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VE.Bus BMS red led on and off

Hi All,

Just installed 4 smart 200ah lithium, with new multi’s (3) 12/3000/120 12v, cerbo, bms etc. Batteries are all fused individual and connected to busbar’s.

Charge disconnect is done via Mastervolt alpha pro, via bms fort the multi’s, load disconnect is organized.

The batteries are new. When charging it worked for about 3 hours with about +/-170 amps (set as limit). After a while the red led on bms started to go on and off and the chargers go up and down as well. Is this a malfunction or are the cells being balanced? the red led says hi voltage or temperature. This is not the case when I check the individual batteries with bluetooth. Some cell imbalance is there in the individual cells.

Is it normal or not?

Thx!

Lithium BatteryBMS
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Have you looked at the batteries via Bluetooth and the Victron Connect App, to see what the individual cell voltages are.

The red LED is the charge disconnect kicking in, and will be because one of the cells is going over 3.75v


The manual has been updated and has a lot of good information. Take a look at it

https://www.victronenergy.com/media/pg/15958-Lithium_Battery_Manual-html5/en/safety-precautions.html

Section 7.2 covers cell balancing, but the entire document is work a read.

I would also check teh firmware of the battery and have a read of this document

https://www.victronenergy.com/blog/2020/07/06/victronconnect-v5-27-lithium-smart-v1-19/

It has some information on charger cycling, and what.

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gertjand answered ·

Current flow drops indeed. So the red led going of and on is somewhat normal and means the cells are belancing. Thx, manual is a excellent tip. What alternator controller do you have? The Alpha pro controller can safely switch off the alternator via the bms if the current would be strong enough. I have the smart battery protect for the load side. Could try it for the charge side well. But I need a on state by default which can be switched off by the bms. (Between the ignition wire and the Alpho pro is a on wire that switches on engine start).

Many thanks bathnm!

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Will try a solid state relay tomorrow

I have a Wakespeed 500 which has a dedicated BMS signal port.

What you could do is insert the SBP in whatever signal the Alternator Control needs to be broken and then use the BMS input into the SBP to break it. So if you need to break the ignition feed, then that is the input to the SBP and output is the ignition input on the controller. If the BMS signals charge disconnect the ignition feed is broken.

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gertjand answered ·

Thx! Will read! Checked the individuals cells and it seems to happen if one goes over 3.75. Firmware is the latest!

Would want the charge disconnect to kick in that much when the dc generator is running :) going to set it the run between 30 and 75% or so.

Setting up an alternator is a tough cookie. The load disconnect doesn’t have enough juice to switch a relais to turn off the alpha pro. Let alone to fix this with a normal alternator without burning it.


small tip. If you want to update the bms assistant in multiple multi’s it can not be done at once. It had to be per multi. Seems to b a small software glitch.

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It will do as 3.75v is the BMS Charge disconnect threshold. I suspect that your batteries are balancing, but be surprised if there is much current flowing at this stage of the charge. From memory, when I commissioned mine the input current was 1-2A max.

I am lucky that my alternator controller just takes the signal from the BMS, when it sense a voltage it will charge and when it drops it switches the alternator to float voltage. If your alternator controller needs more, then have you thought about a Smart Battery Protect and using the BMS signal to switch the Smart Battery Protect on and off. Just be sure there is enough current flowing through the SBP otherwise it won't switch when signalled.