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I have a couple of deep cycle lead acid 12V batteries (Kirkland Brand), 125 amp-hours each.

I want to run a 120 volt dryer-blower off a 2000 watt inverter for 20 minutes.

I calculate 2000 watts/120 volts = 16.6 amps on AC side,
16.6 amps X 120/12 volts = 166 amps on the DC side.
166 amps X 20 minutes = 55 amp-hours.
Add efficiency losses and we are still under 75 amp-hours.
So, the capacity is there, even with just one battery (and I have 2).

Question: If I am drawing that much power from the battery, are there any problems or concerns? Overheating? Safety?

I realize that this will shorten the battery life somewhat, but I only expect to do this a few times each year.

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  • \$\begingroup\$ 125 Ah = 1.5kWh / battery ( if new and fully charged) What is the Vmin cut-out for the inverter? Does dryer consume less than 2kW or more on startup? and will it support that ? Otherwise 20 minutes should be OK for 2 batteries . Normally Ah rating for these are 20h ratings not 1 hr or less where capacity drops ~ 50% and if aged moreso. So lets assume 2 batteries of 3kWh on 2kW load wont get you 40 minutes but 20 minutes is close. In theory with perfect batteries and no inverter loss you expect 1.5h, But your results may be less. so test them \$\endgroup\$
    – D.A.S.
    Commented Jul 1, 2018 at 3:23
  • \$\begingroup\$ If you dont have a manual read this batterystuff.com/files/781-lifeline_tech_manual.pdf \$\endgroup\$
    – D.A.S.
    Commented Jul 1, 2018 at 3:28
  • \$\begingroup\$ At 166 amp discharge from a 125 Ah battery you have a 132 C discharge rate (166/125). That may work with an advance lead carbon battery, not likely with a single Kirkland AGM. If you use both batteries, you should be okay. Monitor the temperature of the batteries during discharge. Higher temperature will negatively affect performance. \$\endgroup\$
    – Misunderstood
    Commented Jul 1, 2018 at 7:01
  • \$\begingroup\$ what sort of appliance is a dryer-blower, do you mean the motor in a gas burning clothes dryer? \$\endgroup\$
    – Jasen Слава Україні
    Commented Jul 1, 2018 at 8:54

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Based on above comments if Costco does not have detailed specs for the Kirkland battery, then you need to test the batteries.

80A per battery may cause H2 outgassing so use in a ventilated area.
1kW = 80A * 12.5V

Although it may work. Your test results are the best bet. No obvious faults except a worn out cell.

Ensure you have the proper charge profile as AGM types need temperature compensated voltages.

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