Ok, so I've been Googling this for a while and for some reason I am stumped to figure this out!
I'm trying to determine how long it will take to charge the battery on my electric bike with a solar panel. Details are as follows:
Lithium-ion battery
48V
14Ah
Solar panel:
68W
Cell efficiency: 23%
22V
3.09A
The solar panel would be charging a power station; the battery would be plugged into the power station to charge.
I don't know why this is so challenging for me to figure out, but there it is. :-[
what if you just used your legs to power the bike? :bd:
Or an army of hamsters on wheels :-"
Quote from: Toonces on November 22, 2021, 05:39:17 PM
Ok, so I've been Googling this for a while and for some reason I am stumped to figure this out!
I'm trying to determine how long it will take to charge the battery on my electric bike with a solar panel. Details are as follows:
Lithium-ion battery
48V
14Ah
Solar panel:
68W
Cell efficiency: 23%
22V
3.09A
The solar panel would be charging a power station; the battery would be plugged into the power station to charge.
I don't know why this is so challenging for me to figure out, but there it is. :-[
Retired electrical engineer here. I'll give it a try.
Ideal system:
Battery: 48V x 14A-hrs = 672 W-hrs
Solar panel: 22V x 3.1A = 68.2 W
Perfect charger: 672 / 68.2 = 9.85 hrs
Now the real world.
1. Given the length of time the sun will move considerably over the sky reducing the solar panel output. Also, clouds will reduce the solar panel output. (Here in Ohio by a considerable amount, I see you're in San Diego so not much at all for you)
2. There are inefficiencies in charging the power station. Usually about 80 to 95% efficient. So let's increase charging time by about 10%
3. These same inefficiencies will slow down the charging of the bike battery. Another 10% added.
Counting 2&3, you're up to about 12 hours. #1 will add way more unless you put the panel on a swivel that follows the sun. I'm guessing 2 full days.
Disclaimer: age and dementia could mean I'm way off on this.
Would the army of hamsters be charging the battery or pulling the bike? Cause I'd probably pay good coin to see the latter. <:-)
Quote from: bobarossa on November 23, 2021, 11:23:39 AM
Disclaimer: age and dementia could mean I'm way off on this.
your calculation is correct and adpation to real world estimations is top notch O0
I am a physicist (think more of a Leonard then a Sheldon so ^-^)
Toonces, two bright sunny! San Diego days ... if its clowdy or overcast possibly a week, when your lucky
(the elctronics involved may have a shutdown trigger and dont accept a rinse of current, so a overcast day could be zero charge
even so the module is tagging along with 5W output by the book)
Perfect guys, thanks! That is exactly the info I needed.