Living off grid with a wheel and only solar ?

[Wonderwebb]

Hi all you tech savvy lot I was watching a show earlier and I wondered how far you could expect to travel in a week if all you had access to was a solar panel . You would have transport the panel on the wheel so size and weight would need to be considerd.  The environment  would provide ample sunlight You would travel until battery was flat preferably at night and then charge  in daytime This is only theoretical but it got me thinking.  Oh and what wheel would you choose for this task?

Be interested to hear your thoughts

[Wazi Bat]

Ohh Man... I'm going to get roasted for this.. but I'll try to math on a forum.  Here it goes.

So, generally 15 watts solar system delivers about 1 AH per hour in direct sunlight.  A 1440w wheel (or an Inmotion V8 equivalent), should have a battery capacity of 17,142mAh.  So it would take about 20 hours of optimal conditions to charge. 

So a good 25 watt solar system panel is about 1ft x 2ft x1in and weighs about 5.5lbs and will give you about 1.5 AH or a 14 hour Charge time.

You would likely need 4 panels or 100watts (@ 22lbs) and find 3.5 hours of strong direct sun. 

You would have to be taking the Mark Watney (the Martian) nap beside your ride. 

Alright shred my math now!  

           

 

    

     

[Wazi Bat]

5 minutes ago, Wazi Bat said:

A 1440w wheel

Refers to the battery configuration, not motor.

  

[atdlzpae]

24 minutes ago, Wazi Bat said:

So, generally 15 watts solar system delivers about 1 AH per hour in direct sunlight.  A 1440w wheel (or an Inmotion V8 equivalent), should have a battery capacity of 17,142mAh.  So it would take about 20 hours of optimal conditions to charge.

Your math is WAY off.

1440Wh / 15W = 96 hours to charge a wheel. And that assumes completely cloudless weather and panels automatically tilting towards the sun. And you need to divide it by 0.8 because of converter losses.

I've done calculations a long time ago and I calculated that I'd need 2 square meters of solar panels (approx. 200W) to keep riding the unicycle without stopping.

2 square meters - so is it possible? Yes. With flexible solar panels it wouldn't even weight that much (probably < 10kg). Would I do it? NO! Riding with anything is a PITA, especially with 2 sq. m. sail that I need to counteract. And it would make it very easy to fall if the wind is sideways.

Also, you'd need to ride north (you want the solar panels on your back, not on your front obscuring your vision).

Additionally, solar panels (flexible ones too) are very brittle, a single crash and your $1000 investment is damaged.

Edited February 5, 2020 by atdlzpae

[meepmeepmayer]

You can just say a 15W solar panel is 15Wh per hour (W = Wh/h). So you can ride a cool extra 750m (0.46 miles) after one hour of charging (assuming 20Wh per km, which is realistic to optimistic) Given that everything works perfectly, you get your 15W, and it's the real usable output of the solar panel.

I think you'd need a backpack with a lot of rollable solar panels for some serious wattage.

More than 1000W solar output do not make sense, because wheels are 100V max and don't allow over 10A charging (100V * 10A = 1000W) so you can't charge faster anyways. Realistically, 74V nominal (84V wheel) and 5A charging means you can use 5*74 = 370W of solar output per charge port.

So 1000W of panel output (that you can't really use) gives you 1000/20 = 50km of range per hour of charging. That is actually doable! Just take an hour break after 50km of riding.

370W of panels gives you 370/20 = 18.5km per hour of charging, which is a bit meh.

Turns out, the limitation is the charge port amperage. So you need to mod in an extra charge port or two unless you want to stand around more than ride. But it is doable with the right setup!

