Looking to do some backpack/biking in a national forest with Orv trails.

Interested in a electric mountain bike with pedal assist.

Besides the weight with a dead battery, what are the reasonable option's to have an ebike recharge with a small solar panel?

Too far of a stretch? I was planning 2-3 days of charging to be considered reasonable.

Opinions? Thanks.

How big of a bike battery (in Wh) are you looking at? How much solar panel capacity?

I think they're in the 709wH range.

The issue is the charger. Most of those folding 109watt panels are USB out.

I'll have to stop at the bike shop and check out the electronics. Might need a Buck/boost in between if they will accept DC input

I don't think it's feasible to have a "capable" solar charger on a bike (unless it's a three or four wheeled vehicle with the charger topside). Look at ebikesca (Grin); the owner raced his "bike" across a continent or two using a solar charger.

I don't think this is possible. You would most likely want to ride the bike at the same time you would want to deploy the solar panels. Even if you could overcome that, the energy the bike needs is likely much greater than the power you could get from solar panels.

Seems maybe its being confused that it'll charge for 3 or 4 days after I ride out to the camp site?

Vs charging while riding? Which complete isn't feasible.

I would take this with a grain of salt, but it is a starting point for reference. This is based on excellent solar conditions.To charge a Specialized Turbo Creo 2 in 4 hours during a Central Oregon summer, you need a solar setup capable of delivering a consistent 80W to the bike's 320Wh battery.

The Recommendation

• Panel Size: A 200W solar panel is ideal. While a 100W panel exists, a 200W unit provides the necessary "overhead" to overcome efficiency losses caused by high-desert heat and conversion.
  
• Physical Dimensions: * Rigid Panel: Approximately 150 cm x 67 cm (59" x 26.5").
  
  • Portable Folding Panel: Roughly 60 cm x 55 cm when folded (briefcase size), extending to 225 cm (88.5") when fully deployed.
    

Key Takeaway Central Oregon offers excellent sun (6.5+ peak hours), but the high temperatures reduce solar efficiency. Choosing a 200W monocrystalline panel ensures you hit your 4-hour charging window even on hot afternoons.

The question is if OP is comfortable carrying 15-20 pounds of solar panel, which is in the ballpark of what a 200W portable panel weighs. Even a 100W one is around 10 pounds. Regardless, none of this will amount to a hill of beans if the campsite is densely populated with sunlight-blocking trees.

A 709WH battery would likely be a 48V15AH pack, Batteries shut off at 40V, so you have 10-15% of capacity left. So I would estinmate there's 600WH useable here, How far can you go on 600WH? On pavement with smooth tires, 50 miles is easy at 12 mph, With a mountain bike on knobbies, carrying camoing gear and also going 10-12 mph, I would guess about 30 miles.

Taking Atlas' post, it would be fair to say a 200W panel should deliver 150W to a battery in good sun, if it has an efficient charger connected up. Figure at least 4 hours to recharge 600WH,
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You might have to rethink the riding for 2-3 days. It's more like one day of riding and you have to break camp at dawn to catch the good light for recharging, Might have to carry a second battery, Anyway, this sounds like fun. If you do it, a report would be appreciated.





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The bigger problem here is I don't think there is anyway to directly charge the bike with a solar panel. You are going to have to use the bike's charger and it require 120v and whatever amperage to work. You would need something along the lines of an Ecoflow River powerstation thing and then use solar to charge that.
https://us.ecoflow.com/products/rive...41636514136137
If you are handy yoy could rig something up with the solar panels on the bike you could charge the Ecoflow while riding at least some.

I see where you can skip the invert-charger combo and get a dedicated unit from these guys for under $200. Get it for your 46V or 48V lithiun-ion battery,Should probably be more efficient too, vs converting the panel to 110V AC and then converting that back to DC,

https://sunforgellc.com/product/gvb-8-wp/

There are other options available.I am not making a recommendation as I never used one. In particular, select one that won;t exceed the charge current of your battery, usually 2-3 amps,

The idea was to camp and charge.

Probably need to use a buck/boost to match voltage

i don't use campsites

​​​​​​I camp where I want as long as its 1 mile from designated camp sites.

I hope they are comfortable sites as if you are planning on recharging your e-bike with solar a 3 day trip could easily take a week.

I don't use campsites.

I pick random places in the national forest and hang a hammock.

Usually nex to a stream or river so I don't need to carry water.

I am hoping you are carrying the necessary purification equipment and not just drinking straight from a stream. I would also generally recommend using campsites unless they allow camping just anywhere. Generally going off the trail is pretty well frowned upon by everyone.

😆

This was clearly the wrong forum to discuss rustic dispersed camping. Especially in national forests.

Do some reading.

​​​​​And I drink right out of the mud hole.

You missed the point. Where you camp is a completely different topic and based on your initial post unrealistic.

The real issue solar panels do not have the energy density to charge your e-bike even under ideal conditions much less camping. You couldn’t get across Death Valley much less in a forest with streams etc.

Perhaps you could get a Dyno Hub on the front wheel and that way you charge while you are moving effectively giving you unlimited range.

Or bring a small Honda EU1000 generator.

This is the best way to get unlimited range. It even works on cloudy days and in the rain. Look up first and second law of thermodynamics for more information on how to do this setup.

I was pondering a buck/boost to step up the DC.

Most of my camping is a week at a time. And to get to most of my locations from where vehicle's stop/dirt bikes start is about 20-30 miles.

I should borrow someone's bike and give it a shot.

Just using solar panels, several days with a 100 W panel should be able to give you enough, you must have the original charger and an inverter. Of course, try this at home first
I can think of 2 alternate solutions:
Get an extra battery for the return trip
or
If possible drop off a power bank (at least 1800W) with original charger at your camping spot or nearby

What reading should I do that I didn't do in your post?

People feel entitled all the time it is not something being pulled out of thin air. They also think that moving water is safe without purification. I have talked to people like that having worked in outdoor retail for quite a number of years now. That is why I hoped you didn't and am not sure. Given what you said "I camp where I want" and generally the rule is camping at established sites (some of which are primitive and not paid campsites but are not just wherever I want), I would still be weary.

What do you except I read? If you are suggesting I read something specific let me know.

IMHO a model that will work is day rides from a campground home base. Keep a power station (e.g., Jackery, etc.) with inverter at basecamp and charge the bike overnight. A decent size powerpack won't need field charging but one can always add a PV panel to top it up while you're out riding.

Multi-night bikepacking in the backcountry doesn't really accommodate recharging but could work with careful power management and probably a second battery. I'd rather buy the lightest standard bike possible and self-propel.

Yes, too far. The benefits of the Ebike are outweighed by the weight of the panels/charger, the charge time in days and the possibility of not being able to charge due to weather or shade.
You could take a bottle of bourbon and ask someone in an RV to swap it for electricity.