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andyjenkins01 avatar image
andyjenkins01 asked

Multiplus DC Input Low Shutdown and Restart Range

Hello,

I have a 12 volt system aboard a Narrowboat with a Victron Multiplus 12/3000/120 inverter charger. I am using a bank of four 115 Ah Lead Acid batteries wired in paralell with three 320 watt solar panels and a Victron 150/85 MPPT controller. I have a Victron Venus GX to connect all the units and log to VRM.

I want to set the DC Input low shutdown on the inverter to around 12.4 volts but this means the DC input low restart value is a whole 1 volt higher at 13.4 volts due to the limitations of the VE configure software.

My only source of power into the boat is through solar so this can take half a day to reach. In reality I would like the restart to happen at maybe half a volt higher than shutdown at around 13 volts. This would allow for any bounce of the voltage once the shutdown happens, the batteries usually come back up by about 0.1-0.15 volts but no more.

I understand the reasons for the 1 volt difference to counter for the bounce in values but after searching the forums and finding this post https://community.victronenergy.com/questions/1366/feature-request-allow-dc-input-low-restart-voltage.html and in particular this section

"Hi all, last Thursday we released the update of VEConfigure allowing a 0.25V hysteresis (for 12V, its 0.5 for 24V and 1 for 48V) between the DC input low shutdown setting and the DC input low restart level. See above for details. "

I thought this would mean the limit had been reduced but on VE Configure version 90.04.226 its still 1 volt.

Can anyone help please, am I being totally dim, or is there anyway to reduce the 1 volt limit between DC Input Low Shutdown and DC Input Low Restart

Thanks in advance

MultiPlus Quattro Inverter Charger
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3 Answers
harold avatar image
harold answered ·
Why don't you use SOC % as switch on/off value?
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andyjenkins01 avatar image andyjenkins01 commented ·

Cheers for the reply. I never found the SOC to be anywhere near accurate. Am thinking now though perhaps I need to go back and check the wiring to the shunt on my BMV 702


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Mike Dorsett avatar image
Mike Dorsett answered ·

referring to :Interfacing with VE Bus products - MK2 Protocol 3.12.doc, there are2 registers, one for the low bat volt setting, and one for the hysterisis.( page 20, 7.3.11.2 Settings, lines 11&12). Use a Mk2 or Mk3 interface and program them directly?

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andyjenkins01 avatar image
andyjenkins01 answered ·

Thanks miked, I was using VE Config software but the allowable range between Low DC input Shutdown and Low DC Input Restart was still 1 volt in that software despite the changes in the link I posted above.

Subsequently I checked the Firmware on the Multiplus and somehow and I really cannot understand how it was massively out of date version 430 yet I am 100% certain I have updated this in the last few months, so somehow its reverted backwards. Anyway I updated to the latest firmware 482 and was then able to access the quarter volt range for shutdown.

Also with the old firmware I had no access to use SOC to shut down the inverter in VE Configure, as Harold suggested even with Battery monitor selected the boxes were not visible, but since the update that is now available so I will probably use that once I have reworked the wiring from the previous owner to make sure all the negatives go through the shunt. Might need a busbar though as there are a lot of em.

Thanks for your help and suggestions.


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