Jump to content

Victron 3KVA Inverter power use


Featured Posts

I'm in the process of doing a power audit, we will soon be taking delivery of our narrowboat to live on. Hopefully someone can answer a question regarding the power use of a Victron 3KVA inverter, I think it is likely to be the Phoenix model (not purchased yet). It will be the 12volt version.

 

We will have a number of 230v appliances, e.g. TV, Music system and wireless router as well as laptop and camera battery chargers. The router will be on 24/7 as I sync data to the cloud overnight (reception permitting). So the inverter will be on 24/7 too. According to the Victron spec sheet it uses 20 watts on zero load.

 

My first question is will it use that 24/7? I'm thinking not as when there is a load it will be working, but need some clarity. 

 

When it is working it states a max efficiency of 93% - so it is therefore using 7% to do the inverting, which I understand as it is doing work. 

 

Does the 7% additional draw need to be included in the audit for each 230v appliance? i.e. uplifting the amps by 7%? I suspect so but again advice welcomed.  I know it is slightly higher than 7% but it is near enough for jazz, especially as I am using worst case scenarios.

 

If I were to use the 20 watts for 24 hours a day that may cover any uplift so it could be a moot point, if my maths are right that means the Victron will draw 40Amp/Hrs a day, which is a lot I think.

 

TIA

Paul.

Link to comment
Share on other sites

If you set the Victron  into powersave mode its about 2-3watts when there is no load.

In powersave mode items such as routers and chargers do not give enough load to make it switch on.

The router can run off 12v, My Huawei 535 does.

Charging can often be run from  USB, so fit USB sockets 

 

  • Greenie 1
Link to comment
Share on other sites

30 minutes ago, PCSB said:

I'm in the process of doing a power audit, we will soon be taking delivery of our narrowboat to live on. Hopefully someone can answer a question regarding the power use of a Victron 3KVA inverter, I think it is likely to be the Phoenix model (not purchased yet). It will be the 12volt version.

 

We will have a number of 230v appliances, e.g. TV, Music system and wireless router as well as laptop and camera battery chargers. The router will be on 24/7 as I sync data to the cloud overnight (reception permitting). So the inverter will be on 24/7 too. According to the Victron spec sheet it uses 20 watts on zero load.

 

My first question is will it use that 24/7? I'm thinking not as when there is a load it will be working, but need some clarity. 

 

When it is working it states a max efficiency of 93% - so it is therefore using 7% to do the inverting, which I understand as it is doing work. 

 

Does the 7% additional draw need to be included in the audit for each 230v appliance? i.e. uplifting the amps by 7%? I suspect so but again advice welcomed.  I know it is slightly higher than 7% but it is near enough for jazz, especially as I am using worst case scenarios.

 

If I were to use the 20 watts for 24 hours a day that may cover any uplift so it could be a moot point, if my maths are right that means the Victron will draw 40Amp/Hrs a day, which is a lot I think.

 

TIA

Paul.

 

To allow for inefficiencies divide the mains wattage figure by 10 to give amps from the 12v batteries via the inverter so 20 watts = 2 amps and 2 amps for 24 hours = 48Ah,

  • Greenie 1
Link to comment
Share on other sites

8 minutes ago, Tony Brooks said:

 

To allow for inefficiencies divide the mains wattage figure by 10 to give amps from the 12v batteries via the inverter so 20 watts = 2 amps and 2 amps for 24 hours = 48Ah,

I’d say that the 10v thing is good for external loads, but the 20w in this case is the internal losses of the inverter so it would be correct to use the actual voltage eg 12.5v or whatever. That would give 38.4Ah for 24 hrs.

 

There is quite a big variation in no load power consumption between makes and models. For example our current Mastervolt Combi uses 9w, which is pretty good. But if I have to replace it, the newer models use more eg around 20w.

 

Regarding the other part of the question, it will use will minimum of 20w and at no load, the efficiency is thus zero. If let’s say you put a 20w load on, it will probably use 40w and thus the efficiency is around 50%. At higher loads you probably still have the fixed usage of 20w plus the output power plus a percentage of the output power (perhaps 5 to 7%, which is lost as heat) so the efficiency approaches the 93%

Edited by nicknorman
  • Greenie 1
Link to comment
Share on other sites

3 minutes ago, nicknorman said:

I’d say that the 10v thing is good for external loads, but the 20w in this case is the internal losses of the inverter so it would be correct to use the actual voltage eg 12.5v or whatever. That would give 38.4Ah for 24 hrs.

