I am working with the ardiuno UNO to sense voltage at every battery in the bank, when voltage drops below a certain voltage it first detects weather there is a land line voltage. If there is no land line voltage it turns on the generator. The generator is connected to the designated charger circuit (the progressive dynamics converter charger, series of eight battery chargers and two lights that when lit indicate that the charging circuit has been activated for the recharging of the battery bank) The adriuono also controls a series of TWO temperature activated FANS that cool the generator. The adriuono senses temperature inside the battery bank as well and will not start the generator if it gets too hot. .The generator ignition is only connected until all the batteries have been fully charged and then it shuts off. If anyone knows how to do all of this and what sensors to buy please let me know.I m also interested in controlling it all from an adafruit.
Duel programmable relay board to voltage detection control off cycle timer??? and relay shields??
Why check every battery in the bank? That is useful to find a faulty battery but not necessary for overall battery voltage. If the batteries are in series you will need to isolate the sensing, if in parallel, they will all read the same anyway. Or are you referring to a number of separate battery banks?
Weedpharma
If you don't keep track of the batteries connected in parallel one or more could be discharged at a faster rate than the others depending on the accessories connected to them.
svarduino2015:
If you don't keep track of the batteries connected in parallel one or more could be discharged at a faster rate than the others depending on the accessories connected to them.
That does not make sense.
Please explain.
Leo..
All components connected in parallel by definition have the same voltage.
I have a 12v battery bank consisting of a number of parallel strings of 6v batteries. All strings have the same voltage but some of the 6v batteries have have unbalanced voltages. Some will be say 5.5v with the other at 6.5v. This tells me that the lower voltage battery is faulty and is removed.
Weedpharma
You are measuring two batteries connected in series.
A defective cell could have a higher voltage during charging, and a lower (or even reversed) voltage during discharging.
Leo..
Hi,
UNO to sense voltage at every battery in the bank
If you don't keep track of the batteries connected in parallel one or more could be discharged at a faster rate than the others depending on the accessories connected to them.
Can you draw a diagram of how your batteries are connected together and how you want to measure them please.
If they are all connected in parallel with suitable cable, they should all charge and discharge at the same rate.
Are they wet cell, gel cell or what type?
Tom..... 
WaWa, I am aware re series batteries, it was meant as an example to OP rather than experienced techos.
Weedpharma
I m not sure yet how to submit drawings with this forum. I am of the scientific belief that if every wet cell 12volt battery is monitored I will know immediately when one has expired or needs to be replaced.
This method will increase safety and reduce the likely hood of a fire. I just ordered the adafruit to control it all with a tiny touch screen. Im so excited and hoping I can figure out how to write the software and do all the right hardware connections. 8)
Hi
SG is the only reliable way of measuring charge and condition of wet cells.
Tom....
would you define "SG"?? I have just purchased two Arduino dual programmable relay boards / 2 voltage detection control / off cycle timers. I think they can do some of the work the system needs
in the hardware department to get r done!
These posts confuse me.
Measuring the voltage of individual batteries that are connected in parallel, a generator, eight battery chargers, two cooling fans, and a 24volt/5A relay board to control it all.
Without a proper explanation, I think OP is in La la land.
Leo..
I agree that a FULL explanation is required. I tried to get more in #1 but was not direct enough.
Weedpharma
I did not say anything about "24v"
"programmable relay board"
"I just ordered the adafruit to control it all"
Without proper info, we start guessing.
Adafruit has a programmable relay board with those specs.
Leo..
click Reply, then "Attachments and other options" and browse to your file to attach it.
Parallelling batteries is usually frowned upon.
One bad battery could drain the lot.
And, because they all share the same voltage, you can't monitor them individually.
Sensing the charge/discharge current of each individual battery might give you some insight in battery condition.
Is this a big working system?
If so, why didn't you choose for 24 or 48volt.
Leo..
Hi,
What is the voltage of each of the batteries and what is the total system voltage that you work with?
Can you post a picture of one or all of your batteries please.
If they are deep cycle batteries, wet cell lead acid, you measure the capacity and condition of them by measuring the Specific Gravity of the acid/electrolyte with a hydrometer.
rimstar.org/renewnrg/measure_battery_electrolyte_specific_gravity_with_hydrometer.htm
Thanks Tom....
Another way is to monitor individual currents from each battery not the voltage, but you will have to build current sensing circuits for that.
You may be able to identify a battery with a damaged cell that way.
However a battery with a shorted cell could drain all the others and overheat/catch fire.
Thats one reason that parallel connection is undesirable, there are others.
At the least you should be using individual protection diodes and charge them seperately