E-bike trailer quandry

[JoySinger]

I am trying to figure out if I can charge my electric bike trailer with solar while on a bike tour. I'm a complete beginner, and I think I might be getting more confused the more videos I watch. Anyways! I would greatly appreciate a bit of help. I have a little electric bike trailer called a Ridekick. I currently have a 24v 12amp SLA battery in there, and the range is not fantastic. The company I got it from used to offer LiFePO4 batteries with 20 amp($719) or 30 amp($945) options, but it looks like they are closing down their business. I'm wondering if anyone might have a suggestion of a good brand of battery that might work? I'm also hoping to tour, and was looking into the Sunpower flexible panels. I was trying to figure out if I might be able to charge with solar, and I got really stuck. I asked the Ridekick folks, and they said I would need a number of panels to make it work. The motor on the trailer is 500w, if that makes a difference. If I'm understanding the math correctly.....I would take the watt hours of the battery (288wh for the SLA, for example) and divide that by the watts of a 100 watt panel, and that would be my charge time? One 100 watt panel would, in a perfect world with 100% efficency, take 2.88 hours to charge?

 

[sunshine_eggo]

I am trying to figure out if I can charge my electric bike trailer with solar while on a bike tour. I'm a complete beginner, and I think I might be getting more confused the more videos I watch. Anyways! I would greatly appreciate a bit of help. I have a little electric bike trailer called a Ridekick. I currently have a 24v 12amp SLA battery in there, and the range is not fantastic. The company I got it from used to offer LiFePO4 batteries with 20 amp($719) or 30 amp($945) options, but it looks like they are closing down their business. I'm wondering if anyone might have a suggestion of a good brand of battery that might work? I'm also hoping to tour, and was looking into the Sunpower flexible panels. I was trying to figure out if I might be able to charge with solar, and I got really stuck. I asked the Ridekick folks, and they said I would need a number of panels to make it work. The motor on the trailer is 500w, if that makes a difference. If I'm understanding the math correctly.....I would take the watt hours of the battery (288wh for the SLA, for example) and divide that by the watts of a 100 watt panel, and that would be my charge time? One 100 watt panel would, in a perfect world with 100% efficency, take 2.88 hours to charge?

Depends. A 100W panel will only put out 100W at high noon. "Perfect" solar energy looks like this:

If it's the middle 3 hours of the day, then you're going to get close to peak energy. If it's in the morning or afternoon, you get far less.

As the sun's position changes latitude throughout the year, available energy decreases as well.

If you're running the motor @ 500W, you're going to get far less than 288Wh from the battery. SLA ratings typically assume they discharge their energy over the course of 20 hours. If you consume current at a higher rate, less capacity is available. That battery will likely only run the motor for ~15-20 minutes at 500W.

 

[solar-e-bike-Derek]

Hi JoySinger, I do solar bike camping but use an e-bike, and use the trailer to haul my gear, solar panel, and battery. Then when I'm stopped I charge up my bike battery. It's not super efficient but it works. The Ridekick is a cool little thing but I've never tried it. I've played with the idea of building a self-powered trailer but that seems way harder to me. I'm in the process of designing my new trailer which will be 95%+ DIY and would be happy to chat with you and bounce ideas around.