How hungry is my inverter

[DanMax&Belle]

Hi All,

I am just doing the sums on my electricity usage and requirements in order to choose the correct fridge, i want to make sure i am doing the correct maths on this.

I have a Victron Quatro 12/3000/120 and am trying to work out what the "no-load consumption" (correct terminology? I mean when it its turned on, ready to power equipment but not powering anything) is.

http://www.victronenergy.com/upload/documents/Datasheet-Quattro-3kVA-10kVA-EN.pdf

From the link above I understand it might be 4 watts (search mode?) or 15 watts AES power (I cant work out what AES is and therefore don't know if it) or 15 watts.

Can anyone help please?

Thanks

 

[Robbo]

I would go by the Zero load only watts which is 15watts as when calculating it's always better to be conservative and go for the worst one. AES is at 10watts.

 

Also with the Fridge on the system may not go into a zero load mode.

 

15watts is 30ah's per day

5 watts is 10ah's per day.

Edited September 15, 2014 by Robbo

[Chalky]

I have a Victron Quatro 12/3000/120 and am trying to work out what the "no-load consumption" (correct terminology? I mean when it its turned on, ready to power equipment but not powering anything) is.

 

It's called the quiescent current. Most of the time it's fairly low - on our Sterling its about 400ma. When its first turned on with no load attached its in the order of 10A for a second or so as it charges up a set of large capacitors.The consumption is caused by things like the power required to run the microprocessor and the power supplies for the gate drives (the power transistors in the inverter will often need their own specific voltages to turn on and off quickly).

[bottle]

AES =Automatic Energy Saving.

 

Basically it goes into standby.

 

Now what ever is switched on has to be large enough to get it out of standby or that item will be running on a low voltage.

 

How do I know this I had an item that did not take it out of standby and that item appeared faulty, almost threw it out but lucky enough another load was applied and the item started working properly.

 

Money saved and the AES turned off.

[RLWP]

I take it you are planning to run a 240V fridge through the inverter?

 

Richard

[PhilR]

I take it you are planning to run a 240V fridge through the inverter?

 

Richard

 

It might also be help people to advise the OP on the choice of fridge if he gives some approximation of the % time the boat will be connected to a shoreline. Or whether he will be relying 100% on the engine/batteries/inverter.

[RLWP]

 

It might also be help people to advise the OP on the choice of fridge if he gives some approximation of the % time the boat will be connected to a shoreline. Or whether he will be relying 100% on the engine/batteries/inverter.

 

That, and the efficiency of converting 12V to 240V for a fridge is where I am going

 

Richard

[Chalky]

We have a Sterling 800W pseudo sine inverter running an indesit larger fridge. Draws about 4 to 7A when running (depends on cabin temp, how full the fridge is etc). We tend to cruise most days on holiday. When moored up for a day or two I tend to run the engine for about 1 to 2 hours to top up the batteries. The fridge is turned off at about 10:00pm and back on at about 8:00am. When the engine is running the thermostat on the fridge is turned to max, min when its not. Never had a load balance problem with the batterys. Always try to keep the fridge full to increase the thermal mass.

[Nickhlx]

For this sort of test, this is exactly what a clamp meter would tell you in minutes ( seconds), and also check the device is taking its 15 watts quiescent and not actually 30 watts or whatever.

 

Recommended for all boaters !!

 

Nick

[Detling]

Also with the Fridge on the system may not go into a zero load mode.

 

15watts is 30ah's per day

5 watts is 10ah's per day.

I have the same inverter and the 30Ah is perhaps a bit high, I seem to use 24 Ah per day. My fridge will not work with AES enabled LG fridge can't remember the number.

[DanMax&Belle]

I would go by the Zero load only watts which is 15watts as when calculating it's always better to be conservative and go for the worst one. AES is at 10watts.

 

Also with the Fridge on the system may not go into a zero load mode.

 

15watts is 30ah's per day

5 watts is 10ah's per day.

Thanks Robbo,

 

So you're saying for the purpose of calculating then go with 15 watts as the quiescent (nod in chalky's direction), with an understanding it is very likely to read less if i was to measure it over a 24 hour period (again Chalky) - is there any equipment that will measure this?

 

Im a little in the dark as to why a fridge, when not working the compressor, would have any power requirement, is this one of those manufacturer or model specific things? is there some way of identifying this from the product specs?

 

Finally is there a table or equation that correlates wattage into ah's per day?

 

cheers

I take it you are planning to run a 240V fridge through the inverter?

 

Richard

Yes I am planning/comparing, I'm certainly interested in the percentage loss here to chuck into the mix.

