08-18-2026, 02:30 AM
(This post was last modified: 08-18-2026, 02:31 AM by Rob Tucker.)
I've been pondering 10's of thousands of local folks without power and not enough generators to go around. Plus the fact that we have thousands of cars which are each more powerful than any Home Depot generator.
So I put it to Chatgpt.
Advise on adding a 110v inverter to a typical automobile sufficient to power a refrigerator and battery chargers. Cost and practical applicability.
Yes. Adding a 120V (nominally 110V) inverter to an ordinary automobile is quite practical for running a refrigerator and battery chargers, but I would design it somewhat differently from the typical inexpensive “plug into the cigarette lighter” inverter.
My recommended configuration
For what you describe, I would use:
Component
RecommendationInverter
1,500–2,000 W pure sine wave
Surge capability
3,000–4,000 W preferred
Input
12 V DC
Connection
Directly to battery with heavy cables, not cigarette lighter
Refrigerator
Normal household refrigerator
Battery chargers
Phones, laptops, power-tool batteries, etc.
Engine
Running while substantial loads are connected
Auxiliary battery
Optional, but worthwhile if refrigerator must operate with engine off
Approx. installed cost
$400–$900, depending on quality and auxiliary battery
The important point is not the refrigerator's running wattage—it is the compressor starting surge. A refrigerator that consumes only 100–250 W while running can momentarily require considerably more power when its compressor starts. Eaton specifically recommends accounting for refrigerator startup surge when sizing an inverter.
I would therefore not build the system around a 500–1,000 W bargain inverter, even though some refrigerators will work with one.
Why 1,500–2,000 W?
A typical refrigerator might look approximately like this:
A 1,000 W inverter can work—there are 1,000 W units specifically marketed for refrigerators—but there is much less margin for an older refrigerator or simultaneous loads.
I particularly recommend pure sine wave, rather than modified sine wave. Modern refrigerator compressors and electronic chargers are much better suited to clean sine-wave power.
The bigger issue is the car's 12V electrical system
This is where the project becomes interesting.
At 1,000 W, a 12V inverter can draw roughly:
1,000 ÷ 12 ÷ 0.9 ≈ 93 amps
At 1,500 W:
≈ 139 amps
At 2,000 W:
≈ 185 amps
Those are substantial currents.
So I would not connect a 1,500–2,000 W inverter to the vehicle's 12V accessory outlet. The inverter should have its own appropriately sized cables and fuse connected directly to the battery. Eaton likewise recommends a direct battery connection rather than relying on a cigarette-lighter connection for higher-power applications.
The alternator is effectively your generator
With the engine running, the alternator supplies most of the energy while the battery acts as the electrical buffer.
That's why this arrangement works particularly well while driving.
For example, suppose the refrigerator averages 150 W and chargers consume another 150 W.
That's only about 300 W AC.
Allowing for inverter losses, the vehicle might be supplying roughly:
330–350 W DC
At 13.5 V that's approximately:
25 amps
That's quite manageable for many conventional vehicles.
The situation changes if you actually try to continuously draw 1,500–2,000 W. Then you're asking the vehicle electrical system for roughly 110–150+ amps continuously. That's a completely different proposition. An inverter should therefore be sized for starting/surge capacity, not because you intend to continuously consume 2,000 W.
I would actually build it this way
Option A — simplest and cheapest
Existing automobile battery + alternator
ENGINE
│
ALTERNATOR
│
▼
┌─────────────┐
│ 12V BATTERY │
└──────┬──────┘
│
heavy DC cable
│
fuse/breaker
│
▼
┌─────────────────┐
│ 1,500–2,000 W │
│ PURE SINE INVERTER│
└────────┬────────┘
│
120 VAC
┌─────┴──────┐
▼ ▼
Refrigerator Battery
Chargers
Approximate cost:
Option B — better system: auxiliary battery
If the purpose is emergency power, rather than merely powering things while driving, I'd add a second battery.
Something like:
Starting battery → isolator/DC-DC charger → auxiliary lithium battery → inverter
The refrigerator can then continue operating after the engine is turned off without risking the vehicle's starting battery.
A 100-Ah LiFePO₄ auxiliary battery contains approximately:
1.28 kWh nominal energy
Realistically, after inverter losses, you might have roughly 1.0–1.1 kWh of usable AC energy.
A refrigerator averaging 100 W could theoretically operate for around:
10 hours
although actual refrigerator consumption varies considerably with ambient temperature, door openings, compressor efficiency, etc.
This approach is considerably more useful for emergency preparedness.
An even better concept for a vehicle emergency system
If this is intended as a portable emergency-power system, I would consider putting the inverter and auxiliary battery into a small enclosure rather than permanently mounting everything into the automobile.
For example:
Vehicle alternator → DC-DC charger → 100–200 Ah LiFePO₄ battery → 2,000 W pure sine inverter
Then you have a portable power source that can:
One important distinction
There are really two different applications:
1. "I want 120V power while I'm driving."
Excellent application.
A 1,500–2,000 W inverter connected to the vehicle battery is quite practical.
You could run:
So I put it to Chatgpt.
Advise on adding a 110v inverter to a typical automobile sufficient to power a refrigerator and battery chargers. Cost and practical applicability.
