Battery Charging Options for Ebikes


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8:23 AM
Sep 8, 2020
So say I’m out for a long camping trip in potentially remote non supported area, car camping. Then in order to support recharging I would have to bring a small generator, right? Or would that support the recharging effort? Or do I have to suck it up and buy extra batteries? Or does anyone make a battery like a juice similar to cell phone recharging? Kind of like a back up?
A generator would be alot to carry lol without a place to plug the only option I see is extra battery or no assist once dead.
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This has been fully discussed on another thread. The bottom line is that you get a 500W inverter, hook it up to your car battery, and charge using that, or you get a GoalZero or Schumacher Storm 700 battery box, or other backup power unit, and charge from one of those.

If you use an inverter, you may or may not need to run the vehicle at least part of the time while charging. If you have a GoalZero or Schumacher, you can get one or two charges out of them before *they* need to be recharged as well.

Keep in mind that most ebike batteries are 400wh to 700wh. A backup battery unit to charge an ebike battery from dead to full is going to cost as much or more as buying a spare battery. An inverter is much less expensive, but you need to get one big enough. The "Big 4" (Bosch, Yamaha, Shimano, Brose) chargers draw 4A/120V, so you need at least a 500w continuous inverter, and those can't be connected to a normal lighter socket in your car, they will blow fuses. You need to wire a separate circuit with a 12V/40A+ fuse or attach directly to the battery with alligator clamps. A stereo installer could wire the circuit for you if you don't want to do it yourself. The big advantages of the separate circuit are that you don't run the risk of frying your car's electrical system, and that you can charge while driving. Otherwise, just pop the hood and clamp the inverter cables onto the car battery while stopped.

If you have a Bosch powered bike, there is one more option, and that is to get the Bosch travel charger which only pulls 2A instead of 4A. With that one, you can use a smaller inverter that plugs into your lighter, but it will take longer to charge the ebike battery.
A 1000 watt inverter generator is $400 at Home Depot. If you’re going to be out in the boondocks charging your eBike battery from your car battery using an inverter, having this along with a 12 volt battery charger might be good. Just remember to use gasoline stabilizer and run it every once in a while.

Another option; get a small battery booster for your car so that you can get it started just in case.
That is what I was thinking. I have been thinking of buying a small Honda generator for when we lose power at the house. That is quiet and should charge it right? Now to understand how long it would have to be on there for a complete charge.
Maybe you can run a test at home so you will know how much fuel your generator will need. Please let us know how you work it out. My knowledge is limited but for campers some use solar. I guess if you use something frequently it might justify some investment but i would simply bring my 21 pounds 29 if i felt it was too expansive. You might want to join a facebook page and ask some experts on off grid. I guess you can search, from memory vanlife is filled with knowledge and nice people willing to help.
The smallest Honda generator is the EU1000i, they are one of the best generators around. Quiet, reliable, efficient, easy to start. You could plug in two ebike chargers at once if you wanted to. Your ebike battery will charge just as fast on a generator as in a wall socket in your house. 4-6 hours if the battery is fully discharged. The specs say an EU1000i will run 3-7 hours on .6 gallons of gas, depending on load. I would guess about 1/2 gal to charge your ebike battery. The EU1000i is very quiet.

Those are awesome generators, but they are $1000. Resale is great on them though, so if you buy one new you will get a bunch back if you sell later. The EU2000 models are easier to find used, but they will run you $800-1000 used, and are heavier and will use more gas.

I usually scoff at brand names, but honestly, for a small generator the Hondas are really good and worth the $$$.

With that said, a 500W pure sine inverter is only about $100.
Mrs levity and I need to charge two bikes at once so went went with Goal Zero's Yeti 1400. When boondocking we keep it charged off the 1900Wh Li-ion battery in our van which is kept up by solar panels. The pic below shows a single bike connected, drawing 168W. It will restore two 500Wh batteries in about 3-4hr or two 700Wh batteries in about 4-5hr. It's quiet and odorless and can be used to run small appliances as well.

Goal Zero's Yeti 1400.jpg
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Camping for a week I usually recharge my pop-up camper battery around 3 times with my Honda EU2000i generator. I don’t bother to bring spare gas. It is very quiet under light load but still I run it only during the day. It starts and runs perfectly fine at 9200 feet elevation but unlikely to produce rated power that high.

I wouldn’t recommend this generator just for charging eBike batteries because it’s quite heavy. (One trip I strained my back lifting it into the SUV and trying to place it forward without getting inside so I’d recommend the lightest inverter generator that will work.)

