How Can I Build My Own Inverter to Convert Car Battery Voltage to 220V AC?

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Discussion Overview

The discussion revolves around building a DIY inverter to convert 12V DC from a car battery to 220V AC, specifically targeting a power output of 500W to 1000W. Participants explore the feasibility of constructing such a device, the necessary components, and the implications of battery capacity and efficiency.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • The original poster (OP) seeks guidance on building an inverter due to local electricity outages and the inability to purchase one online.
  • Some participants discuss the power requirements, indicating that a 500W inverter would require significant current from the battery, potentially leading to rapid depletion.
  • One participant suggests that a 40Amp/h battery could last approximately 30 minutes under a 500W load, considering inverter inefficiencies.
  • Another participant mentions that a typical car battery should not be discharged below half its capacity to avoid damage, suggesting the use of deep discharge batteries for backup power.
  • There is a discussion about the varying factors affecting battery performance, including discharge rate, battery condition, and temperature.
  • One participant argues that purchasing a commercially available inverter may be more cost-effective than building one from components, even if labor is not factored in.
  • Clarifications are made regarding the relationship between amps, amp-hours, and energy capacity, with some participants noting the OP's confusion on these concepts.

Areas of Agreement / Disagreement

Participants express differing views on the practicality of building an inverter versus purchasing one. There is no consensus on the best approach to powering devices with a car battery, and discussions about battery capacity and efficiency remain unresolved.

Contextual Notes

Participants highlight limitations in understanding the relationship between amp-hours and energy usage, as well as the need for specific types of batteries for deep discharge applications. The discussion also reflects varying assumptions about the efficiency of inverters and the implications for battery life.

MedoTech
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Hey all .. i happy to join this forum because of the amount of information that it has ..

In our city , the electricity cut down for long time may be 10 hours in a day ..
I want to make a device so i can convert the car battery voltage ( 12V DC) to (220V AC)
this device called Inverter .. i searched for it on amazon , its price was very suitable , but the problem it i can't get it in our city ..
So i want to make it myself , so please give me the help and steps to build it , the needed inverter is 500W or 1000W inverter ( at least 500W) ... and please me a devices which contains the electronic parts that i can use in the inverter .. we have difficult to find the parts in the shop ... so please give me a way to build it by electronic parts which is most common in the shop or the old devices .

another question is how many hours that (a buttery with 40Amp/h ) can give me hours with 500w device
Thank you very much
 
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For each amp you get at 240 volts, the battery has to supply 20 amps plus whatever losses occur in the inverter.
So, even at 300 watts out, the inverter will flatten a typical car battery in less than an hour.

Plus, you have to pay for the power to charge the battery.

Have you considered getting a small gasoline generator to provide power?

another question is how many hours that (a battery with 40Amp/h ) can give me hours with 500w device

500 watts is 41.66 amps at 12 volts. So if the inverter was 100% efficient, the battery would last 57.6 minutes. However, inverters are not 100 % efficient and the amp-hour rating of batteries is only a guide, so it would be more like 30 minutes.
 
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no need for gasoline generator to provide power .. the electricity cut for 10 hours and then it get back for the remain time (14 H) ...
and i can understand from your reply that the battery with 40amp can give me just 1 hour ? for a device work on 500w ...

thanx vk6kro
 
Yes, a 40AmpHr battery contains 12*40WHr of energy
And a car battery can only be discharged to about half the rated capacity without damaging it.
For a backup power you need deep discharge (also called marine) batteries - they are, of course, more than twice as expensive.
 
mgb_phys said:
Yes, a 40AmpHr battery contains 12*40WHr of energy
That depends greatly on how fast you try to use the energy, condition of the battery, and its temperature.
 
mheslep said:
That depends greatly on how fast you try to use the energy, condition of the battery, and its temperature.

Yes - and I pointed out that you can only get about half this out of a regular car battery.
But the OP was confused about the whole Amps/Amp-hours/ Energy/capacity thing
 
Last edited by a moderator:
mgb_phys said:
Yes - and I pointed out that you can only get about half this out of a regular car battery.
Ok, though it is also true (energy is not a constant V*amp-hours) of the deep discharge marine batteries.
 

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