48 volt 1000 watt hub motor add solar ?

[kingidea]

I have an electric bike with 48 volt battery. I have a volt meter hooked up to my system fully charged battery is 52.6 volts i think. I found a small solar cell 5 x 5 inch 6 volt 1.5 watt. If I hook this right in with the battery will it burn out the controller or battery. I hooked solar up without the battery my volt meter read 7.5 volts. I wanted to build the small cell into my top bag. I think at 15 mph I could possibly get 100 miles on a sunny day. Because at 15 mph if I petal I can create more energy then I use the way I have it geared. Add that extra 7.5 volts????

Will it work or do I have to have something to install between the solar and battery????

Any help I would be grateful for!!!

 

[lionman]

There is no point connecting a 1.5w PV cell to your bike.

Even after 10 hours of sunlight, the most it will add to your pack is 15wh of energy, which is basically nothing for an ebike.

Also, if your pack is based on li-ion cells, then its fully charged voltage will be 54.6v. You cant charge a 54.6v battery with a 6v source, it needs a 54.6v source. You could use a DC-DC converter to step up the voltage to the required level, but it wouldn't be worth it with such a tiny solar cell.

 

[parajared]

In regards to Suntrip (the long-distance solar bike challenge): https://www.thesuntrip.com/presentation/our-solar-bikes/
Everyone seems to pack a fair amount of battery. 800-1100 watt hours of battery pretty much across the board. I didn't see any packs above 1100 watt hours so I presume ruling must have limited that or all the riders favored lighter weight.

Here's a list of some panel sizes (from what I could gather) just to give you some ideas.
Raf Hulle: 280watt
Tom Papay: 220 watts in use 440 watts parked and unfolded
Dirk Huyghe: 250 watt
Oliver Reginensi: 300 watt
Antonio De Chiara: 500 watts while in use 700 watts parked and unfolded
Denis Bertet: 240 watt
Arno Liegeon: 250 watt
Paul Bermejo: 200 watt
Henri: 200 watt
Pauline de la Marnierre: 300 while riding 600watts deployed.
Francois Mendez: 300 watts
Andreas Nandita: 260 in use 390 watts parked and unfolded

Nearly all rider favored fixed position solar panels over aimable panels. With regard to the tiltable panels used most were tiltable only with the bike parked. With my own personal setup the amp-input was nearly the same even if the panels were shoddily pointed at the sun. 20 degrees off and I was still getting pretty good amp flow. The greatest benefit to tilting was very early morning and very late afternoon where I opted to camp and tilt my entire rig on it's side to benefit from the aim.

I found tour-de-Mongolia to be a very interesting solar e-bike read.

 

[parajared]

I personally use a 9-panel 450 watt panel system but if I had endless money and could simply re-build it all over again I would have just bought three HQST "lightweight flexible" 100 watt panels and serialized them together for 300 watts.

 

[amberwolf]

There is no point connecting a 1.5w PV cell to your bike.

Even after 10 hours of sunlight, the most it will add to your pack is 15w of energy, which is basically nothing for an ebike.

That would be 15wh (watt-hour), not 15w (watt).

 

[lionman]

There is no point connecting a 1.5w PV cell to your bike.

Even after 10 hours of sunlight, the most it will add to your pack is 15w of energy, which is basically nothing for an ebike.

That would be 15wh (watt-hour), not 15w (watt).

Thanks for picking up that typo.

 

[dogman dan]

That panel would work for charging a small thing, like a phone, or your light battery, but only after a voltage converter turned it into useable voltage. This is what parajed does, panels produce what voltage they will, then it goes into a converter to make it into the voltage his pack needs.

The basic thing on solar powering your bike is the voltage needs to be close to your packs full charge voltage, but not over it.


Then it needs to be big enough to bother with. Lets take a small 12v 25 watt panel for example, they are about 2 feet square or maybe a bit less. So at peak operation, it would put out about 25 watts of 14v. so in an hour, it puts out 25 watt hours.

Now take your bike, cruising at about 20 mph, it should be pulling about 500 watts. So your 25w panel would power the bike for 1 20th of an hour. That is 3 mins of that hour of riding. See where this is heading?


Carrying 100w of panels starts to make some sense, especially if you run on half that 500w. If you are pulling only 200w cruising much slower, then the panel starts to put out half your needs.


I's still like to make a solar trailer, but lack of cash keeps the idea on hold. 200w of panel, which would be about 8 foot long by 2 feet wide.