Overpaneling

[Spicyguy]

I have a jackery 500 that I have just been charging off the wall where I can findfpower but I'm looking on getting a solar panel.  It has a pwm controller and is current limited at 3.5 amps and can accept voltages up to 30
 The recommended panel is 100 watts but I have heard about others overpaneling these with up to 300 watts. I'm curious how this works or if it would be an effective way to boost charging times during winter. Thanks for any help. I'm a noob with this stuff.

 

[willprowse]

Yes the jackery can be overpaneled. 

How to know if your small solar generator (jackery) can be over paneled:
If you can connect the solar input of your solar generator to a cigarette lighter (the jackery comes with a cable to do this), you can safely overpanel it with solar panels. 

Technical reason: The jackery has current limiting. It is designed to be connected to an "amp source". This means you can connect multiple panels, and the current limit will not be exceeded. 

How to safely overpanel:
Just make sure that the input voltage of the jackery is not exceeded, so put your panels into parallel, not in series. If you have 2x 100w solar panels in parallel (use a mc4 branch adapter), you will be set. 


I made a little tutorial with a diagram here: https://www.mobile-solarpower.com/ultra-portable-systems.html

Only problem with overpaneling is that the jackery will still take a long time to charge. The amp limit is pretty bad on those. Unfortunately.

 

[Spicyguy]

Thanks for the response Will and thanks for the link to your site. I watched some of your videos as well which are very helpful. So just thinking aloud....

The jackery input Max is 100watts....or about 3.5 amps at 30 volts....so ideally I'd want a solar panel that pushed out 30 volts in order to maximize that 100 watt input capacity...but I'm not sure any 12 volt panel goes much above 20. So if I can push 20 volts the most I can hope for when charging solar being that I'm limited to 3.5 amps is 70 watts. 

So in the case of over paneling a jackery, would having 200 watts of solar panels really make a difference anyways in charge times in the real world? I'm not quite sure how this works in practice as opposed to theory. I'm especially concerned about how this works in winter as opposed to Summer specifically with pwm...which I've heard takes a hit....or is it just that mppt improves and pwm stays the same. 
Anyways,    being that the jackery  cannot even suck down what a 100 watt panel can produce (because of it being limited to 3.5 amps at 20 volts=70 watts), how is over paneling beneficial to charge times? What I'm missing is the real world component...or non optimal scenarios that affect solar output that would make doubling my panels more effective. Thanks again!

 

[willprowse]

Great point! It doesn't make a big difference. it can in a larger system if you are far from the equator, but that's about it. The jackery solar input is very limited. Solar performing generator in all other regards, but it takes forever to charge. I connected 300 watts to my 240wh one and I could never get higher than 60 watts. So you are probably better off sticking with a 100w panel.