I wonder how much 1000W (effective output!) worth of rollable solar panels are (in price, weight, and size) though

[atdlzpae]

4 hours ago, Wonderwebb said:

You would travel until battery was flat preferably at night and then charge  in daytime

This is possible. Make a tent, put solar panels on it, sleep during the day, ride during the night. 200W of solar, and you can charge MSX in 8h in theory.
Obviously this has to be done in the summer.
There are many problems with such approach:
- Sleeping in a tent during the day is really challenging. You may be risking a stroke. I've slept in a car (station wagon) quite a lot during the day and I needed to have a fan running constantly to pump fresh air in, otherwise it became an oven.
- You risk anyone just stealing your solar panels.
- Transport... Weight is not a problem - flexibles are lightweight. But folding them is not an option or they will crack, so you can't buy a cheap 100W one, you need to buy many 25W ones.

8 minutes ago, meepmeepmayer said:

I wonder how much 1000W worth of rollable solar panels are (in price, weight, and size) though

Looking at our Polish Amazon analog it looks like it's about $150 per 100W of flexible panels. Not that bad.

[meepmeepmayer]

I'm intrigued by the fact that this is much more doable than I expected! Infinite EUC riding

Let's say you have 3 charge ports (mod them in). That's around 400W per port and 1200W altogether. If your panels can supply that, you just take your regular breaks (an hour every 40, 50, or 60km) and roll/fold out your solar "meadow" while you relax. And then you go on with a full battery

[FreeRide]

33 minutes ago, meepmeepmayer said:

I'm intrigued by the fact that this is much more doable than I expected! Infinite EUC riding

Let's say you have 3 charge ports (mod them in). That's around 400W per port and 1200W altogether. If your panels can supply that, you just take your regular breaks (an hour every 40, 50, or 60km) and roll/fold out your solar "meadow" while you relax. And then you go on with a full battery

Hmm a 1200W is like 12 large solar panels, or 6 very large panels.  A folding 100W panel is still quite large even folded typically about 50cm or 20" could be 20% larger in the one dimension, and maybe 20% shorter in the other, and you're not likely to get 100W out of it and being typically a 12V nominal panel you're going to need some electronics to get the voltage right and a solar charge controller.... not really seeing this as very practical right now. 

Edited February 5, 2020 by FreeRide

[Wazi Bat]

2 hours ago, atdlzpae said:

Your math is WAY off.

1440Wh / 15W = 96 hours to charge a wheel.

Obviously a rounding error!   Anyway I think I stick with a bicycle in this scenario.  By the way never ask a geographer to do an electricians job. 

[atdlzpae]

 

[mike_bike_kite]

Rather than carrying the solar panels, could you put them on a small, very lightweight, trailer? A one wheel trailer would obviously suit an EUC but I think it would be a pain to control. If you were going to sleep during the day then I'd look at Hennessy Hammock tents as they're really light weight and fairly cool but you do need a place to hang them.

Here's a report that shows which wheels give you the most range. The Monster tops out with 220km but it has an 84v battery with 2400Wh capacity. Maybe you could ask on a solar power forum (here or here) how many panels you'd need to fully recharge the batteries we use. Remember that, if you're asleep, you can't turn the panels into the sun all the time - that will make them more inefficient. You could test carrying panels in a trailer on your MSX and see what's possible. I'd use an EUC that takes a seat as that will be more efficient through the air (just stand up for the photo shoots).

Then again, rather than an exhaustive trip across the Sahara, you could go for a long weekend down to Brighton and leave the MSX solar charging for the ride home

[Espen R]

With all the fun killing range anxiety I had with the Onewheel+, I did a lot of calculations like this, but a 300W charger combined with solar in Scandinavia, doesn’t add up to something practically feasible. The only thing that could work was a small gasoline generator, but then I finally was able to admit that 20 min of fun followed by 30 min of charging wasn’t really my kind of fun. I traded the OW+ for a KS-16S, and a few days after that ordered the KS-18XL, and that solved all my problems until this fall, when my girlfriend and I bought a campervan. It has two 50W solar panels, so again I started to do the math, but again came to the same conclusion, a small gasoline generator.

