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Smart Shunts disappear from Cerbo on VE Direct/USB

Hello, this is the 2nd time I have lost a Smart Shunt from my VRM console.

I have 10 banks of batteries (each bank is a pair of 12v/206Ah SOL batteries, for a 24v/206Ah bank) Each bank has a smart shunt attached to monitor charge, voltage, current in and out, temperature and general condition of the pair of batteries making up the bank.

Each shunt is connected via a VE Direct/USB cable to a USB hub, and the HUB is wired to a Cerbo GX,. I have 2 such hubs, each connected directly too the Cerbo. One HUB holds 6 VE Direct/USB shunt cables, the other 5. This week, shunts labelled 4-5-6 disappeared. VRM shows they haven't been seen in 5 days. Using the Victron Connect Bluetooth app, they show up fine.

This happened to me last year, when one shunt disappear for several days, only to randomly rep-appear a few days later. My gut feeling is something is amiss at Victron server end, and perhaps the VRM instances are being misconfigured or blocked.

anyway, its very annoying, and any ideas what to try? (I have already tried plugging one in directly to a Cerbo USB port, disconnecting the cable completely. Replacing the cable, rebooting the Cerbo)


Graydon asked
Graydon answered ·

7 Answers

Smart Shunt and Phoenix strange behavior



I use in a Island setup a Victron Smart shunt (500A/50mV) to measure the current from the battery to a Victrom Phoenix without and a 48V/12V Inverter for 12V LED lighting.

If the 48V/12V Inverter sucking energy, everything is a s expected, the Smart shunt shows a negative energy consumption. But if the Phoenix sucking energy, the energy consumption is POSITIVE!!

What is wrong here, someone have a idea, what is the problem?

buddhafragt asked
buddhafragt answered ·

1 Answer

SmartShunt miscalculating Consumed Ah

Hi folks - I recently built a cabinet for a LiFePO4 house battery and Victron Orion-Tr Charger in the back of my truck, primarily to supply a Dometic 12v fridge. The setup works great, but the SmartShunt is miscalculating the amount of current used.

For example, yesterday, the SmartShunt went from 66% SOC to 100% SOC in three minutes. I anticipated it would, because the voltage was increasingly nearing the charger's specified Absorption voltage (14.4v) as I drove. The charger had already been on Absorption charge for nearly an hour of driving; and as I watched, it steadily increased voltage and decreased current, as it should. It was still reporting 66% SOC and -19.7Ah right before hitting the absorption voltage, and then it jumped to 100% SOC once the conditions for a full charge had been met (charge voltage, tail current, 3m wait).


I believe the discrepancy has more to do with discharge calculations than charge calculations: in another experiment, the SmartShunt showed a 0% SOC at 12.58v which should be somewhere in the neighborhood of 5% SOC for the LiFePO4 (and where I don't intend to take it regularly); but more to the point, it was showing that I had used 72.8Ah, from my 54Ah battery. So somehow the calculations are off in a way that reports more current loss than has actually occurred. I observe that the reported SOC is always lagging on each and every recharge cycle.

I'll post my settings below to see if there's something I can adjust to get accurate measurements.


- I don't believe the issue is with any of the full charge settings like Charged voltage, Tail current, or Charged detection time, because based on indicated voltage, full charge is being reported at the correct time.

- I don't know much about the Peukert exponent but perhaps it's something to look at. I've read here that the PE doesn't account for temperature, but I don't know how significant a factor that could be.

- Charge efficiency factor is set to 99% as a default for LiFePO4 batteries - we can adjust that if it could help.

- I don't know how the Current threshold is used, but this is the default, and we can adjust it.

- The Time-to-go averaging period is 3m by default; I changed that to 12m trying to even out the cycles of the fridge's compressor - when it's running versus when it's off - which report very different Time-to-go values.

- My battery is a Dakota Lithium 54Ah LiFePO4

Any help appreciated - I've read here on the Victron support forum that the defaults are only starting points and that massaging the variables is necessary in some cases - but this is off by such a significant amount.

itllgrowback asked
itllgrowback commented ·

7 Answers

Can Multiplus read Battery voltage and temperature from Cerbo GX?


