question

teloth avatar image
teloth asked

Multiplus II GX 5000 SOC jumping to 100% with no reason , batteries nowhere near full

soc-2.jpg



soc-1.jpg

As per title , this happens at least once a week from what I can tell.


This morning , it has just jumped from 73% to 100% , solar PV only just started kicking in , system voltage is way below still at 53.80 volts , absorbtion is set for 55.70 on MPPT controllers and in Multiplus is set to assume 95% SOC at 55.70 volts.


Any ideas?


I have just downloaded the data in excel where it confirms this as well.


Please see attached screenshots

SOC
soc-1.jpg (87.4 KiB)
soc-2.jpg (109.2 KiB)
soc-3.jpg (196.6 KiB)
soc-4.jpg (188.3 KiB)
16 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.

klim8skeptic avatar image klim8skeptic ♦ commented ·
You forgot to include a screenshot of the inverters general tab, regarding SOC settings.
0 Likes 0 ·
teloth avatar image teloth klim8skeptic ♦ commented ·

I did not forget , as I already put that information in original message , " Multiplus is set to assume 95% SOC at 55.70 volts. " ie. state of charge when bulk is finished = 95%

0 Likes 0 ·
marekp avatar image marekp commented ·

Are you using "2 signal BMS" assistant or ESS with this settings set in it?

0 Likes 0 ·
teloth avatar image teloth marekp commented ·
I am not running ESS or any assistants.
0 Likes 0 ·
marekp avatar image marekp teloth commented ·
What battery you have?
0 Likes 0 ·
teloth avatar image teloth marekp commented ·
LifePO4 480Ah , not connected in any "clever" way like CANbus or anything.


State of charge is purely determined by Absorbtion voltages , in Multiplus , after the bulk finished. It works perfectly fine most of the time, but this phenomenon occurs once a week or so and it messes up SOC.


After 2 hours ago it happened this morning , it is obviously still showing me 100% SOC , luckily it is going to be an OK day today to truly hit 100% , but if it was a winters day , it will falsely claim 100% early in the morning , when in reality the SOC could be 70% for example and it will never reach where it is supposed to be. So I will go into the night thinking batteries are 100% , where they obviously are not.
0 Likes 0 ·
marekp avatar image marekp teloth commented ·

@Teloth

Voltage is not the best way to measure the SOC of the LFP battery.

If you want the SOC properly measured use SmartShunt or BMV.

BTW.

If you do not have a "clever" or other method of signaling to your chargers that the LFP battery cannot be charged or discharged for any reason, your battery will not last long.

You can of course relay on internal BMS (if it has one) that have a way to disconnect the battery from chargers/loads, but it is very poor way.

0 Likes 0 ·
Show more comments
teloth avatar image teloth commented ·

@mvader or other Victron Gurus , would you mind looking at this to see what might be causing the issue?

0 Likes 0 ·
nickdb avatar image nickdb ♦♦ teloth commented ·
Get yourself a proper installer instead of arguing with people trying to help.

You won’t get any official help for batteries that aren’t on the compatible list.

Having lithium batteries without a bms or a properly setup shunt will just cause issues.

There are tons of topics here you can search for with all the information you need.

Its not a glitch, you just haven’t set it up right.

5 Likes 5 ·
1 Answer
snoobler avatar image
snoobler answered ·

Why are you complaining? You clearly don't care about actual battery SoC since you're using one that can't count the incoming current from the PV.

Contact your reseller for support.

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.

Related Resources

Additional resources still need to be added for this topic