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**Dockhead** · 13-02-2013, 07:35

It occurred to me that I have no idea how much AC power my battery charger uses. This datum is nowhere in the literature. Does anyone know what the typical efficiency is?

My charger will put out 70 amps at nominal 24 volts, so in reality the maximum output must be 70 amps * 29.4 volts = 2058 watts. I wonder how much AC power it takes to produce this?? It's not a trivial question, actually, for one who sometimes has to use 4 amps (!) French shore power connections. If it's 80%, then it's about 2.6kW or more than 11 amps at 230 volts.

goboatingnow · 13-02-2013, 07:53

somewhere between 80 to 95% efficiency in reality, the rating plate is supposed to state the actual mains consumption , so that can sometimes be used, not often its off.

Dave

Bash · 13-02-2013, 07:56

Peak efficiency on a Xantrex Freedom inverter/charger is 82%

http://www.xantrex.com/documents/Inv...F1000-1800.pdf

btrayfors · 13-02-2013, 07:58

It would really help others to respond to your queries if, when asking these types of questions, you'd include the make and model number of the equipment you're talking about. "My battery charger" just doesn't cut it.

Not all chargers are created equal. Some use Power Factor correction, which impacts on the AC draw.

All electrical equipment sold in this country, and most other parts of the world, has this type of info on a plate somewhere, or in the instruction manual.

Bill

**Dockhead** · 13-02-2013, 08:17

Quote:

Originally Posted by btrayfors

It would really help others to respond to your queries if, when asking these types of questions, you'd include the make and model number of the equipment you're talking about. "My battery charger" just doesn't cut it.

Not all chargers are created equal. Some use Power Factor correction, which impacts on the AC draw.

All electrical equipment sold in this country, and most other parts of the world, has this type of info on a plate somewhere, or in the instruction manual.

Bill

It's a Victron Multiplus 3000/70/24 charger-inverter, 230 volts, 3000 volt-amps (actually 2.5kW continuous) inverter, 70 amp charger at 24 volts nominal.

Incredibly, the AC power consumption appears no where in the manual or data sheet. Perhaps it's on a plate somewhere, but the unit is now buried in my engine compartment . . .

**Dockhead** · 13-02-2013, 08:26

As to AC input, all it says is this:

AC Input Input voltage range: 187-265 VAC Input frequency: 45 – 55 Hz

Power factor: 1

Dsanduril · 13-02-2013, 08:43

From some sales fluff, so no idea as to accuracy:

Technical Specifications:

Model Multiplus 3000VA
Continuous Output Power 3000VA
Max Output Power 6000W
AC Output Voltage 230VAC/240VAC Regulation ±3%
Frequency 50Hz±0.1%
Efficiency >94%
Output Wave Form Pure Sine Wave
Temperature Protection YES
Input Low Voltage Protection YES
Input Reverse Polarity YES
Circuit protection YES
Output Short Circuit Protection YES
Overload Protection YES
With 70A battery charger, AC input and
UPS function.

DeepFrz · 13-02-2013, 08:45

Look under the "Technical Specifications" section of your manual, in first section, it should give you the efficiency %. If not there check the manual online.

Dsanduril · 13-02-2013, 08:52

Quote:

Originally Posted by DeepFrz

Look under the "Technical Specifications" section of your manual, in first section, it should give you the efficiency %. If not there check the manual online.

It should be, but I'm with Dockhead on this one. Not in the user manual, not in the installation manual, not in the datasheet, not in the whitepaper on testing (interesting whitepaper on generators though, and specific fuel consumption of various brands/models). Not even in the CE certificate of conformity and there are CE requirements for efficiency and power factor.

The tech specs are as Dockhead posted, AC voltage, frequency, and power factor are specified, as are DC output values. But no specification for either AC input current (from which we might be able to calculate efficiency) or efficiency.

Since the company still exists, think you may have to hit them up with an e-mail. Otherwise, would assume worst case is low 80's.

hellosailor · 13-02-2013, 09:42

Dockhead, if you really want to know, buy a "Kill A Watt" which is a $25-30 gizmo that plugs in between any AC device and the wall socket. It is a cumulative wattmeter, recording how much power is sucked through it. Voltage, amperage, can also display cumulative costs if you tell it what you're paying for electricity.

That way you can just run the charger for 24 hours, read what it took, and get an actual number for it. Or anything else that works on AC power.

btrayfors · 13-02-2013, 10:29

Yes, it IS confusing with the Victron MultiPlus. They don't publish a single AC amp consumption figure, perhaps because you can easily set the maximum amperage draw you'd like.

This is actually a very nice feature, especially for use with smaller generators. With the remote control, you can dynamically dial in the maximum amperage draw. You can also use the internal dip switches to set the draw anywhere from 6A to 16A (for the model with the internal 16A transfer switch), or to 50A (for the model with the internal 50A transfer switch).

Easiest way to know exactly the maximum amperage draw is to use a clamp-on AC/DC ammeter. You can then turn off all DC loads except the charger, have the batteries at a suitable low SOC, and turn on the Victron. Be sure you know whether or not it's set for maximum current delivery....the default is 75% only (about 53A with the 70A 24VDC charger). Then, when you see something approaching a charge rate of 70A, measure the AC input current.

If you don't really need to know this with precision, just use the current limiting feature and the maximum percentage charge feature to limit the current input to something you can live with :-)

Bill

motion30 · 13-02-2013, 11:01

I know my 55AMP Iota chargers draw 13amps

DeepFrz · 13-02-2013, 11:04

http://www.victronenergy.com/upload/...%20EN%20NL.pdf

Maximum efficiency for your unit I believe is 94%. I think that was the question, but maybe I am wrong.

**Dockhead** · 13-02-2013, 11:16

Quote:

Originally Posted by DeepFrz

http://www.victronenergy.com/upload/...%20EN%20NL.pdf

Maximum efficiency for your unit I believe is 94%. I think that was the question, but maybe I am wrong.

That's the inverter! The charger is a whole different ball of wax!

**Dockhead** · 13-02-2013, 11:18

Quote:

Originally Posted by btrayfors

Yes, it IS confusing with the Victron MultiPlus. They don't publish a single AC amp consumption figure, perhaps because you can easily set the maximum amperage draw you'd like.

This is actually a very nice feature, especially for use with smaller generators. With the remote control, you can dynamically dial in the maximum amperage draw. You can also use the internal dip switches to set the draw anywhere from 6A to 16A (for the model with the internal 16A transfer switch), or to 50A (for the model with the internal 50A transfer switch).

Easiest way to know exactly the maximum amperage draw is to use a clamp-on AC/DC ammeter. You can then turn off all DC loads except the charger, have the batteries at a suitable low SOC, and turn on the Victron. Be sure you know whether or not it's set for maximum current delivery....the default is 75% only (about 53A with the 70A 24VDC charger). Then, when you see something approaching a charge rate of 70A, measure the AC input current.

If you don't really need to know this with precision, just use the current limiting feature and the maximum percentage charge feature to limit the current input to something you can live with :-)

Bill

Well, of course, that is what I do. The current limiting feature is great. But I am still curious. I'll take my clamp meter and do as you suggest