So who's our electrician?

Discussion in 'General Survival and Preparedness' started by melbo, Sep 17, 2005.


  1. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I have some questions about a Solar panel rig I have and how to not overcharge some small electronics...
     
  2. ghostrider

    ghostrider Resident Poltergeist Founding Member

    What is the output voltage of the panel, and what are you trying to power.
     
  3. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I knew it would be you.. brb
     
  4. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I have the Brunton Solaris 25. It's a 25 watt(max) solar array that has an output of 1.3 amps. 12 V
    http://www.brunton.com/product.php?id=243
    It comes with a cigarette lighter adapter as well as a direct 4 prong universal cable. I know that if I charge something through the cigarette lighter adapter, it should regulate fine. But what about if I plug in a Yaesu radio that has a 11mA battery direct? How does 1.3 amps translate to mA's or is it not important?

    Smae thing for Cell phone charging, I have the cig light adapter, but what if I had the Radio Shack cable to bypass my regulator? Can I plug my phone right into this thing and will the 1.3A hurt it?
     
  5. ghostrider

    ghostrider Resident Poltergeist Founding Member

    1.3 A is 1300 mA, so it would probably fry your stuff. Some rechargeable batteries, like in the cell phone, are Zener diode regulator protected to prevent overcharging, or charging at too fast a rate. Some aren't, they rely on the charger to regulate voltage and drop enough current with a series dropping resistor to not overcharge. Overcharging can actually make the batteries burst or explode. If the Yaesu radio has one battery, it is probably 1.5 VDC, so a possibility would be a voltage divider, to supply the required voltage and amperage to your various devices. I can't do that off the top of my head, a voltage divider's outputs can be different if you load part of the circuit and not the other.
    http://www.sengpielaudio.com/calculator-voltagedivider.htm
    http://en.wikipedia.org/wiki/Voltage_divider
     
  6. melbo

    melbo Hunter Gatherer Administrator Founding Member

    The Yaesu has 1100mAh batteries and the supplied wall charger is a 200mA output.
    It's not a smart charge and I have gone with the Battery divided by the charger output:
    1100 / 200 and always charged it for 5.5 hours
    I take it that I should always have a charge regulater in between the Solaris and the Battery then.

    OK, another question then. When I plug my laptop into my cigarette lighter, the transformer, (if that's what it's called) heats up. If I take the same charger and plug it into the gig/out on the Solaris, is it 'stealing' power and cutting down on the efficiency? It's a 75 watt power supply and the Panel only puts out 25 watts, so I can't run it in real time unless I hooked 3 of these panels together.
     
  7. ghostrider

    ghostrider Resident Poltergeist Founding Member

    You really can't transform DC, at least not like AC. The plug in heats up because that's the series dropping resistor dropping the voltage down to a safe level. It turns the voltage into heat.
     
  8. melbo

    melbo Hunter Gatherer Administrator Founding Member

    So the plug in cord for my Passport radar detector does what? regulates the Voltage coming off the Battery that is fluctuating from the alternator which is changing from engine RPM.

    I see that it's not transforming, 12 V is 12 V. And my Laptop power supply has 1 jack fot the 2 prong and another jack for the cig lighter. So it's a different path altogether and shouldn't rob my efficiency?
     
  9. ghostrider

    ghostrider Resident Poltergeist Founding Member

    The worst thing, with two devices, you will just charge slower.
     
  10. melbo

    melbo Hunter Gatherer Administrator Founding Member

    thanks ghost
     
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