# Car chargers for ebikes



## Francis Cebedo (Aug 1, 1996)

Ebikes work well on road trips or camping trips since one can explore the unknown. And even bad trails are good adventures.

What's the best way to charge an ebike from the car? I assume it's best to keep the car running.

Any links to specific, proven models out there?

How many watts do we need exactly for a Shimano or a Brose system?


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## ziscwg (May 18, 2007)

fc said:


> Ebikes work well on road trips or camping trips since one can explore the unknown. And even bad trails are good adventures.
> 
> What's the best way to charge an ebike from the car? I assume it's best to keep the car running.
> 
> ...


I think emtb did a video on alternative charging methods on youtube


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## 33red (Jan 5, 2016)

I will fallow this. I was asking myself can i spend a month in a van? Do i have to pay a campground or take my non Ebike to save $?


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## mtbbiker (Apr 8, 2004)

I’d like to see a link to amazon on what will work! 


Sent from my iPhone using Tapatalk


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## portnuefpeddler (Jun 14, 2016)

A cheap non sine wave inverter works fine, no need for a more expensive pure sine wave. I use a Harbor Freight piece of crap, rated at 700 watts, continuous. You will need to upgrade your existing 12 VDC outlet, get a real good quality one, marine catalogs are good for this. Go right to your battery, with 10 gauge 2 conductor stranded wire (any big truck supply house will sell this by the foot, and it has a tough outer jacket kind of like Romex, but is UV resistant, DO NOT USE ROMEX) use a fuse, you will pull more amps then the stock outlets can handle and if you try it you will just blow fuses, use a bigger fuse and you will fry wiring. You need a whole separate outlet to do it right. I use a 30 amp fuse, and pull about 22 amps (as I recall) when charging my 52 VDC battery at 3 amps. 

To really do it right, get a Prius, then you can just leave the car "on" (engine will be off) and walk away, go eat lunch, whatever. The main traction battery (I have a plug in Prius, but the regular ones work the same way) keeps the 12 volt acc. battery topped off, and eventually when the big battery gets low, the car auto starts, runs a few minutes (and at an extremely efficient fuel burn rate, nothing like a regular car sitting there idling) and then shuts off again. I've taken multi day trips and never turned the car off, a Prius and a ebike is a great combo. If you're not into that type of work, take your car to any competent car stereo installer, along with your heavy duty 12 VDC marine outlet, and they can knock it out in an hour or so, piece of cake.


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## honkinunit (Aug 6, 2004)

Another option is to use a battery/inverter box like Goal Zero (but hopefully less expensive). I have a cheaper and much heavier (almost 60lb!) Schumacher "Storm 700" portable charger, it is large and on wheels. It has a deep-cycle lead-acid gel battery and a 700W pure sine wave inverter. It will take a 500Wh Bosch battery from one bar to five. Of course, then you have to charge the battery box. I lucked out and found on on a closeout rack for $320, but it is normally about $475. An inverter attached to a car battery is cheaper, for sure. On the plus side, the battery box is also a nice unit for camping and I even used it during a power outage to light up my internet router.

Bosch offers two chargers. The standard one draws 4A at 120V, so you need at least a 500W inverter to use that one, which means you shouldn't plug it into an inverter attached to a standard lighter socket in a car. They also have a smaller "travel" charger that only draws 2A, so you could plug that one into a 250W+ inverter attached to a standard lighter socket. In their European catalog, Bosch used to show a 12V charger that plugs directly into a lighter socket, but I think they may have withdrawn that one.

https://www.bosch-ebike.com/us/products/charger/

Bosch covered the contingency where you want to run off of a car inverter. I do not believe the other have optional chargers. Correct me if I am wrong.


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## levity (Oct 31, 2011)

We went with a Goal Zero Yeti for simplicity (good price if you can find them on sale). The 1400Wh Yeti has two charging ports so we can recharge both Levos from empty in ~4hr (same as when directly plugged into 110V). The only problem is that the Yeti recharges slowly, taking ~24hr from empty. No big deal as we connect it to our Sprinter van battery (1900Wh) at night or while we're out riding, and solar panels on the van roof keep the van Li-ion battery fully juiced.

I wrote a short report about e-biking "off-grid" last year, and there are some other suggestions for chargers as well in the replies:

https://forums.mtbr.com/e-bikes/e-biking-%93off-grid%94-socal-desert-1066412.html









With a pure sine wave inverter the Yeti also powers our Nespresso coffee maker!