Yes. Adding a 120V (nominally 110V) inverter to an ordinary automobile is quite practical for running a refrigerator and battery chargers, but I would design it somewhat differently from the typical inexpensive “plug into the cigarette lighter” inverter.
My recommended configuration
For what you describe, I would use:
Component
RecommendationInverter
1,500–2,000 W pure sine wave
Surge capability
3,000–4,000 W preferred
Input
12 V DC
Connection
Directly to battery with heavy cables, not cigarette lighter
Refrigerator
Normal household refrigerator
Battery chargers
Phones, laptops, power-tool batteries, etc.
Engine
Running while substantial loads are connected
Auxiliary battery
Optional, but worthwhile if refrigerator must operate with engine off
Approx. installed cost
$400–$900, depending on quality and auxiliary battery
The important point is not the refrigerator's running wattage—it is the compressor starting surge. A refrigerator that consumes only 100–250 W while running can momentarily require considerably more power when its compressor starts. Eaton specifically recommends accounting for refrigerator startup surge when sizing an inverter.
I would therefore not build the system around a 500–1,000 W bargain inverter, even though some refrigerators will work with one.
Why 1,500–2,000 W?
A typical refrigerator might look approximately like this:
- Running: 100–250 W
- Compressor startup: potentially 500–1,500+ W
- Battery chargers: 50–300 W combined
- Miscellaneous electronics: 50–100 W
A 1,000 W inverter can work—there are 1,000 W units specifically marketed for refrigerators—but there is much less margin for an older refrigerator or simultaneous loads.
I particularly recommend pure sine wave, rather than modified sine wave. Modern refrigerator compressors and electronic chargers are much better suited to clean sine-wave power.
The bigger issue is the car's 12V electrical system
This is where the project becomes interesting.
At 1,000 W, a 12V inverter can draw roughly:
1,000 ÷ 12 ÷ 0.9 ≈ 93 amps
At 1,500 W:
≈ 139 amps
At 2,000 W:
≈ 185 amps
Those are substantial currents.
So I would not connect a 1,500–2,000 W inverter to the vehicle's 12V accessory outlet. The inverter should have its own appropriately sized cables and fuse connected directly to the battery. Eaton likewise recommends a direct battery connection rather than relying on a cigarette-lighter connection for higher-power applications.
The alternator is effectively your generator
With the engine running, the alternator supplies most of the energy while the battery acts as the electrical buffer.
That's why this arrangement works particularly well while driving.
For example, suppose the refrigerator averages 150 W and chargers consume another 150 W.
That's only about 300 W AC.
Allowing for inverter losses, the vehicle might be supplying roughly:
330–350 W DC
At 13.5 V that's approximately:
25 amps
That's quite manageable for many conventional vehicles.
The situation changes if you actually try to continuously draw 1,500–2,000 W. Then you're asking the vehicle electrical system for roughly 110–150+ amps continuously. That's a completely different proposition. An inverter should therefore be sized for starting/surge capacity, not because you intend to continuously consume 2,000 W.
I would actually build it this way
Option A — simplest and cheapest
Existing automobile battery + alternator
ENGINE
│
ALTERNATOR
│
▼
┌─────────────┐
│ 12V BATTERY │
└──────┬──────┘
│
heavy DC cable
│
fuse/breaker
│
▼
┌─────────────────┐
│ 1,500–2,000 W │
│ PURE SINE INVERTER│
└────────┬────────┘
│
120 VAC
┌─────┴──────┐
▼ ▼
Refrigerator Battery
Chargers
Approximate cost:
- Quality 1,500–2,000 W pure sine inverter: $250–$500
- Heavy cable/fuse/disconnect: $75–$150
- Installation: $100–$250
- Total: approximately $425–$900
Option B — better system: auxiliary battery
If the purpose is emergency power, rather than merely powering things while driving, I'd add a second battery.
Something like:
Starting battery → isolator/DC-DC charger → auxiliary lithium battery → inverter
The refrigerator can then continue operating after the engine is turned off without risking the vehicle's starting battery.
A 100-Ah LiFePO₄ auxiliary battery contains approximately:
1.28 kWh nominal energy
Realistically, after inverter losses, you might have roughly 1.0–1.1 kWh of usable AC energy.
A refrigerator averaging 100 W could theoretically operate for around:
10 hours
although actual refrigerator consumption varies considerably with ambient temperature, door openings, compressor efficiency, etc.
This approach is considerably more useful for emergency preparedness.
An even better concept for a vehicle emergency system
If this is intended as a portable emergency-power system, I would consider putting the inverter and auxiliary battery into a small enclosure rather than permanently mounting everything into the automobile.
For example:
Vehicle alternator → DC-DC charger → 100–200 Ah LiFePO₄ battery → 2,000 W pure sine inverter
Then you have a portable power source that can:
- run a refrigerator
- charge cordless tools
- charge phones
- charge laptops
- power lights
- run small pumps
- power medical/electronic equipment
- recharge from the automobile while driving
One important distinction
There are really two different applications:
1. "I want 120V power while I'm driving."
Excellent application.
A 1,500–2,000 W inverter connected to the vehicle battery is quite practical.
You could run:
- refrigerator
- chargers
- computers
- TVs
- small electronics
- modest power tools
