BYD battery rapid discharge after 50%

Question

question

kixx asked Jan 13, '24

BYD battery rapid discharge after 50%

Victron energy multiplus 48/5000/70-100 BYD off grid solar system

The system was fitted 4yrs ago and usually works perfectly but last year noticed that when the batteries were discharged down to the 40% mark ( couple of cloudy days ) without any change in load they would rapidly discharge to 8 or 9 % in just a few hours.

This has happened a few times now, above 50% percent no issues.

battery charging

1

2 |3000

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

kixx commented · Jan 13 at 04:52 AM

Screenshot over two days

0 ·

screenshot-20240113-044710-chrome.jpg (245.4 KiB)

kevgermany answered · Jan 13 at 07:57 AM

Are the numbers coming from the batteries, or a shunt/BMV?

First impression is that it's a battery/BMS problem.

1

2 |3000

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

kixx commented · Jan 13 at 11:00 AM

I don't know too much about it, just reading the info from the app

0 ·

kevgermany answered · Jan 13 at 11:51 AM

Do you have any way of charging manually. If they haven't been fully charged for a long time, the app may be out of sync and giving a false reading.

1

2 |3000

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

kixx commented · Jan 13 at 01:03 PM

They are usually fully charged every day 100% and maybe only discharge down to 60% in the morning

0 ·

Modifications Space

Node Red Space

Answer 1 · 2024-01-13T04:53:37Z

kixx answered · Jan 13 at 04:53 AM

@Kixx

Screenshot over two days

screenshot-20240113-044710-chrome.jpg (245.4 KiB)

2 |3000

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

question