VRM screen shots. Post them!

[SoakedUp]

I just can’t get over the inefficiency of my 12v all Victron system. My multiplus 2k tends to run in the 70-80% efficiency range but I’ve seen it down in the high 60% range when I get towards its upper limits.

Here’s an example:



So I’m producing 1683w of solar at this moment in time. My Aircon compressor is on (I’ve tried this with purely resistive devices like a 1500w radiant heater and the result are the same. It’s not a power factor issue) so my AC out load is 1423w. PV should cover the entire load but I’m some how pulling 321w from the battery still.

Side note, I have the DC power meter on even though the only things I’m powering directly via DC is a 5 watt rv light and the cerbo itself which is 3w. Less that 10 watts total DC power and the light isn’t even on. The 83w you see being used is not accurate. It jumps from 10-300w trying calculate the efficiency losses that are occurring.

Let’s do the math:

1683 + 321 = 2004w being consumed

1423/2003 = 71% efficiency

580w just dissipating into my system making heat. The weird part is wires, connections, devices aren’t hot to the touch. Warm, yes, but not to the point of concern.

Is this just normal for a 12v system? For LF Victron inverters? I’m having to seriously over panel to make up for these losses and it’s pissing me off. I plan to go 48v in the future but would like to see some VRM 12v screen shots for y’all’s systems to see if it’s just me.

Please share!

 

[chrisski]

I just can’t get over the inefficiency of my 12v all Victron system. My multiplus 2k tends to run in the 70-80% efficiency range but I’ve seen it down in the high 60% range when I get towards its upper limits.

So I’m producing 1683w of solar at this moment in time. My Aircon compressor is on (I’ve tried this with purely resistive devices like a 1500w radiant heater and the result are the same. It’s not a power factor issue) so my AC out load is 1423w. PV should cover the entire load but I’m some how pulling 321w from the battery still.

How much wattage of solar panels do you have?

I need at least 2200 watts of panels to cover loads like you mentioned but in the shorter days of the year, I have put 2500 wats of panels out and its not enough.

When I run my AC I get 89% efficiency:

Watts From Battery: 1650
Watts From Inverter: 1470

This is how I measured the AC with loads through a day with 2250 watts of panels; 1650 on the roof and 900 on the ground :

1:33 pm Stats
Outside Temp—(80f)
Battery temp— 77 F
Inverter—94 F (1537w)
Total Solar Production-1732 wat
Solar SCC 1– 96 F (439w)
SCC 2—99 F (832w)
SCC 3—90 F (459w)
Main bus bar—83 F
Battery busbar—78 F
BMS—82 F (-50 watts)

2:36 pm Stats
Outide Temp—(82 f)
Bat temp —81F
Inverter—95 F (1538w)
Total Solar Production —1560 watts
SCC 1 —96 F ( 377w)
SCC 2 —117 F ( 830w)
SCC 3—91 F ( 349w)
Main bus bar— 88 F
Battery busbar—82 F
BMS—84 F (-255 watts)

3:43 pm Stats
Outside Temp-(82 F)
Battery temp— 81 F
Inverter—94 F ( 1530w)
Total Solar Production –1170 watts
SCC 1 — 95 F( 291W)
SCC 2 — 103 F ( 650 W)
SCC 3 — 89 F ( 228 W)
Main bus bar-87
Battery busbar-82
BMS — 85 F ( - 770 W)

4:43 pm Stats
Outside Temp — (81 F)
Bat temp — 81
Inverter — 92 F ( 1530w)
Total Solar Production—841 Watts
SCC 1 — 94 F( 115 w)
SCC 2 — 105 F ( 600 W)
SCC 3 — 87 F ( 121 W)
Main bus bar 84
Battery busbar 82
BMS—82F ( - 800 W)

 

[Brucey]

Here's the efficiency curve of a 3kVA:

Multiplus-II 48/5000 efficiency curve - Victron Community

community.victronenergy.com

 

[Drunkin Solar]

He's running at 12V so I wonder if the efficiency is worse with a lower voltage model?

He also forgot to deduct his DC load in the calculation so the efficiency is somewhat better than shown.

