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--- lifestyle:faq_solar_generator [2020/05/20 11:22]
frater_secessus [technical discussion]
+++ lifestyle:faq_solar_generator [2020/05/20 11:40]
frater_secessus [Charging from solar panels]
@@ Line 52: / Line 52: @@
   * Will you have 8hrs of usable solar harvest?  Do check the [[electrical:12v:electrical_notation|Vmax and Imax specs]] for the device if you intend to charge with solar;  the max input voltage is usually quite low.
-==== technical discussion ====
+====Charging from solar panels====
-===Charging from solar panels===
 Charging these devices from solar panels will probably be [[electrical:solar:output|slower than you might expect]].
-Devices that claim to have internal solar controllers (probably mppt) will cost more but will make much better use of panels for charging.((4S or greater Li configurations will also charge better from solar due to higher voltage))
-  * in the absence of an MPPT controller((sometimes present on higher-end devices)) [[electrical:solar:output#charge_controller_type|panel output is hamstrung by battery voltage]].  You may see a device listing 60w max input but specifying a 100w panel for use with it, and now you know why.
+  * in the absence of an [[electrical:solar:charge_controller#mppt|mppt controller]]((sometimes present on higher-end devices)) [[electrical:solar:output#charge_controller_type|panel output will be hamstrung by battery voltage]].  You may see a device listing 60w max input but specifying a 100w panel for use with it, and now you know why.
   * devices with 3S lithium cells will hamstring the panels even worse((3S Li voltage can be as low as 9v, and maxxes around 12.5v.))
+  * long wire runs (as seen with portable panels set outside) result in voltage drops
+  * sunlight is limited to a certain number of hours.  Some units require more hours of charging than there are hours of sunlight in a day.
-Poly panels will typically [[http://bdp.mousetrap.net/index.php/2019/11/13/pwm-loves-poly/|make more power]] in this scenario due to their lower voltage / higher current.((mppt-equipped models will charge equally as well from both panel types))
+Poly panels will typically [[http://bdp.mousetrap.net/index.php/2019/11/13/pwm-loves-poly/|make slightly more power]] on normal (non-MPPT) devices due to poly's lower voltage / higher current.  Devices with internal MPPT controllers will use both panels equally well because they decouple battery and panel voltages.
 Note:  it is possible to [[https://www.youtube.com/watch?v=yXNW-4fNZVk|place a small DC-DC converter between the panel and input port]] to get the panel up near max power.  Doing so will make it even more important to manually disconnect the panel when charging is complete.
@@ Line 74: / Line 73: @@
-===Charging from wall socket===
+====Charging from wall socket====
 Wall charging is typically fastest because the manufacturer gets total control over the adapter's voltage and current output.  Note that they might not include a fast charger to reduce cost or heat stress on the battery.((particularly for Li))
-===Charging from car outlet===
+====Charging from car outlet====
 Car charging is typically slow because [[electrical:12v:alternator|alternator]] voltage tends to be fairly low((particularly for charging lead)) and [[electrical:12v:ports#the_cigarette_outlet|ciggy outlet]] current limited to 10A.  Unless one is on a road trip there is probably not enough time spent driving the vehicle to charge the device fully.

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