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Smartshunt DC energy meter for case grounded alternator

I have a Smartshunt ready to install as a DC energy meter on my boats domestic alternator, but this has the negative via the grounded case and engine. I also have a separate engine battery and alternator but they share the common negative return via the engine. This will add to the existing BMV702 on the domestic batteries. I have seen many comments that in this case, you need to have a shunt in the positive cable.

Thinking about this, I believe that I can wire it up in the negative cabling per the attached sketch. The negative return from both alternators splits at the new Smartshunt to separate out the current from the two alternators so it will only measure the domestic alternator. In the existing wiring, the alternator negative, the ground and the engine battery -ve all connect to the -ve bus and this works OK with the BMV. The boat is steel hulled and it is not used for any negative returns, everything is fully wired to the -ve buses.

The sketch ignores fusing, isolation switches, minor wiring to the shunts.

Am I missing something in my wiring layout.


pwfarnell asked

0 Answers

ESS Inverter response too slow - tripping utility meter

Hello Community,

Our company is struggling with a number of installations in the Tshwane (Pretoria) region of South Africa. The municipality (utility provider) has rolled out the installation of Conlog meters. The majority of these meters are overly sensitive to reverse energy detection. One of the meter models is the Conlog BEC42X (Single Phase).

Many of our installations consist of an ESS setup like the following: MultiPlus II 5kVA, BlueSolar MPPT Charge Controller, Color Control GX, Carlo Gavazzi Energy Meter, BMV700 and a Lithium Battery.

Many of these installations, in the Tshwane area, are experiencing frequent tripping of the Conlog utility meter.

Some forums have indicated that these meters are tripping at a point as low as 20W over 15 seconds - or some 300 Joules of reverse (export) energy detected. This is incredibly sensitive and clearly the root problem. However, this is very difficult to resolve with the municipality (utility provider) and they are mostly unwilling to assist.

We have had to resort to setting the grid set point significantly higher than desired, sometimes around 300W and have had to limit inverter power, in some instances to as low as 750W. With these restrictions placed on the system, we are mostly unable to process (store and discharge) all of the solar energy available from the solar array resulting in compromised economic performance.

What can we do to improve the control of export power to the utility?

It is inevitable that some export energy will be supplied to the utility in a grid-connected ESS system, but one observation that we have made is that the MultiPlus & Quattro inverters appear to react quite slowly AFTER a large load is switched off - this observation comes from the Color Control display panel where we can see the grid import/export as reported by the Carlo Gavazzi Energy meter, as well as the amount of power being discharged by the battery, as reported by the BMV700.

Once a large load is dropped, can the inverter not reduce it's power faster to avoid overshoot and subsequent export energy being supplied to the utility?

From this link, we see that the response time of ESS has been limited to 400W per second as per ESS version 162... but now we need a work around?

This thread comments on a similar aspect:

After reading the above thread, can we not adjust the refresh rate and baud rate for the energy meter (Carlo Gavazzi) to aid the situation in swiftly recognizing the change in the grid import/export condition?

Alternatively, is the 100A:50mA Current Transformer a temporary solution for MultiPlus II ESS installations?

If this cannot be achieved with the ESS assistant, is there a combination of assistants that will allow us to operate in a similar fashion to ESS while overcoming the issues presented by the hard-coded rate limiting?

Thanks in advance for your input and suggestions.

Nicholas Herbst asked
logan-dunbar commented ·

4 Answers

ET112 energy meter / Cerbo GX. baud rate

I have a ET112 energy meter, a RS485 to USB (serial) cable and a cerbo GX. What is the serial baud rate (9600 ??, 115200 ??) the cerbo uses over the USB serial connections ?.

CONTEXT: the ET112 and the Cerbo are remote, and I am building my own device to connect the USB serial on the ET112 side to the USB serial on the cerbo side.

I know about the zigbee adaptors, but do not want to use those.

Thanks you

pabou38 asked
lifeingalicia answered ·

1 Answer

Ct clamp over ip ethernet.

Anyone know of a analog to TCP/IP transmitter/receiver?

Ct clamps are £15

Em24 £200+

So anyone know of a solution of sending ct signal over ip and then back so I can send it over ethernet. With parts less then £185....



matt1309 asked
lifeingalicia answered ·

6 Answers

Communication Problems with ET112: Modbus number not being shown

My system is not showing the Modbus Channel and other problems.


My system is a fairly standard ESS set up with Solar PV linked through to Batteries and grid metering via a Multiplus.

  • My set up is as follows:
  • 4kW grid tied Fronius PV inverter;
  • ET112 Carlo Gavazzi meter;
  • 3000VA Multiplus@48V ( ~V.xxxx494);
  • 2 x Pylon US3000 Batteries
  • Venus GX on v2.87 with ESS mode.

