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Resistor replacement in solar light

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jakethepup

New Member
I hope I am posting this in the correct thread.

I have a solar spot light that I have been trouble shooting, and I think I have found the problem with the light, there is a resistor that is rated at 10 k at 10 watts, when I check this resistor it is open zero resistance. Ok hold your breath, I know you should not do this but, if I use a jumper and across the resistor and just tap the connection the light comes on. Like I said I just do that just for a second and the light does come on, so I think this proves that the resistor is open. I went to Radio Shack and they did not have a 10k resistor rated at 10 watts, but they did have 10k resistors rated at ½ watt, so could I put 20 ½ watt resistors in parallel and get the 10 watts needed and will this keep the resistance still at the 10k.


Thanks in advance, sorry if this is real basic for you pros.
 

sheldonstv

New Member
simple answer is NO!!! obtain the correct resistor ,putting resistors in parallel decreases the resistance...... use the correct replacement resistor
 

Sceadwian

Banned
A 10k 10 watt resistor for a solar light doesn't make any kind of sense, could you descirbe your circuit better?
 

jakethepup

New Member
Sure I can descirbe the setup a little better. This is not a little solar pathway light. The solar panel is a 20 watt solar panel, rated at 1.19 amp, the light bulb itself look very much like a MR16 style halogen light like used in a track lighting is it led and the bulb itself is rated at 6 watts. The battery is a 12 volt lithium ion battery I do not see the current rating on the battery. For the circuit itself and really not technical enough to describe each piece of the circuit but the main electronics are a photocell a couple of 10k resistors, a transistor and I think it is rated around 5 amps, a couple of 470 ohm resistors, and then also the circuit has what I am guessing is a charging controller for the battery. What I do know that the battery is charging and staying charged so the charging part of the circuit is working.

I hope I have provided enough information, if not I can try to take a picture if needed.

Thanks again in advance for any help.
 
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Sceadwian

Banned
You could use 20 500 ohm 1/2 watt resistors in series. It'd be bulky and funny looking though, get yourself a proper 10k 10watt resistor.
 

kpatz

New Member
Are you sure it's 10K (as in 10,000 ohms) and not 10 ohms?

To dissipate 10 watts through a 10K resistor, you need to run 316 volts through it (with a resulting current of 31mA). To dissipate 1 watt, you need 100 volts/10mA. Your circuit sounds like it doesn't have more than 12 volts in it, unless it has a step-up circuit or something,

If it's really a 10K resistor, a 1 watt one will most likely be adequate. But if you want to do it right, Mouser has 10 watt 10K resistors.

I'd like to see a pic of this 10K 10watt resistor. :)
 

Sceadwian

Banned
Me too, it still doesn't sound quiet right.
 

jakethepup

New Member
I must say I have to hang my head in shame, because you are a correct the resistor is 10 ohms not 10k and it is not 10 watts, I looked the resistor up on the internet and I misread the color banding on the resistor. After reading you guys replies, I decided to pull the board all the way out where I could really get a good look at that resistor, what I found after I pulled the board I found that one end of the resistor was loose I soldered both ends just to make sure they were soldered tight and put the board back in hooked up the battery held my hand over the sensor and the light came on. I am up early and the light is still on so I guess it is fixed. I took a flash light out and shined on the sensor and it went off.

I would like to thank everyone for their time and feedback on this problem. As you can tell I like electronic but I don’t know too much about it, just learning.

Thanks again
 

Sceadwian

Banned
Glad you got your problem solved, even if it wasn't what you originally, thought.
 
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