I have a 24v model and see efficiency numbers similar to what you have shown here @Brucey

 

[Q-Dog]

It does seem something is wrong. I have a 24v Multiplus 3000VA and it is less efficient when running near its upper limits but I haven't done an efficiency calculation because it seems normal to me. It takes energy to run the cooling fan, but certainly not that much.

By the way, your Multiplus 2000VA is rated for 1600 watts continuous, so at 1423 watts you are near the top of its capacity.

The sun isn't above the horizon yet, but this is what I see here. Just boiled water for tea, but no real loads running at the moment.

 

[SoakedUp]

He's running at 12V so I wonder if the efficiency is worse with a lower voltage model?

He also forgot to deduct his DC load in the calculation so the efficiency is somewhat better than shown.

I have a 24v model and see efficiency numbers similar to what you have shown here @Brucey

Virtually no DC load. Re read my original post.

 

[ScrotusGobbleBottom]

I was pulling in 56 watts for a couple minutes.

 

[SoakedUp]

How much wattage of solar panels do you have?

I need at least 2200 watts of panels to cover loads like you mentioned but in the shorter days of the year, I have put 2500 wats of panels out and its not enough.

When I run my AC I get 89% efficiency:

Watts From Battery: 1650
Watts From Inverter: 1470

This is how I measured the AC with loads through a day with 2250 watts of panels; 1650 on the roof and 900 on the ground :

1:33 pm Stats
Outside Temp—(80f)
Battery temp— 77 F
Inverter—94 F (1537w)
Total Solar Production-1732 wat
Solar SCC 1– 96 F (439w)
SCC 2—99 F (832w)
SCC 3—90 F (459w)
Main bus bar—83 F
Battery busbar—78 F
BMS—82 F (-50 watts)

2:36 pm Stats
Outide Temp—(82 f)
Bat temp —81F
Inverter—95 F (1538w)
Total Solar Production —1560 watts
SCC 1 —96 F ( 377w)
SCC 2 —117 F ( 830w)
SCC 3—91 F ( 349w)
Main bus bar— 88 F
Battery busbar—82 F
BMS—84 F (-255 watts)

3:43 pm Stats
Outside Temp-(82 F)
Battery temp— 81 F
Inverter—94 F ( 1530w)
Total Solar Production –1170 watts
SCC 1 — 95 F( 291W)
SCC 2 — 103 F ( 650 W)
SCC 3 — 89 F ( 228 W)
Main bus bar-87
Battery busbar-82
BMS — 85 F ( - 770 W)

4:43 pm Stats
Outside Temp — (81 F)
Bat temp — 81
Inverter — 92 F ( 1530w)
Total Solar Production—841 Watts
SCC 1 — 94 F( 115 w)
SCC 2 — 105 F ( 600 W)
SCC 3 — 87 F ( 121 W)
Main bus bar 84
Battery busbar 82
BMS—82F ( - 800 W)

I have 1920w (6 320w panels) array feeding a 150/100 mppt that maxes out at 1450w into the battery

I also have a 500w (5 100w panels) array feeding a 150/45 mppt that could potentially max out at 630w into the battery but I’m only getting about 450w right now from the 500w of panels. I’m planning on switching out these panels for 4 320 panels for a total of 1280w which should help max out the 150/45 for most the day.

I have 3 206ah SOK batteries which recommend a max of 50a charge per battery which is why I have a 100a and 45a charger.

I’m wondering if I can swap the 45a mppt for another 100a mppt so I can produce more solar and have the solar go directly to the loads so I don’t go over my 150a charge rate.

 

[Drunkin Solar]

Virtually no DC load. Re read my original post.

Virtually and no (none) are two different things
83 watts at 6.10 amps Dc load so lets redo the math and your efficiency improves....no?

 

[SoakedUp]

Virtually and no (none) are two different things
83 watts at 6.10 amps Dc load so lets redo the math and your efficiency improves....no?

