MPPT stuck in Bulk even past float voltage

Question

question

danielbeck500 asked Nov 7, '22

MPPT stuck in Bulk even past float voltage

Image Caption Hello, I have been running self consumption hub on my setup until experimenting with ess. After reverting back to self consumtion hub my 150|100 charge controller stopped following the values for bulk float and absorption. This leads to voltages of over 33V shutting my 24V victrons down. You can see how I set 32.57V as my bulk voltage the system reaches 32.61V and is clearly still in bulk. It dose eventually go to float and absorption, but but at inaccurate voltages and often exeeds my systems max voltage.

MPPT Controllers

e4b937b2-2772-41df-9bde-309df8a63eb1.jpeg (1.5 MiB)

91eee8ec-1393-4ba6-aebb-29b105480bd3.jpeg (1.2 MiB)

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.

JohnC answered · Nov 07, 2022 at 01:26 PM

@Danielbeck500

If that Temp Comp figure is in play the setpoints get changed. That won't show in the settings, but the real V it's targeting will alter.

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.

danielbeck500 commented · Nov 08, 2022 at 10:27 AM

Bingo fixed!! For now I’m going to be running without this feature, until I do some research for the correct value to use for my temperature compensation. In any case I’m running my batteries safe as the main limiting factor is the maximum system voltage of 33V, that corresponds to a individual cell voltage of 4.1V so still far from the max charged voltage for these prismatic cells, but still enough to enter the balancing phase.

Thanks a lot, as I always overlooked this setting when trying to fix this problem.

0 ·

Modifications Space

Node Red Space

Answer 1 · 2022-11-07T13:09:11Z

kevgermany answered · Nov 07, 2022 at 01:09 PM

Before trying to answer, please give us more information. You have 24V batteries?

System is configured for 36V, but voltages are set too low for that?

Running 24V batteries at 36V will kill them very quickly and will lead to poisonous gas being emitted.

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.

danielbeck500 commented · Nov 08, 2022 at 10:29 AM

Sorry for not mentioning it before in my original post.

I’m running a 8S prismatic cell configuration.

0 ·

Answer 2 · 2022-11-07T13:15:48Z

klim8skeptic answered · Nov 07, 2022 at 01:15 PM

You have set you battery voltage in the mppt as as 36v?

And a bulk / absorption as 32.57v?

Yet your float voltage is higher at 32.73v?

And you have 24v system components?

You need to check your battery and system parameters again.

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.

danielbeck500 commented · Nov 08, 2022 at 10:31 AM

Those are test values for the purpose of this problem of overcharging that I’m having. Normally I run closer to 33V, as it is a 8S lithium Ion cell configuration.

0 ·

question