GivBat 9.5 charging slowly

After a few months of happy use, our system has started to behave very strangely over the past few weeks. The main problem is around charging - the battery will charge at full rate for a short while (say half an hour) and then the rate will drop to less than 300W and stick there. It means that e.g. we can't take advantage of cheap overnight tariffs because the battery will only partially charge by the morning. RIght now, it's sunny and although the battery is at 60% we're exporting most of the energy whilst charging at only 288W again.

Here's last nights graph, for example - the large charge chunk was 2-2:30 and then it trickle-charged at 286W between 2:30 and 5.

I've emailed support but haven't received any response as yet, it's very frustrating. Has anyone else had similar issues?

eta: We were on Octopus Intelligent Flux when this problem first started to appear. I initially thought it was caused by them, so switched to normal Flux, revoked the api access for Octopus and re-set the inverter. It's still happening.

Check in the portal that the battery isn't paused at the time the charge rate drops back. Pausing the battery seems to still allow it to charge at 200-300w.

TimHutchings I also noticed, after upgrading to 309, that if you have a timed-discharge with a limit set, and the battery is below that limit, it charges at around 300W. (I had been usimg timed-discharge as a way to implement a timed-pause, but that stopped working.)
https://community.givenergy.cloud/d/4705-hybrid-309-and-discharge-limits

Another possibility might be if the system has lost track of the state of charge, and is charging slowly because the voltage is higher than expected. Maybe this can happen if it rarely gets low, in which case fully discharging at some point might allow it to get its bearings.

Its slightly rarer than just glitched settings but a cell out of balance will also result in very slow charge rates. I'd download the rubikube app if you don't have Home Assistant setup.

hoggy Its slightly rarer than just glitched settings but a cell out of balance will also result in very slow charge rates.

Would allowing it to continue to charge slowly balance the cells out, or would it just charge all cells slowly until that high cell reached the limit, then stop ?

DD the theory will be that it allows the balancer to try and shift things around to pull cells up or down. But realistically it'll only be at high SOC when it'll do much good as that'll be when iffy cells show their hands. (The knee part of the LFP charge curve)
The balancer is however pretty weak so it could take days to sort and then the question remains - how did it go out of balance to start with (if its not say a brand new pack with a from factory fault)
A truly faulty cell would never stay balanced so it'd be stuck going through that cycle forever.

hoggy as an aside, there is BMS fault status we can look to add to the library, I don't think that gets decoded currently (similar to the inverter one)

Thanks for the replies all.

I finally got through to support yesterday, they think it's possibly a cell alignment issue. They've upgraded the firmware to 3017 and kicked off a re-calibration... fingers crossed it sorts out the problem.

I started having this issue yesterday. It charges as usual up to 90% and then it exports most of it. I restarted the inverter and battery today and it went from 89 to 100% in 15 min and for the last 2 hours its been at 100% even though it’s discharging to the house.