Electron Solar Kit Charging Indicator?

Is that all it takes? I think its more complicated than that but I’m not sure.

@ScruffR @peekay123 Any advice on this?

Looks like that setChargeVoltage function takes only two inputs at this time, 4208 and 4112. 4112 is safer and for temps over 45 deg. C.

Not sure if it needs to be setChargeVoltage(uint16_t 4208), or just setChargeVoltage(4208).

Then again, I’m not a programmer by any means, so…

From my first original post.

What are the voltage specs on the solar panel your using?

Solar panels output less voltage when its warm and sunny so I’m not sure what the output voltage is during peak sun but it may also be contributing to only going up to 75% via solar.

Its the 6W panel supplied with their solar kit. It was generating 5 volts indoors not in direct sunlight. I’d guess it is capable of 6+ volts.

Looking at the Voltaic site, their 6w has the following:

Solar Panel Output
Monocrystalline cells - 19% efficient Open Circuit Voltage: 7.0V Peak Voltage: 6.0V Peak Current: 1.02A Peak Current: 6.1 Watts

Should be fine then.

Yeah, its the nicest panel I’ve ever seen; way over-built, which explains the price tag. 19% efficiency is quite good.

Yes they are nice epoxy coated solar panels.

The best solar cells are made by Sunpower and today they are in the 22-23% efficiency range.

Here is one I had made for a specific project. Its a 5v 350mA panel using Sunpower cells.

Nice clean look.

Sunpower’s site says their top panel is about 21%, but that was 2014.

What did it cost to make that 5v panel?

Yea its 21% efficient after you add in the power loss from connection resistance for the large panels.

The acutal cells are looking to actually be above 23% now:

I think the cost was $3-4 per watt.

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That’s a great price for what looks like a nice panel. Was that retail?

For setting the charge voltage that should be it, but if this actually will have the effect you are looking for I can’t say.


@ScruffR Ok I tried to add

setChargeVoltage(4208); to the setup code but I get the following error:

So I searched the forum for “Not Declared In this Scope” issues and came across a few suggestions which I tried but they only produced more errors or different compile error messages.

I’m sure I’m missing something really simple but so far no luck.

I have to run for now but if you have any suggestions please do share.

I tried adding the .H file that has this function but that didn’t help. I tried declaring the function above setup but I don’t think I had the format right. Looks like I’m about to learn something new :smile:

This function is a method of the PMIC class.
As you yourself posted the respective code snippets, I supposed you’d know how to access such methods.

I have some knowledge of creating and modifying Libraries/classes to for the battery management code you helped with awhile back.

@ScruffR I spent the last 30 mins watching a video that taught about classes / libraries and how they work and I feel like I’m further along now but still no dice.

Based on what I have seen the code below should work but it’s not so I still have more to learn.

I’m I getting closer or am I way off somewhere?

I think you got bitten by a preprocessor issue here.

// PMIC setv(); // should work but doesn't
// normally this should work
PMIC setv; 
// but you'd also need to call
  // before doing anything with the object

@ScruffR Your a programming master :smiley:

With your help I figured it out and successfully changed the charging voltage.

The problem is that still does not charge up past 4v which for me still keeps me at 86.5 % SOC max. See the Ubidots graph below:

One thing that does happen when you up the charging voltage is that the RED charging indicator will flicker like crazy at different patterns once you get close to 4v where the charging stops which is less than desired.

As soon as I set the voltage back to the default 4112v the charging indicator went back to normal.

The chip is able to charge up to 4.44 v based on the spec sheet for the chip so I think a higher voltage than 4208v is possible and may help but I"m going to have to be setup to build locally before I will be able to change the code in the .cpp file for the set charge voltage function.

@RobotChicken since your SOC is only going up to 75% I wonder if the chip has some sort of temp compensation feature for lowering the charge voltage based on the battery temp.

Since your unit it outside it’s possible the higher heat is causing the temp compensation to lower the charging voltage. This is a feature used on many different battery chargers. We would have to look at the spec sheet to find this one out.

I’ll have to look at the fuel gauge settings to see if we can change anything there also. If not then we can always just scale the 0-86% SOC readings to 0-100% and call it a day :smile:

3.86MB at 7:00AM 3/5/2016… 4.76KB / hour. That’s a significant improvement, but will still be around 3.5MB per month.

Even though I went to 30 minute publish intervals from 15 (15 minute intervals and cell chip on was 14.8KB / hour), leaving the cell chip running instead of turning it off after each publish period effectively cut my data usage in half (4.76KB / hour).

@RWB I don’t think that is the case; there was snow yesterday and still 75%. So I’ve been in the 30 - 60 degree range with no noticeable difference in battery charging, <75%. That anomaly on 2 Mar. is when I plugged it into USB.

this is one kickass thread.

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