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Topic: Simple Harware for Monitoring AGM Batteries [need help] (Read 247 times) previous topic - next topic


I have a 24v battery pack composed of 2x 12V 115 Ah Deep Cycle AGM batteries (Producer's site )

Can you please suggest me the design of a simple hardware to monitor charge and number of cycles?

I need to process this information with Arduino UNO, so if there's something off-the-shelf that can provide
those information and can, in some ways, interface with Arduino, feel free to post a link.

I look forward to read from you soon




You can make a voltage divider with a couple of resistors to provide a 0-5v range that the Arduino can measure with its ADC.

What do you mean by the number of cycles? How is a cycle defined? How long does a cycle take?

How often do you want to take measurements?
Where are you planning to store them?
How many measurements do you want to store?

Two or three hours spent thinking and reading documentation solves most programming problems.


Hi Robin,

I'm new with Arduino and electronics in general, so be patient If I'll ask stupid questions.
As cycle, I mean charge cycle. Producer says that the battery lasts up to 800 cycles. I need a warning when it's time to change them. There's a discharge curve in this Datasheet. Don't know if it can help.
Don't need to store charge data, only cycles for the reminder. I need to know charge, not neceassary in realtime. A small delay 1-2 mins could be acceptable.

I hope this could be of help.



The life of a lead acid battery is a very complex subject. As far as I can tell it depends on how much use the battery gets - that is how many amp-hrs go in and out. Also the rates of charge and discharge have a big impact. Another important factor is how long it is left in a discharged state and how often it gets a really complete charge - ideally about once a week.

I don't think you will get any useful information counting cycles. The battery might last 200 or 2000 cycles before it becomes useless for your requirement.

Tell us how you propose to use the battery. What sort of load will be be supplying and for how long? How and when will it be charged?

From a programming point of view you need to tell me how the Arduino will know when a cycle starts and ends. If all you want to do is keep a count of the cycles you could just store the latest number in the Arduino's EEPROM memory. I presume the count won't increase more than about 1 or 2 per day.

PS If long battery life is important and if there is no requirement for the batteries to be maintenance free and able to turn upside-down wet deep cycle lead-acid batteries may be a more economical option.
Two or three hours spent thinking and reading documentation solves most programming problems.

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