DVCC not controlling MPPT

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Kevin Windrem asked Sep 5, '19

DVCC not controlling MPPT

I have DVCC enabled but the Blue Solar MPPT controller is apparently not being controlled.

System: MultiPlus Compact 12/2000/80, Blue Solar 100/30, BMV 500, CCGX, 2 BattleBorn 100AH LFP batteries. Installed in a travel trailer. All components running most recent firmware/software at time of posting.

I am not running ESS and the BattleBorn batteries qualify as "Normal".

Currently, the MPPT state shows a state that has no correlation to that of the Multi.

Prior to June 28, the MPPT state shown in VRM was normally "Ext Control" with occasional switches to other states. Since that date, VRM shows the MPPT never entered into the Ext Control state.

The DVCC section of current CCGX manual seems to indicate this is normal (DVCC on, ESS off, Normal Battery). Has this behavior changed? If so why?

Is there currently a way to control the MPPT state so it is in sync with the Multi? That's what DVCC is supposed to do, right?

I currently don't have access to the MPPT settings. These were supposedly set up by BattleBorn prior to shipment. I have a VE.Direct to USB cable on order and it'll be here in a few days.

DVCC

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Answer 1 · 2019-09-05T23:12:32Z

nebulight answered · Sep 05, 2019 at 11:12 PM

Interesting, I just checked mine and it's the same.

When I check on the GX (Pi) it states that the Mode setting is external control:

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Answer 2 · 2019-09-05T23:25:46Z

nebulight answered · Sep 05, 2019 at 11:25 PM

Actually I just reread the manual and it looks like with the firmware 1.42, it uses the internal algorithm, but still uses DVCC for current control. With a drop in battery, you won't need the GX to control charge since the battery doesn't provide any specs to do so. And since you don't have an ESS setup, it wont' use the multi either.

4.3 DVCC effects on the charge algorithm

Our inverter/chargers and MPPT Solar Chargers use their own internal charge algorithm when in stand-alone mode. This means that they determine how long to remain in Absorption, when to switch to Float, when to switch back to Bulk, or Storage. And in those various phases they use the configured parameters in VictronConnect and VEConfigure.

In certain systems, the internal charge algorithm is disabled, and the charger is then working with an externally controlled charge voltage target.

This guide explains the different possibilities:

Internal

The internal charge algorithm (bulk → absorption → float → re-bulk), and the configured charge voltages are active.

Inverter/charger indicated charge state: bulk, absorption, float, and-so-forth.

MPPT indicated charge state: bulk, absorption, float and-so-forth. (firmware version v1.42 onwards. Earlier versions have a bug that make the MPPT say “Ext. Control” when it is only being current limited; its internal charge algorithm still active.

Link to DVCC manual section: https://www.victronenergy.com/live/ccgx:start#dvcc_-_distributed_voltage_and_current_control

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Answer 3 · 2019-09-05T23:35:41Z

Kevin Windrem answered · Sep 05, 2019 at 11:35 PM

I see the same thing. If I turn off DVCC (and reset the Multi) Networked turns to NO. Is it appears that DVCC is working. There must have been a change to the status display some time back. I actually prefer knowing what state the MPPT is operating in rather than it just saying "Ext Control".

That leads to another question: Why are the charge states of the Multi and MPPT different?

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Answer 4 · 2019-09-06T00:02:26Z

Kevin Windrem answered · Sep 06, 2019 at 12:02 AM

Well, the mention of a bug explains why things are different now. Thanks.

Still a question: Why doesn't DVCC set the MPPT to track the Multi charge state?

Also, why does ESS cause the MPPT to track the Multi even with DVCC turned off?

I had hoped that DVCC would work around not having the tools needed to set the MPPT charge profile. (I only have the rotary switch on the unit and that doesn't match BattleBorn's specs (close though).) I'm fixing that: the VE.Direct to USB cable has been ordered.

The GX can do remote VE Config for the Multi. Maybe it could do the same for the MPPT and allow VictronConnect to access the files.

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nebulight commented · Sep 06, 2019 at 05:05 PM

Why doesn't the DVCC set the MPPT to track the Multi Charge State?
This is because that's not how it works with a normal battery (non-intelligent) in a NON-ESS battery. DVCC still works by limiting charge current, but it won't match the charge states of the multi in a non-ESS setup. This is probably because with a non-ESS setup, it's possible that the multi could be turned off (just guessing here)

Also, why does ESS cause the MPPT to track the Multi even with DVCC turned off?
I don't know much about ESS as I have a camper van, but I think it has to do with how ESS works with the multi (it's a main component of ESS). DVCC and ESS are two different things. Someone with more knowledge with ESS might chime in.

Sadly, it won't work the way you want though having a ve.direct to usb cable isn't a bad piece of kit to keep with you. As you said, pos 7 will work for your battleborn (i'd keep it there if it were my setup). However I think they suggest high voltages in order to give the battery a chance to balance more regularly. I only charge to 14v on my lifepo4 setup, but drop in batteries with the way they balance suggest higher charger rates (they only balance on the charge cycle and at higher voltages).

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Kevin Windrem nebulight commented · Sep 06, 2019 at 08:34 PM

This is fast becoming an academic issue as I now understand how it works and assume it's "as designed" so it won't change.

The DVCC section of the GX manual defines what happens when the Multi goes off line: all devices revert to their internal controls. So I'm not completely buying the argument that it works this way just in case the Multi is turned off.

Also, with a smart battery (one that reports its charging needs) it does not appear DVCC needs to be enabled at all, at least according to the chart in the manual.

A better way to do synchronized charger control might be to provide the GX with its own charger setup then use that to instruct all devices what to do.

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