We both ride EUC’s, we both have 300W smart chargers, and we both will need to charge in the evening or during the night, so the cost of the added solar panels and batteries needed to do this became a bit too high for us. It really sucks having to use a gasoline generator, but we will divide our weekend trips between on-grid in small towns and off-grid in the deep Swedish forests or the Norwegian mountains, so I guess I’ll be able to live with this blemish on my environmental consciousness:)   

[LanghamP]

On 2/5/2020 at 4:29 AM, Espen R said:

With all the fun killing range anxiety I had with the Onewheel+, I did a lot of calculations like this, but a 300W charger combined with solar in Scandinavia, doesn’t add up to something practically feasible. The only thing that could work was a small gasoline generator, but then I finally was able to admit that 20 min of fun followed by 30 min of charging wasn’t really my kind of fun. I traded the OW+ for a KS-16S, and a few days after that ordered the KS-18XL, and that solved all my problems until this fall, when my girlfriend and I bought a campervan. It has two 50W solar panels, so again I started to do the math, but again came to the same conclusion, a small gasoline generator.

 

We both ride EUC’s, we both have 300W smart chargers, and we both will need to charge in the evening or during the night, so the cost of the added solar panels and batteries needed to do this became a bit too high for us. It really sucks having to use a gasoline generator, but we will divide our weekend trips between on-grid in small towns and off-grid in the deep Swedish forests or the Norwegian mountains, so I guess I’ll be able to live with this blemish on my environmental consciousness:)   

 

I used to follow this guy Will Prowse for his RV camping off grid. He does mostly solar power nowdays.

Over the past few years solar power has gone from heavy, expensive, and not very effecient to light and foldable, cheap, and very efficient indeed. I think a camper van done with not much care with solar panels could power two large EUCs if you bought a modest number of lithium ion batteries to be fully charged before your trip.

[Espen R]

8 hours ago, LanghamP said:

I used to follow this guy Will Prowse for his RV camping off grid. He does mostly solar power nowdays.

Over the past few years solar power has gone from heavy, expensive, and not very effecient to light and foldable, cheap, and very efficient indeed. I think a camper van done with not much care with solar panels could power two large EUCs if you bought a modest number of lithium ion batteries to be fully charged before your trip.

I have followed the development of both battery technology and solar panels for many years, I've done the math and even calculated in the average number of high power sunny vs medium power cloudy days during the summer here in Scandinavia, to estimate the needed size and effectiveness of the solar panels, and it can be done, but not at a price that makes sense to us. Just the cost of the ideal 12v Li-ion batteries would be close to 6000 usd, nickel iron about 5000 usd, normal 12v led batteries, which wouldn't last long with the power draw we need, would be 1500 -2000 usd. Then there is the size of the campervan, 17 feet long, and the fact that we live pretty far north, 59 latitude, so the solar panels we can fit on the van have to be the very effective kind, aka not the cheapest, and we would also have to angle our solar panels, 350 usd just for the brackets. The absolute lowest total cost, with the non-practical foldable panels (not enough space to store them inside the van), is 2000 usd, the lowest priced practical solution, with batteries and panels that really aren't ideal: 2800 usd, the lowest priced solution that actually would work comfortably: 6500 usd. Gasoline generator: 350 usd.

PS: The panels and battery we currently have on/in the van produces and holds enough power to run the lights and (daytime) phone/laptop charging, but they would have to be replaced if we were aiming for EUC charging.

Edit: I know there are battery diy solution, and cheap-ish battery pack solutions out there that would reduce the cost a bit, a surprisingly tiny bit, but I don’t have the time or patience to deal with that. Foldable solar panels could be stored on the outside of the campervan, and that would solve that problem, but we bought the van because my girlfriend owns a Health Food/Shoe shop, so we don’t get long holidays, and when we go away on long weekends with the van, we want it to be as relaxed and hassle free as possible. Setting up foldable panels with the wind and unpredictable weather we have here, it isn’t exactly hassle free, and if I didn’t carry the batteries from the camper van to the apartment and charged them before we left, I would have to setup the panels when we arrived in the evening or get up early to do it in the morning.

