Hi, I have set up VRM to send me Warnings and Alarms and I often receive High DC Ripple Warnings that typically last for no more than 20 seconds. Investigating VRM I note these warnings often happen when drawing only moderate grid power (eg 1KW on a 3KW Multiplus) and an archived post on this forum suspects DC Ripple warnings could be due to intermittent heavy DC loads. At the moment of a warning yesterday, the “System - Battery Voltage and Current” graph indicates drawdown from the battery of only 2A but the “VE.Bus DC Voltage and Current” graph indicates a momentary current of -80A, any explanations would be helpful. My inverter is a Multiplus 12/3000/120-16, firmware version 413 and VE.Bus version 2609413. I note that Victron advise not to update the firmware unless you have a problem but I think v413 must be quite old now, should I upgrade to the current version? Thanks in advance.
Yes pls upgrade to 552
Good morning,
Did the firmware upgrade solve your ripple alarm or is it still coming now and then with heavy loads?
If so, can you show that in a graph from VRM?
See this topic also, VDC ripple improvements
Regards, Jeroen.
Hi Jeroen,
Thank you for your enquiry and link to your topic thread. I have set up VRM monitoring for ripple and when compared against the high DC ripple warnings I really can’t see anything adverse on the ripple graph which stays within 0.1V peak to peak, I’ll see if I can attach a screenshot. I have postponed updating the firmware until after Christmas.
Regards Ian
Good morning Ian,
Indeed, the ripple is so high and so short it is most probably “missed” to register in the graph.
You can open this graph and use the second slide bar to go to detailed view.
That might show the ripple.
Also at that point your DC voltage should drop for the same period and the amperage very high.
Do you have a DC amperage clamp meter, with that one you should be able to see how high the amperage is when you start your heavy load.
Please double check all cable connections, since at low amperage with a “dirty” cable lug the ripple and voltage drop might be good, but at high amperage you might see this.
Also, check inside your inverter if the cabling there is tightened to the mosfets and capacitors, if just one is slightly “loose” you might see also what you experience.
If nothing helps, then 2 of these babies, Kemet ALS71A184MF040 capacitors (or others) should solve your issue.
These can handle about 27A each, giving you an healthy boost when starting heavy loads.
Mount those directly on the battery connection in the inverter with as short possible cabling.
Before connecting, charge these first through a resistor, as these really burn connections when not charged.
Regards, Jeroen.
Use a DMM and check the ripple with it.