Victron BMV Pros?

[snoobler]

Installed my BMV-702 today, and I have a new piece of info... "DC Power" - 15W in the screen cap above. This seems to fluctuate quite a bit and seems proportional to the AC loads. I have NO DC loads in the system. The only thing pulling DC is the Quattro (okay and the CCGC and MPPT).

Is is possible that this number is a combination of the consumption of the BMV itself as well as power loss across the shunt? Here it is with the RV fridge running on AC:



I've ctrl-f'd the manual, and I didn't find anything pertinent.

 

[John Frum]

Not an expert but...
373 ac watts x 1.1 conversion efficiency + 46 dc watts = 456.3 watts.
Maybe the 46 watts is fixed overhead for the inverter.
Seems high for a Victron though.

 

[snoobler]

Good guess. That may be it, but it seems large.



123 (total discharging) - 76 (AC) - 15 ("DC") = 32W

Before the BMV, it was always very close to a 30W deviation between that "Discharging" number and the AC loads number. The presence of the BMV means I consume more power now...

 

[snoobler]

Ah... should have checked with the victron community forum. I had a setting enabled in the CCGX - "HAS DC SYSTEM" - I don't. Now that "DC Power" display is gone, but there's still something amuck with the "AC Power" and "discharging" values skewing with larger consumption.

I suspect it's the inefficiencies or a calibration issue with the BMV. The pre-BMV values were pulled from the Quattro battery monitor, so it was only looking at DC current/voltage in and AC Power out - and it should be accurate. It always showed about 30W extra for the inverter.

I may need to tweak the BMV, or this is just reality.

Thanks!

 

[HRTKD]

There are plenty of phantom DC loads in my RV. The CO2 detector, the radio (It has off and really off positions. The former draws a measurable load, the latter doesn't.), the AC-to-DC converter, etc. I'm sure the main distribution panel has a constant load also, but I haven't bothered to isolate that to see.

 

[Zil]

My BMV-702 only measures dc current. All the items you list do use dc current even when off. How do you get your 120 volt ac? The inverter uses dc when off.
"There are plenty of phantom DC loads in my RV."

 

[HRTKD]

My BMV-702 only measures dc current. All the items you list do use dc current even when off. How do you get your 120 volt ac? The inverter uses dc when off.
"There are plenty of phantom DC loads in my RV."

I don't measure 120v AC. My inverter isn't that smart.

 

[snoobler]

I think Smoov called it. Even with the "DC Loads" feature disabled, I'm still seeing an increasing inverter output vs AC Power, so it's probably the inefficiency of the conversion.

 

[Zil]

I didn't say you measure 120V AC. I guess my post is a bit confusing. I would expect the phantom dc loads to be measured. Even if less that 1 amp.