arduino voltage sensor 48v

See the circuit below. So while, dBC, your result falls within my definition of "several times", I restrained myself to "well in excess". During the early stages of the COVID-19 Pandemic there was high demand for personal protective equipment. Junior employee has made really slow progress.

Basic and the most popular individual battery monitoring technique using microcontrollers in practice is voltage divider circuit.

In parallel combination batteries are connected to increase the shelf life of the source or increase the time of power source to supply suitable voltage to load before needed to be recharged.

Theres been several posts about this topic and weve used that knowledge to help point us in the right direction.

Robot and AI waste management technology helps produce responsibly made recycled products, reduces waste and builds a cleaner, healthier world. Thanks for the additional information and insight.

But in many cases, the cost (I'm including battery life as a potential 'cost') or complications of including an op-amp and providing a power supply are unacceptable or unwarranted. These calculations will also be suitable for 1/2 Watt and 1 Watt resistors.

Aside from the inline fuse lead, which connects to Batt+, all other inputs/outputs are handled by a terminal block at the bottom of the board. What happened after the first video conference between Jason and Sarris? Well a little more mathematics is involved here.

I used arduino mega to monitor a cluster of 32 batteries with the same relay method.

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In this case R1 could be made up of 2-3 resistors in series: To correct this, we feed the output of the voltage divider into an op-amp. One has to measure mV from these devices so precision is required, and I used a Max 6126 for this.

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No problems so far (over 3 years), but better power monitoring would be nice. Measuring an individual battery voltage or a whole bank of battery using any microcontroller(arduino, microship pic, Avr, Atmega, Intel, NXP, stm32)is an easy task. Next Steps

Hi @PeterJennings , I have tested the boards I have, they read max input (1024) at 3v (not 3.3 like the specs say) so I'll adjust accordingly, thanks. However, if you are interested, a op-amp circuit can be built from a 741 IC (among others) and is configured like this: It sounds as if you have tried using far too small a value resistors.

An extra power some time is also needed to power the optocoupler. !

SolarMill: As you were making a PCB and providing a power supply for other reasons, then adding an op-amp was undoubtedly the best way to go.

See the DIDRn registers for details.

So far this article has been helpful, it talks about a voltage divider with a opamp to get more accuracy, but I need a bit more advice from someone that knows more than myself.

Optocouplers also increases the circuit cost. Almost all of the current will be going from your source, through the resistors (R1 & R2) to ground. The Adafruit forum also suggests that 1V is the maximum.

We also added a 12v Supply to power a Hall effect break out board.

Similarly if battery-3 is at 23v. My test above was just performed on a single part, and the ADCinternal series resistance can varyanywhere from 1K to 100K. I made a simple diy project with the same above logic. That said, any other thoughts about the design that could be improved or tweaked? As you pointed out, there are additional benefits to the opamp that still justify its usage.

For these boards the input range is 0 to 3.3V.

This means an op-amp buffer is not needed.

Looking forward to getting feedback on our design.

You connect the -input to the output, (turning into a voltage follower), you tie the +input to a defined in-range voltage (which could be + input of the other half - it looks to be as good a place as any, and a by-product of doing that is you have a buffered version of the divided-down battery voltage, should you want it.) In parallel combination voltage across each battery remains same.

So standard quarter watt E24 series 1% resistors should be suitable.

Digital pins of microcontrollers are required to activate the relay coils and for individual battery an individual pin is required.

At the end the major drawback is, it still requires a dedicated microcontroller analogchannel to measure each individual battery.

If all goes well, we'll proceed to work on the Hall effect portion of the design.

The formula to calculate the output voltage is: I would up R1 to 100kOmega; as it will only result in a 1% error. (It happen with me) .

In the above circuit four voltage divider circuits are used to measure voltage across each battery. That needs just two wire links on the underside of the PCB. The technique is to measure the voltage across high potential battery first, than against the lower ones and negating the subsequent batteries voltage from the one at higherpotential.

Considering thatthe opamponly cost $2.65, it seemed like a safe route to go with some additional perks along the way. As soon as we get the boards in from OSH Parkwe'll give an update with how well it works as well asdetails on how to integrate it with the Arduino.

So this method is feasible only when batteries in series combination are not greater than 4. Vin is 18 volts when the battery is charging(worst case scenario).

