A guide to Direct Solar Charging your Kuberg Freerider
(or any other 48V 10A Electric Vehicle)

The simplest way to your first off-grid Solarpunk Dirtbike. by Coin3ip

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Solar Kubie is apparently is World’s First Direct Solar Charging Dirtbike.

Direct Solar Charging means no inverter, no buffer battery. This opens the way to truly portable 48V solar arrays that would give the bike a virtually unlimited range by allowing us to recharge anywhere, and so, continuing to move forward, even in the middle of the desert. But we’re not there yet. This article presents some of the available options today. To help you start converting your bike to Direct Solar Power. For convenience. For ecological purposes. For silence. For autonomy...

This article is not sponsored by any of the companies mentioned.


Even though I’d like to work with some of them to develop a specific system optimized for our usage.
I call this system “M.A.S.C” (Mobile Autonomous Solar Campsite), and I talk about it quite everywhere on my website and social media.

 

Note: I’m an artist, not an entrepreneur. My personal goal in this is not to make a company to compete with the ones I mention here, but making a film using this tech so it’s not “Science-Fiction” anymore... #eenola2025

How it works

Direct Solar ChargingPanels - MPPT - Bike

It's super simple. You set up a solar array that can output the at least the same specs than the DC output of the original charger (54.6V 10A. so above 550W). You connect the array to a MPPT (Maximum Power Point Tracking) charge controller that can output the correct signal to charge the Lithium-ion battery of the bike, and you connect the MPPT directly into the bike's battery via the charging port. (Note: the actual procedure is to connect the MPPT to the battery first, and then the panels to the MPPT. And disconnect the panels first when charging is done).

 

The only custom part of the setup at this point is the cable from the MPPT to the bike’s battery.

The Freerider’s charging cable uses a male 3-pin XLR port that you’ll need to source (Note: pin 1 is positive. Pin 2 is negative. Nothing on pin 3). I bought mine on Ebay (they’re used in a lot of applications. Music equipment, for example) and I had my cable made by my local solar equipment supplier (thanks Bluenergy ^^). Same for the MC4 cables sticking out of my MPPT (for convenience, as you'll have to disconnect the panels from the MPPT at the end of each charge).

Compatible bikes

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All Kuberg Freerider, Challenger, Ranger, and X-Force models

(max. charge: 54.6V)

 

The all 48V line-up of Kuberg bikes are compatible with Direct Solar Charging.
It's THE main reason I've chosen the Kuberg in the first place (I'm working on this project for more than 2 years now). 


And any other 48V Electric vehicle (battery) with equivalent max charge voltage will be compatible also.


Potentially the Cake Kalk could be compatible (not rated 48V. max charge: 59V)
I’d love to try and make it possible though. I'm not sure it is, though.
 

Sorry to the Surron people, the 69V (nice) charger makes it unsuitable for this kind of setup (or this specific MPPT). 

 

Link to Kuberg's website

Solar charger (MPPT)

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Victron SmartSolar MPPT 100|20_48V (200€)


There’s no contest here. This is THE MPPT to get. It’s small, lightweight, and it’s very easy to setup in Bluetooth via their app (I made a preset for it I can post on Discord, but I’m sure it could be more optimized).

The 100|20_48V changed everything, and made everything easier. The MPPT I used before was the 150|45 and was the smallest 48V MPPT. The 100|20_48V is listed in the 24V category besides the other 100|20(non48V), and not in the 48V category... 

 

This would need a waterproof version of it, at least. And if necessary, a version that would cover the Cake Kalk specs.

 

Link to website
Link to datasheet

The Solar panels

This si where it gets a little bit more complicated. There is nothing on the market that is specifically made for this use (yet). nothing we can carry around and open up to recharge anywhere. That's what I want to change with the M.A.S.C. But for the moment, here is a selection of already available panels based on my own market research. Prices are based on manufacturer documents, or online seller, at the time of writing (summer 2020).

 

With our current tech, the size of the solar array needed will be around 3m². 

 

The charging time depends on a lot of factors, but if the setup can maintain the desired output, the charging time should be the same as the regular AC charger on a conventional 220V outlet.

Note: You could do it with less and/or smaller panels, but it would also be extensively slower. So I only show arrays "at spec", capable to output whatwe need without boosting the voltage. 

The "simplest" option

Light and Flexible

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Solbian SXX 240W (27.9V 8.6A) - x2 (2 series) - 1800€ x2 (3kgs x2)

or

Solbian SXX 180W (20.9V 8.6A) – x3 (3 series) – 1340€ x3 (2.4kgs x3)

Those are ALMOST the ‘best’ option. It would only need a few more cells to the 240W to make it perfect, though. It's by far The most expensive option. But also the lightest at around 6kgs for one setup.

 

Link to website
Link to datasheet 

Link to Price list


I’m using those cells to calculate my future M.A.S.C setup.

(concept designs are available on Discord)

The "Value" option

any +300W 24V panels

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Example:

Trinasolar Honey M DE06M(II) 340W (34.2V 9.9A) – x2 (2 series) – 150€ x2 (20kgs x2)


There are a lot of equivalent options in this category. More or less the same prices and specs. This example is the panels I’m using right now. It’s the cheapest and more reliable option, but also it’s very heavy. Choose the specific panels that are available to you. I don't have a special recommendation for them.

As a reference, This summer, I usually charged 2/3 of the 22Ah battery in 2hours, from 11am to 1pm (In the south of France - So pretty ideal conditions).

 

 

Link to website

Link to datasheet

The "Best" option

Affordable and Flexible

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Sunpower 170W (29.4V 5.8A) – x4 (4 series parallel) – 220€ x4 (2.9kgs x4)


Connection is a bit more complicated, as we need to make 2 parallels groups in order to push more amps, but it should work fine.

 

Probably the most practical and sensical choice at the moment. 
(I'd really like to try a setup like this)

 

Link to website

Link to datasheet

The "Portable" option

Not quite optimized (yet)

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Flexopower Mojave 220W (18.1V 12.2A) – x3 (3 series) – 560€ x3 (5.6kgs x3)


These look promising “on paper”. On their site, they only advertise parallel connection for their panels to maximize amperage. But in our case, we need to maximize Voltage with their panels. So it would need confirmation on if this is actually feasible. I Would also change the connectors on the panels for more universal MC4.

 

The advantage here, is that the panels are already made to be transported around and be simply put on the ground.
 

Link to website

Another "advantage" of Direct Solar Charging is you don't need a lot of space. 
Now it's Autumn here, Sun's getting lower, and I have to adapt my janky setup to it. 
I put down the panels  for a few hours to charge the bike, and when I'm done, I get the space back. Even with the big boy non-flexible heavy panels.

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The "M.A.S.C" concept

Mobile Autonomous Solar Campsite.

 

This is what I'm trying to develop. A travelling solar array we’ll be able to carry with us on the bike, so we can charge anywhere. Using the bike as a stand, and the room underneath to put a small tent.

Support me by joining my Patreon (starting 1$/month) and Discord to get more data and insights on everything. 

MASC 3D 01

To finish, here's another picture of Solar Kubie ^^ 

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