Pairing up two power supplies

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In summary: Thanks for the link! In summary, the author has done a good job of fitting a 500W inverter into his car's boot, but he wants more power. He is considering connecting the inverter to two power supplies to get more power, but he is worried about the current and the potential for problems. He has also considered using a dedicated generator to get more power.
  • #1
Adder_Noir
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Hi Guys,

I've done a nice job of fitting a 500W inverter in my car's boot which gives me mains voltage in my car the likes of which I'd normally only have coming out of the wall sockets in a house 230V 50Hz AC.

The only problem is I want more power. 500W at 230VAC is not enough to boil even a travel kettle without overloading the power supply and triggering the warning alarm on it. Sure I could get a 2kW inverter but they cost over £1000! Naturally it wasn't long before I thought of using two power supplies in tandem. This does of course come with some rather big problems though. Firstly the power supplies in question are nowhere near of high quality enough to be producing exactly the same voltage so they cannot simply be connected in parallel. They only cost around less than a $100 each.

What I was initially thinking of was connecting them in series to make roughly 450VAC and then pass this through a good voltage regulator to get the voltage back down to 230VAC whilst still making use of the fact that two power supplies would give enough power to boil a kettle without using enough current to operate the thermal shutdown and overload alarm on either unit.

I then realizes that this analogy is false however due to the fact that when connected in series the current through each will actually increase and thus almost certainly trigger the thermal shutdown and overload alarm on both units. So this is a no go.

So:

The only thing I can think of now would be to connect each power supply to it's own precise voltage regulator to give a very accurate output and then connect the output from the two voltage regulators in parallel thus providing 230VAC and plenty of power to the appliance (e.g. a kettle).

However, it then further occurred to me that there is still a problem when it comes to frequency. Just because they are switched on at the same time it doesn't necessarily mean that the two power supplies will be in phase. The worst case scenario I can imagine is that they may be perfectly out of phase where no voltage would be generated at the appliance terminals at all, but a huge current would circulate and cause catastrophic problems.

So:

Is it economically viable and practical to acquire two decent voltage regulators accurate enough to keep circulation currents through supply devices down to a minimum, and also to purchase a device to keep the output of both regulators in phase with each other to prevent nasty problems such as differences in potential between both positive output terminals?

Sorry to be so long-winded but I wanted to show you that I've done a lot of thinking about this, instead of just throwing out a half-assed idea and allowing other people to think it through to completion for me. Thanks for any help you can offer!
 
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  • #2
Voltage regulators are for DC, not AC.

Also, you are limited in your 230VAC output power by what your car's electrical system can stand to put out. You'd be better off getting a dedicated generator for making higher 230VAC output powers. Car electrical systems are not designed to support large external loads.
 
  • #3
Thanks for the reply berkemeister. Yeah I know the car isn't designed to run high power drains consistently, I just want it to be able to boil say a 600W kettle when the engine is idling which it should be able to handle. I've run seven stranded 10mm cable to the existing power supply through the car so there's plenty of cable there to handle the current too so that's not an issue. Don't really want to have to get a generator.

To be honest I'm just looking for an interesting project to keep me occupied. Is it possible to get a device which can keep two power sources at 50Hz synchronised in phase with each other?
 

1. What is the purpose of pairing up two power supplies?

Pairing up two power supplies is a method used to increase the overall power output and reliability of a system. By connecting two power supplies in parallel, they can work together to provide a higher current output, or in the event of one failing, the other can take over to prevent a power outage.

2. Can I pair up any two power supplies?

No, not all power supplies are designed to be paired up. It is important to check the specifications and compatibility of the power supplies before attempting to pair them up. Matching the voltage and output current of the two power supplies is crucial for successful pairing.

3. How do I connect two power supplies in parallel?

To connect two power supplies in parallel, you will need to use a power supply splitter cable. This cable will have a single female connector that connects to the system, and two or more male connectors that connect to the power supplies. Make sure to connect the positive and negative terminals of both power supplies together.

4. Is there a limit to how many power supplies I can pair up?

Yes, there is a limit to how many power supplies can be paired up. The maximum number will depend on the specific power supplies being used and their capabilities. It is important to consult the manufacturer's guidelines and specifications to determine the maximum number of power supplies that can be safely paired up.

5. Are there any risks involved in pairing up two power supplies?

Yes, there are some risks involved in pairing up two power supplies. If not done correctly, it can cause damage to the power supplies and the system. It is important to follow proper procedures and guidelines to ensure safe and successful pairing. Additionally, using power supplies from different manufacturers or with different specifications can also pose a risk and should be avoided.

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