We are using the standard EmonPi to monitor all incoming grid power though our main breaker box.

This is because we used high value resistors" is based on a misconception and there is no discernible effect in practice, and so there is unlikely to be a significant effect until the source impedance is well in excess of the 10 k recommended maximum. Maximum input voltage of pin A0 = 1V Than 36v-23v gives 13v.

We'll write a follow up with a bill of materials and the design files.

But if for any reason the battery negative is not earthed, then you have a potentially dangerous situation.

For safety, we included an inline fuse thats rated for 125v DC with a value of 315mA. Thanks. For higher string of batteries more analog channels are required and microcontrollers usually have 8 analog channels at max.

rev2022.7.29.42699.

Lets calculate it.

Project contains free source code and circuit diagram.

Measuring 12 V via voltage divider: choosing the right resistors, Voltage, current measurement from solar panel using INA219 and ESP-12F, Battery voltage measurement with voltage divider, How to automatically interrupt `Set` with conditions. e6)EIgf"{lf||U7$8GzR'F5'_)F]TH_rGetd|lF hV23dp",5g;p~Y7U?K

We have an off grid 48V system here as well.

From automation in big factories handling bread, dough, fish, meats and vegetables to the living room and universities where they still can grip everything you throw on them and still be squishy and safe to be around for students.

but with all values I have tried one resistor almost melts as soon as you connect to battery.

Analog multiplexers can also be used instead of relays. We know Vout can be up to maximum 5 volts since nodemcu works and accepts maximum 5 volts at its I/O pins. If the two relays accidentally switched on at the same time their will be a huge blast due to short circuit of batteries.

Using an esp8266, how can I create a circuit to measure 2 different analog inputs (not simultaneously) with only one ADC pin available (A0), How to select which resistor is required for my curcuit to reduce voltage.

How ratio is calculated is below. I am also going to add some margin above the 65V max that the solar panel can output (plus it makes the math easier).

They will draw a maximum of 65V/(360K + 5K6) = 0.18mA and the 360K resistor will dissipate about 10mW.

Solar charge controller also output voltage approximately equal to 15 volts to charge the batteries. However, it's quite conceivable that at some combination of parameters (inter alia temperature, clock speed, supply voltage) 10 k is a critical limiting value.

Relays can also be used to measure voltage across batteries. In voltage divider circuit two resistors are connected in series and source (battery) voltage is applied across its ends. The design of any voltage divider also depends on the input impedance or load imposed by the ESP8266.

The best answers are voted up and rise to the top, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company. I also made an internet of things project on battery voltage monitoring over WiFi. amp's usefulness for scaling and providing the required offset, but I'm surprised you found that the varying input impedance of the multiplexer has a significant effect. Our PCB combines three basic circuits: a voltage divider, anopamp, and a power supply.

Is Vcc the same as Vcc-? Microcontroller can not measure 12 volts directly. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media Privacy Policy | Advertising | About Us, Voltage divider voltage divided against two resistors, Voltage divider resistance value calculation, Voltage drop against resistances of voltage divider circuit, Series batteries combination voltage monitor by microcontroller, Optoisolated battery monitor with microcontroller, Series battery monitoring with microcontrollers. Why does connecting them to either0v or Vcc have the same effect? The major differences between this and the standard Emon setup: So far weve spent the majority of our effort working on the voltage monitoring portion.

We just received the PCB boards in the mail and and already found a minor issue with them: the pads for the DCDC supplies are flipped from where they should be (at the opposite edge of the part than where they belong).

The battery bank voltage swings from 42V minimum when they are almost empty to 65V maximum when the batteries are being equalized.

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It is not usual to have components at weird angles (R1, R2) and there's no need for it.

Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. 1/4 Watt resistors are common and easily available so I will base my calculations on that.

Order confirmation and Order shipped emails are the same day or next day. Similarly if battery-3 is at 23v.

A linear optocoupler is one which can perform the job at best.

1) Are working within their wattage rating. This is where the OPAMP might come into play. Click the below button to take the tutorial.

Referring to standard resistor values, 360K and 5K6 in series will be very close to 64:1 (64.28:1).

