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geraldb avatar image
geraldb asked

VE.Bus - Charge Voltage Setpoint - where is this value entered?

VE.Bus System - Charge voltage setpoint 30.4V.pngVC-Multi-General.pngVC-Multi-Charger.pngVC-Multi-Inverter.pngVC-Multi-Product-Info.pngHi - I could not find out despite studying the many instructions from where "the System" retreives the 30.4V Charge Voltage Setpoint!? Nowhere this value has been entered. Please find my Multiplus II settings. From the Battery supplier instructions the Charge Voltage shall be 29,2V - so I understood the "Absorbtion voltage" = "Charge Voltage"? - but the VE.Bus- Data records still shows me 30.4V - can somebody help me out please.

Multiplus-II
vebus-system-charge-voltage-setpoint-304v.png (9.8 KiB)
vc-multi-general.png (36.5 KiB)
vc-multi-charger.png (91.1 KiB)
vc-multi-inverter.png (87.3 KiB)
vc-multi-product-info.png (24.9 KiB)
3 comments
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kevgermany avatar image kevgermany ♦♦ commented ·
Need more info.

Is there a GX device in the system?

What other devices?

What type/make model of battery?


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geraldb avatar image geraldb kevgermany ♦♦ commented ·

LiFePO4 AmpereTime Batt Data 200Ah 24V.pdfDevice List - VRM Portal.pngHi, here are the requested data - for Battery in German - if required I can look after EN Version. Many thanks for investigation . CerboGX - VRM Portal.pngDevice List - VRM Portal.pngLiFePO4 AmpereTime Batt Data 200Ah 24V.pdf

Additional BMV-700 Settings for Battery. VC-BMV-700-Batt.settings.png

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cerbogx-vrm-portal.png (17.7 KiB)
device-list-vrm-portal.png (13.5 KiB)
lifepo4-amperetime-batt-data-200ah-24v.pdf (180.4 KiB)
Keith Arnold avatar image Keith Arnold commented ·

screenshot-45.pngI have asked the same question, no answers as to where this comes from. My system also does not have a compatible BMS. Also have battery BMV. VE.Bus Charge Voltage setpoint is on 57.5 V when in Bulk, it does change to the 53.5 V in Absorbtion and 51 V in Float. the latter i know where they set but the 57.5 V is a mystery. My battery BMS isolates the battery at 55 V so when grid fails and the multi tries to dump the excess power from AC coupled Fronius it spikes the DC voltage up to 57 V, battery does not like it, switches off, power fails. a few moments later everything returns to normal and the Multi starts up again. BMV700 regularly picks up High Voltage spikes, normally these spikes occur when the bus state changes from Bulk (57.5 V setpoint to Absorbtion 53.5 V. and no spikes when the setpoint changes to Float 51 V). I assume most of them are short duration and the BMS does not trip the battery.

So, anyone know where the VE Bus Charge Voltage Setpoint in Bulk is found?

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screenshot-45.png (180.8 KiB)
6 Answers
kevgermany avatar image
kevgermany answered ·

Sorry, missed your reply.

I don't know the definition of that metric.

But... the charging system is being controlled by the BMS in the battery (current limit overruled by remote) This overrides your settings, which are there for safety in case the BMS communication fails.

First guess is that the value comes from the BMS and that the datasheet gives slightly more conservative values in case the charger is a bit over enthusiastic.

Ho pefully someone else chimes in.

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geraldb avatar image geraldb commented ·
Hi - not sure if I use this community function correctly - should I reply in here (add comment) or reply with "Answer" as I did right now?
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Paul B avatar image
Paul B answered ·

the charge settings are normally set in your multiplus - however if you have a connected BMS to the cerbo then the BMS overides this setting and this is then controled by the batteries bms and dvcc in the cerbo, so its not a cut and dried answer

using the ve configure program and a mk2 usb adapter you can change the multiplus charger settings - but the bms settings well that depends on the bms installed

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geraldb avatar image
geraldb answered ·

