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John Rushworth avatar image
John Rushworth asked

DVCC Questions & Feedback

My 'portable' powerpack consists of:

1 x Lithium HE battery 24V / 200Ah

1 x MultiPlus C 24/2000/50 (Latest firmware 433)

1 x Lynx Ion BMS 400A (v1.14)

1 x Color Control GX (v2.23)


Fitted in my motorhome garage per photo and used primarily for recharging electric bicycle batteries offgrid. Charging by shore power when available.

I am aware of the DVCC manual and Guy's 'accepted answer' https://community.victronenergy.com/answers/3212/view.html

Questions

1) Should I expect DVCC to sync to 100% when left on charge. I have fully charged a number of times but only one sync. Currently after a few hours the SOC shows 98%, V 27.92, 2.6Ah consumed and remains holding at that voltage with no change. Zero Amps in and Zero Amps out. The CCGX shows as still in 'absorption'. The voltage doesn't fallback to the 27,5V 'float' as in the Lynx Ion datasheet. Charge voltage in parameters on CCGX is fixed at 27.93, but datasheet shows 28.4V for 'absorption.'

2) Is there a problem with my system as going by SOC and Ah consumed I calculate the battery Ah to be 150Ah whereas of course it is 200Ah.

3) Unlike my boat system with Lithiums and Multi I am unable to set the Multi input current limit to Zero. I control this using the CCGX. It is impractical to use a remote panel so I really need this to ensure the system can go to Passthru, otherwise whilst camping on hookup the battery (per question 1) is simply going to remain held at that charge voltage all the time. Surely this is not good for the battery and indeed I would have expected the system to have dropped to 'float' voltage first and at that point that would prompt me to switch to Passthru, which I'm unable to do.

4) I understand DVCC takes control of charging/discharging but I have also set the Multi up as I would do on the boat and I think realised the Multi settings have little or no effect. I assume this is a good idea in case DVCC fails/goes wrong and if that were to happen would the Multi ensure the safety of the battery with the settings I have used, which are similar to those I've used on my boat as suggested by Johannes

Feedback

1) I really like DVCC as it was easy to setup with my system, and without all the refs to DVCC which I have read through here in the Community I would have been baffled as to the logic and settings it uses. Even so I still feel in the dark and concerned my system is not working correctly as detailed above.

Lithium BatteryDVCC
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2 Answers
Pat Davitt avatar image
Pat Davitt answered ·

My system is functionally identical to yours. Except I am running a Lynx Ion BMS 1000, a Quattro, and two Victron HE 200AH batteries in series. I have had DVCC enabled from the start.

So far, the system has performed flawlessly, I give most of the credit to the Lynx Ion BMS and the HE batteries. In my opinion this BMS and DVCC were designed to work together. Others, using different BMS's seem to have more questions about DVCC.

When I first set my system up I entered the basic information, but I did not provide any charging information to the Quattro or my Victron MPPT. I just plugged everything in and turned it on. I then turned on DVCC with shared voltage and temperture checked. I took two or three minutes, but DVCC was successfully enabled and went to work.

As you discovered the SOC does not work until the first time you let the batteries charge to 100%, "and perform a synchronization". Synchronization, or what really should be called "cell balancing" is only performed when the BMS determines it is necessary. The fact that your system has only synchronized once should not concern you. In the many months my system has been operational, the batteries have only been synchronized nine times. And, as you discovered their is no way to synchronize them manually. Many people have a hard time trusting computers to run their system, but, that's the way it is.

The fun thing to watch is how the BMS controls the charging. The Quattro starts out in Bulk and feeds as many amps as the BMS lets it, at some point, it varies, the BMS switches the Quattro to Absorbtion and ,over time, you can watch the amperage drop down to 0. Then the Quattro just sits there, in Absorbtion, waiting on the BMS to tell it to do something different.

Don't you just love computers.