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## portnuefpeddler (Jun 14, 2016)

Using a pure sine wave inverter for loads that don't require it, is like burning premium gas in a rig that can burn regular, there is NO advantage. I was off grid for 28 years (and now grid tied for the last 13) and in general going pure sine wave is the way to go, except for task specific loads like running an e bike charger. I had to laugh when I bought my cheap POS Harbor Freight mod sine inverter, something I would never do or use for a:small cabin, home, van conversion. But as I use it only for the charger loads, and it was so damn cheap, I thought I'd give it a try, and it works fine for THAT purpose.

Point being, an ebike charger is a "dumb" load, and it won't care about the inverter's sine wave. Other more sensitive loads for sure will require a pure sine wave, not an ebike charger.


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## portnuefpeddler (Jun 14, 2016)

I had to run out to the hangar and get their website address: (https://uniregistry.com/market/doma...nderid=solarconverters5d06f72dd940b1.10284057) but this outfit (probably just one or two people,, maybe just one) has been around for over 30 years, in the off grid solar world anyway.

My former use (one of many) for their products was a voltage controlled relay, that would sense when my 1000 gallon home water storage tank was full, and then it would take that incoming PV power that was running the well pump, and instead, charge the batteries, back when I was off grid. Fast forward 30 years or so, and I now had a 52 VDC ebike battery I wanted to charge, while flying my small light sport plane, with it's limited inflight charging capability. I provided them with the amp draw in 12 VDC I could provide , without impinging on my other existing electrical loads, and the end voltage I wanted (58.3), and in a couple weeks and for around $200.00 I think it was, I received a nice little box that had an illuminated rocker switch and clearly labeled wiring, indicating 12 VDC IN, 58+ VDC OUT. As a bonus, they also designed in a voltage sensor that auto disconnects the converter when I shut the plane down, making it idiot proof in use! If I forget, despite the lighted rocker switch, that the charger is on, once the voltage falls below a pre set value, as it will once the engine is is not running/actively charging the plane's battery, I don't have to worry about it running down the plane battery. They love this one off kind of stuff, give them the specs you want, and they will take it from there. As a bonus, this will be the MOST electrically efficient way to charge an ebike battery, stepping up DC to a higher voltage DC. Running a 1q20 VAC inverter, off of 12 VDC, to make 120 VAC, to run a ebike charger that then makes 36 or 52 VDC, is grossly inefficient, like using a chainsaw to cut butter. It works but......

I have no idea, but I get the impression it may be may one person show, some electrical geek, with a real job, who runs this sideline company because he or she likes playing with this stuff and can also make a few bucks. So be patient, if you order something, they are not Walmart, but what you get will exactly what you want and be the best way to charge by far.


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## honkinunit (Aug 6, 2004)

portnuefpeddler said:


> Using a pure sine wave inverter for loads that don't require it, is like burning premium gas in a rig that can burn regular, there is NO advantage. I was off grid for 28 years (and now grid tied for the last 13) and in general going pure sine wave is the way to go, except for task specific loads like running an e bike charger. I had to laugh when I bought my cheap POS Harbor Freight mod sine inverter, something I would never do or use for a:small cabin, home, van conversion. But as I use it only for the charger loads, and it was so damn cheap, I thought I'd give it a try, and it works fine for THAT purpose.
> 
> Point being, an ebike charger is a "dumb" load, and it won't care about the inverter's sine wave. Other more sensitive loads for sure will require a pure sine wave, not an ebike charger.


I can only speak for the Bosch system, but the Bosch charger and battery are NOT "dumb" loads. There is circuitry in both the battery and the charger that negotiate the charging amperage depending on age/number of charges the battery has, the state of charge, the temperature, and the phase of the moon. The battery itself knows exactly how many charges it has in it, and keeps a log of how discharged it has been before charging, temperatures, loads, etc. When it is inserted into the the bike, it syncs with the controller and the data is saved. If you go to a Bosch dealer, they can download the battery history.

I don't know if a Bosch charger/battery will survive bad power, but since the battery is $900 and the charger is another $150, I wouldn't risk it. You aren't plugging in a "dumb" battery charger/battery, you are plugging in a computer system.

I'm guessing the Shimano, Yamaha, Brose, etc. batteries and chargers are similarly sophisticated. As much as these batteries and chargers cost, it is false economy to use a cheap ass mod sine inverter.


