Other than decreased resistance, is there any benifit to a 24 volt vs a 12 volt system?

Question

I am setting up a battery buffered system where no wires will be longer than a couple feet. I can set this up either 12 or 24 volt.
This is a continuiously running system, however the charger will only be in use part of the time.

120v in (batt charger) > 12v or 24v batt bank > inverter > 120v out

Are inverters more efficient at higher input voltages?
This is in Alaska, is higher voltage less susseptible to cold?
Is there benifit to more storage or more volts?

Answer 1

Simply stated, the power is a product of the amperage times the voltage (P=IE).
In other words, you can transfer a lot more power through smaller wires with a lot less IR drop or loss through heat/resistance with the higher voltage.
For instance, the starter cables on the older 6 volt vehicles had cables that were similar in size to your thumb - the same power can be transferred to the starter with a pinky size wire at 12 volts.
In your application, it is simply more efficient to put 24 volts into your inverter for 120 volts output - for the same reasons as previously mentioned. More real power in - more real power out.

Answer 2

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RE:
Other than decreased resistance, is there any benifit to a 24 volt vs a 12 volt system?
I am setting up a battery buffered system where no wires will be longer than a couple feet. I can set this up either 12 or 24 volt.
This is a continuiously running system, however the charger will only be in use part of the time.

120v in (batt charger) > 12v or 24v batt bank > inverter...

Answer 3

The only real difference in the 12v or 24v as relates to converting it back to 120v is that you would have a greater amp draw on a given load with the 12 v than the 24 v. If your load on 120 v is 10 amps then your load on the 24 v will be 50 amps. if you use 12 v your draw will be 100 amps. your wattage will be the same on both sides. wattage is a measure of heat. It's just like amplifiers on a car system. the speakers (your load) have to match and be matched by your amps (in your case the inverter.) It's real easy Watts = volts X amps. Anytime you run anything electrical, you must make sure you've got wire that's rated for the kind of voltage and amperage you're gonna be putting through it.

If you plan on putting a good sized load on it and have trouble finding wire rated for the amperage you might be better off to run the batteries in series and increase the voltage up to 120. batteries ran in series increase voltage, ran parallel, they increase current (amperage).

Also, make sure you you put in circut breakers to protect your equipment. You need to make sure your breakers will fail before anything expensive does. Example: if you're running a system where the inverter is rated at 2400 watts, you need to make sure the circut breaker is rated no higher than 100 amps on the 24 v side or 20 amps on the 120v side. I'd say you'd be better off with more like 75 amps (1800 watts) on the 24 v side, and 15 amps (1800 watts) on the 120 v side.

Hope this helps.

Answer 4

I would use 12 volt as there are many things that will run directly from 12v and if you have 24v there's always the chance of connecting 24v to a 12v appliance.I had a similar setup here in the cold part of Tasmania.I think the 24v inverters are slightly more efficient but not woth the hassle .I also have some machinery on 24v and its a pain in the but,any sort of short or bad connection usually blows something apart.Go with the 12v

Answer 5

The advantage of higher voltage is lower current and therefore thinner wires can be used. Most airplanes today use 24 volts for their DC power because thinner wires are lighter and that's important for airplanes. For what you're doing, it's not such a factor, so go with what's more convenient. One person made a good observation about the likelihood that someone might inadvertantly hook up something with the wrong voltage if you don't stick to what's most common.

Answer 6

There's actually no decrease in resistance; there would be an increase in current.

Airfields use battery back-up systems for emergency landing services. They don't switch to higher voltages, what they do is switch to 12-volt "deep cycle" batteries to get more time out of them.

Answer 7

No. If 24 volt had any significant advantages, it would have become the standard by now.

Answer 8

For short runs like that 12V should be OK. You can always compensate for resistance by making the wiring double the cross-section. Just don't send 12V over more than a few metres.

Answer 9

More torque and cranking power. Many large capacity diesel engines have 24 V starters for this reason.

Answer 10

By using 24V you could use a smaller gage wire to carry the same amount of power.