It's just that alot of the designs used around here do monitor signals with a source impedance of roughly 10K and with no op-amp between them and the ADC input, so if there were a problem with a 4.7K source impedance, people would rightly want to know more. Voltage is divided against the two resistors according to the resistor ohmic values.

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We are are using a dual opamp, so there's only one left over. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. An additional benefit of the opamp is it isolates the battery side of the circuit from the Arduino.

The question now is how the 3.33 volts is converted to 12 volt by nodemcu or how from 3.33 volts we can predict that at the battery side the voltage is 12 volts. To subscribe to this RSS feed, copy and paste this URL into your RSS reader.

We put our selected components into a PCB design program (Eagle) and after using their automatic routing option, spent a few hours cleaning up the design to make it look pretty. The first 1.5 ADC clocks (out of a total of 13 for a conversion) charge the sample-n-hold cap. We added a capacitor on the input side of the circuit to filter out some noise and act as a local power supply to our DCDC converters. Arduino relay is used in the project.

So it would seem that "the Arduino's impedance varies while sampling, in such a way that the voltage divider's output will be affected. Four 12 volt batteries are connected in series to output 48 volts. Values of R1 = 49.5k and R2 = 500 would also work.

Here are some options: https://www.robotshop.com/en/1-channel- Hey guys Im back!

Circuit may also be messy. In a state with the common law definition of theft, can you force a store to take cash by "pretending" to steal? We can also offset these values so they better fit into the range of the Arduino's inputs.

This is because we used high value resistors in our divider to minimize the wasted power.

Other batteries voltages can be calculated with same method. Let's simplify.

Click the below button to take the tutorial.

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well in excess of the 10 k recommended maximum.

Closest equivalent to the Chinese jocular use of (occupational disease): job creates habits that manifest inappropriately outside work.

Your source impedance is 4.7 k.

Since we're gonna have to get them remade anyway, we can incorporate those changes into the opampwhile we're at it. So their pins are also working on 5 volt TTL logic. So higher is better but unfortunately you also need 2) that resistance to be low compared to the input impedance of the analog input. Do we just connect the unused pins to ground or do we need a resistor in there? We run everything from thickness planers and miter saws, to routers and table saws with this setup. I've clocked it at about 800uA per pin on a 5V 2560 whichpotentially dwarfsanythingsaved by going with a high resistor divider. I was making progress though when I had time and want to share my latest progression updates. Arduino relay is used in the project. Those digital input buffers are at their best when you feed them 0V or Vcc;leavethem floating (or feedthem an analog signal)and they start to suck current.

Eventually the voltage monitoring PCB and the Hall effect PCB can be combined into a single unit much like the EmonTX. However, we still need to measure the current of some additional DC loads that do not go through the inverter and we also need to measure the voltage levels of our battery bank.

You must have JavaScript enabled in your browser to utilize the functionality of this website. Standard 1/4 watt resistors are going to melt when overloaded 10 times. First i short circuited the 2 batteries and it cost me much at the end i finally fixed the code and inserted some delays which increased the hardware efficiency. RoboCup is the largest scientific annual event to advance A.I., robotics and automation in the world.

What does "Check the proof of theorem x" mean as a comment from a referee on a mathematical paper?

Can adjustable constant current/voltage source be made with Arduino? Take a look I will discuss circuit its pros and cons below the diagram.

Well in excess might be a bit bold, but I think if you stick with the 10K recommendation you should be fine. Also, using a voltage divider creates a (small) drain which I would like to avoid.

For example, Free shipping on orders over USD $ 100.00 *, Data Communication and Human Input Devices, Defense, Security, Surveillance & Inspection, * Subject to approval and not available for products shipped by others sellers through the RobotShop Marketplace, My order was quickly processed and shipped. Consequently wires can melt down in seconds.

We modeled it in the software, and also with the online calculators but without the type of lab equipment you guys have it was hard to verify. https://openenergymonitor.org/forum-archive/node/11011.html.

I've built a circuit to measure DC Voltage with full galvanic isolation using the HCPL-7520, and an Isolated DC-DC Converter to supply power to the isolated side, only pencil diags thus far, so will post more details later once I have done formal schematics. Were selling off the extras for anyone thats interested. I have tried creating a voltage divider with 2 resistors but with all values I have tried one resistor almost melts as soon as you connect to battery.

Double pole single through relays with batteries and microcontroller connections are shown below.

