ZBasic Forum

I'm looking for a battery charging circuit that is controlled by the microcontroller. I have a project that is currently working and battery operated. The problem is that the it could be up to a 1000ft from a charging source, and what I would like to do is remotly charge the batteries if a few conditions are met.

Does anybody have a simple circuit that would work. The batteries are 12 Volt 7.5Ah sealed lead acid.

Thanks

Patrick

Patrick,

I see that there are no replies on this. I will give some of my thoughts.

This is a popular issue. There are some answers to be found out there.

The questions you need to think about are:

1) What should your "charging" voltage and current be?
2) At what voltage should you drop into "trickle" charge?
3) Does temperature have any influence on the above?
4) What should the "trickle" current be to avoid drying out the electrolyte, yet still maintain the charge. How does battery type and capacity influence this?

Probably the charging will be constant voltage and current limited.
Probably the trickle will be constant current, and voltage limited.

In the end, I could not find definite answers and I _did_ dry out the electrolyte on one battery, So, I just bought a "battery minder" that so far seems to be perfectly safe for the batteries, and is capable of handling all types of lead-acid batteries including AGM, gel cell, and wet cell types. Plus, FWIW, it is also supposed to prevent sulfation of the electrodes.

Once you can answer questions 1-4, then it is a "simple" matter of hooking up parts to achieve these goals. A microprocessor does enhance your ability to adapt to changing conditions more that analog circuits. But, I bet the Battery Minder will cost less in the end.

-Tony