I have two solar panels. One is 310 watt 39 volt 8 amp and 2nd is 250 watt 37 volt 8 amp. The 310 watt one burned down a 12 volt fan, then I bought a 24 volt fan and have operated it on both panels but it is getting overheated again.

Guide me on what to do to use these 12 V loads with either 250 watt or 310 watt panels without getting burned down, please.

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    \$\begingroup\$ So you are running a 24V device with 39V and are wondering why it doesn't work? \$\endgroup\$ – PlasmaHH May 8 '17 at 11:10
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    \$\begingroup\$ You plugged your 39 volt solar panel into your 12 volt fan, and you are wondering why it burned out - you may need to learn some electricity basics before continuing to mess around with these (unless you have a lot of money for new fans :P). \$\endgroup\$ – user253751 May 8 '17 at 11:22
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    \$\begingroup\$ It is worth noting that the solar panel's output won't actually be 39V when the fan is connected, if that is its maximum voltage, but it could still be higher than 24V and definitely higher than 12V. \$\endgroup\$ – user253751 May 8 '17 at 11:31
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    \$\begingroup\$ I nominate this for dumbest question of the month. \$\endgroup\$ – Olin Lathrop May 8 '17 at 12:14
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    \$\begingroup\$ @OlinLathrop don't encourage them to top that. \$\endgroup\$ – Marcus Müller May 8 '17 at 12:39

You are running your fans at up to 39 V, which is far above their rated voltage (12V, 24V). That will mean overheating and, eventually, burn out (provided they don't get destroyed straight away when you first connect them, as it happened to the 12V fan).

You only have 2 options here:

  1. Buy a fan that can tolerate at least 39 V (which may be expensive or difficult to find).

  2. Step down the voltage to a level safe for your fan. Because of the huge potential difference, a linear regulator is not a good option. You should look for a switching regulator or a DC-DC buck converter than can tolerate your 39 V input (some derating would be wise: look for a converter that can tolerate up to 48V in) and that is able to output the voltage and power required by your fan. There are a lot of modules to chose from, with adjustable output voltage and a wide input voltage range, at the usual part suppliers.


You are missing two important elements of a Solar Power System, the MPPT Charge Controller and Battery.

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