Is it common to lose 10 percent to your shunt compared to AIO input?

[PotusGobbleBottom]

Just wondering if this is an issue. This is a EG4 6000 Xp going to a Victron shunt shown in solar assistant.

 

[Vigo]

I believe what you are looking at is just the efficiency loss of the inverter. Remember that when we talk about 'idle draw' of a large inverter (which can range up to ~120w from what i've seen), that number actually scales UP with load on the inverter. The ~300w you're missing is probably mostly going on in the inverter itself. Even if the mppt section was only 97% efficient that would account for ~80w by itself. Not sure if the way the numbers are being measured would account for that or not, though. The battery charging efficiency and inverter efficiencies are probably both in the lower 90s and making up the rest of the 'missing' ~300w.

It's kind of unintuitive but considering that the inverter has a 'baseline' consumption, its actual efficiency at PRODUCING power starts out horrendous and gets better the higher the load is, although it might reverse and start trending downward again at some point. Like, if you had a 60w idle draw and then make 40w of actual power, is that like 40% efficient? Technically i think yes! I dont know what the optimum load % for efficiency would be on an inverter but i can say for certain that it is NOT at light loads like 500w (assuming a large 3kw+ inverter).

 

[PotusGobbleBottom]

I believe what you are looking at is just the efficiency loss of the inverter. Remember that when we talk about 'idle draw' of a large inverter (which can range up to ~120w from what i've seen), that number actually scales UP with load on the inverter. The ~300w you're missing is probably mostly going on in the inverter itself. Even if the mppt section was only 97% efficient that would account for ~80w by itself. Not sure if the way you the numbers are being measured would account for that, though. The battery charging efficiency and inverter efficiencies are probably both in the lower 90s and making up the rest.

It's kind of unintuitive but considering that the inverter has a 'baseline' consumption, its actual efficiency at PRODUCING power starts out horrendous and gets better the higher the load is, although it might reverse and start trending downward again at some point. I dont know what the optimum load % for efficiency would be on an inverter but i can say for certain that it is NOT at light loads like 500w (assuming a large 3kw+ inverter).

I figured. Got ya. Worse efficiency at low loads, 3 percent loss at mppt stage, plus 80-120 w draw from 6000xp

Thank you for your explanation confirming what I suspected. And also for the new information to me regarding efficiency curve based on load.

 

[AZ Solar Junkie]

The MPPT efficiency is rated at 99%, but the battery charging efficiency at 93%. 93% of 2750 comes to about 2550 watts. The total of the power going into the battery plus the load power plus the internal consumption all pretty much adds up.

 

[PotusGobbleBottom]

The MPPT efficiency is rated at 99%, but the battery charging efficiency at 93%. 93% of 2750 comes to about 2550 watts. The total of the power going into the battery plus the load power plus the internal consumption all pretty much adds up.

Thanks for your reply.

 

[Zwy]

Just wondering if this is an issue. This is a EG4 6000 Xp going to a Victron shunt shown in solar assistant.

View attachment 198056

One thing to remember is the Load shown by SA is updated at a much lower rate than the Battery draw/charge. You can't just add the 2 together and think it is 100% accurate.

I run a Batrium with it's own shunt and it doesn't agree 100% with the Victron Smartshunt connected to SA. It's close enough to monitor SOC and compute loads/charging but there will always be some inaccuracies due to connections and cabling increasing resistance.

 

[PotusGobbleBottom]

Load shown by SA is updated at a much lower rate

Yes, noted a 3 or so second time gap. Solar assistant does a MUCH better job than the EG4 software for updating the data.
Thanks for your input.

 

[Buff]

I had the same question when I started using my 6000xp. This is my first AIO and coming from Victron SCCs that are very efficient at charing batteries from little solar power, I was surprised to see how much loss there was with this. In grid bypass it uses little to no power. Even when straight battery inverting the efficiency is quite good. But as soon as the MPPT kicks on the efficiency takes a huge hit. I don't have that much solar so I am not sure what I want to do yet.

 

[PotusGobbleBottom]

I had the same question when I started using my 6000xp. This is my first AIO and coming from Victron SCCs that are very efficient at charing batteries from little solar power, I was surprised to see how much loss there was with this. In grid bypass it uses little to no power. Even when straight battery inverting the efficiency is quite good. But as soon as the MPPT kicks on the efficiency takes a huge hit. I don't have that much solar so I am not sure what I want to do yet.