The Start of the Problems

The system was working well until I started getting "PassThru" errors. After some research this was fixed temporarily by simply unplugging the Victron RS485 lead and plugging it back in again. However the errors returned. I shortened the 5 metre RS485 cable down to the minimum needed of 50cm but this only cured the problem intermittently, and the GX and the ET112 would not communicate. I also tried different combinations of direct wiring to the ET112, and via the RJ45 port. Although I tried termination of the RS485 cable, (by shorting pins 3 & 5 with a cut down Ethernet cable). Given the short lengths of cable this did not seem necessary, and it made no difference.

I've now replaced the RS485 cable (for a newer style one). The ET112 is now recognised by the Venus GX, but not exactly as it should. It won't show the Modbus Channel under the "Energy Meters" menu in the GX. It does show the serial number of the ET112 (as checked from the Carlo Gavazzi software), but not the Modbus address, ie 257341A, per screenshot).

Phase type 
Grid meter 
Single phase 

I've managed to communicate with the ET112 directly via the Carlo Gavazzi software, and it appears that the modbus channel that the ET112 is now on is Channel 1 (and not 30, or 32 etc).

I have tried getting the Venus GX to "forget" the existing ET112 and try to recognise it again when I have manually changed the Modbus channel to 30 via the Carlo Gavazzi software. However the GX and the ET112 will not communicate with the ET112 when the channel has been changed to 30, even after rebooting and "forgetting" the Grid Meter and rebooting again.

I am not sure that the GX has completely forgotten the ET112 even after I press "Remove Unused Devices" (or whatever words it is) under the Device list of the GX. The same serial number of the ET112 still appears in the Settings\Energy Meters section of the GX.


So while the system is working, I am not sure exactly what is happening - how do I get it to completely forget the ET112, or how do I get the GX and the ET112 to talk to each other when the Modbus address is manually changed to eg 30?

What is the significance of the Modbus channel number being missing from the GX\Settings\Energy Meters section (even when the Devices List shows there is a working Grid meter)?

I bought a new ET112 in case the meter was the problem, but there is no evidence that the ET112 is at fault. I am reluctant to swap out the old ET112 as this needs me to get involved with the AC wiring and I don't want to if I don't have to.

I would like to get the system to recognise more than one meter eventually as I can then put the spare ET112 meter on the PV side of the set up too.

Thanking you all in anticipation of your assistance.


mikepaterson asked
matt1309 answered ·

2 Answers

Can a BMV-700 be configured as a DC Energy Meter?

I've read the thread about a Smartshunt being configured as a DC Energy Meter, and a vendor webpage indicates that BMVs (the page doesn't say only 712's) can be as well. Can a BMV 700 be configured as a DC Energy Meter? We have a couple of BMV 712's and the option in VE Connect shows up, but not on the BMV 700's when connected to a bluetooth dongle. BMV700's firmwares are up to date according to VRM. I just want to be sure I'm not missing someting and if they can or can not as I'm determining what I add'l Victron kit I need to order ... BMV712's or repurpose a couple of BMV700's if they are capable of DC Energy Meter mode. TIA

Raymond Walker asked
Raymond Walker commented ·

1 Answer

Data Showing incorrectly - 3 Phase Grid, 3 Phase PV (Enphase), 1 Phase ESS (MultiPlus-II)

We are using two ET340 Meters, one for the incoming Grid and one for the PV.

The calculations of AC Loads and Critical Loads are very obviously wrong.

Basic Drawing:


Tests Done:

With no PV


With just L1 Enphase inverters on:


With all 3 phases on:


If we change the Meter programming to AC Input (intentionally wrong but just testing):



Incorrect load showing on critical (as expected because the PV is physically on the AC output.)

It seems that the loads are being calculated wrong. L2 and L3 are showing critical load when there is no MultiPlus on there phases and the total calculated plus the grid export is higher than the Production by nearly double.

Try turning “Inverter AC output in use” which removed the Critical load calculation and the AC Load calculation still reads wrong values.



Anything else we can try?

ben-stanton asked
ben-stanton commented ·

1 Answer

Multiplus: I don't want to use battery power on AC2 dump load

I have a MultiPlus II 8000, MPPT RS450/100 and 18 x 370w solar panels. I have a 8kw lithium battery bank. I am not allowed to feed into the grid. I don't have a ET112 energy meter installed currently. My whole DB board goes through the system. Critical loads on AC1 and 2 geysers and a small stove on AC2. I live in SA and we have blackouts twice daily for 2 hours Which uses about 30% of my battery bank (maximum).

When the geyser and stove switches on the solar power is usually sufficient but sometimes there is a shortfall and is supplemented by the battery instead of the grid. What are my options here?

1) Is there a way to program ESS / another assistant to ensure that the battery is not used for AC2 loads?

2) Do I need to take these loads off the AC2 and bypass the system and then use the ET112 Energy Meter to power these extra loads with excess solar power and grid only.

A best practice and long term solution answer will be appreciated. Thanks.

jond asked
lifeingalicia answered ·

2 Answers

Very long RS485 cable for ET112


I have a question about my methodology for running a long RS485 cable, beyond 30 meters, especially in regards to the USB-RS485 adapter and the wiring for the 120 Ohm termination resistors either end.