Thanks @kevgermany and @Paul B for your reply. As the Battery BMS is not connected to anything (its installed Battery internally without any communication to the outside world) I assume you're saying that the BMV-700 is acting as a Battery BMS? Attached are the actual settings of my BMV-700 - "Charged voltage = 27,3 V" .... the BMV-700 is connected via VE.Direct to the Multiplus.... Hope this can help, Thanks!VC-BMV-700-Batt.settings.png


vc-bmv-700-battsettings.png (52.5 KiB)
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Paul B avatar image
Paul B answered ·

the bmv does NOT control the charging system in ANY way, its a battery monitor.

the charged setting is used only to reset the soc to 100% when that condition is reached. it is not a bms and does not change or act on any charging systems except its own internal SOC reading

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JohnC avatar image
JohnC answered ·

Hi @GeraldB I've reposted your screenpic.. 1675163550536.png

That looks like a custom widget to me. The name in white is chosen by the creator, but the one in blue I don't think is editable, and is chosen from the section called 'VE.Bus System'. And I can't find anything called that on my VRM.

If you didn't create it, maybe a remnant from who-knows-where. If it turned up on my VRM I'd just delete it.



1675163550536.png (34.2 KiB)
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geraldb avatar image geraldb commented ·

Hi @JohnC ... just for your Information - I believe everybody should be able to create this custom widget..... have a look to the screenshot, you do not find this paramater in your selection? Custom Widget Charge voltage setpoint.pngVE.Bus System - Charge voltage setpoint 30.4V.png

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custom-widget-charge-voltage-setpoint.png (33.6 KiB)
JohnC avatar image JohnC ♦ geraldb commented ·
@GeraldB

I found it, ta for the education. On my system devoid of data. But I've no bms either. And no idea of it's intended purpose.

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geraldb avatar image
geraldb answered ·

Yes @JohnC created by myself because I was (I am) interested in the "Charge Voltage Setpoint" ;-) ... So as far as I have learned this setpoint will be given by the connected BMS. In my case, no BMS is connected ..... so, as @Paul B said, this value will be set in the Multiplus...here are the currenty charger settings in my Multiplus...no value at 30,4V.....

So do I have to understand I should not care about this value given from the VE.Bus System? But how to find out the "Charge Voltage setpoint"? It's not the same as the "Absorption Voltage" , right, it must be higher.....VC-Multi-Charger.png


vc-multi-charger.png (91.1 KiB)
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JohnC avatar image JohnC ♦ commented ·

@GeraldB

Ok, so maybe a remnant from an attempt to install a bms, and it's stuck in an inaccessible register. May be harmless, but I don't know that for sure. Maybe try the Redetect/Reset options to see if that will rid you of it..

1675174093178.png

That's not to say VRM will rid itself of the history of it being there though..

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geraldb avatar image geraldb JohnC ♦ commented ·

Hi @JohnC - I've "rededect" and "reset" the System , but once I switch on the multiplus this data jumps to 30,4V and remains there..... So, maybe this value is wrong or better say, not active - but how can I verify the "Charge Voltage Setpoint" - Value? How can I know what value the Multiplus works with?

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JohnC avatar image JohnC ♦ geraldb commented ·
@GeraldB

Probably just confirm it by the actual results you get. As long as the Multi isn't showing 'External Control' or something strange, then it should work to it's own settings.

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kevgermany avatar image kevgermany ♦♦ commented ·
Could be coming from the battery's BMS
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geraldb avatar image geraldb kevgermany ♦♦ commented ·
No Battery BMS connected.....
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Keith Arnold avatar image Keith Arnold geraldb commented ·

jip very frustrating. no BMS on mine either. i added a screen shot of mine. i get a voltage spike every time the charge voltage set point changes. the phantom setting 57.5 V is in bulk, when the bus state changes to Absorbtion (53.5 V set in multi) the BMV registers a spike. change to float is no spike. NO battery likes repeated high voltage spike! so this is something i would really like to get resolved.screenshot-45.png

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screenshot-45.png (180.8 KiB)