DVCC benefits vs reasons to not use?

Question

question

geomz asked Oct 27, '19

DVCC benefits vs reasons to not use?

I have a Quattro 5000 in ESS, CCGX with 2 100/30 mppt controllers and a bmv managing a 24v lithium system.

I’ve read the dvcc documentation several times and am still confused :)

Should I or should I not use DVCC and does it actually buy me anything (in my config)?

My batteries have their own BMS, and their parameters are working fine on the Quattro.

I read a note in the docs that says not having dvcc enabled can cause issues with reduced PV output, with near-full batteries and the “keep batteries charged” ESS profile

Reading the docs, dvcc enabled in a “normal battery” (non-intelligent) configuration defers battery managment profile to the inverter

And if enabled, the SVS (shared voltage sense) can be turned on (which sounds like a good thing).

I am not using a charge control limit

So,

Is there any point to my having dvcc on? (Noting above mentioned issue with ‘keep batteries full’)

Do I gain any benefit from the way I have it configured?

Is there any harm in keeping it enabled (the dvcc text on screen on the gx sounds kinda ominous and foreboding :) )

As always, thanks for any help or advice

Lithium Battery DVCC

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.

ejrossouw answered · Oct 30, 2019 at 08:21 AM

@Geomz and @blond2silver My thoughts are that the battery BMS is the best single source of truth in Lithium given each cell is monitored and managed individually by the battery BMS. Currently owning an ESS and off grid system, both are managed via DVCC with STS and SVS off. Why "confuse" matters if the battery knows best?

2

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.

blond2silver commented · Oct 30, 2019 at 06:48 PM

Hi ejrossouw, Yeah, I would definitely agree about BMS as source. I should have mentioned that this system's battery bank is comprised of a 1/2 dozen battleborn batteries in parallel. So the BMS an integral part of each battery. Even though, each battleborn has protection circuitry of temp and current, I still decided to implement DVCC as a macro-systems configuration - hence the BMV-712 as the source.

0 ·

ejrossouw blond2silver commented · Oct 30, 2019 at 07:15 PM

My system design philosophy is to keep is simple and automate as much. I have BMV712's, but in the end they proved redundant as everything else is working so well. Does not mean one cannot have fun with it though ... until something does not add up an then you may have more fun and complications.

0 ·

Modifications Space

Node Red Space

Answer 1 · 2019-10-30T05:10:56Z

blond2silver answered · Oct 30, 2019 at 05:10 AM

I was somewhat confused in reading through the DVCC documentation as well. So I posted several questions to this forum to gain a better understanding. Yeah, this forum has been a great resource for gaining knowledge, and making decisions with overall system parameter settings.

Below are the two main reasons where DVCC made good sense for this installation.

1.) Managing the total charger amperage with DVCC "limit charge current". I confirmed this works by VE configuring the Multiplus to 120 amps, and then setting the DVCC charger to 85 amps. I actually desire 80 amps charge max, but the DC system influences the max charge current somewhat.

2.) STS enabled, and enabling the BMV-712 as source in the CCGX gateway parameters. Note for temperature, requires a temp probe connected to + battery, and the BMV-712. Then within the MPPT settings, setting the MPPT charge to shutoff charging at 32 degrees. I confirmed this works by setting the MPPT to 50 degree F which is the max value the MPPT setting allows.

As an aside, I also enable DVCC "SVS", but I really don't see any influence - that's still a TBD?

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