batteries running to 0% at night

[FlyingScot]

Originally Posted by s/v Jedi

I don’t get these idle loads and will assume the 200W is the load of a running freezer in addition to the idle load of the inverter.

I have two (!) Victron Multiplus 3000’s in parallel and together they draw 22W idle and this includes an auto transformer as well.

This would be a downright miracle. That or Victron published specifications are wrong. The zero load specs for one unit are 20/20/25w depedning on 12/24/48v input with 230v output.
http://www.victronenergy.com/upload/...VA-5kVA-EN.pdf

Our two 12/3000/120 in parallel use closer to 50w at idle. We turn them off when not in use. The specifcation is 20w each for the 120v output model.
http://www.victronenergy.com/upload/...120V-US-EN.pdf

I haven't updated to the latest f/w yet on ours, but I can't imagine that two inverters remaining synchronized will power down in any way except to completely off.

Side note: Interesting that the 48v unit uses 25% more power at idle.

Edit: This assumes Multiplus. If you have the newer Multiplus-II they are more efficient.

[WE9V]

Originally Posted by Xavierp

I am wondering what a decent level in the morning is supposed to be?
Or what people get in the morning

After solar stops working, I usually use the microwave for a few minutes for dinner, I watch 4-5 hours of TV (TV + Raspberry Pi + Internet), anchor light, cellphone charging, fridge/freezer, and then I use the electric kettle in the morning to make coffee, all before the solar starts working. This is usually under 50Ah of usage before solar starts charging. If you exclude the microwave and electric kettle, it's more like under 30Ah used.

Originally Posted by Xavierp

We have on DC fridge that draws 40w and one AC freezer 65w.
1 AC fan 20w

Those fridge/freezer loads "should" be cycling, not constant. My compressor is 45w but only runs 33-50% of the time. So that's an average of 15-23W.

Ditch the AC fan. Get a Caframo 757 fan (DC), or several. Only 5W and no inverter inefficiency. Get everything off the inverter, as the inverter has inefficiencies that you pay with Ah.

[FlyingScot]

Originally Posted by s/v Jedi

At least it is BS from a qualified engineer to make such claims… it may even be something to consider seriously…

Remember old light bulbs, 60W. That’s a lot of power… where does it go?

If it uses 60w at idle, it mostly goes to heat. The lightbulb you speak of likely transferred 90% of it's input to waste heat as well.
I'm sure you know this, not sure why you didn't just say so.

I wouldn't be shocked to find an example of a 60w idle load inverter. Sailorboy, what model inverter did you have?

[GordMay]

Originally Posted by GordMay

... For a 1000W inverter, the average idle power consumption could be around 10-20 watts, while for a 2000W inverter, it could be around 20-40 watts ...

Originally Posted by WE9V

That seems like a lot. My 3000W pure-sinewave inverter uses 0.7A when on/inverting and no load. That's less than 10W. When it's in the power saving mode (searching for a >10W load), the average current is 0.16A.

Using a “power saving” [no load] mode, consumption could drop to 5-10W [0.37 - 1.35A @ 13.5V], on a 3 kW sinewave high frequency inverter.
However, in idle/standby mode, I would expect that 3 kW to use 30 to 50 watts [2.2 - 3.7 Amps @ 13.5V] power.
So, yours [@ 2.16 W] is much better, than I would have expected .
Likely, I’m really out of date.

What make/model have you?

[WE9V]

Originally Posted by GordMay

What make/model have you?

Kisae SWXFR1230 3000W Pure sinewave
https://www.kisaepower.com/products/swxfr1230/

[Pete7]

Originally Posted by Xavierp

Victron monitor shows the data

I don't have the Victron shunt kit, but believe that they require properly setting up prior to use and regular resets during use to keep them telling the truth.

Perhaps those Dakota LFPs are really full or even 3/4 charged before the sun goes down. This along with the other calculations earlier might explain why the batteries are flat at dawn. BTW any blue tooth displays from the batteries themselves are best treated as an approximation rather an accurate measurement.

