# Multiplus II 2x120 flapping between Inverting and Bulk Charging **URL:** \ **Category:** DIY\ **Tags:** rv, multiplus-ii, victronconnect, diy\ **Created:** [8 November 2024 00:21 UTC](https://community.victronenergy.com/t/multiplus-ii-2x120-flapping-between-inverting-and-bulk-charging/10855 "2024-11-08T00:21:59Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Persius](https://avatars.discourse-cdn.com/v4/letter/p/a88e4f/32.png) [@Persius](https://community.victronenergy.com/u/Persius)\ **Post date:** [8 November 2024 00:21 UTC](https://community.victronenergy.com/t/multiplus-ii-2x120-flapping-between-inverting-and-bulk-charging/10855/1 "2024-11-08T00:21:59Z")
I have a Multiplus II 2x120. It’s plugged into shore power. It’s connected to two Victron 200ah lithium batteries. The Multiplus is flapping between inverting and bulk charging every 20 or so seconds. I do not see any alarms with the connected CerboGX I connected it to a laptop running Victron Connect and a MK3-USB. I tried to edit the settings, but it says it’s running a unsupported firmware and I am unable to make any changes. I clicked on Product Info to update the firmware. None of the listed firmware options are apparently compatible with my Multiplus. Thoughts? I’d manually update from a local file, but have no clue where the firmware files are. ---
**Author:** ![Bki](https://avatars.discourse-cdn.com/v4/letter/b/f08c70/32.png) [@Bki](https://community.victronenergy.com/u/Bki)\ **Post date:** [9 February 2025 18:19 UTC](https://community.victronenergy.com/t/multiplus-ii-2x120-flapping-between-inverting-and-bulk-charging/10855/2 "2025-02-09T18:19:00Z")
> [@Persius](#): > > I have a Multiplus II 2x120. It’s plugged into shore power. It’s connected to two Victron 200ah lithium batteries. The Multiplus is flapping between inverting and bulk charging every 20 or so seconds. I do not see any alarms with the connected CerboGX I connected it to a laptop running Victron Connect and a MK3-USB. I tried to edit the settings, but it says it’s running a unsupported firmware and I am unable to make any changes. I clicked on Product Info to update the firmware. None of the listed firmware options are apparently compatible with my Multiplus. > > Thoughts? I’d manually update from a local file, but have no clue where the firmware files are 1/ First: Victron connect work better without shore power: only battery. 2/ Check if you have the last version of “victron connect” on your laptop. You need to unintall the old “victron connect” before and download and intall the new. May be your old “victron connect” don’t know the multiplus II. ---
**Author:** ![ChriSolar](https://avatars.discourse-cdn.com/v4/letter/c/e47c2d/32.png) [@ChriSolar](https://community.victronenergy.com/u/ChriSolar)\ **Post date:** [4 December 2025 22:14 UTC](https://community.victronenergy.com/t/multiplus-ii-2x120-flapping-between-inverting-and-bulk-charging/10855/3 "2025-12-04T22:14:03Z")
Did you ever solve the problem? My MP 12/1200/50 is doing the same thing… ---
**Author:** ![AteTeVoortwis](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@AteTeVoortwis](https://community.victronenergy.com/u/AteTeVoortwis)\ **Post date:** [20 October 2026 13:21 UTC](https://community.victronenergy.com/t/multiplus-ii-2x120-flapping-between-inverting-and-bulk-charging/10855/4 "2026-10-20T13:21:16Z")
I’m running into this as well. My setup: - Multiplus 12/1200/50 - Connected to 230V shore power (measuring 230V ± a couple of volts at the terminals, also under load) - Lifepo4 140Ah battery connected, at 99% SOC - 1kW consumer connected (heater) The MP will start bulkcharging the battery with the shorepower connected through. The ‘something’ happens, that causes the shore power to be rejected and the bulk charging to stop. I’m not sure which happens first. In VE Configure I do see a Low Voltage warning, but I cannot see the AC IN voltage drop. Also, it seems related to the MP, the load is not changning… Anyone with an idea?