Electrical Mod -- Feedback Requested

[jh.xsnrg]

I am surprised how much power is being consumed if all you have on are the inverter, fridge and other normal 12v parasitic loads. You might want to get a DC clamp meter and put it on each of your DC lines off the distribution block to better understand what is happening. One thing that is interesting is the initial set of pictures. The 712, which is the absolute power being drawn, is showing 75w being pulled, but the AC load is only 17w. 58 watts are being consumed by DC loads including the Victron itself. Given the last readings, it appears this also does not include the refer running yet?

Now I need to clamp the AC circuit on our refer and see what it pulls. Our parasitic load is quite a bit less, so I hope it is not the Victron itself pulling that much current.

Jim

[howson]

Howard,

Do you have any idea about how much charge to expect from the tow vehicle in terms of alternator output to the trailer and charge duration based on that output/input?

Thanks!


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I really don't know what I'll see, thus when the batteries are a low point (after the current refrigerator test is over) I'm going to hook up to the truck with the inverter in "charger only" mode and see what happens. I'll report back later today.

[Cate&Rob]

Hi Howard,

To have used 140 Ah in 4 hours would mean a steady draw of 35 amps (about the 37 amps shown in the status at 40 hours). It seems like the fridge is not cycling. I would agree with Jim @jh.xsnrg that a DC clamp meter can tell you how that 37A current is divided.

Rob

[howson]

After a little over 8 hours here's what it looked like:

[howson]

I am surprised how much power is being consumed if all you have on are the inverter, fridge and other normal 12v parasitic loads. You might want to get a DC clamp meter and put it on each of your DC lines off the distribution block to better understand what is happening. One thing that is interesting is the initial set of pictures. The 712, which is the absolute power being drawn, is showing 75w being pulled, but the AC load is only 17w. 58 watts are being consumed by DC loads including the Victron itself. Given the last readings, it appears this also does not include the refer running yet?

Now I need to clamp the AC circuit on our refer and see what it pulls. Our parasitic load is quite a bit less, so I hope it is not the Victron itself pulling that much current.

Jim

The refrigerator was running off the inverter when the first set was taken. The appliance was not cycling as it was cold enough and the interior of the RV was also relatively cold.

With an AC load of 17W the inverter was generating a whopping .14a of 120vAC. (120v*.14a=17w) Where the other ~5.3A of 12vDC was being consumed is a mystery at the moment. I *know* everything was off, as I have a picture I took with nothing on except for parasitic loads (1A, 13W). I need to do that part again.

[howson]

Hi Howard,

To have used 140 Ah in 4 hours would mean a steady draw of 35 amps (about the 37 amps shown in the status at 40 hours). It seems like the fridge is not cycling. I would agree with Jim @jh.xsnrg that a DC clamp meter can tell you how that 37A current is divided.

Rob

What is also unknown is how much draw those six fans I added (four in the back, two in the interior) that are driven off the thermostat from the Fridge Defend installed.

The refrigerator was definitely running both times I checked (at the four hour mark and 8 hour mark). It was hot inside the RV as documented in the pics. Before I get to checking all that though I have a different issue. Going to post separately to keep the issues separate.

[howson]

It seems like the fridge is not cycling.

I am surprised how much power is being consumed ...

Rob & Jim,
For reference, here's the CCGX display when the refrigerator was working:



This is what I *think* is happening. Please--correct me if this is wrong.

The AC load when the refrigerator is running showed 392W. (392/120)*10=32.67 amps of 12vDC. That is not unexpected. Round up to 33 for ease of reference. (Note the monitor is showing 38 being pulled from the batteries.) 38-33=5 amps left.

With the inverter idling, *nothing* on except for the normal parasitic loads so the AC load shows 0, the 712 reports 56W (4.3 amps of 12vDC) being consumed. Round down to 4 amps consumed for the inverter and any other parasitic devices.

That leaves 1 amp of 12vDC which can easily be explained by the 12vDC circuitry in the refrigerator.

Am I still missing something?

[Cate&Rob]

Rob & Jim,
For reference, here's the CCGX display when the refrigerator was working:

Hi Howard,

Just as a reference . . . I have 9 cu ft "apartment size" residential fridge on my boat. It is 120VAC only.
Without shore power or generator, it runs through an inverter from a battery bank.
It draws about 2.5 A at 120V which translates to about 30A from the battery bank through the inverter (with conversion losses).
But . . . it typically runs a 50% duty cycle so that the "average" over time works out to 15A, or about 120 Ah in 8 hours.

Rob

[howson]

Hi Howard,

Just as a reference . . . I have 9 cu ft "apartment size" residential fridge on my boat. It is 120VAC only.
Without shore power or generator, it runs through an inverter from a battery bank.
It draws about 2.5 A at 120V which translates to about 30A from the battery bank through the inverter (with conversion losses).
But . . . it typically runs a 50% duty cycle so that the "average" over time works out to 15A, or about 120 Ah in 8 hours.

Rob

So I think that proves I have a refrigerator that isn't well insulated. At least it stays cold (due to all the extra fans I installed?). It didn't get above 37 F.

[gbkims]

A post on TDR of the Victron Multiplus 12/3000/120 caught my eye:
"This is pretty sexy. You can hook up to it with a laptop and configure it to do things such as bring the genset automatically on/off based on power needs or even if say the temp gets to a certain level while you're gone and you want the A/C on. It can also aggregate multiple power sources and use them each individually or consecutively based on a priority you set. I've also read of people for instance running a 15k BTU A/C with only a 2k genset. So when the A/C kicks on, it will pull as much power as you set (say 1,500 watts) from the genset, and supplement that with the inverter/batteries. When the compressor kicks off, it can run straight from the genset....then boom, compressor kicks on and it pulls from both sources again. Pretty cool. Ain't cheap, but the chicks dig dudes with the cool toys:"