High DC Ripple on VE.Bus System and quickly clearing, unclear cause

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bholla asked Apr 23, '24

High DC Ripple on VE.Bus System and quickly clearing, unclear cause

Hi folks,

On two occasions in the past two weeks (after doing firmware updates for all applicable components) I've received High DC Ripple warnings on the VE.Bus. These warnings always seem to clear within a minute or so. The most recent time the system was under a fairly heavy load (air conditioner) and connected to 30a shore power (the system powers an Airstream).

I've reviewed past related posts and cannot seem to find a likely cause. It's recommended to check connections but I'm unsure which ones I should be focusing on. Aside from solar panels, the system is within one of the minimally accessible storage bays under the bed. I checked connections between the batteries and everything seems solid. Also, I have basic electrical knowledge but am far from an expert. The Airstream dealership installed the system.

Here are screen shots from my system monitor. The latest occurrence was at 17:00. Is there anything here I should address? What about the cable connections? Are there connections I should make sure I check?

System:

Cerbo GX (Firmware: v3.30)
MultiPlus-II 12/3000/120-50 120/240V (Firmware v483)
SmartShunt 500A (Firmware v4.14)
SmartSolar Charger MPPT 100/50 (Firmware v1.61)
4 100ah BattleBorn Li batteries + 4 100W solar panels

Thank you! I appreciate everyone's help.

Bill

Multiplus-II VE.Bus ripple

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screenshot-2024-04-22-at-55841pm.png (689.3 KiB)

screenshot-2024-04-22-at-55902pm.png (384.0 KiB)

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Alexandra ♦ commented · Apr 23 at 06:15 PM

@bhollaThe fact that is happens under high load pints to the DC side being not quite enough.

Common cause is undersized battery bank(not in your case) undersized cable (2x 1/0 min requirement) or high resistance on the DC side.

Are the batteries daisy chained? Can also be the issue.

Loose connections as well are a big one.

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bholla Alexandra ♦ commented · Apr 23 at 11:56 PM

Thanks, @Alexandra. They appear to be wired in parallel, not series (which I assume you mean by daisy-chained?).

When you say loose connections, can you be more specific on which connections I should be looking at? Also, if I'm examining cabling, is the standard encoding similar to 2x 1/0 so I know what to look for? I'm coming at this with minimal experience.

Lastly, it's interesting that it doesn't always happen under heavy load. It's been twice (3x in one night, and 2x in the afternoon two days ago, each occurrence for <30s) in the past month, and we've had light and heavy load since. If it happens again I'll look at each of the charts to see if I can discern a pattern.

Also, no rebooting has occurred. Just the warnings.

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Alexandra ♦ bholla commented · Apr 24 at 04:11 AM

If they are not on a bus bar, what happens is the end batteries get hurt while the middle ones are on holiday. There is a neat layman explanation in wiring unlimited by victron as to why.

Are the links between the batteries also beefy ones?

So you would need to check all battery terminals, all connections to fuses and switches. And as @philippe mentioned the actual fuses and volt drop is a good indicator that something is dragging in the system.

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bholla Alexandra ♦ commented · Apr 24 at 08:24 PM

The links appear to be pretty beefy. And they're all solidly attached to the battery terminals. I'll check the other areas though.

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Modifications Space

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Answer 1 · 2024-04-23T18:34:23Z

philippe answered · Apr 23 at 06:34 PM

I had it yesterday under heave load.
After I noticed the system rebooted very often, I noticed when under load de voltage dropped from14,2 to approx. 6V
The fuse (63A) between the battery and the system melted but not completely.

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