Designing my first basic circuit - But have a few Questions

Thread Starter

Justj0n

Joined Nov 13, 2016
3
Ok… So I am new to all of this type of stuff. So I may be asking very simple and/or stupid questions but I figured I would ask and get feedback from people who know what they are talking about.

So I have been trying to design a simple(ish) circuit to run two 12V DC motors. BUT I want to run them from a Battery and make it useable via the mains while the battery charges. In addition to this I wanted to add a Battery Indicator (to see the battery charge), a Switch (turn on/off) and a Speed Controller (to adjust the speed on the motors). So I have had a go at drawing it out and wanted to get some feedback on it to see if it would even work…

So the main questions I have our:

- Would this circuit even work?

- Do I need to put in Resistors or something to reduce the Amp’s from the Charger going into the battery’s? Or will the Battery be ok taking 10Amp from the battery?

- Placements of the parts in the circuit? Will the battery indicator just show me the charge of the battery or will it show its fully charged when plugged in?

- Would I be able to do this only using a Positive and Negative wire or do I need an earthing wire?

- Is there anything I am missing/overlooked?

I think that’s everything…
 

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Ramussons

Joined May 3, 2013
1,417
Circuit 2M.jpg

Is the charger capable of supplying power to the Motors AND Charging the battery simultaneously?

If Yes, then it will have a Separate Output Terminals for the Load (Motor) and Battery; in which case, the circuit (circled) needs to be modified.

If No, then you will need a charger for the battery and another power supply for the motor with a changeover.

The Resistors do not play any useful role in this setup.

A battery charger needs to monitor the charging current of the battery for proper functioning, and connecting the load across the battery (as now shown in youe schematic) defeats the purpose.
 

Ramussons

Joined May 3, 2013
1,417
What you have is a 12 Volt Power Supply Adapter with a 10 Amp Capacity, not a charger.

A Lead Acid Battery needs to be charged at 13.8 Volts with the current limited to 1/10 th of the Battery Ampere Hour Capacity. In your case, its 9 AH, so normally, the battery needs to be charged at 900 mA upto 13.8 Volts.

On a pinch, you can float the Battery at 12 volts with a Resistor to limit the charging current, say 1.2 Ohm / 2Watts with a Bypass Diode for discharge, as a short term measure. The Battery will have to separately charged to maintain its life.
 

Thread Starter

Justj0n

Joined Nov 13, 2016
3
If I wanted to keep the same battery and get a new more appropriate charger that was able to both charge the battery while allowing me to use the motors at the same time, is there something that you would be able to recommend?
 
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