# MPPTs are being switched "OFF" and "ON" every few seconds - WHY? **URL:** \ **Category:** DIY\ **Tags:** gx\_device, beginner, cerbo\_gx, victronconnect\ **Created:** [18 April 2026 10:31 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672 "2026-04-18T10:31:27Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [20 April 2026 15:34 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/42 "2026-04-20T15:34:56Z")
Nothing that I can see โ˜น ![image](https://europe1.discourse-cdn.com/victron/original/3X/d/a/dafa4e96a586a4a7d2f2b0d162cb1754fe5a4b57.png) Should I try to set Limits here? ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [20 April 2026 15:37 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/43 "2026-04-20T15:37:30Z")
Tried this: ![image](https://europe1.discourse-cdn.com/victron/original/3X/8/7/87f6b2f7b64c79b81a78e7104dd9fdd111cdea58.png) Did not change anything in MQTT ![image](https://europe1.discourse-cdn.com/victron/original/3X/b/7/b70446a4e6e4ee63357431a51b22f5ad253f9ab9.png) ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 06:05 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/44 "2026-04-21T06:05:27Z")
This morning, I did a full โ€œpower on cycleโ€ of the MPPTs, the Cerbo and the BMS. Then I checked via MQTT again and found 2 sets of **BatteryOperationalLimits 1)** vebus 261 ( Venus GX VE.Bus port (ttyO5)) 2) vebus 276 ( Cerbo GX VE.Bus port (ttyS4)) and MaxChargeVoltage has different settings ๐Ÿค” ![image](https://europe1.discourse-cdn.com/victron/original/3X/4/2/42281041eced1d0fafe9c4c9d1ffb0ca53d1881d.png) Which one is used to control the MPPTs? ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 08:31 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/45 "2026-04-21T08:31:01Z")
It started again ๐Ÿ˜ญ ![image](https://europe1.discourse-cdn.com/victron/original/3X/0/5/051463896c83f9b2c93eaf13c871e5fa14f2ac4c.png) ![image](https://europe1.discourse-cdn.com/victron/original/3X/7/d/7dee1c99b3d3426e4c69418dd7f403a76497894d.png) ---
**Author:** ![chrigu](https://avatars.discourse-cdn.com/v4/letter/c/ba9def/32.png) [@chrigu](https://community.victronenergy.com/u/chrigu)\ **Post date:** [21 April 2026 09:03 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/46 "2026-04-21T09:03:03Z")
> [@Jurgen\_Pflug](#): > > ![image](https://europe1.discourse-cdn.com/victron/original/3X/2/6/264c93d99dfb90f93542fe037a4ab7a1c84dfe6f.png) What is the Lynx Shunt doing exactly, and why are its values completely different to the batteries BMS? Is the communication to the BMS solid? In DVCC you have set controlling BMS to auto, so if the BMS coms are not solid then maybe Victron falls back to the Shunt as the BMS, and since its values are totally different, DVCC then also reacts different. > [@Jurgen\_Pflug](#): > > **1)** vebus 261 ( Venus GX VE.Bus port (ttyO5)) > 2) vebus 276 ( Cerbo GX VE.Bus port (ttyS4)) I assume thats just a typo, otherwise it would be interesting to know how you combined two GX devices into one system. You can look up VE.Bus IDs in the VRM device list for example, to find out which devices are ID 261 and 276 ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 09:06 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/47 "2026-04-21T09:06:52Z")
> [@chrigu](#): > > What is the Lynx Shunt doing exactly, and why are its values completely different to the batteries BMS? The Lynx shunt is NOT monitoring the SolarBattery! It is used to keep track the DC Distribution in the house ๐Ÿ™‚ ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 09:08 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/48 "2026-04-21T09:08:19Z")
> [@chrigu](#): > > I assume thats just a typo, otherwise it would be interesting to know how you combined two GX devices into one system. > > You can look up VE.Bus IDs in the VRM device list for example, to find out which devices are ID 261 and 276 Those names came from the: CCGX-Modbus-TCP-register-list ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 09:13 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/49 "2026-04-21T09:13:44Z")
> [@chrigu](#): > > VRM device list for example, to find out which devices are ID 261 and 276 These IDโ€™s are NOT displayed in the device-list of VRM. I believe this is, because they are part of the Gateway (CerboGX) โ€ฆand do not show as individual VRM instances Last year, I replaced the Venus with a CerboGX MK2 The ID 261 is just a left over on MQTT Broker, from the previous installed Venus so disregard this ID ๐Ÿ™‚ ---
**Author:** ![chrigu](https://avatars.discourse-cdn.com/v4/letter/c/ba9def/32.png) [@chrigu](https://community.victronenergy.com/u/chrigu)\ **Post date:** [21 April 2026 09:44 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/50 "2026-04-21T09:44:02Z")
> [@Jurgen\_Pflug](#): > > The Lynx shunt is NOT monitoring the SolarBattery! > It is used to keep track the DC Distribution in the house ๐Ÿ™‚ Ok, but then the follow up question would be why the Shunt measures such a big voltage difference compared to the battery? I assume the shunt is measuring essentially busbar voltage, while the BMS of course measures voltage on the cells. So you are loosing 1.28V inbetween the busbars and the cells, which is a lot. Whats the output voltage on the MPPTs at this power level? ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 09:44 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/51 "2026-04-21T09:44:18Z")
