# BMS high voltage alarm on VRM **URL:** \ **Category:** Q&A and troubleshooting\ **Tags:** battery\_protect, parallel, expert, vrm, ess\ **Created:** [18 September 2024 19:40 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189 "2024-09-18T19:40:45Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![dgmar\_ni](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/dgmar_ni/32/8060_2.png) [@dgmar\_ni](https://community.victronenergy.com/u/dgmar_ni)\ **Post date:** [18 September 2024 19:40 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/1 "2024-09-18T19:40:45Z")
Hello, I have a system recently installed using third party Lithium battery with BMS accepted by CAN connection on Cerbo GX. The systetm is configured on ESS. It turns out that system send an alarm from the BMS instance with high voltage alarm (the limit is 57V) but the solar charger shows only 55.6V. However on MPPT detailed history shows on battery a max value of 59.82V. We have three batteries of 104Ah 51.2V in parallel, two Multiplus 5kW and 100A 150V MPPT solar charger. The alarm comes from battery BMS. Absorption and float charge parameters in solar charger are 58.4V suggested by manufacturer. This alarm only appears when batteries are 100% SOC. We don’t know why batteries get a max value of 59.82V if solar charger paramteres are lower than this value. Any help will be appreciatted. ---
**Author:** ![alexpescaru](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/alexpescaru/32/270_2.png) [@alexpescaru](https://community.victronenergy.com/u/alexpescaru)\ **Post date:** [18 September 2024 19:50 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/2 "2024-09-18T19:50:03Z")
The MPPTs are still functioning after the battery is fully charged, in order to supply power to inverters. Now, with variable load conditions, the MPPTs are a little slower to adapt and there are cases when the solar production can overshoot. This translates with a slight increase of the DC voltage. 1.4V overshoot is not much versus 58.4V set voltage. It’s just 2% more. BUT… 58.4V is way to much for charging voltage. It’s 3.65V / per cell, absolute maximum allowed for LiFePO4 chemistry. Set instead absorption and float charge parameters to 56.8V (3.55V / cell). Even better 56V (3.5V / cell). ---
**Author:** ![dgmar\_ni](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/dgmar_ni/32/8060_2.png) [@dgmar\_ni](https://community.victronenergy.com/u/dgmar_ni)\ **Post date:** [18 September 2024 20:04 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/3 "2024-09-18T20:04:07Z")
Thank yoy for your reply @alexpescaru. I have set a lower charge voltage and the system doesn’t shut down althought VRM still shows the alarm. Even with a BMS tool connecting batteries it doesn’t show any alarm but VRM does. However, I don’t mind if the sytem still runs in ESS mode. ---
**Author:** ![lxonline](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/lxonline/32/25567_2.png) [@lxonline](https://community.victronenergy.com/u/lxonline)\ **Post date:** [19 September 2024 18:44 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/4 "2024-09-19T18:44:14Z")
Have you tried to manually clear the alarm in vrm ---
**Author:** ![dgmar\_ni](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/dgmar_ni/32/8060_2.png) [@dgmar\_ni](https://community.victronenergy.com/u/dgmar_ni)\ **Post date:** [19 September 2024 19:53 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/5 "2024-09-19T19:53:12Z")
Yes I did but it appears again. I have read this is a regular alarm on new LiFePO4. I hope it will stop as battery bank is cycled over time. ---
**Author:** ![kbb](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@kbb](https://community.victronenergy.com/u/kbb)\ **Post date:** [19 September 2024 20:14 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/6 "2024-09-19T20:14:24Z")
It happens every day as soon as battery reaches 100%. As @guystewart explained in the topic below, cause is incompatibility of chineese BMS with Victorn specifications. Instead of lowering CVL, BMS sets CCL to zero when battery is full. I tried to contact Basen Green (my battery brand) with questions about Victron compatibility (which they declare), but was silently ignored. Thus have to live with it. > [@MPPT charger in limiting mode / DVCC / external control](https://community.victronenergy.com/t/mppt-charger-in-limiting-mode-dvcc-external-control/398): > > The system is under BMS control. The battery SOC is 100%, so the BMS has disabled charging. Excess DC-coupled PV energy is supposed to be fed into the grid; however, the MPPT charger is in limiting mode. Is this a bug? [image] [image] [image] ---
**Author:** ![BjoernK](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/bjoernk/32/89_2.png) [@BjoernK](https://community.victronenergy.com/u/BjoernK)\ **Post date:** [19 September 2024 21:19 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/7 "2024-09-19T21:19:39Z")
@dgmar_ni have a look on battery safety controller. It’s a free software ond free hardware that is plugged in between the Cerbo and the BMS and has several optons to manipulate BMS data. Though \ **[GitHub - shining-man/bsc\_fw: Firmware battery safety controller (BSC)](https://github.com/shining-man/bsc_fw)** > > Firmware battery safety controller (BSC) ---
**Author:** ![kbb](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@kbb](https://community.victronenergy.com/u/kbb)\ **Post date:** [20 September 2024 09:32 UTC](https://community.victronenergy.com/t/bms-high-voltage-alarm-on-vrm/4189/8 "2024-09-20T09:32:44Z")
Seems that Basen BMS (Tianpower) is not supported by this controller