Recharging in the wilderness

[Hyena]

So I've had a few people ask me lately about recharging in the wilderness, where there's no AC power available.
Surprising actually - 3 people in a month from different states have asked me almost the same question about wanting my help in building an ebike they could take out into the wilderness for weeks at a time.

I had a few thoughts on the matter but I'd be interested to hear if the combined minds here had any other suggestions.

The criteria is it has to be portable enough to take on their bike with them.

The obvious first choice is solar and one of those flexible rolled up panels would be ideal.
Wind would be another option but not particularly portable.
My other thoughts were a small ICE powered generator. Maybe something built from a little weed eater motor ? Or have the engine powering the drive of the bike as a hybrid, with the back wheel elevated and and the brake levers held in to activate regen. They can't really set it up as a hybrid from the get go as they're riding in places you can't take ice bikes. They'd be likely to come across rangers too who would ping them for the engine even if it wasn't running at the time (thought they could likely get away with running it for a short period of time of a night)

Then my thoughts turned a little more whacky - how about a small steam or hot air powered turbine generator , something that could be placed over a fire. Or a hydro turbine set up, something that could be dropped into a fast flowing stream ?

Anyone got any other ideas ? Ideally practical ones but by all means lets have some wacky ones too

 

[spinningmagnets]

The numbers have been crunched, and the answer has no other competitors that are even close. Get a very small and reliable generator that is gasoline powered, perhaps a Honda GX 4-stroke? mount it on a trailer.

You can run the gen to power the bike and charge up the bikes battery,...when the battery is full, turn off the gen and run on the battery alone until it reaches the lowest point you dare and then restart the gen.

With just a small effort, a very quiet housing can be made for the gen, with an added electrical fan to keep the air-cooled motor from overheating. Just my opinion, best of luck...

 

[Andje]

fyi im pretty sure most of the "small rollable" type solar panels will be an extremely low amperage. I know around my Canadian Tire they sell the trickle charge ones which are 24v or 12v and do about 20w...
Sadly, and ICE would be the obvious solution.

On the other hand, i recently went camping and took my ebike battery which is in a backpack with me. It is a 100v battery, and had no problem making us coffee using our 900w usually AC coffee machine that we also brought with us

 

[fechter]

Something powered by a wood fire would be cool, but nothing will be as compact as a ICE generator I'm afraid.

One possible wood-fired approach would be a bunch of Peltier effect coolers hooked up as generators.
You get one side hot, the other side has cooling fins to dissipate the heat. You can get the Peltier modules fairly cheaply from surplus places. One challenge is they can't tolerate above around 150C or the semiconductor junctions will break down or the solder joining them will melt. You'd need some kind of thermostatically controlled thermal barrier to regulate the hot side temperature. The cold side will need some fans, but they can run off the generated power.

 

[Hyena]

The numbers have been crunched, and the answer has no other competitors that are even close. Get a very small and reliable generator that is gasoline powered, perhaps a Honda GX 4-stroke? mount it on a trailer.

Yeah a trailer mount would be the easiest solution, but not for rough and very narrow tracks.

On the other hand, i recently went camping and took my ebike battery which is in a backpack with me. It is a 100v battery, and had no problem making us coffee using our 900w usually AC coffee machine that we also brought with us

haha not really roughing it are you ? :lol:

One possible wood-fired approach would be a bunch of Peltier effect coolers hooked up as generators.
You get one side hot, the other side has cooling fins to dissipate the heat.

Hmm, I didn't think about peltiers. Do they have enough guts that you'd get meaningful power from them ? especially when running fans too ?
I guess the easiest way to crudely regulate the temperature would be to just place it a reasonable distance from the fire. Have a temp probe with a beeper on it and it's getting too hot then just move it back a few inches.

I guess there's a few options here - one would be something that is strictly portable the other would be something that you could assemble and leave there if you're visiting the same spot frequently. If you're returning there lugging a big lead acid battery and leaving a solar panel permanantly across it would probably be the best bet. Alternatively I reckon you could make a pretty cool paddle wheel type hydro generator if you were by a stream

Anyone know how much lead you'd need to encase a chunk of uranium ? :lol:

 

[wesnewell]

Regen controller with rear DD motor. Put bike on stand. Pedal and recharge battery.

 

[fizzit]

I've experimented with peltiers... they're really inefficient. I got about 4w from a 8.5x11 sized fresnel lens focused onto one, with a big CPU heatsink and a fan on the other side. I say solar is the best route, next to human power. It seems especially irresponsible to go out in the wilderness on an electric vehicle to avoid rangers and other people, and then plug in a smoke-belching generator and crap all over the environment that you and other people are enjoying :lol:

 

[amberwolf]

Yeah a trailer mount would be the easiest solution, but not for rough and very narrow tracks.

BOB trailer could do it, or other single-wheel trailers. Might need to add a bit of suspension to the trailer to keep a rough track from shaking the cargo/gen/etc apart.