 

There is quite a big variation in no load power consumption between makes and models. For example our current Mastervolt Combi uses 9w, which is pretty good. But if I have to replace it, the newer models use more eg around 20w.

If the inverter is in use, then would I be right in using the 10v equation as Tony descibes? I'm gussing that the 20w no load wouldn't apply when in use too.

Link to comment
Share on other sites

31 minutes ago, Loddon said:

If you set the Victron  into powersave mode its about 2-3watts when there is no load.

In powersave mode items such as routers and chargers do not give enough load to make it switch on.

The router can run off 12v, My Huawei 535 does.

Charging can often be run from  USB, so fit USB sockets 

 

Addendum the 3kva inverter is 8-10w in search/powersave mode.

Link to comment
Share on other sites

Do you really need a 3kVA inverter? What is the highest single power user you intend to connect to it? None of the items you mention, TV, Music system and wireless router as well as laptop and camera battery chargers, even all on together remotely approach 3kVA. A smaller inverter may have lower power use. Additionally, they will be cheaper to buy. A mains fridge or freezer needs a 1kVA, or thereabouts inverter minimum to handle the initial surge current for a fraction of a second when the compressor starts. Only things like automatic washing machines need anything approaching 3kVA. Such a big inverter will cane the batteries if used to its full capability for anything more than a very short time. I installed a 1600VA inverter and that was only to run a mains vacuum cleaner. That cleaner has now been replaced by a battery one, so if/when the inverter dies, its replacement will be 1kVA.

Jen

Link to comment
Share on other sites

5 minutes ago, Jen-in-Wellies said:

Do you really need a 3kVA inverter? What is the highest single power user you intend to connect to it? None of the items you mention, TV, Music system and wireless router as well as laptop and camera battery chargers, even all on together remotely approach 3kVA. A smaller inverter may have lower power use. Additionally, they will be cheaper to buy. A mains fridge or freezer needs a 1kVA, or thereabouts inverter minimum to handle the initial surge current for a fraction of a second when the compressor starts. Only things like automatic washing machines need anything approaching 3kVA. Such a big inverter will cane the batteries if used to its full capability for anything more than a very short time. I installed a 1600VA inverter and that was only to run a mains vacuum cleaner. That cleaner has now been replaced by a battery one, so if/when the inverter dies, its replacement will be 1kVA.

Jen

Hi Jen, yes we do need a 3kVAinverter, we will have a washing machine as we don't want to always rely on launderettes when we are out cruising. 

Link to comment
Share on other sites

29 minutes ago, PCSB said:

If the inverter is in use, then would I be right in using the 10v equation as Tony descibes? I'm gussing that the 20w no load wouldn't apply when in use too.

 

In my view yes because even if the inverter has a better efficiency you will have overestimated the Ah required and that may be a good thing as the batteries will gradually lose capacity (assuming lead acids).

Link to comment
Share on other sites

2 minutes ago, Tony Brooks said:

 

In my view yes because even if the inverter has a better efficiency you will have overestimated the Ah required and that may be a good thing as the batteries will gradually lose capacity (assuming lead acids).

Thanks Tony, I'd rather have some inhand so to speak so makes perfect sense. I have been generous already with how long we will use various things, so hopefully plenty of leeway in there. And yes LA batteries.

 

ETA: I just wanted to make sure I understood the specs properly from Victron. Appreciate everyones input.

Edited by PCSB
Link to comment
Share on other sites

31 minutes ago, PCSB said:

If the inverter is in use, then would I be right in using the 10v equation as Tony descibes? I'm gussing that the 20w no load wouldn't apply when in use too.

Yes. 10v is a bit of a ballpark figure but good enough for power audits. The thing is that under very heavy loads the battery voltage decrease and the voltage drop in the cable means that the voltage is maybe only 11v at the inverter terminals, so when you apply the 93% efficiency 10v gives a pretty good answer. At light loads the battery voltage might be 12.5v or more and with minimal voltage drop in the wiring, 10v is rather pessimistic.

  • Greenie 1
Link to comment
Share on other sites

Something it would be useful to get for doing a power audit would be an energy monitor for the mains kit. Plug each gadget in turn and find out the real consumption under typical usage, rather than rely on the manufacturers figures. Something like this:

https://www.screwfix.com/p/energenie-ener007-energy-saving-power-meter-socket/3477h#_=p

Jen

  • Greenie 1
Link to comment
Share on other sites

23 minutes ago, Tracy D'arth said:

Very few inverters use less than an amp in power save standby, and quite a bit more when idling and not in power save  mode.