I came from a Victron SCC that was only a charge controller. Those things are TANKS and Victron VRM is awesome.
I was shocked just like you but I had no idea or measurement of the inverters efficiency that I was using at the time.
Moving to the 6000XP puts all the losses in the same spot and easy to measure. So good and bad I guess.
Thanks for your comment.

 

[MisterSandals]

Moving to the 6000XP puts all the losses in the same spot and easy to measure. So good and bad I guess.

They've made it easier to watch the money you "saved" buying value priced equipment trickle away.

 

[PotusGobbleBottom]

They've made it easier to watch the money you "saved" buying value priced equipment trickle away.

I have a victron SCC and an AIMs toroidal based inverter. I was under the impression that switch mode inverters were more efficient.
What do you recommend for an efficient setup?

 

[AZ Solar Junkie]

They've made it easier to watch the money you "saved" buying value priced equipment trickle away.

True in a way - but the advantages for me more than offset the downside of losing a couple of kWh a day to efficiency losses. Going to be quite a long time before those efficiency losses are going to add up to spending 2-3X more for the equipment. Plus, in my case I'm getting more than enough solar even in February to cover my loads. Batteries discharge to 30-40% overnight and are fully charged by 1pm. Higher efficiency would only mean the batteries are fully charged a little earlier, but wouldn't equate to any difference in energy savings...

 

[MisterSandals]

Batteries discharge to 30-40% overnight and are fully charged by 1pm. Higher efficiency would only mean the batteries are fully charged a little earlier, but wouldn't equate to any difference in energy savings...

You have nicely engineered a system that works with your AIO. Well done.

 

[AZ Solar Junkie]

You have nicely engineered a system that works with your AIO. Well done.

Yeah everyone’s needs are different eh. I might sing a different tune when I get more circuits/loads on mine next month when I get wired into the Pro Tran transfer switch. More loads overnight means the batteries will get lower and more loads during the solar day means less power going to the batteries for charging. Going to be a balancing act determining which loads to put on the solar system.

 

[time2roll]

Virtually no losses through the shunt.

 

[PotusGobbleBottom]

Going to be a balancing act

That act never ends.

 

[marionw]

What does the bluetooth app for the shunt show compared to what SA is showing?

 

[wattmatters]

Aside from what's been mentioned, some AIOs are notorious for poor measurement accuracy. Solar Assistant has this reminder posted on the Total's tab:

 

[PotusGobbleBottom]

What does the bluetooth app for the shunt show compared to what SA is showing

I have the shunt piped right into solar assistant via bluetooth on the raspberry pi. They are the same and in sync.

 

[marionw]

This is the data available from a Victron Shunt via it's VE.Direct port. The Inverter is on but idle, no battery charging and no Inverter AC Load:

PID 0xA389 Product ID
V 52408 Channel 1 Battery Voltage
I -1755 Channel 1 Battery Current
P -92 Instantaneous Power
CE -221331 Consumed Amp Hours
SOC 279 State-of-charge
TTG 0 Time-to-go
Alarm OFF Alarm Condition Active
AR 0 Alarm Reason
BMV SmartShunt 500A/50mVModel Description
FW 0414 Firmware Version (16 bit)
MON 0 DC Monitor Mode
H1 -291483 Depth Of deepest Discharge
H2 -221332 Depth Of Last Discharge
H3 -123791 Depth Of Average Discharge
H4 2 Number Of Charge Cycles
H5 0 Number Of Full Discharges
H6 -651399 Cumulative Amp Hours Drawn
H7 5974 Minimum Battery Voltage
H8 56627 Maximum Battery Voltage
H9 447960 Number Of Seconds Since Last Full Charge
H10 1 Number Of Automatic Synchronizations
H11 0 Number Of Low Voltage Alarms
H12 0 Number Of High Voltage Alarms
H15 -7 Minimum Auxiliary Battery Voltage
H16 0 Maximum Auxiliary Battery Voltage
H17 3413 Amount Of Discharged Energy / Amount Of Produced Energy (DC monitor)
H18 4880 Amount Of charged Energy / Amount Of Consumed Energy (DC monitor)

There are an number of items that affect the accuracy of the shunt's reports, the biggest being how does the shunt calibrate it's knowledge of battery capacity and actual 100% SOC. My six EG4 LifePower4 batteries are at 98% SOC
Battery Voltage x Battery Current (multiply each for correct value i.e. 52408 * 0.001 for battery voltage and -1755 * 0.001 for current) does equal -92 Instantaneous Power but the SOC is wildly off.