question

pbilka avatar image
pbilka asked

low battery shut down

Hello, I have recently experienced the following condition:

"Low battery" LED on (solid) and "mains" LED on (solid). No other lights were on, Inverter/charger NOT running. The batteries were showing at 75% SOC before and after this event. No history is recorded on VRM while the event lasted (~3 hrs).

Can you please tell me, is this some kind of a system fault (of what?), so we automatically switch to grid? What is the proper recovery steps?

I have Quattro 5000/48/70 and BMZ 7 batteries.

Thank you so much if you can spare some knowledge.

Peter

p.s. I know this topic exists, but circumstances are different, e.g. they have flashing led and/or charger/inverter on.

MultiPlus Quattro Inverter ChargerLithium Battery
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Alexandra avatar image
Alexandra answered ·

@pbilka

1. disconnect all loads on the output. There should be breakers.

2. Shut down solar (if you have) by disconnecting panels. You can also isolate from the battery if that is set up.

3. Shut down incoming AC

4. Switch off inverter (front rocker or GX software switch.)

5. Shutdown or disconnect battery.


Troubleshooting.

1. Swirch on battery -is there output (checked with DMM)?

2. Connect mppt. Does it power up? Connect panels- does it charge? If it is then continue.

3. Switch on inverter - is it inverting? If it is, then continue.

4. Switch on AC in, is it connecting to and charging from AC? If it is then connect loads and continue.


For situations like these a system bypass should've been installed. If you dont have one look into adding it. You can get some din mounted ones that are quite neat.

11 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

pbilka avatar image pbilka commented ·

thank you so much... what do you think could be possible causes of going into a state like this?

0 Likes 0 ·
Alexandra avatar image Alexandra ♦ pbilka commented ·
@pbilka


A weird one. Usually if there is an internal faliure you see other lights.

So you need to rule out a battery or cable/fuse issue.


0 Likes 0 ·
pbilka avatar image pbilka Alexandra ♦ commented ·

thank you again for your help... i see you all over the board ;--) are you with Victron?

0 Likes 0 ·
nickdb avatar image nickdb ♦♦ pbilka commented ·
How is this battery connected to the system? Have you tried to use their CAN interface?

How are you reading the SOC?

The BMS could be disconnecting/shutting the battery down, that would trigger the behaviour.

It would be useful to have the battery vendor connect to the pack and see if it has anything in its logs. Always a good place to start.

Make sure the individual components have had their limits set, you would need to provide a lot more info on the system setup to make an informed stab at it, details are a bit vague at the moment.

0 Likes 0 ·
pbilka avatar image pbilka nickdb ♦♦ commented ·

The battery is shown as "CAN-bus BMS battery".

My installer said the BMS shut down because there was no comms. Not sure that makes complete sense to me... maybe there was a coincidence of other events.

thank you so much for your help.

0 Likes 0 ·
nickdb avatar image nickdb ♦♦ pbilka commented ·

The bms broadcasts, its not 2-way, so if it shut down it is because what it was expecting (power/discharge etc) was exceeded.

0 Likes 0 ·
pbilka avatar image pbilka nickdb ♦♦ commented ·

One other thing... the SOC has been acting stragely lately. Tends to jump from 70% to 100% within minutes. That used to work fine... something changed.

I get the SOC reading in Remote console and also from Quattro (thru VRM). Most of the time they are the same, but sometimes not.

0 Likes 0 ·
nickdb avatar image nickdb ♦♦ pbilka commented ·

Soc is determined by the bms and sent to the cerbo. It will be authoritative if it is the default set In system setup.

0 Likes 0 ·
pbilka avatar image pbilka nickdb ♦♦ commented ·

So that would mean somehow the battery is reporting the wrong SOC -- is this possible? There was some maintenance done on the system a couple of months ago.during which all batteries were shut down. Maybe they didn't bring them back online in the correct order?

0 Likes 0 ·
Alexandra avatar image Alexandra ♦ pbilka commented ·

Yes it is possible for the battery to be incorrect, i know a few that have false 100% triggers.

Happens especially when it was charging from grid and the gris drops off, charge stops and 100% triggers a few minutes later. But the battery can be charged or take amps even after that.


If it really is an issue, it may be best to get a bmv installed and run the battery 'dumb', if they are able to.

Some batteries need a keep alive signal - BYD is one of them. But most do not.

0 Likes 0 ·
pbilka avatar image pbilka Alexandra ♦ commented ·

Thank you for your help. I'm still working on this issue (year later)... At this point I am determined to find another source of SOC that the system can use, including a shunt.

One question: there is a setting under System Setup in Cerbo that allows you to choose Battery Monitor. If I were to choose Quattro from this list (instead of the battery BMS), would that provide it's own SOC calculation?

0 Likes 0 ·