Charts

12V 100Ah battery runtime chart

This chart estimates AC runtime for a 12V 100Ah battery at common load levels. It cannot confirm that a battery or inverter can supply the requested power.

Quick answer

Planning estimate

At a continuous AC load

Compare the 100W row, then use the calculator for your load.

Reference load 100 W

LiFePO4
9.23 h
AGM
4.59 h

Continuous load and duty cycle

Refrigerators and compressors cycle; nameplate watts are not continuous. Use measured average watts or 24-hour Wh.

Estimated AC runtime for one 12V 100Ah battery by continuous load. Planning estimate.
Load (W) LiFePO4 preset (h)AGM preset (h)
10 92.3445.9
20 46.1722.95
30 30.7815.3
50 18.479.18
75 12.316.12
100 9.234.59
150 6.163.06
200 4.622.3
300 3.081.53
400 2.311.15
500 1.850.92
600 1.540.77
800 1.150.57
1,000 0.920.46
1,500 0.620.31
2,000 0.460.23
Load (W): 10
LiFePO4 preset (h)
92.34
AGM preset (h)
45.9
Load (W): 20
LiFePO4 preset (h)
46.17
AGM preset (h)
22.95
Load (W): 30
LiFePO4 preset (h)
30.78
AGM preset (h)
15.3
Load (W): 50
LiFePO4 preset (h)
18.47
AGM preset (h)
9.18
Load (W): 75
LiFePO4 preset (h)
12.31
AGM preset (h)
6.12
Load (W): 100
LiFePO4 preset (h)
9.23
AGM preset (h)
4.59
Load (W): 150
LiFePO4 preset (h)
6.16
AGM preset (h)
3.06
Load (W): 200
LiFePO4 preset (h)
4.62
AGM preset (h)
2.3
Load (W): 300
LiFePO4 preset (h)
3.08
AGM preset (h)
1.53
Load (W): 400
LiFePO4 preset (h)
2.31
AGM preset (h)
1.15
Load (W): 500
LiFePO4 preset (h)
1.85
AGM preset (h)
0.92
Load (W): 600
LiFePO4 preset (h)
1.54
AGM preset (h)
0.77
Load (W): 800
LiFePO4 preset (h)
1.15
AGM preset (h)
0.57
Load (W): 1,000
LiFePO4 preset (h)
0.92
AGM preset (h)
0.46
Load (W): 1,500
LiFePO4 preset (h)
0.62
AGM preset (h)
0.31
Load (W): 2,000
LiFePO4 preset (h)
0.46
AGM preset (h)
0.23
Sources: SolarMathKit calculation methodology NIST SI units and electrical relationships Reviewed Jul 25, 2026

Assumptions

LiFePO4 uses 90% depth of discharge and 95% battery efficiency. AGM uses 50% depth of discharge and 85% battery efficiency. Both use 90% inverter efficiency and 0W idle draw.

How runtime is estimated

The shared runtime model converts 12V × 100Ah to 1,200Wh, applies the selected usable-capacity and loss factors, then divides by the AC load.

Related calculator

Battery runtime calculator for Ah, Wh and watts

Continue with the 100Ah refrigerator guide

Read the 100Ah refrigerator guide

Related reference charts

Questions people ask

How long will a 100Ah battery run a 100W load?

With this chart's assumptions, about 9.23 hours for LiFePO4 or 4.59 hours for AGM. Inverter idle draw would reduce both.

Why can actual runtime be shorter?

Temperature, battery age, discharge rate, inverter idle draw, wiring losses, and equipment cutoff settings can all reduce runtime.