Edited February 7, 2020 by Espen R

[atdlzpae]

@Espen R Can you please specify the numbers? For example you're talking about "2800 USD of solar panels" wthout specifying what wattage would that system have... The same with batteries.

I've bought 2kW of second hand solar panels for around $600, which can charge my MSX in 1h with direct sunlight.

You can buy new 2.5Ah 18650 (9Wh each) for $4, making a ($6000 + a week of soldering battery) a 12kWh monster. If you went for salvaged one (I did ), you can get the price to be even lower than lead-acid.

[Espen R]

1 hour ago, atdlzpae said:

@Espen R Can you please specify the numbers? For example you're talking about "2800 USD of solar panels" wthout specifying what wattage would that system have... The same with batteries.

I've bought 2kW of second hand solar panels for around $600, which can charge my MSX in 1h with direct sunlight.

You can buy new 2.5Ah 18650 (9Wh each) for $4, making a ($6000 + a week of soldering battery) a 12kWh monster. If you went for salvaged one (I did ), you can get the price to be even lower than lead-acid.

The total cost numbers include solar panels, batteries, mounting brackets, inverters and so on. As I wrote in my edited post, I know there are diy solutions that would be cheaper, but with my limited amount of time to do this and my current soldering skill level, I don't really see it as an option. I looked at solder free solutions, like a readymade 3D printed bracket to stack 18 650 batteries in, but they were surprisingly expensive. If you know of cheaper solder free options, please let me know.

Because of the angle and power output of the sun this far north, especially in the early spring and late fall, the panels I needed that could fit on our 17 feet long campervan and realistically produce enough power even on cloudy days in April, March, September and October, was also fairly expensive. Solar power is a fairly limited market up here in the north, so the chance of finding the right panels suited for our camper van used, is about the same as winning in the lottery:)

Edit: It's 2 x 100ah 12v batteries I’ve calculated we would need to charge both of our wheels, and the minimum need would be a total of 400W solar panels, to be able to charge the batteries during the day, ideally 5-600W for cloudy days in the spring and fall, and the largest camper van ready panels I’ve found are 180W, so we would need 3. Here in Sweden the cost is 1400 usd for 3 180W panels.

Edit II: I saw that a 12v 100ah Li-ion battery now costs 1300 usd a piece. That’s a hefty price reduction since last I checked.

So, after looking up the current prices, the grand total would be about 5000 usd for the Li-ion option. 

Edited February 7, 2020 by Espen R

[mike_bike_kite]

I'd just like to  know what the math is. What variables are used etc. Then we can use it for any wheel or solar power combination. 

[atdlzpae]

42 minutes ago, Espen R said:

If you know of cheaper solder free options, please let me know.

Used electric car batteries are both solder-free and cheap.

https://allegrolokalnie.pl/oferta/tesla-model-s-2016-modul-baterii-90kwh-65000-km
I'll translate because the link is in Polish: Old Tesla 6p 5.62kWh for $1030. That's 32kWh for $6000. Even if they are 50% degraded it's still cheaper than lead-acid.

Unfortunately 6p (I find 7p to be perfect for 24V inverters), but still a bargain.

Ps. That's not an outlier, I've seen quite a few similarly priced offers.

42 minutes ago, Espen R said:

Solar power is a fairly limited market up here in the north, so the chance of finding the right panels suited for our camper van used, is about the same as winning in the lottery:)

Yeah, that's right. I was very lucky because I bought mine just after Germans started massively selling theirs. Also, the seller had a metric ton of them, so I was able to test and skip damaged panels.

 

Edited February 7, 2020 by atdlzpae

[Espen R]

4 minutes ago, mike_bike_kite said:

I'd just like to  know what the math is. What variables are used etc. Then we can use it for any wheel or solar power combination. 

