How to get victron battery monitor and JBD BMS to read same %

[sunshine_eggo]

Ah, got you
You are saying when charging I should be leaning towards the "at rest" numbers

No. I literally said "HIGHER than resting."

 

[Simi 60]

The solution to your query is to charge the battery to 100% and allow BMV and BMS to sync to 100. Do that a couple times per month, or you'll be back here.

Yeah, but the BMS has NEVER shown 100% on the gauge
That's the issue me thinks.

 

[Simi 60]

Now I'm thinking I may need to hook up the Mk3 usb and check settings.
Maybe they are set a bit to low to get to 100%
I though cutoff was set at 28.4v but it may have been done at 27.2v

 

[Bob B]

Yeah, but the BMS has NEVER shown 100% on the gauge
That's the issue me thinks.

You have that setting at 3.5 .... if you only charge to 3.4, it is not going to reset to 100%

 

[sunshine_eggo]

Yeah, but the BMS has NEVER shown 100% on the gauge
That's the issue me thinks.

Is it because you have NEVER fully charged the battery?

Now I'm thinking I may need to hook up the Mk3 usb and check settings.
Maybe they are set a bit to low to get to 100%
I though cutoff was set at 28.4v but it may have been done at 27.2v

28.4 should be fine provided you don't have excessive voltage drop. 27.2V will never hit 100%.

 

[Simi 60]

Is it because you have NEVER fully charged the battery?

Well, it did get fully charged while doing the initial top balance while on a bench.
But yes, I see what you are saying.

I need to be brave and get out the Victron USB dongle
I never did the initial settings as then, I didn't have one but the electrician who did the install and big wire connections did.

 

[sunshine_eggo]

Well, it did get fully charged while doing the initial top balance while on a bench.
But yes, I see what you are saying.

Yep. Until the BMS sees the 16S @ 3.5V+, it's not going to show 100%.

I need to be brave and get out the Victron USB dongle
I never did the initial settings as then, I didn't have one but the electrician who did the install and big wire connections did.

Multiplus?

 

[Simi 60]

Yep. Until the BMS sees the 16S @ 3.5V+, it's not going to show 100%.



Multiplus?

8s3p
And yes to the multiplus
5000/24/120

Will need to double check what setting be put into the Midnite Classic 150 as well

 

[sunshine_eggo]

The aforementioned 28.4 absorption and 27.2 float should do the trick.

 

[Simi 60]

A new day.
Ran Genset and punched batteries up to 27.2 and float kicks in but as it's a sunny day, we still have 90 amps coming in from solar while Genset remains running
This has been going for over 30 minutes now

It seems at this stage the Midnite Classic 150 was set with a higher cutoff than the multiplus.
Will be interested to see if we get to 3.5v & 100% now.

 

[Simi 60]

Ok, so seems the Midnite classic and solar gets the batts to 100% and I hit sync when they did

Of interest is the multiplus seems to have a glitch where it won't go to bulk charge if batteries register higher than 26.??v
With Genset running it would put them on float.

Multiplus not bulk charging - Victron Community

community.victronenergy.com

 

[sunshine_eggo]

Ok, so seems the Midnite classic and solar gets the batts to 100% and I hit sync when they did

So are the two devices in agreement now? Expect them to drift over time.

Of interest is the multiplus seems to have a glitch where it won't go to bulk charge if batteries register higher than 26.??v
With Genset running it would put them on float.

Multiplus not bulk charging - Victron Community

community.victronenergy.com

Thanks for that. I had no idea, and it explains some things I've experienced with my Quattro. My Lithium-NMC battery has "odd" voltage compared to lead-acid and LFP. Now I know to set the float way high to force bulk charging.

 

[Goboatingnow]

The passage of time can only make it worse. Battery monitors need to periodically be set to a known SoC. Victron states "a couple times a month."

You will never get Soc readings to agree unless each device usually exactly the sane methods to calculate and reset Soc. forget about it.

 

[Simi 60]

So are the two devices in agreement now? Expect them to drift over time.


.

Close enough
Victron says 73%
Batts say 71%
I can live with that and thank for the help.