As much as I hate the idea, the gen is the simplest most efficient way of doing it.

Solar would be ok, but the only good way I can think of to do it is to have two or more sets of battery packs for the bike, and keep all the ones not being used at that moment attached to a stationary solar charging station with a suntracker on it. Solar also doesn't work well in a forest or many mountanous areas, as the sun gets blocked too easy too much of the time, by trees or clouds. Works ok in a desert or flat bushland ok, I'd bet, assuming the suntracker is on it, and that no one steals it or your batteries while you're away from it.

 

[liveforphysics]

Little Honda Gen.

Otherwise, a solar array that you setup at camp, and have charging a battery that you swap out as needed to run the bike.

 

[dogman dan]

Daytrips to the wilderness and return to car camp at night is nearly the only option. Then you have your generator there, could be gas, could be wind.

A small panel, say 45 watts, will take quite a while to charge a bike battery. Just like the cheap lipo chargers do. So panels at the car camp, or at least small enough to pack in a few miles.

One possible option would be micro hydro, assuming the wilderness is wet and steep. A tiny nozzle and generator, some kind of pipe attached to a flexible sheet, and some super light polyethylene or pvc hose. Make small dam with flexible sheet and some rocks, get a flow into the hose, and run downhill to get a head on it.

Once set up, it could be your base camp in the wild, and daytrip from there. The basecamp could be fairly close to the trailhead, but still allow a camp where you don't listen to other peoples crappy music. Cool thing about this is the abilty to charge overnight.

If not too far a pack in, the same thing could be done with a small wind generator. Say 200 watt model.

 

[Hyena]

One possible option would be micro hydro, assuming the wilderness is wet and steep.

I realise you're talking hydro electricity, which is what I was getting at before (I was thinking more along the lines of turbine in a small length of say 4" PVC pipe positioned in a fast flowing stream) but I just had another idea - hydrogen! No need to worry about carrying fuel then, just a bag of salt and the basic gear you'd need. Making it is easy, being able to utilise it meaningfully is another story... haha

camp where you don't listen to other peoples crappy music. Cool thing about this is the abilty to charge overnight.

heh I'm talking proper wilderness not the local camping grounds. The sorta place where if you take enough supplies you won't see another soul for months. There's a few different scenarios though - one guy wanted to travel 20miles from where he could park to his destination, camp and fish there for a few days then ride back. Another wanted to essentially go on an e-walk about and just explore for days or weeks at a time, another wanted to set up a base miles into the trip that he could then venture out from in any given direction but return there at night to recharge.

Me personally I have a way of pinching a bit of power on the sly for a recharge when out in the local national park. It's not remote by any stretch of the imagination - only 5-10 miles from civilisation but when you're out roaring around like a maniac it's good to be able to top up before cruising home. I found a toilet block in a camping ground miles from anything else - no other facilities, no power points, no phone - BUT, there is lights in the roof. Enter, home made light adaptor - unscrew globe, screw in insulated plug made form an old globe and dangle the cord down to your charger. I call it my mosquito charger
(obviously I don't recommend this to others because if you don't know what you're doing you could electrocute yourself)

 

[thewmatusmoloki]

I was in Jaycar the other day and saw one of these portable wind generators for the first time :
the MG4570 in this link http://solarsunpower.com.au/products/wind-turbines/

Cool, thinks I. It stands about 500mm high and I could get the readout to light up with a quick spin by hand in the shop, had to stop after a couple of goes because the shop dude was frowning at me . Only 50 watts out but the 12 to 16 volt output is useful. I think the price was about $390 in the shop , so pretty expensive really for just 50 watts in a windy campsite but still a step in the right direction when combined with the roll up solar. This thing is only slightly smaller to carry than the small honda genny and much lighter but no noise or smoke.

Don't know if the're any good just throwing it out there. The petrol genny idea still easily wins for decent power for fast charging.

 

[patrickza]

If you're near your car and have regen just get someone to tow you for an hour or so.

Kind of defeats the object of being on an electric though...

 

[Andje]

if youre near a working car and dont care about the huge waste just plug a lipo charger to the car battery; most are designed for that since recharging rc batts in the field is common.

 

[John in CR]

If money is no object then BigMoose has the connections and know-how to come up with a small free piston stirling engine designed for a fire as a heat source with a linear alternator that spits out 50hz AC. If money really really is no object then it's also possible for one that doesn't even need a fire. The heat comes from radioactive decay of some unobtainium material, and those units were specifically designed for space travel where size and weight are even more of a premium than on our bikes.

There are some small 80W stirling coolers out that are for vending machines that might be hackable to run in reverse at the temps available with a fire, but I've never gotten my hands on one to play with.

 

[mdd0127]

I have a few designs drawn up for a 4-lb mirco-turbine generator that's powered by those little camp-stove propane bottles.

I still don't like the idea of using propane though. A small solar setup on an auxiliary charge transfer battery would be better. You'd just have to set it up at camp while you're out messing around.

