some assistance on how to "step up" from 110V to 220V if this is even possible.

Please take note: NEWBIE HERE! Looking forward to your input

CHeers!

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#2674708 15-Mar-2021 09:03

Depending on what you're trying to power, things like laptop chargers are multi voltage. Have a read of the fine print on the device(s), they may say input 110-240V or be switchable between the 2.

SirHumphreyAppleby

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#2674709 15-Mar-2021 09:05

The voltage is less of an issue than the frequency, which will be 60Hz vs 50Hz. This makes it unsuitable for devices with AC motors in for example.

The majority of things you power from a small inverter will probably accept 110v/60Hz input anyway (such as wall warts), so you may not need to step up at all.

Yoban

447 posts

Ultimate Geek

#2674711 15-Mar-2021 09:05

hi there, can recommend these guys https://www.aliexpress.com/store/1230818?spm=a2g0o.detail.1000007.1.68056238pRELQ9 and the Belttt brand.

I have a 1000W that I used for my UPS in conjunction with 50aH battery. They work really will run cool and easy to install.

BushRat

4 posts

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#2674712 15-Mar-2021 09:06

This will be used in my vehicle 12v system to power some items used for camping, that are not 12v. Small appliances basically that require 220V. And then also being able to get the required watts. Just found a step/up transformer that looks like it would be able to do this.

richms

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#2674722 15-Mar-2021 09:25

Adding a large transformer to the output will mess up your efficiency, will result in higher load on it because of power factor, and probably be really noisy because it doesnt have a real grid driving it any harmonics from the load will be much worse.

Richard rich.ms

Scott3

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#2674732 15-Mar-2021 09:37

Yes, you can get step up transformers, But there isn't really significant demand for them in NZ (generally we want step down transformers to run US appliances on NZ power) so you will likely need to import one. As an example:

https://www.amazon.com/PowerBright-Transformer-Countries-Convert-220-240/dp/B00O4JFLV6/ref=pd_lpo_23_img_2/131-2386128-5765809

As it is a proper transformer it will be big and heavy (12kg+ for 2000W) which will make it both expensive to buy & freight, and bulky / heavy in your vehicle. I think the cost and weight of this will make it not viable.

Also the power that you will get off it will be 220V, 60HZ. NZ power is 230v, 50HZ. Voltage is likely close enough to be within the tolerances of appliances, but some appliances (partially those with induction motors) are frequency sensitive. Others like the universal motor on your blender are not.

Frankly I think you should pick from one of the following:

Buy a 115V inverter and only run 115V appliances off it. (things like you laptop chargers are likely to be compatible with 115V power.
Buy a 230v / 50Hz inverter locally
Import a 220 or 230v 50Hz inverter from asia or the UK.

djtOtago

1149 posts

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#2674746 15-Mar-2021 10:07

@BushRat

What exactly are you trying to power and for how long?

You are talking about 2000w inverter and running it from you vehicle's battery.

Even if you only have a 1000w load on this, it will flatten a standard car battery in about 30 minutes. And will not be very good for the battery.

Even if you have your vehicle running, you will still flatten your battery as the average car alternator puts out less than 700 watts.

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BushRat

4 posts

Wannabe Geek

#2674749 15-Mar-2021 10:14

It will be running off an auxiliary battery(100amh lithium) being charged by a 60amp DCDC smart charger connected to the starter battery/alternator. Also will have a MPPT solar charger connected to auxiliary battery for when off the grid for long periods not running the vehicle. Plan is to have the inverter connected to the auxiliary making it possible to run DC appliances off the auxiliary battery.

But thinking the inverter might be a bad idea. I believe that 1amp DC will pretty much be draining 10amp AC off the auxiliary battery. Which is going to require a much larger auxiliary battery or much more regular charging. Might be better to buy all new 12v appliances.

Thoughts?

tripper1000

1617 posts

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#2674768 15-Mar-2021 11:04

With batteries and solar, you have a very limited about of power, and inevitable run out, so you need to be conscious of inefficiency. Every voltage conversion results on lost power, so the fewer conversions you have, the better. It is more efficient to go from 12v to 230v than 12v to 110v to 230v. Cost wise, I doubt you will be saving any money, once you buy a step-up transformer.

