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Jonny Sollid avatar image
Jonny Sollid asked

DVCC volt with to desimal for better charge limit.

I have dynamos with a total of 500A and in combination with lithium cells and Wakespeed I use DVCC volts to limit charging. The optimal voltage for "Float" is 13.25v, not 13.2v or 13.3v available in DVCC. Is this something that could be integrated in future updates?

I have previously used DVCC current limit, but the advantage of volt regulation is that I get support from the dynamo when needed and the battery is kept in a fine balance. For winston lithium cells that I have, the "float" voltage of 13.25v will be equalized at SOC 95% and that is a fine regulation in my opinion.

Venus OS
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3 Answers
nickdb avatar image
nickdb answered ·

It is unlikely the equipment measurement/response is sufficiently accurate and fast that such a niche requirement would make any difference with a second decimal.

Nothing in this space operates with such tolerances.

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Jonny Sollid avatar image Jonny Sollid commented ·

I have tested with volt regulation for a few months with Wakespeed on my two Balmar xt250 dynamos and 13.25v vs 13.3v makes about a 50A difference when I charge lithium batteries at SOG 50%, and more if the battery is discharged to 20-30%. At 13.25v, charging stops at approximately 95%, which is often desirable for lithium batteries. I don't want to draw unnecessary power from the engine when I don't need charging and 50A makes a difference. Two decimal places for volt regulation on lithium cells is necessary yes.

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trip-tracks avatar image
trip-tracks answered ·

Try setting on the dbus (use dbus-spy) instead of the console.
You can set to extra decimal places, but I haven't verified it uses the value or if it is rounded.
The value read back in the console is rounded.


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Jonny Sollid avatar image Jonny Sollid commented ·

Using dbus-spy was a good suggestion if I could change the setup in venus OS to use two decimal places in the GUI, is that possible? I need to be able to easily change the value via the GUI in order to be able to regulate the current as needed.

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Alex Pescaru avatar image Alex Pescaru Jonny Sollid commented ·
Yes, it's possible, read my answer below...
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Alex Pescaru avatar image
Alex Pescaru answered ·

Hi @Jonny Sollid

If you are feeling confident with your computer skills, you can modify the "/opt/victronenergy/gui/qml/PageSettingsDVCC.qml" script, in order to have as many decimals you need.

Search for the "Maximum charge voltage" spinbox and modify there the "decimals" key from 1 to 2.

Also modify the "step" key from 0.1 to 0.01, in order to provide the proper granularity when setting.

That's all. Have fun!

Alex

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Jonny Sollid avatar image Jonny Sollid commented ·

I have no knowledge of modifying scripts, have limited knowledge of terminals and only used "dbus-spy" to change "instance". Will try to learn this too. Thanks for the reply, then I know what needs to be changed.

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Alex Pescaru avatar image Alex Pescaru Jonny Sollid commented ·
If you've used dbus-spy, then you know about SSH and logging into VenusOS.

Use WinSCP to login in a "graphical" way to VenusOS, navigate to that folder and edit that file/script to make those modifications. Then reboot Cerbo.

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Jonny Sollid avatar image Jonny Sollid Alex Pescaru commented ·

Which protocol and port should I use in WinSPC and what is the username in Venus OS? Sorry to have to ask yet another question and thanks for the valuable answers. Is so close, but stands firm when I lack simple details.

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