My generator has been completely reliable over the last 16 years. For light use, though, the Honda is way more than you need.
The little Honda is great, as is the littlest Yamaha. I opted for the Yamaha as it's 1 lb lighter and a tad quieter, but you can't go wrong with either one. The Yamaha is equally rated as reliable etc. I paid around $800.00 for it including shipping, 2 years ago.

The Goal Zero is a slick piece of packaging and marketing, but all it is is a battery and an inverter. Do not confuse it with the utility of a gas genset. You could buy a inverter, aux. battery, for much less and make your own box for it. Get a solar panel and controller also. But do the math first, and I bet you'll find the very small amount of gas needed to run a small genset to run your charger like at home will be very cost effective.

My ebike batteries are charged by my home's grid tied wind, solar, and micro hydro system BTW, and I was off grid for 28 years before moving onto property that had utility power. Since I produce on an annual basis about 130% of my needs, I can claim my e bikes are renewable energy powered, which I never do unless somebody asks how much it costs to charge. I can also plug in directly to my hydro inverter before it ties into the grid, so as I told a snowboarding buddy I ride ebikes with, my bike is powered by the snow we rode on last winter, after it melts, as the ski area is above my place. Weird but true!
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Elegant solution, but $$$$. 1800 of them.

I honestly don't know why Honda doesn't make an EU1000i model with a built in battery. It would sell. A lot of campgrounds prohibit generators after 9 or 10, but if the generator had a battery built in, the gen could charge the battery while it was powering other stuff during the day, and then keep on powering through the same inverter at night without the engine running.

A generator with built in in batteries would be awesome.
One positive aspect of the Goal Zero (et al.) approach is that you can solar charge its battery during the day and then quietly charge your bike at night.
Not knowing a lot about the Goal Zero and what I would need can anyone advise to a perfect rig to have for what I want? Car camping and needing to recharge my bike without plugging into my car. What solar panel and Goal Zero would work for that?
@vcyclist - Goal Zero sells a range of Yeti Li-Ion power stations (150-3000Wh) as well as solar panels to charge them when off-grid. MSRP costs run high, look for sales!

Once your original battery is down a Yeti 1000 would get ya a couple of more rides without even having to recharge the Yeti. A solar panel would allow you to restore the Yeti for even more fun; you just need to calculate the wattage the panel can provide. (We're out 4+ weeks powered by sunshine on longer trips in our van with two 190W panels.) As an example here's a package that GZ sells that should provide 400Wh a day assuming decent sunshine:
The Goal Zero components are primarily a battery, and an inverter, the rest is bells and whistles, packaging and marketing. You can put your own setup together for a fraction of the cost. An experienced off grid home supplier, like, will be able to help you. Lean on their experience, they have been doing alt energy for 30 years or so, and then buy from them. You will get more for less money, just no fancy box for it all.

Before you contact them, buy a WattMeter, one of those devices you plug into your home outlet, that digitally displays the amount of watts being used by the thing you plug into it. Or do the math, but have a number to give them, "X amount of watts." Then determine how long a fully discharged bike battery takes to re-charge. That's all they need. This is off grid design 101. I will be very surprised if you don't end up with twice the power for half the cost of buying a Goal Zero. Charge the big battery at home to start, solar can always be added later, 100 watt panels with controller less then $100.00 delivered. Or just buy a small generator, quick and dirty, but would work for sure.

For my plane, I had a custom built voltage booster made, so while flying, my plane's 12 VDC system is charging my 52 VDC bike battery at a bit over 2 amps. Solid state, and highly efficient, and that's important because I only wanted to draw about 12 amps out of the plane's system. I just checked their site so I could provide a link, and the 30+ year company has closed it's doors, retired. Some one else can no doubt do something similar, a much better way to go then inverting 12 VDC up, to run a charger, and then converting it back down.
No one mentioned the inergy battery. It is more powerful than goal zero and lightweight
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Dirt simple, least cost out of pocket? Cheap inverter, and a decent quality small jump pack.
Start charging your bike, in 15 minutes start your rig, listening for any sign of a depleted car battery. Then go 30 minutes, repeat. Worse case, you run down your car battery by no running the engine enough, so you use the jump starter and next time you shorten up the intervals of not running the car engine, until you hit the sweet spot of minimal engine run time. You could do the math: car alternator charges at X amount of amps while idling, inverter sucks X amount of amps charging, easy peasy.