# Help understanding solar battery use

1. ## Help understanding solar battery use

Hi,

Battery: 12V DC, 125Ah. It says 'deep discharge' on the sticker.
DC to ~230V AC inverter: It says 1200W/2500W on the sticker. I assume 1200W is for 230V AC and 2500W for 120V AC.

Can someone please tell me battery duration with the examples below of what can be powered at 230V AC and for how many hours when the battery is fully charged?

e.g.
A laptop that uses 1.6A at 230V AC
A 600W, 230V AC vacuum cleaner
A 30W, 230V AC soldering iron: how many hours can each be powered, theoretically?

I don't trust my own guesstimates much as they must be wrong and would appreciate input from someone who knows the formulas.

Many thanks.

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2. ## Re: Help understanding solar battery use

Hi,

I won't do simple + - × ÷ math for you....

Energy = power x time.

I assume you are able to calculate the energy stored in the battery by your own.
Now divide it by the load power to get the time.
Multiply the time with the expected power conversion efficiency.

A laptop that uses 1.6A at 230V AC
is no useful value, because power factor is missing.

Use the "actally drawn power" instead of the "rated power".

Example: My 50W soldering iron will draw about 25W when "active" ... and even less when it's in sleep mode (when placed in the holder).

Klaus

1 members found this post helpful.

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3. ## Re: Help understanding solar battery use

Hi Klaus,

Thank you, that helps a lot.

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4. ## Re: Help understanding solar battery use

A laptop drawing 1.6A at 230V AC..... That is approximately 370W !

You must have a very big lap d123, or at least a very hot one!

Brian.

5. ## Re: Help understanding solar battery use

Hi Brian,
The sticker says that and then 19.5 V DC, 3.3A; the laptop is about 18 years old... Here's a fair comparison:

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