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## honkinunit (Aug 6, 2004)

craigsj said:


> Is it though? How does a computer system know, or care, what the shape of the AC waveform is driving its power supply?
> 
> Lots of modern AC devices work just fine on DC provided the voltage is high enough. Anything with a switching front end is unlikely to care. That would include anything with a wide range AC voltage input. How clever a charger is at managing a battery is irrelevant to what it's source power requirements are.


https://www.pedelecs.co.uk/forum/threads/inverters-or-12v-chargers-for-bosch.32182/

Maybe the charger will survive a cheap inverter or generator, maybe it won't. Maybe the charger dying would not zap the battery, maybe it would.

With the replacement costs of this stuff, plus the inconvenience of getting your hands on it (it would suck to have a charger or battery die while on a nice vacation), I'm not going to risk it. I have a couple of coworkers who had laptops killed by trying to use sketch generator/inverter power sources, and an ebike charger/battery are essentially the same scenario.

600W Pure Sine inverter made by a company you could actually email in English, $129:

https://invertersrus.com/product/aims-pwri60012s/


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## honkinunit (Aug 6, 2004)

craigsj said:


> How do you know this one is safe though? Are you claiming that "pure sine" is a promise of compatibility?
> 
> The forum post you linked to says nothing. Who knows what that problem was.
> 
> ...


I don't know what you mean by "universal supplies". That the input is voltage switching and can accommodate 110V-240V? Sure. But Bosch for sure, and almost certainly the others of the "Big Four" do not use simple chargers. You can't just hang voltage on the +/- lines and charge a Bosch battery. They have been hacked, and apparently it isn't that hard, but they are clearly trying to protect themselves from people pushing too many amps into the battery, blowing it up, and blaming Bosch for the flaming aftermath.


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## honkinunit (Aug 6, 2004)

craigsj said:


> Yes, universal supplies accept worldwide voltage standards.
> 
> Don't know how this new "simple charger" term moves the needle or what "+/- lines" means. Seems like you're just offering more hand waving.


Here is the point. Plugging a Bosch, Shimano, Yamaha, Brose charger into a shitty WalMart modified sine wave inverter is risking frying the charger, the battery or both.

Have at it if you want to save $50 on your inverter while risking ten times that. Let us know how it works out.


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## portnuefpeddler (Jun 14, 2016)

I thought I did let you know how it worked out, with a cheap mod sine inverter, no problems! Over three years now. Granted, it was only with using a $100.00 LUNA advanced charger, which has several levels of adjustable charging amp levels, a digital volt and amp display, and three levels of completion (80, 90, and 100%). Now, with your uber sophisticated high dollar "better" Bosch etc. Euro type chargers, and your $900.00 dollar 500 watt (?) batteries (versus my Panasonic GA celled 884 watt battery I paid a bit over $600.00 for) it may be a different story.

But, if one feels a pure sine wave inverter for the auto charging mode is a must, buy one that is promoted and sold by one of the long time off grid solar outfits, like Backwoods Solar, or Northern Arizona Wind and Sun, rather then the cheapest offered on Amazon or Ebay. They have decades of experience and the small pure sine wave inverters they offer are the best, proven over time. The one you linked to is probably OK, but they have no rep at all in the off grid power community, never heard of them. Samlex has been around for quite a while, and has established a solid rep in the small pure sine wave biz, as has Exeltech, https://www.solar-electric.com/samlex-pure-sine-wave-inverter-pst-600-12.html. https://www.solar-electric.com/xp-6...WXWeWUlVUEz4ucEx54jOE7C5DL35pyMUaAmqIEALw_wcB ANY charger worth a hoot, operated on ANY type of inverter power, will protect the battery no matter what, that concern, battery damage, is moot.

Back to my "system", either I was going to try a POS no name/Harbor Freight unit, or I was going to spring for a name brand pure sine wave, and at the time the difference in price between the two was MORE then what the charger cost, so what the hell, and it turns out after all that mod sine wave works fine for MY charger, but I'd guess (with your money ha ha) they would work fine with all ebike chargers.


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## portnuefpeddler (Jun 14, 2016)

craigsj said:


> So true, to suggest otherwise is silly. All hell would break loose if major manufacturers like Bosch would have charger defects like this. Even worse if the BMS allowed a defective charger to do damage. It would be a gross failure of basic engineering.
> 
> Have you had good experiences with this? I've had two and find them unreliable and not properly calibrated. The percentage settings seem random and if you leave the charger plugged in it will be damaged in short order. Worse, my current one charges almost a volt over (but I lower the percentage to compensate). The Grin chargers are great though, but at triple the price.


 No issues with any of my three LUNA chargers, 1 the latest "advanced" one, one a earlier version with no amp control, and one a cheapie but light no name 2 amp model I got for airplane trips because it's very light.


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