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Can the Cerbo GX be connected directly to solar panels without solar chargers or an inverter?

Hello,

I am curious about connecting a Cerbo GX to solar panels.

What is required to do this?

I suspect current transformers are required.

Which current transformers? How are they physically connected to the Cerbo GX?

blue-sails asked
blue-sails edited ·

2 Answers

Metering Overall DC Loads (and Excluding Sources) When System Includes a Third Party Inverter/Charger?

Disclaimer: While I am somewhat experienced in the area of off-grid electrical systems, I have yet to have any hands-on experience with Victron's products, so the following question comes from the perspective of someone who has only been able to read the datasheets and manuals.

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A friend of mine is tired of having to run the noisy fuel-guzzling generator every day to recharge the battery bank on his 49 ft sailboat. Instead of incrementally installing random PV panels until the problem goes away, he wants to first install equipment for recording his DC usage this cruising season so that he can determine his real-world requirements and design a system that balances the desire for extra capacity against seaworthiness concerns and aesthetic considerations.


The plan is to meter the loads downstream of any charging equipment, so as to not have the data obscured when the "service"/"house" battery bank is being charged, such as when motor-sailing or running the generator. For typical DC loads, this is fairly straightforward, and Victron's SmartShunt product in "DC energy meter" mode looks like a good option. If combined with one of Victron's "GX" products, I gather there is even the option of taking the sum of the values from multiple SmartShunts in "DC System" mode, which would be convenient if my friend later decides that he wants to get collect data on individual system branches while still seeing/recording his overall energy use.


The main complicating factor is his third party inverter/charger, which can either be a DC load or a DC source, depending on whether or not he's got the generator running (or is connected to shore power). Short of replacing the inverter/charger with discrete devices, I can think of a few approaches to this issue, some of which are better than others, but none of which seem ideal:

  • We could install a single SmartShunt downstream of the inverter/charger, but then we'll fail to account for all of the DC that goes into supporting AC devices via the inverter.

  • We could install parallel SmarShunts (one for the inverter/charger and one for everything else), but then I would imagine our "DC System" readings in the GX software will be thrown off whenever the inverter/charger is in charging mode.
    • A less-than-complete workaround here would be to suppress/zero-out the readings from the inverter/charger's SmartShunt whenever the inverter/charger is acting as a source. Is there a way to do this in the GX software? If not, has anyone achieved this by using a high-current relay/contactor to bypass the SmartShunt and short the inverter/charger's DC- connection directly to the upstream DC- bus? (I'm imagining an AC relay/contactor that is activated whenever generator/shorepower is live.)

    • I have characterized the workaround discussed in the previous sub-point as less-than-complete because it fails to allow us to take into account for what the DC inverter's consumption would have hypothetically been if generator had never been switched on. Does anyone have a solution here? Does Victron have a standalone GX-compatible AC current sensor that we could use to record the load on the third-party inverter/charger's AC output at times when it is in AC bypass mode due to generator/shorepower (and only at those times)? The idea would be to convert use the data for these periods into estimations of what our inverter/charger's DC use would have been had the generator/shorepower not been online, taking into account the inverter's conversion loss.


Thanks in advance for any solutions!

aaron508 asked

0 Answers

Monitoring of non-PV DC generation through CCGX

This has been mooted as a possible new feature for some time. Is there any prospect soon? I have three systems that could do with this, or a better work around than the 'Has DC System' fudge.

@Guy Stewart (Victron Community Manager)

@Daniël Boekel (Victron Energy Staff)

@Oekosven

@48V on 56North

@Chase Martin

@Sam Salwei

Any news gratefully received!

Similar posts:

https://community.victronenergy.com/questions/46329/integrate-a-2000w-48v-dc-wind-turbine-into-the-vic.html

https://community.victronenergy.com/questions/51762/two-dc-inputs-on-ccgx.html

jonaaal asked
wkirby answered ·

1 Answer

Inverter only plus 2 BMVs

I'm building a system for my RV. I have a 12V 460AH LiFePO4 bank with a JBD BMS (to be connected using 485-USB ). For that bank I also have a BMV-702 (to be connected via VE.Direct-USB ). I have a Victron BlueSolar 75/15 charger (to be connected via VE.Direct-USB ). I'll be adding an Inverter (Victron Phoenix 1200VA 12V/120V60Hz to be connected via VE.Direct-USB ). I also have a 60A converter configured for lithium charging. I want to add a second BMV (SmartShunt) to monitor converter output.

Is it possible to show this second BMV in the screen as another charging source in addition to the BlueSolar?

jimmym asked
jimmym commented ·

1 Answer

Smart shut as DC meter for DVCC - correct placement

I'm wanting to use a Smart Shunt as a DC meter instead of a battery monitor. (My BMS is providing battery monitoring) My goal is to use the DVCC features of the Cerbo GX to be kind to my battery, however I want to increase the charge current when I have a high DC load attached (solar dump load into hot water tank)


My understanding is that if I configure the Smart shunt as a DC meter the DVCC will then factor in any DC loads and increase the current charge limit. (CCL) - For example, charge current set to 25A as requested by BMS, but there is a 25a DC load, CCL will be set to 50A)


I want to know if I need to reposition my shunt in my circuit for it to perform this function correctly.

I have a relatively simple setup in a campervan:

Lifepo4 battery > lynx distributer as a busbar > Smart Shunt on the negative between battery and lynx.

Solar MPPT, Orion Smart DC2DC, Multiplus II, & DC loads all connected to the lynx busbar.


My question!

Should I move the Shunt to only be on the DC load negative or is it ok for it to remain on the main battery negative?


Obviously the Cerbo can only see and control the multiplus and mppt sources, the Orion is not monitored / controlled. I cant work out what will the DVCC will do if there is input from both the Orion and the solar while battery is full and dump load is on. e.g. What will happen if I'm driving with a full battery and have the dump load on? Will the DVCC compensate and allow the solar to dump or will it reduce the current.


Hope this makes sense, appreciate anyones thoughts before I go rewiring things!


liam-tuvey asked
liam-tuvey answered ·

2 Answers

BMV712 Battery Monitor vs DC Current Monitor

Maybe it is so simple, but looking at the BMV manual there is nothing about it, so I prefer to ask.

What is the difference between the 2 options?

I'm using it in a van, with a cerbo, mppt, Orion and multi. Configured as a battery monitor because the other option didn't exist when I bought it. Now with the installation of a BMS I'm not sure how do I have to configure it.

Any help please?

Thanks!

llubi asked
llubi commented ·

1 Answer

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