Solar panel charging question.

[Zarathustra1984]

It's likely some of you will have a chuckle at this question. I'm interested in doing up some type of portable solar panel charger for a 10AH 48v pack. Is it possible in any way to use one of those foldable USB-out solar panels such as :
https://www.amazon.com/dp/B01EXWCPLC/?coliid=I24OPDNHOIDUHI&colid=3RZHL09DXQX7Y&psc=1&ref_=lv_ov_lig_dp_it
with a DC/DC converter to step up 5v/2.4or4.8A to charge the battery at a very slow rate? A full charge wouldn't be required, just for emergency such as long-term power outage.

If not, what about charging a 20,000mah power bank with similar output and then using the bank to somehow give the energy over to the 48v pack? Try not too laugh to hard and thanks

 

[amberwolf]

Something like what you propose may work, and has likely already been done here before.

If it's useful, there is lots of solar charging info in many ways in some of these threads. Not everything is relevant, but you can generally tell by title what might be. There are also other posts and threads that don't come up in this search:
https://endless-sphere.com/forums/search.php?keywords=solar*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
One of the most useful is solarEbike's. Cowardlyduck's BikeE thread may help too.


BTW, those "powerbanks" don't actually have anything like the capacity they say they do. YOu can look around the forum for threads about those, too, to see why. Same applies to these lists as the above.
https://endless-sphere.com/forums/search.php?keywords=powerbank*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
https://endless-sphere.com/forums/search.php?keywords=powerbank*&terms=all&author=&sc=1&sf=firstpost&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search


You can also look up threads about the efficiency of conversions from one power form to another, if there's not enough info in the other two types of threads, to see why it's not as useful as it might seem.

 

[LeftieBiker]

Assuming 100% efficiency in conversion - which is not the case - then the 28 watt maximum output of that panel (probably requiring a planet with at least two suns shining on it, or a system of mirrors) becomes ~2.8 watts at 50 volts, which is what you'd need to get maybe a 60% charge. In reality it would be more like one watt, and only then in full sunlight. So while the concept can work, the execution would require at least two of those portable PV stations, and probably more...

 

[Zarathustra1984]

Thanks again Amberwolf, and LeftieBiker. FWIW, regarding yesterday's thread; took it out today and it immediately died with throttle, so I ended up reducing the controller amps from 22 to 20 on the LCD3 and accel/speed remained the same with no more shutoffs :wink: @ ~47v sag. 1800w became 1500 with a 30 second fix. Rode the 10AH 15 miles basically 30mph non-stop in the city until the battery (lifepo4) dropped at the expected time - then it shutoff on a throttle rip. $200 battery; Can do

 

[pullin-gs]

I took another approach. Instead of mounting panels on trike I just use them to charge battery. I plug up when I get home after each ride. 100W panel works nicely for my packs (I have two 8AH 12S packs).
Panel is mounted to outside of garage wall. Charge controller (programmable for lithium chemistries up to 90v) is inside garage.