If you need to charge a 1554Wh wheel to 80%, you would need something like a 100ah 12v battery, preferably Li-ion, and to charge that, under ideal conditions, you would need a 240W solar panel, and it would take 5 hours. It is much easier to use google or online calculators than to do the math manually:)

[Tazarinho]

On 2/5/2020 at 11:29 AM, Espen R said:

It really sucks having to use a gasoline generator, but we will divide our weekend trips between on-grid in small towns and off-grid in the deep Swedish forests or the Norwegian mountains, so I guess I’ll be able to live with this blemish on my environmental consciousness:)   

@Espen R Maybe this could be a solution as well?

 

[Espen R]

12 minutes ago, Tazarinho said:

@Espen R Maybe this could be a solution as well?

 

As a range extender or on shorter weekend off-grid trips where only 1 charge is necessary, yes, but it wouldn't work on a 4-day long weekend trip as a EUC charger. It's an awesome product though, and it's almost half the price of a 12V 100ah Li-ion battery, which has 100wh less than this! Would be great to have in the camper van to reduce the usage of gas. Thirsty charger though, do you know the minimum wattage it would take to charge? If we could slowly charge it with the van's 2 x 50W solar panels, so that it would fully charge it selves on the weekdays when the van is not used, then this would definitely be something I could use.

Would still need a gasoline generator to charge the wheels, but we could probably do most of the water boiling and some of the cooking needed on a 4-day trip with 1 of these.

Thank you for the tip:)

[LanghamP]

1 hour ago, Espen R said:

If we could slowly charge it with the van's 2 x 50W solar panels, so that it would fully charge it selves on the weekdays when the van is not used, then this would definitely be something I could use.

Could you just stop at a coffee shop and surreptitiously charge this battery? It'd cost the coffee shop maybe $25 cents...

 

[Espen R]

16 minutes ago, LanghamP said:

Could you just stop at a coffee shop and surreptitiously charge this battery? It'd cost the coffee shop maybe $25 cents...

 

When we plan to go on off-grid trips deep in the Swedish forests or up in the Norwegian mountains, there aren't any coffee shops or other shops with available power outlets around. I know it sounds strange, but Norwegians, like my girlfriend and I, like to go to secluded places where there are no other humans. If we see a motor home or a camper van at the place we had planned to visit, we will turn around and search for another place. It's not that we don't like other people, it's just that we really like to be on our own:)

[Tazarinho]

On 2/7/2020 at 5:21 PM, Espen R said:

Thirsty charger though, do you know the minimum wattage it would take to charge? If we could slowly charge it with the van's 2 x 50W solar panels, so that it would fully charge it selves on the weekdays when the van is not used, then this would definitely be something I could use.

Sorry, I haven't used it myself so unfortunately I have no idea.

 

On 2/7/2020 at 5:21 PM, Espen R said:

As a range extender or on shorter weekend off-grid trips where only 1 charge is necessary, yes, but it wouldn't work on a 4-day long weekend trip as a EUC charger. It's an awesome product though, and it's almost half the price of a 12V 100ah Li-ion battery, which has 100wh less than this!

Yes indeed, it would only give you one extra charge, so you would still need to find a power outlet every other day.

I like the idea of going into the more remote places, it's what I used to do as a kid. Unfortunately in Belgium it's hard to find any place without people.

[Jean eRide.ie Community]

With wheels like the Veteran Sherman and Monster Pro coming out. 

I think the electric unicycle could act as the power bank for the RV, to power anything needed (charging phones, others), rather than buying an expensive Li-ion power station with plugs on it and less battery than these wheels. 

Sure, would need to get something that connects to the charging port (and uses it to discharge the wheel), that converts the energy to AC again and has plugs to use for mobile, laptop, other... 

Any ideas around here already? 

And then the EUC could be recharged from time to time at 5-10A somewhere on a plug (restaurant, other...). 

Edited September 5, 2020 by Jean Dublin