You obviously didn’t re read the post…the DC calculation on VRM is an estimate. It’s not accurate in my case. I literally only have the cerbo (3 watts) and a small DC light (5 watts) which isn’t even on. The DC draw I’m seeing on VRM jumps around wildly from 10w to 300w every couple seconds and appears to be trying to calculate the inefficiencies it’s seeing in the whole system which is my whole point of this thread. Therefore I don’t deduct the DC load numbers from the calculation because it’s not actually a load I’m producing on my end.

 

[Brucey]

I have 1920w (6 320w panels) array feeding a 150/100 mppt that maxes out at 1450w into the battery

I also have a 500w (5 100w panels) array feeding a 150/45 mppt that could potentially max out at 630w into the battery but I’m only getting about 450w right now from the 500w of panels. I’m planning on switching out of these panels for 4 320 panels for a total of 1280w which should help max out the 150/45 for most the day.

I have 3 206ah SOK batteries which recommend a max of 50a charge per battery which is why I have a 100a and 45a charger.

I’m wondering if I can swap the 45a mppt for another 100a mppt so I can produce more solar and have the solar go directly to the loads so I don’t go over my 150a charge rate.

Sounds like you would just need to enable DVCC on the Cerbo to define what your battery max charge rate should be (it will allow you to limit charge rate to battery to say 150A and use the other 50A for loads (assuming you can max out the second 150/100).

 

[Drunkin Solar]

Can you try turning off all loads except Cerbo with the inverter on and see if your idle load is within spec at about 10w?

That efficiency number does seem way to high. Something is not accurately reporting or some other problem

 

[Brucey]

Here's my 48/1200 idling, 10W which is expected spec. Disregard the charger/charging difference there's another battery on the other side of the shunt which VRM doesn't see.

 

[Raul a/3]

Here is mine in the van, with identical 2kva/ 12v inverter, idling. The only difference is the output is 230v mono phase. The DC load supplies a LTE router, and a motion triggered camera. Router is 24/7 on, camera is on stand by.
I also see a sub 80% efficiency with 1400w AC load, a small portable oven, but never bothered me. I only turn the inverter on when needed, then rest of the time, only DC loads are used.

 

[SoakedUp]

I would think 200-500watts of dissipation would be fairly significant in heat inside the multiplus. I love my Blue gear and still think it’s superior to a lot of other brands but what a bummer seeing all that wasted power.

 

[SoakedUp]

Sounds like you would just need to enable DVCC on the Cerbo to define what your battery max charge rate should be (it will allow you to limit charge rate to battery to say 150A and use the other 50A for loads (assuming you can max out the second 150/100).

I do have DVCC set to max 150a charge but I thought that limited the charge controllers from producing more than 150a for some reason. I just messed around with it does seem I can allow more than 150a from charge controllers while still limiting the battery from charging above 150a.

 

[Q-Dog]

Cloudy and cool so no big loads running. but charging OK. I'll try to remember to do a screen cap next time we run a heavy load.

 

[Drunkin Solar]

Q-Dog that screenshot shows about identical loss I would see on a 24v 3000w Multi with a light load. When my loads start approaching the 1500w to 1600w range the loss is a little over 100w or so. By rough calculation still in the range of 90% efficiency (approx).

The OP in the low 70% range seems out of wack to me.....

 

[Raul a/3]

I don't think the multiplus measures the AC output correctly, its just a calculation estimated. If you want accuracy , fit a AC sensor on the output, then select in the GX to use the sensor rather than VE bus data for AC out.
On my previous snap shot post, it shows 16w load, but nothing is connected to AC out in that moment. Sometimes shows 19 or even 22w without load. Its a calculated aparent power, the only real data comes from BMV shunt..

 

[SoakedUp]

Q-Dog that screenshot shows about identical loss I would see on a 24v 3000w Multi with a light load. When my loads start approaching the 1500w to 1600w range the loss is a little over 100w or so. By rough calculation still in the range of 90% efficiency (approx).

The OP in the low 70% range seems out of wack to me.....

Any chance you have a screen shot of your VRM page showing that 90% efficiency at that load?

I’m not always at 70%.

I’m currently sitting at about 75%



1692-673 = 1019

769/1019 =75% efficiency

* As you can see the DC power now shows a 187w draw but I only have my cerbo connected to DC at (3 watts)