Please sir my 1600va Victron combi is 2-3 watts in search mode ;)

one of the reasons I chose a 1600 rather than a bigger one.

Link to comment
Share on other sites

2 minutes ago, nicknorman said:

Yes. 10v is a bit of a ballpark figure but good enough for power audits. The thing is that under very heavy loads the battery voltage decrease and the voltage drop in the cable means that the voltage is maybe only 11v at the inverter terminals, so when you apply the 93% efficiency 10v gives a pretty good answer. At light loads the battery voltage might be 12.5v or more and with minimal voltage drop in the wiring, 10v is rather pessimistic.

Thanks Nick, makes sense.

2 minutes ago, Jen-in-Wellies said:

Something it would be useful to get for doing a power audit would be an energy monitor for the mains kit. Plug each gadget in turn and find out the real consumption under typical usage, rather than rely on the manufacturers figures. Something like this:

https://www.screwfix.com/p/energenie-ener007-energy-saving-power-meter-socket/3477h#_=p

Jen

Thanks Jen, it isn't expensive so will get one ordered :)

Link to comment
Share on other sites

15 minutes ago, PCSB said:

Hi Jen, yes we do need a 3kVAinverter, we will have a washing machine as we don't want to always rely on launderettes when we are out cruising. 

Check the power requirements of the washing machine carefully my compact one 3.5kg only requires 1400va.

  • Greenie 1
Link to comment
Share on other sites

1 minute ago, Loddon said:

Check the power requirements of the washing machine carefully my compact one 3.5kg only requires 1400va.

Will do as that will be the biggest draw especially when it heats water! A monitor like the one Jen linked to will help with that as I'm struggling to find the info (it shows it as 193KWH per year of typical usage, that is no use to man nor beast).

Link to comment
Share on other sites

19 minutes ago, PCSB said:

Hi Jen, yes we do need a 3kVAinverter, we will have a washing machine as we don't want to always rely on launderettes when we are out cruising. 

Washing machines only use that much power when heating the water. The power used in spinning the drum is much less. Search back through the forum for ways to fill your machine with hot or warm water (from your calorifier, instantaneous gas water heater or central heating boiler) to save heating it electrically in the washing machine.

  • Greenie 2
Link to comment
Share on other sites

1 minute ago, PCSB said:

Will do as that will be the biggest draw especially when it heats water! A monitor like the one Jen linked to will help with that as I'm struggling to find the info (it shows it as 193KWH per year of typical usage, that is no use to man nor beast).

Fill it with warm water via a thermostatic blending valve and save lots of energy.

  • Greenie 1
Link to comment
Share on other sites

1 minute ago, David Mack said:

Washing machines only use that much power when heating the water. The power used in spinning the drum is much less. Search back through the forum for ways to fill your machine with hot or warm water (from your calorifier, instantaneous gas water heater or central heating boiler) to save heating it electrically in the washing machine.

 

Just now, Tracy D'arth said:

Fill it with warm water via a thermostatic blending valve and save lots of energy.

Thanks both, will do a bit of digging :)

Link to comment
Share on other sites

Just to aid power consumption we do cold washes most of the time when running from batteries.

I used to use Thermostatic Valve but it has to be switched to cold before the rinse cycle :(

  • Greenie 2
Link to comment
Share on other sites

2 minutes ago, Loddon said:

Just to aid power consumption we do cold washes most of the time when running from batteries.

I used to use Thermostatic Valve but it has to be switched to cold before the rinse cycle :(

We've been washing at 30C for a while as it saves money and the clothes seem just as clean. I'll certainly look at a thermostatic valve. I suspect most times the washer will be going is whilst we are cruising so I'm pretty certain I'd forget to switch it back!!

Link to comment
Share on other sites

If it's a new boat with a modern engine, chances are it will have a pretty powerful alternator that can cope with the washing machine heater, either entirely or mostly. Even if the latter the batteries will be charged again before the wash cycle is finished, because as said for most of the cycle, the washer doesn't use much power. So the moral is to do the washing whilst you are cruising, then you don't have to worry about hot water fills etc.

Link to comment
Share on other sites

1 minute ago, nicknorman said:

If it's a new boat with a modern engine, chances are it will have a pretty powerful alternator that can cope with the washing machine heater, either entirely or mostly. Even if the latter the batteries will be charged again before the wash cycle is finished, because as said for most of the cycle, the washer doesn't use much power. So the moral is to do the washing whilst you are cruising, then you don't have to worry about hot water fills etc.

Yep the domestic alternator is  175 Amp so pretty pokey :)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.