How to Measure many voltages (Uno) - Analog extenders a good option?

Maybe the board you have has different built in scaling. We run a woodshop on solar power, but some parts of the shop (lighting, mini fridge, office computer) are still on the grid. Since the resistor values are fixed we can calculate the voltage ratio across the resistors with respect to the source and use it in code for actual voltage at source. Now all we have to do is calculate for R1. The data sheet recommends a source impedance of less than 10 k so that the sample & hold capacitor, which is quite small, charges adequately quickly.

"A few days after sending off the board design"

In our package, we have 3 pins left unconnected: 2out, 2in-, and 2in+. Price Match lets you match the price of any item sold and shipped by RobotShop with a competitor's price! Help understanding several components in the sch of eMonTx 3.4, http://www.maximintegrated.com/en/app-notes/index.mvp/id/1957. I just did a spot check on a random ATmega2560 I had handy.

For the same reason, always enable the pull-ups on unused pins. Announcing the Stacks Editor Beta release! Microcontrollers work on 5 or 3.3 volts(From here on we will take in to consideration 5 volt, techniques listed below can also be applied to 3.3 volt microcontrollers). For example two 12 volt batteries are connected in series to build up 24 volts.

The design is somewhat restricted because it does not provide you with galvanic isolation on the voltage, and as a consequence of that it requires the battery negative to be both earthed and the common GND connection for the Arduino. Both are adressed in the link posted by VE7JRO.

Why is the comparative of "sacer" not attested? The demand for PPE exceeded the supply available from traditional manufacturers and a rapid solution was needed. Current must be measured by either shunt resistors (invasive) or hall effect sensors.

Optocouplers also isolates the microcontroller from the battery voltage and provides safety from high spikes. Finding a suitable multiplexer and its configuration is as difficult as of optocoupler.

How can we determine if there is actual encryption and what type of encryption on messaging apps?

This can also be used to power the Arduino, which is nice. We can't feed this output directly to the Arduino though.

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You need a voltage divider with resistors that have large values.

I used ULN2003 relay driver to drive the relay coils. These are some of the ways through which batteries connected in series or parallel can be monitored.

We could use lower values, but the amount of current constantly passing through them would be a drain on the batteries. A. Digital pins can be reduced by using multiplexers.

So always use sufficient amount of resistors for bigger ampere hour batteries. It also has the longest history of robot competition since 1996. Let's simplify by initially calculating the resistance required if R1 & R2 were combined into a single resistor: I would go further and say double that because I never like operating a resistor right on its maximum power rating. Would a 100K resistor connected to ground pull an open analog line down to 0.

It's always like that!

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The "TurtleBot" might have the name of one of nature's slowest creatures but make no mistake, this powerful piece of equipment represents a rapid leap forward for robotics development. [op-amp isolation just means current/voltage isolation, not electrical isolation like with an optical isolator] We decided to use a Texas Instruments LT1013CP opamp. The trace below is the voltage at anADC input pin being driven to 0V through a 10K R. Immediately before initiating a conversion on this pin, I was doing a conversion on a different pin being driven to 5V, ensuring the cap was fully charged.

The higher the battery capacity, the longer it will run, but the more it wil Hi! For example for the above circuit the measured voltage across battery-1 is 48v and battery-2 is 36v. 468). How to read high voltage (40-65v) from a Solar Battery bank, electronics.stackexchange.com/questions/42710/, Measurable and meaningful skill levels for developers, San Francisco? Marketplace sellers offer different shipping options. The battery bank voltage needs to be stepped down for input into the Arduino. Since ours is a 48v battery system, we used resistor values of 80k and a 5k to divide the voltage down to 2.82V, which is nicely in our range for Arduino measurement.

Are those two benefits worth the inclusion of a $2.65 part?

First of all, I ended up caving in and doing a full blown 3d model blueprint of the robots entire skeletal structure to scale Hello @devvitltd and welcome to the RobotShop forum! How to tell reviewers that I can't update my results. This suggests that you have been using values that are too low.

like a circuit (from AliExpress) or using some other component that would be greatly appreciated. So we can not measure individual battery voltage in this case.

This almost certainly meets the requirement of not significantly loading the battery. In the above circuit four voltage divider circuits are used to measure voltage across each battery.

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