I have read through the available documentation from Victron and FTDI and I have arrived at what I *believe* is the correct method I should be using.

Can someone please confirm that my understanding of this is correct based on my attached picture.


In case any questions come up in regards to moving the Multiplus/MPPT/Cerbo/Batteries closer, please note I do not have the space to do this. I can only feasibly extend the AC-in side to my main consumer unit and extend the RS485 connected ET112 data back to the DC installation 35 meters away.


jc2010 asked
matt1309 commented ·

11 Answers

ET112 + Current Transformer - AC Loads reading

It's been a known fact that ESS system with ET112 as grid meter is responding very slowly to high load change and that the same system with CT clip is responding much quicker.

On the other hand ET112 is much more accurate in terms of energy usage calculations.

I thought it will make perfect sense to use both... CT to get fast responds and ET112 to get accurate grid usage readings. So I've wired up my system like on the diagram below:


I've noticed that after connecting CT to Multi I'm getting fast responds to load as expected but, on the VenuxGX diagram my AC Loads has not been calculated correctly (the actual load is about 800W), the meter settings is set to Settings-->ESS-->Grid Metering-->External Meter


Correct diagram, but AC Loads inaccurate

So to get accurate AC Loads readings I had to set Settings-->ESS-->Grid Metering-->Inverter/Charger, and now I'm getting accurate readings on the AC Loads, but the diagram is incorrect:


AC Loads correct, but wrong diagram

Is there a way to use both ET112 and CT clip and set this up to show correct diagram with correct AC Loads readings?

mysik asked
mysik commented ·

3 Answers

ET340/ PV on output

I think this question is what i am asking, the answer seems to be yes, its fine, but then some issues arose, so i thought i'd double check.

I want to use a single ET340 to both monitor total grid usage, for both direct loads and via the multiplus, and also monitor solar production on 'output' connected ac coupled PV.

Is this connection acceptable?

(Electrically, i don't see it as any different to 3 phase going off to multiple multi-pluses. )

Unfortunately, while the microinverters report their production via a console, the noise from the multiplus seems to disrupt the power line communication, so they typically report very infrequently. I'm hoping the ET340 will show (more) accurate production. I realise ESS will sort it out anyway, but i'd like to know what is going on.


russ asked
maa answered ·

3 Answers

What meter do you use over 65 A ?

hey, What meter I can use to measure grid 125 A per phase ? Is there any supported device by victron ?

mk1 asked
wkirby answered ·

1 Answer

Second Energy Meter deleted but remains on GX Device

Client had an ET340 and then changed mind and got a single phase supply and replaced ET340 with a ET112.

I deleted the ET340 that "had not been seen in x days" from Device List, but it is still showing in Venus OS and the readings we're getting on VRM are bull:


Feed in is disabled, setpoint is 50W:


Device list:


Warwick Bruce Chapman asked
blacksun answered ·

3 Answers

Unbalanced load in a 2x Multiplus II 3000/48 system (Germany)

Hi there!

The new Multiplus II has anti-islanding and a lower standby-consumption than the classic one at the same price (I hope it will be the same quality anyway ;)). But it is only available as a 3000VA Version. In an ESS-system this normally would be enough to providie enough power for the most devices, e.g. a washing machine. Unfortunately if you strive to get 100% self consumption in summer you can only use one device at the same time. So in an average household you need at least two Multiplus II if you don't want to turn the lights or TV off when the washing machine is running.

There are countries with a monophase utility grid like some areas in Italy, which would make this easy. But there are also countrys with a 3-phase grid utility like Germany.

Now in Germany and other countries the maximum unbalanced load of the phases is allowed to be 4,6kVA. Btw: Is that why there isn't a 5000 Multi II, yet?

I have one question about this "problem".

(How) can I provide 4,6kVA to all three phases with the ESS without buying a 3-phase Multiplus 5000 system with external anti-islanding? I think (but don't know) that 2 parallel MP3000 aren't allowed in only one phase, although that would be the best and cheapest solution with an energy meter and phase compensation. When using a 3-phase 3000-System and there is a load of 4000W on L1 - what happens? Two parallel Multi II could cover this to 100%, no matter on what phase it is needed (when having the correct power meter). But is it allowed?

If it matters: there would be a 20kVA-Fronius-Symo-3phase-Inverter at the AC-In of the Multis (because of the 1:1 rule) and a small 1,2kWp DC-Victron-MPPT.

Thank you very much!



porcini asked
lifeingalicia answered ·

2 Answers

ET112 Neutral wiring UK Single Phase


When looking at the ET112 wiring diagram it shows two ways of which this can be wired. Can the ET112 have the main neutral wired through it like figure 3? My electrician wants to check to make sure these are designed to have the main neutral fed through.

This is the UK and we have a Single phase, 100amp supply fed via 25mm tails after the meter.


Many thanks

jon-young asked
jon-young commented ·

2 Answers

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