Pete

[wholybee]

Originally Posted by Xavierp

Hi all
2x 400w solar
2 mppt
2x 200Ah Dakota Lithium battery

All is off on my boat and I still draw 200w…. It’s nighttime. I unplugged the fridge and Starlink. No fans running. No phone chargers connected
Any idea?

Thx!

Trying to get back on topic. Get a clamp on Amp meter, or learn to use a regular DMM to measure current. Then start measuring current to find out where it goes. That is the only way to figure it out. 200W is ALOT. That is more than I typically use with everything on.

It could be a measurement error. Using the wrong shunt for a SOC meter, or having the meter set for the wrong shunt. Or maybe a damaged shunt.

It is possible that your battery is discharging through your solar panels, but that would be unlikely with any modern controller and panels. It could be a failed switch on your engine keeping your alternator energized. Or stuff that stays on all the time even when all the switches are off. I have seen boats where the inverter was permanently on, AIS permanently on, and it is common for the bilge pump to be permanently in auto.

It could be a combination of several things, as I said 200W is a lot.

[sailingharry]

Originally Posted by SailingHarmonie

It is REALLY important to confirm this is real, and fix it. If you have 200 W of stray current running around the boat in places it does not belong, you are VERY rapidly dissolving metal--somewhere.

I'm really not on board with "stray" current, the type that dissolves metal. 200W is 15A, and I can't imagine that 12V can push that much current through salt water (I can be convinced otherwise, since this is pure conjecture on my part). I do electrolytic rust removal by submerging a metal part (with a negative cable) and a sacrificial plate (with a positive cable) in highly conductive water, all powered up with a battery charger, and I rarely see 2A.



I'd be much more likely to believe "stray" current, the type that is running through a device that isn't turned off. Like an inverter, or a bilge pump stuck on, or the pressure water pump not shutting off.

[Montanan]

Originally Posted by sailingharry

I'm really not on board with "stray" current, the type that dissolves metal. 200W is 15A, and I can't imagine that 12V can push that much current through salt water (I can be convinced otherwise, since this is pure conjecture on my part). I do electrolytic rust removal by submerging a metal part (with a negative cable) and a sacrificial plate (with a positive cable) in highly conductive water, all powered up with a battery charger, and I rarely see 2A.



I'd be much more likely to believe "stray" current, the type that is running through a device that isn't turned off. Like an inverter, or a bilge pump stuck on, or the pressure water pump not shutting off.

FYI, Helpful guidance from AB Marine:


Category - Cathodic Protection
Understand the types of corrosion that occur on your boat and how to prevent and mitigate them.

How do I test for leaking current in my boat’s electrical system?
Posted
May 23, 2022

By
Jennifer Escher

https://ab-marine.com/knowledge-base...0.001%20amp%29.
First, turn off all electrical equipment and fixtures aboard, then disconnect the positive connector from the boats’ battery terminal and connect the positive lead of the multi-meter to the battery post and the negative lead to the connector. Starting at the 10 ampere (or highest current) range of the meter, check to see that there is no current flow, then switch to the low current ranges. With the perfect boat wiring and equipment, no current should flow at any setting. A normally ‘clean’ electrical system will have a leakage current of less than 1 milliampere (0.001 amp). Leakage of a few milliamperes indicates a small amount of corrosion – hardly dangerous – but something to locate and correct. However, if the meter shows a sizable fraction of an ampere, separate circuits should be switched off one at a time to find which is at fault, and the wire or equipment repaired or replaced promptly. If leaking of this magnitude is found, leave the battery disconnected until the trouble is cured.


Where should I look for corrosion?

https://ab-marine.com/knowledge-base...for-corrosion/

[GordMay]

Originally Posted by WE9V

That seems like a lot. My 3000W pure-sinewave inverter uses 0.7A when on/inverting and no load. That's less than 10W. When it's in the power saving mode (searching for a >10W load*), the average current is 0.16A.

