watt usage battery recharger

you need to factor in the efficiency .

480 Watts sounds a bit high to charge a battery. You need to multiply the battery current by the BATTERY voltage. Correct wattage is probably around 24 watts or a bit higher, depending on the battery voltage.

Friday

If I understand you correctly, you want to convert 12v to 240v, then use a 240v charger to charge a battery pack (not the battery pack that you're converting to 240v)? Is this correct? And you want to know how many watts the 12v to 240v invertor has to be able to output to do this task? And your battery is rated at 2Ah?

First of all, you need to know the charging rate. Does your charger have a sticker or manufacturers plate on it? That may tell you what the charging rate is. Otherwise, how long does it take to charge a completely flat battery? That would also tell you how much power it's putting into the battery, and therefore how much power it needs at 240v.

Let's say, for example, that your dewalt battery is 12v, and that the charger is putting 1A into it (ie, it takes 2 to 2.5 hours to charge the battery). That means (in round figures) that the charger is supplying

12 watts (12v times 1A) to the battery. The charger will be inefficient, lets pick a figure of 75% or so, so call it 15 watts. Round that up to 20w because it's always best to over-estimate.

If what you're trying to do is "size" your 12v to 240v invertor, then basically anything you can buy will be suitable, since I think they start at 60w or so.

Peter

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