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cebonvieuxmaxou avatar image
cebonvieuxmaxou asked

Battery charging on a VW California

Hey guys,

I installed a 100W panel on my VW California, with 75/15 SmartSolar regulator.

The installation is properly done, the Bluetooth app tells me it charges correctly.

The screen of the California indicates a charging percentage of the battery.

My question is what matters, the tension of the battery or the percentage of charge?

Because meanwhile the tension on the screen is nearly the same as the one indicated on the Bluetooth app, the percentage of charge always drops, like even at 20% while the tension says 13V...

I wonder if I need to set something differently...

Thanks for your time!

battery charging
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2 Answers
JohnC avatar image
JohnC answered ·

Hi. It depends what your 'screen' is and where it sources it's information. If it's Victron branded it will have something feeding it that info - something serious..

If it's some other brand, it may be just a simple translation of V to SOC%. In that case really a worthless conversion, and you may as well just watch V. You could test for that by applying a fresh charge to a standing batt, and if you see the % jump fairly quickly, then it's 'making it up'. There's plenty kit out there that does this, and it's inherent value is for you to decide.

The relationship isn't necessarily linear, but if the % always matches a certain V, then you can discount any real value.

But you may have better stuff?..


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cebonvieuxmaxou avatar image cebonvieuxmaxou commented ·

Hi, thanks for your answer.


My screen is the central control panel of the car, it indicates, the voltage, the amperes consumed in live time, and the percentage of the battery.


My concern is that when I plug the van to the electricity (wall plug), or when I drive, the ampere consumption is in positive (meaning it's charging), while engine off and unplugged with only the solar panel, it doesn't change anything (while on my SmartSolar App, it clearly says sun is charging).

Example: today was a really sunny day (490Wh, with 84% in Bulk and 16% absorption)

My control panel says 70% of charge, while it should say 100% right ? (absorption means it's full no?)


I think the problem comes from a fuse that's on the battery, had this idea suggested on another forum.. I was asking because maybe someone had the same installation ^^

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JohnC avatar image
JohnC answered ·

Ok, seems like your system has an onboard shunt (a current detector), and that's good. That 'fuse' on the batt may actually be that shunt (they can look alike), and if your solar has bypassed it, then that would explain your symptoms. Ie. the reg wired directly to the batt will be functional, but won't get measured.

The relationship between SOC and Abs time is a little mushy. But usually after an hour or two in Abs (especially after a long Bulk) you could expect >95%. Daily-cycling Pb's never theoretically make it to 100%, but for practical purposes are often allowed to show that.

Pic of a Victron shunt: https://shop.pkys.com/Victron-Energy-1000-Amp-50-mV-shunt-for-use-with-BMV-Meters_p_6779.html?gclid=CjwKCAjwlPTmBRBoEiwAHqpvhc1olPXHq5j3ydxXWLQohHKwyB6lXMJ3_oRikF-lpUE1Xe5A7ex_NBoCgLMQAvD_BwE

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