treichhart
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Joined: Sat Nov 08, 2014 4:33 am

Is there anyway that I can monitor deep cycle batteries?

Fri Jun 30, 2017 7:20 pm

Mods
If this not in correct forum please move it.

My question is there anyway that raspberry pi can monitor like voltage and how much battery left in an deep cycle batteries and display it on webpage like nut can?

Reason why I am asking this I made homemade ups for remote site using utility power connected to meanwall ac/dc then to solar controller then down to 2 deep cycle batteries I just to need to monitor the batteries and voltage.

pcmanbob
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Location: Mansfield UK

Re: Is there anyway that I can monitor deep cycle batteries?

Fri Jun 30, 2017 8:12 pm

Hi.

To measure the battery voltage you would need an analogue to digital converter and some external circuity to connect it to your battery.
If your batteries are just lead acid deep cycle batteries the is no way to directly measure capacity remaining.
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Ferdinand
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Joined: Sun Dec 01, 2013 2:24 pm
Location: Leiderdorp, NL

Re: Is there anyway that I can monitor deep cycle batteries?

Fri Jun 30, 2017 8:51 pm

Hi treichhart,

Search for 'coulomb counter'. It is a micro controlled counter used in ebikes, ecar batteries a.s.o.
Perhaps you can use it.

Follow this link for a simple circuit. It is just an idea.
https://learn.sparkfun.com/tutorials/lt ... okup-guide
Success with your project!
Ferdinand

treichhart
Posts: 3
Joined: Sat Nov 08, 2014 4:33 am

Re: Is there anyway that I can monitor deep cycle batteries?

Sat Jul 01, 2017 1:55 am

I'm just using 12v marine deep cycle batteries so is there like 12v analog to digital converter out here for raspberry to use?

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ab1jx
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Re: Is there anyway that I can monitor deep cycle batteries?

Sat Jul 01, 2017 2:31 am

Measuring the state of charge of lead acid batteries by an instantaneous voltage measurement is probably not going to work very well. See https://www.google.com/search?q=battery ... 8&oe=utf-8 The temperature of the battery can have as big an effect as the charge. Measuring the specific gravity with a hydrometer is probably better.

But what also works and is within the realm of what could be done with a Pi is to monitor the watt hours or amp hours in and out. Set up an A/D converter of some sort (I think I've seen USB ones) so you can monitor current, positive is charging and negative is discharging. Do it often, maybe a few times a second. Multiply the time spans by the current readings. Think of them as amp-seconds or whatever, but you should be able to get as many out as you put in. There will be some loss, you won't get back 100% of what you put in. Also most batteries will last longer if you avoid pulling them down low, at least often. Most car batteries will only stand being pulled down to 0 volts about 3 times in their life of several years. Try to stay above 50% charge, they should have an amp hour rating.

Ideally you'd want to have a thread on a computer monitoring fulltime and always have a number like a bank balance that's the result of monitoring charging and discharging. You'll probably be able to convert volts to digital, you'll need a series or shunt resistor to change amps to volts. That can be something like a paper clip but it has to be stable, if it rusts after being overheated that will change the reading. A piece of nichrome wire from a toaster or electric clothes dryer might be a good start. Remember Ohm's law and you'll probably want to pick up a cheap DMM for calibrating. Not to mention a package of alligator clip leads for temporary connections.

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