For this sort of test, this is exactly what a clamp meter would tell you in minutes ( seconds), and also check the device is taking its 15 watts quiescent and not actually 30 watts or whatever.

 

Recommended for all boaters !!

 

Nick

Sorry Nick, just seen your point. A clamp meter is what i need?

 

http://www.ebay.co.uk/itm/like/281353241333?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

 

..... like this?

[ditchcrawler]

Thanks Robbo,

 

So you're saying for the purpose of calculating then go with 15 watts as the quiescent (nod in chalky's direction), with an understanding it is very likely to read less if i was to measure it over a 24 hour period (again Chalky) - is there any equipment that will measure this?

 

Im a little in the dark as to why a fridge, when not working the compressor, would have any power requirement, is this one of those manufacturer or model specific things? is there some way of identifying this from the product specs?

 

Finally is there a table or equation that correlates wattage into ah's per day?

 

cheers

Yes I am planning/comparing, I'm certainly interested in the percentage loss here to chuck into the mix.

Sorry Nick, just seen your point. A clamp meter is what i need?

 

http://www.ebay.co.uk/itm/like/281353241333?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

 

..... like this?

I don't think that will measure DC amps even though part of the description says it does.

[bottle]

This is the one usually recommended on the forum, can be got cheaper on E-bay apparently

 

http://www.maplin.co.uk/p/uni-trend-203-dcac-current-clamp-multimeter-n41nc

[smileypete]

There's links to a few clamp meters in this post:

 

http://www.canalworld.net/forums/index.php?showtopic=69198&p=1378873

 

cheers, Pete.

~smpt~

Edited September 16, 2014 by smileypete

[Paul C]

ll

For this sort of test, this is exactly what a clamp meter would tell you in minutes ( seconds), and also check the device is taking its 15 watts quiescent and not actually 30 watts or whatever.

 

Recommended for all boaters !!

 

Nick

I was going to post earlier, but forgot, but Nickhlx has basically said what I was going to. Don't rely on the user manual or specifications looked up on th e internet, actually measure the items to do an accurate power audit. So, the recommendation of a clamp ammeter is a good one. And of course, you can measure everything else too. Admittedly, with a fridge (because its not continuously running) you'll also need to find out how often it cycles on-off, and of course this also varies with ambient temperature, fridge temperature how often you open the door, how much stuff is in it etc.

 

The other device which is hard to properly estimate from specs is laptops, they are best measured too. Other items like lights, pump are easier to "guesstimate" reasonably well.

PS Sorry, the quote became muddled, I was quoting post #9.

[DanMax&Belle]

I have the same inverter and the 30Ah is perhaps a bit high, I seem to use 24 Ah per day. My fridge will not work with AES enabled LG fridge can't remember the number.

Good to know Detling, presume you can change this (turn off AES) on the laptop interface? If you were purchasing your fridge from afresh with this knowledge would you choose a different fridge or are you happy keeping AES off (i.e what do I lose with it permanently switched off?)?

 

thanks

[DanMax&Belle]

 

It might also be help people to advise the OP on the choice of fridge if he gives some approximation of the % time the boat will be connected to a shoreline. Or whether he will be relying 100% on the engine/batteries/inverter.

Hi PhilR,

 

Yes 100% engine/batteries/inverter no shoreline. 760 Watts of Solar, 917ah of traction batteries, 175A alternator, this gennie https://www.machinemart.co.uk/shop/product/details/clarke-ig2200-2-2kw-inverter-generator%C2'> goes through the charging function in the Quattro).

 

Thanks

[by'eck]

Good to know Detling, presume you can change this (turn off AES) on the laptop interface? If you were purchasing your fridge from afresh with this knowledge would you choose a different fridge or are you happy keeping AES off (i.e what do I lose with it permanently switched off?)?

 

thanks

 

There are three modes of operation for the inverter.

 

Normal: inverter draws 15 watts with no AC load

 

AES: power consumption with no or light loads is reduced by 20% by "narrowing" the sinusoidal voltage - this equates to inverter draw of 10 watts with no AC load - software configurable

 

Search: inverter switched off until configurable turn on power is exceeded, and staying on until AC draw drops below the lower shut down power - 4 watts draw with no AC load (inverter off) - software configurable.

 

Its this latter mode that would seem the most useful in power saving although you may need to tweak the turn on and shut down powers to take account of permanently connected very low current draw devices such as microwave displays etc. which may otherwise toggle to inverter on/off continuously.

[Jambo]

If you're looking for high efficiency 230V fridges then http://www.sust-it.net is your best starting point.