My setup is constituted with DIY LiFePo4 battery bank, a SmartShunt, a Cerbo GX, a MultiPlus II and some MPPT. I'm in the middle of setting all this up...

And unfortunately, I have forgotten to wire the battery voltage sense wires and temperature sense cable between the battery and the MultiPlus. A wall is separating the battery and the MultiPlus II, and it's quite cumbersome to have to wire additional cables.

A Ve.Bus cable is wired between the MultiPlus and the Cerbo GX.

Can the Cerbo GX share the battery voltage and Battery temperature reading (both read from SmartShunt, wired in Ve.Direct) with the MultiPlus, so the charger and inverter knows these values and works efficiently?

fguiot asked
fguiot edited ·

3 Answers

MPPT charger taking voltage from SmartShunt instead of SmartSensor

The MPPT charger gets voltage value from the SmartShunt, if the shunt is added to the network.

But we can do better, with the SmartSensor, so it's a more precise "four wire" measuring, and that way also it disregards voltage drops along the cables and bus bars and so on.
So I have the Smart Battery Sense connected right at the battery terminals, I add it to the network, and it says sending battery voltage and temperature "to the network". Great.
I go back and check the MPPT charger and now it says it's taking temperature from the Smart Battery Sense, but still says it is taking voltage from the Smart Shunt. And I don't see a way to fix that.
The only way to have the MPPT charger to take both, battery voltage and temperature from the Smart Sensor, is to remove the shunt from the network. I am fine with that, as I think the most valuable function of the shunt is to tell me, the SoC of the battery, but I wold think SoC would be valuable data the MPPT could use.

cranky-yoda asked
ako answered ·

3 Answers

Smartshunt Configuration


At Christmas, I purchased a 200W solar array (Renogy), a SmartSolar 100/20 MPPT and a SmartShunt for our RV. I am having a real challenge configuring the seems like a little bit of hocus pocus to me. I am currently bench-testing before installing in the trailer come the spring.

Battery specs: 12V Lead-Acid (maintenance-free w/ vents) 105aH. History is unknown, Suspect it has seen a few 0% draw-downs. Came to me used. Small battery/small trailer - when this batt is dead, plan to upgrade.

Notes: battery can be charged from shore power or off vehicle starter battery/alternator when installed in trailer

Question 1: Some people seem to think that the 'Charged Voltage' spec on the shunt should be 0.2 or 0.3 V below the Absorption charge (for solar applications) contrary to Victron's recommendation of 0.2 to 0.3V below Float voltage. Does this not start counting the SOC down early?

Question 2:: With a .77A load on the battery in full bright sunlight, the SmartShunt is starting to countdown the SOC. Charged voltage currently config'd to 12.9. If the solar/MPPT is harvesting enough energy (it very much is), to keep the battery charged, why is the shunt counting SOC down?

Question 3: Can someone confirm if there's a calculation for figuring out how much SOC is in the battery based on voltage UNDER seems that resting voltage and voltage under load are two different numbers and trying to get the capacity based on resting voltage is futility in a trailer (must be such-and-such-temperature for such-and-such time, etc.). I had the battery on around a 1amp 12V load overnight and my batt showed 12.17V (under load) in the morning...but the SOC showed 85%...there's a mismatch here. Just trying to figure out what I should set my voltage alarm to.

Forgive the novel here, but my google searches haven't yielded much luck.

highlandbishop asked
kevgermany answered ·

3 Answers

possible to add wind and alternator (both via shunt to VRM)



I would like to know if you can ipdate the VRM web based to be able to add besides solar also other energy sources in the dashboard for example I have a shunt of the engine alternator and a shunt on wind silentwind turbine. it would be great






Daniele Calabrese asked

0 Answers


I have a Balmar 618 regulator without their smart shunt. I do have the VICTRON 712 battery monitor with its shunt. Can I use the 712 smart shunt instead of the Balmar one. if not, how do I add a second shunt to the system?

krogen48 asked
krogen48 commented ·

2 Answers

Smart shunt 500A blinking blue light consumption

Hello everyone,

I'm curious on the CO sumption ot the blue led light on the smart shunt. I have hooked up my shunt before the batter on off switch so even when the system is off I can monitor the voltage of the batteries through the shunt, but... How much does the light consume. I'm trying to find out how much it drains my batteries, thanks!

teddysx3 asked
Matthias Lange - DE answered ·

1 Answer

How to calculate expected tail current when battery internal resistance while fully charged is know?