Originally Posted by WE9V

Kisae SWXFR1230 3000W Pure sinewave
https://www.kisaepower.com/products/swxfr1230/

That looks like a very nice unit.
According to the specifications:
INVERTER STANDBY CURRENT: < 1.5A [@ 12.5VDC = 18.76 Watts]
Specs ➥ https://www.kisaepower.com/products/swxfr1230/

* What current do you measure, at the moment it turns on, & searches?

[s/v Jedi]

Unfortunately we just put Jedi to sleep as we make ready to cross the Atlantic as passengers with the Holland America Line

The 22W zero load number for two parallel Multiplus 3000’s isn’t from the spec sheet (which does say 20W for one unit) but is actual measurement. Of course it’s easy to do a more accurate measurement than what the Cerbo GX does so I will do that next time I am aboard.

That said, specs mean that the units meet -or exceed- those numbers. The problem is that one can’t count on better performance but it doesn’t mean it isn’t possible.

[Fuss]

Multi plus 24 3000 - 200w for my resting inverter, I would never tolerate that. I have 2, can be used in series or individually.

[CaptainRivet]

Originally Posted by MIRELOS

200 is a tremendous load, I have 2 refrigerators and a freezer plus the Starlink,
computer and Tv...I don't exceed 80ah overnight.
How did you calculate your load?
Do you have stray current somewhere?

Starlink is 50W per hour, 12h overnight is 600wh/13.5V=44,4AH assuming your starlink is modified to 12V…if not add inverter and you are already at 80AH…
Then 2 fridges and 1 freezer…I have minus one freezer but a quite efficient toploader and my overnight draw is about 120Ah.

[CaptainRivet]

Originally Posted by GordMay

Typically, the no-load standby/idle power consumption of most modern inverters is relatively low, typically less than 1% of their rated power output.
For a 1000W inverter, the average idle power consumption could be around 10-20 watts, while for a 2000W inverter, it could be around 20-40 watts.
Some inverters automatically switch to standby mode, when no loads are detected, while others require manual activation. In addition to standby mode, some advanced inverters offer power-saving modes. These modes further reduce power consumption, by adjusting the inverter's internal components and functions, such as reducing the idle current, or adjusting the frequency.
If you anticipate long periods of inactivity, or know that you won't require AC power for a while, consider completely disconnecting the inverter, from the power source, eliminating any standby power consumption.

That’s a theory and marketing of even the big ones… several inverter incl. the Victron multi 12/3000 is in reality in 45 W range, yes they have this pulsing standby which gets you down to Jedi’s 22W but you cannot use that with a compressor fridge or freezer means it’s always full on and then drawing in the 45W range in 12V version.

I can highly recommend to the op to first check with the manufacturer of the fridge what it draws in 12V DC and in AC…meanwhile they are a lot out that do significantly better in AC.
If it’s significantly better in AC get a small inverter, my top pick here is the Victron Phönix 500 or 800W as they are in real full power standby below 8W and just run your freezer of that…would always get the 800 as that gives you headroom for another 240V 24h equipment like eg starlink and difference 500 to 800 is 1W. You often get them used for a bargain as people upgrading to the big ones.

[CaptainRivet]

Originally Posted by s/v Jedi

Unfortunately we just put Jedi to sleep as we make ready to cross the Atlantic as passengers with the Holland America Line

The 22W zero load number for two parallel Multiplus 3000’s isn’t from the spec sheet (which does say 20W for one unit) but is actual measurement. Of course it’s easy to do a more accurate measurement than what the Cerbo GX does so I will do that next time I am aboard.

That said, specs mean that the units meet -or exceed- those numbers. The problem is that one can’t count on better performance but it doesn’t mean it isn’t possible.

Do you have it on in the pulsing power saving standby mode…cannot do that with compressor fridges and freezers, they need to be on full on.
Solution take a smaller one that run your 24h loads. I prepared for that and kept the old 3x2.5mm main AC cable as a spare in that goes from inverter location to AC switchboard while a new 3x6sqmm connected to switchboard to run all AC loads of eg a full electric galley. The 230V freezer will connect then via breaker it’s circuit to the old ac main cable to a 800W Phönix.