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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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