> [@chrigu](#): > > s the communication to the BMS solid? In DVCC you have set controlling BMS to auto, so if the BMS coms are not solid then maybe Victron falls back to the Shunt as the BMS, and since its values are totally different, DVCC then also reacts different. I will disconnect the Lynx shunt, to see if it makes a difference - thx for the idea ๐Ÿ™‚ ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 10:13 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/52 "2026-04-21T10:13:48Z")
> [@chrigu](#): > > the shunt is measuring essentially busbar voltage, while the BMS of course measures voltage on the cells. So you are loosing 1.28V inbetween the busbars and the cells, which is a lot. Correct I disconnected the Lynx shunt for now. Comparing the fully charged Battery BMS voltage = 56.18 @ 1.5A MPPTs @~55A both ~56.4 Volts I would think that that is OK? I will check with a meter to verify the Voltage readings. I already checked ALL DC connections - and found nothing wrong ๐Ÿ™‚ ---
**Author:** ![nickdb](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/nickdb/32/51440_2.png) [@nickdb](https://community.victronenergy.com/u/nickdb)\ **Post date:** [21 April 2026 11:33 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/53 "2026-04-21T11:33:37Z")
not sure where you are getting the other entry from for vebus, should only be one under the cerbo serial number. ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 12:45 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/54 "2026-04-21T12:45:23Z")
As I mentioned above: > [@Jurgen\_Pflug](#): > > Last year, I replaced the Venus with a CerboGX MK2 > The ID 261 is just a left over on MQTT Broker, from the previous installed Venus > > so disregard this ID ๐Ÿ™‚ ---
**Author:** ![nickdb](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/nickdb/32/51440_2.png) [@nickdb](https://community.victronenergy.com/u/nickdb)\ **Post date:** [21 April 2026 12:50 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/55 "2026-04-21T12:50:11Z")
Ah. ok. Well then the 276 instance should be reporting the battery CVL. Hereโ€™s mine, MaxChargeVoltage is mirroring the BMS CVL and constantly adjusting the maxchargecurrent to offset against the configured max CCL of 100A, less what the mpptโ€™s are providing. ![Screenshot 2026-04-21 at 14.48.51](https://europe1.discourse-cdn.com/victron/original/3X/a/3/a3a8e98596fddf02b3ff05de180544a8919b3f84.png) ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 13:23 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/56 "2026-04-21T13:23:09Z")
Yep 276 it is ๐Ÿ™‚ ![image](https://europe1.discourse-cdn.com/victron/original/3X/d/b/db72f711960dfd6de547f6c2ee3f29c473217a88.png) The only thing that worries me here, is the MaxChargeVoltage of 55.0 which does not match the DVCC settings ๐Ÿง ![image](https://europe1.discourse-cdn.com/victron/original/3X/b/7/b77902239e8be830a1904ef27c25f84b8bbdbb80.png) ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 13:42 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/57 "2026-04-21T13:42:55Z")
You are right, the 55V come from the BMS, @~11h40 the battery was fully charged (changed from 56.5 \> 55) ![image](https://europe1.discourse-cdn.com/victron/original/3X/f/0/f0b3578516933ae8c772b6b6ee16613dea0b6c05.png) So the 55V seam to be OK I will still monitor that value ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [21 April 2026 16:39 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/58 "2026-04-21T16:39:57Z")
I think found something interesting ![image](https://europe1.discourse-cdn.com/victron/original/3X/9/f/9f5b4296b14a5b244158278d1550d98e54a6de86.png) This is plotting the BMS CCL and the MppOperatingMode. About 2seconds after the CCL drops to โ€œ0โ€ the MPP Operating Mode changes to โ€œ0โ€ = Off after the CCL changes to anything above 0 the MPPOperating mode also changes to 1 and the 2 again When PV excess feed-in is enabled? Should that be like that? here is another zoomed in plot ![image](https://europe1.discourse-cdn.com/victron/original/3X/2/6/26eeae9d3dbea3f214a76ad3f35faea33ee611be.png) ---
**Author:** ![nickdb](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/nickdb/32/51440_2.png) [@nickdb](https://community.victronenergy.com/u/nickdb)\ **Post date:** [21 April 2026 17:18 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/59 "2026-04-21T17:18:39Z")
This is what I was asking about earlier on. Settling ccl to 0 can have some undesired consequences. ---
**Author:** ![Jurgen\_Pflug](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@Jurgen\_Pflug](https://community.victronenergy.com/u/Jurgen_Pflug)\ **Post date:** [22 April 2026 04:26 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/60 "2026-04-22T04:26:19Z")
Good morning. So what must I do to change this? โ€ฆand should the ESS thingy not continue, keeping the MPPT running, when DC excess feed-in is enabled?? The system was working the last 7 years, with this BMS. I suspect some VenusOS or ESS changes, causing this behaviour ๐Ÿ˜ณ ---
**Author:** ![nickdb](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/nickdb/32/51440_2.png) [@nickdb](https://community.victronenergy.com/u/nickdb)\ **Post date:** [22 April 2026 05:42 UTC](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672/61 "2026-04-22T05:42:28Z")
I would log a ticket with BYD, ask them to check the battery and see if there are any firmware updates. You can also try reduce the battery charge current in DVCC, see if that helps. [Previous page](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672.md?page=2) [Next page](https://community.victronenergy.com/t/mppts-are-being-switched-off-and-on-every-few-seconds-why/56672.md?page=4)