My lead acid batteries are brand new. The manufacturer supplies a value of 0.33mOhm of internal resistance when a battery is fully charged at 25°C.

We are talking about a 12x2=24v battery bank. So let’s forget about the cables connecting the batteries (2x70mm2 BTW) and assume a total resistance of 12x0.33mOhm = 3,96mOhm

Under an absorption voltage of 28,8v at 25ºC how much tail current should one theoretically expect when SOC=100%?

Does anyone know the proper math?

hvalentim asked
kevgermany answered ·

2 Answers

SmartShunt DC Energy Meter question

I know this is still brand new and may not be in a production release yet but is anyone using a SmartShunt in DC Energy Meter mode to monitor a 3rd party solar controller? Does it show up on the monitor screen (CCGX/Touch 50)? How about the VRM? I would assume there is or will be a Voltage/Current widget for it?

I'm running the V2.80~33 beta of Venus OS on my Cerbo.


kamflyer asked
metz-producties commented ·

7 Answers

Shunt questions

I am seriously considering adding a 500 amp Shunt so Im reading the manual to find out more about them first . There are a couple of paragraphs that i cant get my head around .

" Although the battery monitor automatically detects the voltage, it is good practice to check if this setting is correctly set. These are the recommended “Charged voltage” values for lead acid batteries: "

They recommend 26.4v for a 24v battery , my charge voltage is much higher at 28.8v and i think many would also be around the same as mine so why do they give one much lower .

What is it that im not understanding .

ako asked
ako edited ·

1 Answer

Different measures of power, multiplus II and smartshunt



yesterday I realised that there was a huge different of power between the measured power from multiplus II and smartshunt, but the strangest is today I check that if I choose multiplus 2 like battery monitor the measured power is almost the same, but if we choose smartshunt the difference is appreciable enough, the load is the same in both examples.


palom170 asked
nuxland commented ·

0 Answers

Smart Shunt Red Wire Removal?

I am installing the 500 amp Smart Shunt in a new and fixed

location. The distance from the shunt to the battery P + possitive

is only a foot or so. I want to make a clean install and want to shorten

the wire and put on a new ferrule rather than coil up 25' of extra wire.

(I am big time exaggerating the length) How do I remove the ferrule and

red wire out of the shunt? I have seen 100% of people saying where to

insert it ... but nobody shows or tells how to remove it. I have read some

have damaged their unit trying to figure it out. I may just shorten it and put

a snap nut on it and be done... ... Thanks.

Pat asked
wkirby answered ·

1 Answer

Need Help with Smart Shunt and Battery Charger configurations

Hello Folks, I recently installed the LiFePo4 batteries (2x100Ah) in my offgrid trailer with Victron Smart Shunt (500A/50mV model) and Victron Battery Charger (Victron Energy Blue Smart IP22 12-Volt 30 amp).

The batteries do have built-in bluetooth as well and currently shows 27% SOC, checking individually since they are connected parallelly.

So my concern now is that when I have my shore power plugged in, it was in absorb state for few mins and then went to Storage.

Shunt does not show anything for SOC value and when I turn on the breaker it shows the -ve Amperage being consumed and nothing going in while its plugged into shore at the same time. When i have breaker turned off, it shows 0 draw being off, but shouldn't be +ve value be shown in shunt since its on shore right now.

I am attaching few pictures to show this as well and please see if someone can guide me through this config. I just want to charge them about 50-60% and then remove from shore as I am not taking my trailer out for now.




rmb asked
rmb answered ·

2 Answers

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