Eco friendly, easily portable power generation is going to be a hot industry in the coming years!

 

[dodjob]

I was in Jaycar the other day and saw one of these portable wind generators for the first time :
the MG4570 in this link http://solarsunpower.com.au/products/wind-turbines/

Cool, thinks I. It stands about 500mm high and I could get the readout to light up with a quick spin by hand in the shop, had to stop after a couple of goes because the shop dude was frowning at me . Only 50 watts out but the 12 to 16 volt output is useful. I think the price was about $390 in the shop , so pretty expensive really for just 50 watts in a windy campsite but still a step in the right direction when combined with the roll up solar. This thing is only slightly smaller to carry than the small honda genny and much lighter but no noise or smoke.

Don't know if the're any good just throwing it out there. The petrol genny idea still easily wins for decent power for fast charging.

lol they are not good. This is the worst wind turbine design. My mini turbines would have been a good alternative for people "wildering" in mountains or see coast unfortunately I had to stop this business reagrding too few demands.
Gruß,
H.

 

[ZOMGVTEK]

These cheap 1000W 2 Stroke generators can be had for <$100 stateside. Not sure about elsewhere. They are absolutely great for most anything, but are a bit on the large side. I picked up 2 of them for $50ea. from a local eBay seller a few years ago.
If its not a super epic trek to get there, or you can take the generator with you in a car, it wouldn't be a remote issue to bring along. Its something like 30 LBS and holds just over 1 gallon of fuel.

http://www.youtube.com/watch?v=-eHYN4VNQj4

This bike felt like hell without a generator, and was quite bad with this mounted up. With a decent bike it would be manageable.
The generator itself I tested with a 700W resistive load (1500W heater on low), and it was sucking 0.197 GPH of premixed fuel, even with the high speed needle fully out to make sure it runs rich and reliable in cold weather.

You are best running this generator nearly full load, something like 600-800W... If you can charge the bike at 600W, losses would bring it closer to 700W draw. You should be able to charge a 1kWH pack from 80% DOD around twice off the stock 1 gallon fuel tank, possibly even more.

 

[corkscrew]

I've wondered about this myself, as I'd like to tour under e-power! How did Justin @ ebikes.ca do it? Just borrowing power outlets from people?

Although this thread has given me an idea - why not install a wind generator on the bike? Current provided by the forward movement from your charged batteries, to continue charging them, or a separate pack?

 

[John in CR]

Perpetual Motion alert!

 

[remf]

How about a fuel cell generator?

Trulite KH-4

http://www.trulitetech.com/products.html

 

[ZOMGVTEK]

Really, the only reasonably priced and practical solution thats going to be super reliable and easy to implement is a gasoline generator. You can go ahead and spend several hundreds on a smaller and lighter 'suitcase' generator, but fairly small and light 2 stroke generators are cheap, reliable, and fuel efficient.

If you are actually serious about doing this, its the only thing that isn't ridiculous. You can recharge reliably in a few hours, not a day or more for some big solar or wind setup. You can even use your current charger. All you need is to find a good way to strap a chinese generator onto your bike. I threw together a mount on my bike, and it worked out alright. Never ended up using it, since I never had any purpose for it yet.

 

[fechter]

I've experimented with peltiers... they're really inefficient. I got about 4w from a 8.5x11 sized fresnel lens focused onto one, with a big CPU heatsink and a fan on the other side.

They're pretty small, so if you put 20 of them on an aluminum plate, it might make useful power from a camp fire. It might start getting heavy though One nice thing is there are no moving parts except for the fan, which is easily replaceable, and it would be pretty quiet.

 

[fizzit]

They're pretty small, so if you put 20 of them on an aluminum plate, it might make useful power from a camp fire. It might start getting heavy though One nice thing is there are no moving parts except for the fan, which is easily replaceable, and it would be pretty quiet.

True. And I don't know where, but I've heard that you can get some thermoelectric units that are optimized for power generation which are a lot more efficient than regular peltier cells.

http://en.wikipedia.org/wiki/Thermoelectric_generator

Wikipedia says 5-10% efficiency. It's all about delta T, so if there was a nearby source of water, a water reservoir could be even better than a fan for the cool side.

Here's some teg's for sale that i just found.
http://www.tellurex.com/products/power.php
$110 for 7 watts... It'd probably be cheaper to buy some bismuth telluride and brew your own

 

[rhitee05]

I'd be curious to try a large array of thermocouples. You'd have to roll your own, but any two dissimilar metals will work and you could probably figure out a combination that's cost effective and produces a decent voltage. Standard thermocouples are made from fairly exotic alloys, so I doubt you could replicate them for a reasonable price.

What I'm thinking is that the thermocouples would have an advantage over the Peltier because you could get a really large delta-T. You could potentially stick the hot junctions right in the fire, or very close to it. Still probably not practical, but would be a cool science project.