Charging e-bikes while car-camping away from 110V grid?

[Telkwa]

Good morning to everyone -

I've been wondering how people charge their e-bikes when RV'ing.

I'm guessing the answer is pretty straightforward if you're slumming in a $400,000 RV with a bank of deep-cycle batteries and a big inverter.

What I'd really like to hear about is the home-grown solutions.

How much solar, battery, and inverter would be sufficient for two e-bikes?

The four chargers I've got are rated from 1.9A to 3A draw. Some experimentation with a Kill-A-Watt meter showed that our two bikes with 400Wh batteries consumed roughly .7 kW to get back to full charge. Obviously, two e-bikes with 500Wh batteries would draw more if they were discharged.

So we're talking about a respectable amount of amperage, especially with two chargers plugged in at the same time, and a fair amount of energy that would have to be created or stored.

 

[Drew]

Here is a post I made last summer, showing my prototype solution for one e-bike:

https://electricbikereview.com/foru...charging-my-e-bike-battery.23803/#post-146474

 

[Mr. Coffee]

I have some experience with the Goal Zero Yeti power banks and charging them with solar panels.

If you have two e-bikes with 500wh batteries, you want at least a 1000wh power bank. With a 200w solar panel and pretty optimum conditions (sunny weather and a good location for charging and periodically adjusting the panels to face the sun properly) you could charge that 1000wh power bank in a day. Although I'd say that in practice conditions are rarely as optimal as you'd expect and charging time rapidly increases as the situation gets less optimal -- so in practice you probably couldn't expect to stay self-sufficient and ride your e-bikes hard every day with such a setup.

A 1000wh battery and a 200w solar panel from Goal Zero will run you about $2000. Goal Zero gear is overpriced and you can get cheaper rigs and build a DIY system but the dominant parts of the cost -- the solar panels, lithium batteries, and the inverter -- probably mean it will be challenging to get the price much below $1200.

You need the battery pack because you probably want to ride your bikes during the day which is also the best time to collect solar energy.

 

[6zfshdb]

My GMC pickup has a 130 amp alternator and built in inverter which powers a 110V outlet in the cab. While on the road, My wife and I use it to charge our spare batteries. We often ride in multiple places in a single day while on a bike trip and use the "windshield" time in between rides to recharge. When we're off the grid for an extended period riding in a single location, we rely on spare batteries. Sometimes I'll let the pickup idle for an hour or so in the evening and use the inverter to top off the batteries.

I realize this isn't a perfect solution since eventually I'll run out of battery power. It's a delaying tactic at best but it does extend our effective riding range. Since the truck came equipped with the inverter, I have $0 invested and instead put the money into spare batteries.

 

[Telkwa]

Wow, I didn't know that some pickups come with inverters, much less ones powerful enough for two e-bike chargers. Is the inverter true sine-wave? Maybe most of them are nowadays.

6z, where did you get your spare batteries? Did you go back to the bike shop where you purchased the bikes and order more?

Mr. Coffee, thanks for providing an outline for a workable solar rig.

 

[6zfshdb]

Wow, I didn't know that some pickups come with inverters, much less ones powerful enough for two e-bike chargers. Is the inverter true sine-wave? Maybe most of them are nowadays.

6z, where did you get your spare batteries? Did you go back to the bike shop where you purchased the bikes and order more?

Mr. Coffee, thanks for providing an outline for a workable solar rig.

I doubt the truck inverter produces a true sine wave. It was part of the plow package I bought with the truck. It's rated at 500 W and is used mostly for auxiliary equipment I use when plowing. I suppose I can't really say I have a $0 investment in my battery charger routine. The plow package added $1200 to the cost of the truck. The battery charging ability was just a side benefit.

I ordered the spare batteries from the LBS where I bought my bikes. He gave me a break on the price since I bought 3 bikes from him. They are 48V ,15AH and cost $695 each.