Regarding DC appliances; yes, it can be more efficient to use DC appliances. Many modern appliances (TV's, LED's, Laptops, phones etc) require DC internally, but are setup to be powered off mains for the convenience of home users. You will find in many cases that you are going 12v to 230v and then straight back to 12v or 5v, so you have 1-2 unnecessary conversions. Also many cheap 230v appliances have terribly inefficient converters in them - 230v LED BC/ES lights are a good example. You will typically lose 1/2 of the power they use due to bad power factor the AC to DC voltage conversion process and it is far more efficient to use DC to begin with.

One common mistake people make when starting out is using heating appliances. It takes an enormous amount of electricity to make heat (far more the most people think), so don't even think about hair driers, toasters, kettles or anything else designed to make heat. To put it in context I explain the following: A toaster uses as much power as a starter-motor - think about how long your battery will last trying to start a broken down engine, and that's how long your battery will last toasting bread.

tripper1000

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#2674770 15-Mar-2021 11:12

BushRat: But thinking the inverter might be a bad idea. I believe that 1amp DC will pretty much be draining 10amp AC off the auxiliary battery. Which is going to require a much larger auxiliary battery or much more regular charging. Might be better to buy all new 12v appliances.

I think you meant to say 1 amp AC = 10 amps DC, you are right in the context but it is far worse that you say. 1 amp AC at 230v = 19 amps DC at 12 volts. (Volts x Amps = Power so 1a x 230v = 230 watts = 19.16a x 12v).

richms

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#2674773 15-Mar-2021 11:17

For short term use like a nespresso machine or smoothie maker or similar, you are fine off an inverter and the vehicle battery, but don't think you will be cooking a roast off solar anytime soon, or running a household fridge.

If you can get your auxiliary system to be 48v instead of 12v that will get you a better selection of inverters to choose from, and 2 panels in series so about 70v will be great to charge that up, lower currents mean lower losses.

Richard rich.ms

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#2674838 15-Mar-2021 12:54

I bought a 2000w "pure sine wave" inverter from Taobao. It's 50hz and around 230v but struggles to power even my single standard fridge compressor. It was cheap though!

What are you looking to power? Pretty much you only really need AC for motors - practically all other devices are actually DC and for things like laptops, phones etc. you are better off to just get a high power car adapter. These run on 12v and can provide the same power for charging a laptop or phone as a "mains" adapter:

https://www.pbtech.co.nz/product/NBPKFD10001/KFD-Universal-USB-C-Type-C-Laptop-Car-Charger-12V

If your device doesn't have USB then you could look at a buck or boost converter depending on your power needs.

If you've got a PHEV or EV car with a CHAdeMO socket you could get one of these bad boys - connects straight into your main battery at ~300v DC - should last ages!!:

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Rikkitic

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#2674860 15-Mar-2021 13:49

http://www.gohz.com/can-a-step-down-transformer-be-used-as-a-step-up-transformer

Plesse igmore amd axxept applogies in adbance fir anu typos

neb

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#2674971 15-Mar-2021 14:58

The whole thing seems like the wind-powered boat from the Red Green Show, where they add a windmill to the boat, some gearing, a generator, electric motors, and whatnot just to get a boat propelled by wind. In this case you're getting an inverter that produces the wrong voltage at the wrong frequency freighted in from the US and then thinking of bolting a huge (and lossy) step-up transformer onto it to correct at least one of the two mismatches... wouldn't it be easier to just get an inverter of the correct type to start with?

BushRat

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#2674976 15-Mar-2021 15:06

neb: The whole thing seems like the wind-powered boat from the Red Green Show, where they add a windmill to the boat, some gearing, a generator, electric motors, and whatnot just to get a boat propelled by wind. In this case you're getting an inverter that produces the wrong voltage at the wrong frequency freighted in from the US and then thinking of bolting a huge (and lossy) step-up transformer onto it to correct at least one of the two mismatches... wouldn't it be easier to just get an inverter of the correct type to start with?

I have come to your conclusion reading through the comments. Being new to this, I only today realized that a step up transformer is actually a stupid, bulky and again stupid idea. Will stick to a local 220v inverter should it be needed. Thinking of just changing all appliances for camping to 12v to avoid another system needing to be installed.

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