uController ADC Solar pannel voltage input for either a common GND or common Positive Solar Charge Controller

Papabravo

Joined Feb 24, 2006
21,264
LM143?
±40V supplies.
But one could argue that if there had never been such a high voltage part engineers would have found a workaround. The fact that there was such a part and it has been discontinued is actually rather better proof that it really isn’t that useful!
It also occurred to me that the early operational amplifiers used vacuum tubes and probably did work at higher voltages than the semiconductor equivalents.
 

Ian0

Joined Aug 7, 2020
10,085
It also occurred to me that the early operational amplifiers used vacuum tubes and probably did work at higher voltages than the semiconductor equivalents.
One of the forgotten names of electronics - Loebe Julie - inventor of the op amp. His only credit was in a one sentence footnote at the end of his PhD supervisor’s paper.
 

michael8

Joined Jan 11, 2015
421
Trying to measure the solar panel voltages (both sides) with ground at the 12 volt battery means the inputs
might see (solar - connected to battery -) +65 (solar + connected to battery +) -53 volts.

Here's a "concept" (not a real design). It's a single supply (battery) circuit and has a differential +80/-80 input range
attenuated by 20 to +4/-4 and offset above ground by 1/2 the battery voltage. I don't think this is
a real solution and in addition it's output is likely too high for the uADC inputs.

The zip file contains the .asc file plus the files needed for the LM324 (.asy .mod).
floatop5.png

I'm wondering if it would be easier to move the micro (or add a micro) to the solar panel side of the controller where
micro negative supply is directly connected to solar negative. Then it only has to deal with a single input of +65 volts.
In addition you could put a current shunt in the solar- lead and measure the solar current too.

The output of the micro would be digital values which could be sent via some non-dc coupled way to the outside
world (opto-isolator, transformer/ethernet, wifi, other).

The issue then would be powering this micro which needs an isolated DC supply, but there are lots of possiblities
for power (solar?, local small battery, isolated DC/DC from ..).
 

Attachments

Thread Starter

gkeep

Joined Oct 21, 2017
76
Trying to measure the solar panel voltages (both sides) with ground at the 12 volt battery means the inputs
might see (solar - connected to battery -) +65 (solar + connected to battery +) -53 volts.

Here's a "concept" (not a real design). It's a single supply (battery) circuit and has a differential +80/-80 input range
attenuated by 20 to +4/-4 and offset above ground by 1/2 the battery voltage. I don't think this is
a real solution and in addition it's output is likely too high for the uADC inputs.

The zip file contains the .asc file plus the files needed for the LM324 (.asy .mod).
View attachment 245788

I'm wondering if it would be easier to move the micro (or add a micro) to the solar panel side of the controller where
micro negative supply is directly connected to solar negative. Then it only has to deal with a single input of +65 volts.
In addition you could put a current shunt in the solar- lead and measure the solar current too.

The output of the micro would be digital values which could be sent via some non-dc coupled way to the outside
world (opto-isolator, transformer/ethernet, wifi, other).

The issue then would be powering this micro which needs an isolated DC supply, but there are lots of possiblities
for power (solar?, local small battery, isolated DC/DC from ..).
All, amazing points!

Well done!

Thanks for the schematic and the simulation. Awesome!

I'm relatively new to this so I'll let you konw how it all goes.

I'll keep you updated with how i progress and let you know the outcome.
 
Last edited:
Top