larry76 Posted June 5, 2010 Report Share Posted June 5, 2010 I am hoping someone here can help. I have been looking all over for help with wiring and no one can tell me whats wrong. My kid just got a toy tractor that runs on batteries, a 12V. I want to install LED lights and I am having a problem. I have everything installed, but when I turn on the lights the batteries, 4 AA batteries get very hot. When I turn off the lights (Toggle Switch), the batteries still get very hot. I went to hobby forums etc, everyone just says to add a resistor and I will be ok. I have added all sorts of resistors and I am still have the same issue. No one can tell me why the battery is getting hot. I am hoping someone here can help. Link to comment Share on other sites More sharing options...
Eric - TIA Posted June 7, 2010 Report Share Posted June 7, 2010 The problem is not a resistor, it is your wiring. There is something that is crossed. If your battery only gets hot when the toggle switch is on, then your pulling too much power. A toggle switch that is off, should not be letting any juice go through and therefore shouldn't cause the battery to get hot. Since the battery is getting hot in the off position, you still have juice flowing through the wires.Lets start from scratch and make it simple, leave out the ground, poles etc. We are just going to focus on two wires, the positive and negative. Picture the whole electric circuit as one complete circle. It doesn't matter what you add or how much you add. The juice starts off at the battery and has to complete a complete travel around the circle, back to the battery. A toggle switch is suppose to interrupt that circle and stop the flow in the off position. When you put the toggle switch in the on position, it puts the circle back in place and allows the eclectic to complete the circle. So this is why I think it is a crossed wire or a wiring problem.A resistor just resists the current or volts. I am not sure if you have the LED system in series or parallel, but that will help guide your resistor. They are completely different on the structure and set up. You said you had 4-AA batteries, my guess is you have parallel because most low voltage is run that way for various reasons. This means you are running 6 Volts through your lines. If your LED lights each can handle 6V, then you don't need a resistor. If they handle less, then this is were a resistor comes in play.Now that we have some differences and why it must be a wiring problem, lets take the problem. Lets go back to basics and take away any doubts. First start from the beginning as you should always do with any problems. Test each light on its own and see if you have the same battery problem. Again make sure you have the right resistor in place so you do not blow any lights. If all the lights work separately, then you know its not a light problem. Now hook them all up to the battery, if the battery gets hot, then you know it is a wiring problem. If the battery doesn't get hot, you know the wiring is OK. So next hook up the toggle switch. If the batteries do not get, your good to go and what ever the problem was, you fixed. If the batteries get hot, then you know you have a bad toggle switch or you have your wiring to the toggle switch wrong. Once you do this, let me knwo what you find and we can go to the next step. Link to comment Share on other sites More sharing options...
larry76 Posted June 7, 2010 Author Report Share Posted June 7, 2010 Wow that's awesome, very detailed. OK I did everything you said. When I hooked up all the lights without a toggle switch, no problems, no heat. When I introduced the switch, the batteries get hot. I went to Radio shack and got another switch and still the same problem. I am lost I need help. I do have everything hooked up in a parallel circuit. I have both the power and the ground going to the switch and the lights turn on and off, but get hot. The circuit seems like the circle you were explaining. The lights are 5mm, 3.6V. The lights do not get hot or burnout. What happens when I turn the lights off, the batteries get very hot, then if I wait about two mintues and try to turn the lights on, they are very dim and sometimes don't even work. Probably because the batteries are so hot. Link to comment Share on other sites More sharing options...
Eric - TIA Posted June 7, 2010 Report Share Posted June 7, 2010 Starting from the beginning helped out, not we know what the problem is and can take it from there. Since we know it is the switch and you replaced the switch, then it has to be the wiring to the switch. By reading what you stated in the previous post, looks like the wiring is the problem. If you look at how you explained how the switch is wired, you actually have two circles and not the one we spoke about. You have both the positive and negative going to the switch and this breaks up the circuit. You should have the positive from the battery going to the switch, then on another pole or pin you should have the positive from all the lights hooked up here. The negatives from the lights should not even be going to the switch, they should all go directly to the battery. Never interrupt the negative. Take a look at it now and you will see how it completes the circuit or the circle. Try this and I bet it works for you, if not let me know and we can look further into the problem. If it works, not you can go to your resistor to see what size you need. Remember since it is parallel, you only really need on resistor between the battery and the switch on the positive wire. Link to comment Share on other sites More sharing options...
larry76 Posted June 8, 2010 Author Report Share Posted June 8, 2010 Awesome, you did it. I only interupted the positive and rewired the switch for the positive as you stated. I put the negative back and everything works great. Thanks for your help Link to comment Share on other sites More sharing options...
Recommended Posts