Hope this helped,

Pat



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John Rushworth avatar image John Rushworth ♦♦ commented ·

Thanks Pat. Yes, it’s doing it all auto it seems but I don’t understand how the SOC is so wrong and indicates a 150Ah battery that is 200 as you know. It has synchronised so I’d expect it to be accurate. As it is I don’t know how far I can discharge based on Ah as I don’t know if the Ah used is wrong too.

I’d read your posts before posting so that had helped. I’m not keen that I can’t switch to Passthru though when on hookup and the voltage just stays at charge voltage.

Hopefully someone can throw some light on these issues.


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Pat Davitt avatar image Pat Davitt John Rushworth ♦♦ commented ·

John,

Where are you reading the 150AH rating from? Concerning "Pass-Through", it doesn't matter what the voltage reading going to the battery is, it's all about the amps. Your Multiplus will pass-through the AC power automatically, less what is being used for battery charging. If no amps are being used to charge the battery then the Multiplus is passing all the power.

In the DVCC setup section of the CCGX their is an option called "Limit Charge Current". If you enable this you can control the maximum amps that will be used to charge the battery, by entering a number in the "Maximum Charge Current" box. These are 24V amps, not 120 or 240 volt amps.

Pat

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John Rushworth avatar image John Rushworth ♦♦ Pat Davitt commented ·

I’m not reading it Pat. If you look at the screenshot in my original post you’ll note the SOC and Ah consumed, so working that out the battery calculates as 150 Ah not 200.


My point re passthru is the input current limit cannot be wound down to zero on the CCGX but can on my boat. There are times when I want to set to Charger only and wind the current limit to zero which on the boat forces passthru of AC, so if I’m away from the boat or van and shore power fails then the inverter won’t kick in because it’s not on. There’s times when I can’t get to the van or boat, in which case the batteries would start to deplete. Admittedly the BMS in both cases would shut down on low voltage but I’d prefer to not have that. I have an alarm email set to know when shore power goes off. That way I can go and investigate.


Yes, re DC charge Amps. Already played with that.


John

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John Rushworth avatar image John Rushworth ♦♦ Pat Davitt commented ·

I’m not currently connected to shore but I’ll do as screenshot and make current zero in Inverter mode and see what happens but presumably the inverter would still kick in on shore power failure. I’ll see what happens when I set to zero on charger only in settings (rather than the input current limit for the Multi on CCGX which doesn’t let it go to zero) and see if it goes to passthru that way.

In the image above on charger only, when I set to zero it goes to 1A so it’s not possible that way to force passthru, but exactly the same works on my boat 800VA Multi and it does set to zero and go to passthru.

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John Rushworth avatar image John Rushworth ♦♦ commented ·

Agree re terms. On my boat I have it set for bulk and then just one hour in so called absorption which is enough time for the current to drop to zero, the cells to balance and then after that hour I have it programmed in my Phoenix charger to go to a lower voltage which we can call float, but as soon I see that I switch via the cccgx locally or remotely to passthru and then at least I know the battery is not attempting to charge which I can’t do with my system similar to yours.

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Pat Davitt avatar image Pat Davitt John Rushworth ♦♦ commented ·

All I can figure is that the Absorption and Float voltages listed in the HE Datasheet are for dumb chargers. A BMS/CCGX/DVCC system the charger "Multiplus" has no say in what it does, it only follows directives from the BMS through the CCGX.

Pat

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John Rushworth avatar image John Rushworth ♦♦ Pat Davitt commented ·

This is what I suspected after carefully programming the Multi. Thanks for the confirmation. I guess though having set the Multi settings correctly it does no harm if DVCC fails as presumably it would then default to the Multi ‘safety’ settings.

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Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Hello All, If the inverter/charger unit is running on DVCC and then the CCGX stops, the controlling of the inverter /charger will stop too and only the inverter will remain in pass through if there is shore power. There is no charging done anymore from then

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