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Inverter power rating?

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james_s:
I don't think you need to worry about the instantaneous draw, battery charger is going to be a fairly well behaved load. I would be surprised if the draw is more than 300W but you could get a 400 or 500W inverter to make sure you have plenty of overhead in case you need to power other things.

soldar:

--- Quote from: iXod on March 24, 2019, 08:30:02 pm --- I need to run a lithium battery charger for power tool from an inverter in my vehicle.

The charger is rated at 120VAC, 2.75A max current. I don't know the PF or efficiency of the charger, but I think these are usually around .8-.85 efficient. It is an SMPS type charger. 
--- End quote ---

Several thoughts:

The charger may be nominally rated for 2.75 A but it may use much less in normal use or a bit more at startup. The only way to know for sure is to measure it. That will give you much better information than relying on the label.

I doubt a small battery for a hand tool would recharge at such rate.  If indeed it uses so much power be careful you do not discharge the car's battery to the point where it cannot start.

Rather than convert 12Vdc to 120Vac you would be much better off getting a charger than ran directly off 12 Vdc. Efficiency and reliability will be much better.

I would not plug something so powerful into the car's lighter because it will probably blow the fuse. I would connect directly to the battery terminals.

iXod:
Thanks for your great reply.

Manufacturer of these tools doesn’t make a rapid charger (which I need) with 12vdc input, unfortunately.

I’ll have to see, empirically—with my planned discharge/charge pattern for the tool batteries—if I need to be concerned about the car’s battery. I have a lithium “jump starter” pack in case car battery goes low.

Inverter will be connected to battery, not lighter socket.

Cheers.

soldar:
If this is for professional work, where you are going to be doing this day in and day out, I would consider getting more batteries so you do not need to recharge as often or as fast. Fast charging kills batteries fast. Slow charging extends their life. If you have several packs you can recharge them overnight and if you have a totally dead one you can give it a slow charge from the car. This is cheaper, simpler and healthier for the batteries.

What is the voltage of these batteries?

iXod:
Mobile car detailing using battery powered 18v buffer.

Appreciate your advice to fully charge batteries overnight. But to cover that plan I'd need several more batteries and 4-6 chargers to charge overnight (or setting the alarm every 90 minutes to get up and swap batteries).

Taking to heart the information about quick=short life; slow=long life. My initial plan does primarily revolve around needing the in-car rapid charger only if I find business especially good one day and run out of pre-charged batteries.

Cheers.

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