How long it will last; 24V, 100Ah Lead Acid Battery powering 350W load at 220V AC through an inverter.?

Question

Assume any reasonable efficency for the battery and inverter.

How about if I make it 12V and 200Ah?

Please take some time to explain. Thanks in advance

Answer 1

As YOHO but the inverter is probably only 90% efficient so 90% of 6.1hrs plus battery loss etc.

Doesn't really  matter about the voltage / current ratio just the total contained energy

12 * 200 * 3600 =8.64 MJ

350 * 3600 = 1.2MJ / Hr

Time = MJ * Hr/MJ = 8.64/1.2 =7.2

Answer 2

Lets call he inverter 90% efficient

that's

350 watts /0.90 =about 390 watts (counted the waste)

390 watts will last

12v*200ah=2400watts  a hour

2400watts/390(used watts)=6.1 hours

24volt at 100ah would math mathematically last the same.

24 volt system would be a little more efficient and would require smaller gauge wire. At 30 amps for the 12 volt system this would require a 7 gauge wire. 24 volt sytem would only need a 10gauge.(both could be smaller if they are short runs)

That is at it's best. It i bet on 5 hours because you couldn't run the battery bone dry the inverter would power it self off before that but that is only a guess.

Answer 3

Other posts are correct, using theoretical considerations.

Looking at real life performance, let's assume you are using a deep discharge gel type battery, so it will last more than 5 or ten cycles. Assume 25C, shorter run time if colder (see link to estimate).

Current needed:

Battery Power = 350W/90% inverter efficiency = 390W.

Current = Power/Voltage

I = 390W/24V = 16.2A

ratio = load/capacity = 0.162C

From http://www.enersysreservepower.com/docum...

This is initially good for about 4.8 hrs. You should not use last 20%, as it reduces the battery life disproportionately.

So, say just under 4 hours at first, gradually decreasing as battery condition degrades with charge/discharge cycles.

12V/200A*hr would be the same, as battery has same energy.

This is only a little less than the theoretical results, because the relatively low drain you are using means the battery doesn't lose too much capacity. For heavier currents, much shorter life than predicted by theory.