Batteries, how much life do they have, and how hard is it to carry a second one?

[Operator7]

Ok, so I am hearing that the estimate of mileage given by the batteries is exaggerated. Can experienced riders give feedback on what to REALLY expect from batteries, despite their claims of what mileage they provide? My commute is 33 miles. I am definitely willing to do SOME pedaling, but am hoping for big assistance from the e-bike. I have seen a number of batteries which state they have a 70 mile distance. Would such a battery not even realistically provide 33 miles, if it is performing at 100% capacity?

How heavy are the batteries, and how much do they cost? Is it impractical to carry a second battery?

 

[opimax]

I answered this in the Electric Bike Primer Ideas... thread. I don't remember what they advertise they would do...if you read it there I alaways have 2 bags on , for more stealthy look and I always carry as many batteries as i can , you never know what the next turn brings

 

[Brambor]

Yes. Please set aside this weekend and rent a bike and try your commute and report back




Depending on the trip type I sometimes carry a second battery. It is ok in my backpack. Carrying 2 batteries is pushing i

Unfortunately, I'm afraid there is no simple answer to your question. Your mileage will depend on many factors such as your weight, traffic encountered (start/stops drain battery), wind, ambient temperature, hills, drive technology, average speed, pedaling style, Eco/turbo mode, etc. This is why range estimates given by manufacturers don't seem to correlate for many people. The best is to rent and try on your 33 mile commute. My guess is that for most bikes you will have trouble going that far in "Turbo mode". Of course, I hope I'm wrong.

You've got to realize that a manufacturer can put a skinny 14 year old kid on a bike, and have him go around and around a flat and windless stadium at 15mph without ever stopping. This will yield spectacular mileage estimates, but is the figure obtained realistic?

 

[Shea N Encinitas]

For example; Tour mode (2nd of 4 levels) on my Bosch mid-drive would just about make 33 miles if it were not for the 600 feet of elevation change, 29 miles is more realistic with my route so I would have to drop to eco for the last 6 or 7 miles. I carry a 2nd battery in the doggie pack (we just got back) or my regular backpack no problem. Weighs less than the dog or my camera with a 300mm lens, point being I'm used to a bit of a load. If you are still shopping see if you can negotiate your 2nd battery at cost plus shipping and order it the same day you buy the bike. Unless the bike is deeply discounted there is plenty of margin for the dealer and they should be happy to resolve your range anxiety to make the sale that day. -S

 

[flymeaway]

Ok, so I am hearing that the estimate of mileage given by the batteries is exaggerated. Can experienced riders give feedback on what to REALLY expect from batteries, despite their claims of what mileage they provide? My commute is 33 miles. I am definitely willing to do SOME pedaling

Howdy,

If you have access to an electric outlet buy a second charger, problem solved, charge the battery at work and at home. Yes mileage claims are wildly exaggerated in some cases. If you find a bike with a 12AH 36V battery (or more) 33 miles shouldn't be a problem, unless it's uphill both ways

Court J.

(PS...it's a bike, it should be pedaled, the motor is for ease of use and assist)

 

[PowerMe]

The only downside to not having an extra battery is having to stop long enough to charge your battery. Easy Motion 12AH batteries take 4 to 6 hours to charge fully. Not a problem if you are at your destination (like work) where you'll be for at least that long. I personally wouldn't want to have to hang out at a coffee shop for 2 or 3 hours waiting for a battery to charge enough to get me back home, if it wasn't something I intended or had time to do. I wish EM had a fast charger, but they don't and it's a slow process.

As for the weight of an extra battery, the Easy Motion 12AH battery weighs 6 lbs. It's dimensions are a bit bulky, but not so much that you couldn't deal with it if you had a case or pannier on your bike in which it could fit. It feels heavy to me, but I'm a petite woman with weak upper body strength. Any of you guys wouldn't think it any big deal.

 

[Reseg]

Okay, this is an ugly area to try and get into because there are way too many factors involved like:
-Wind resistance (how aero you and the bike are as well as current/average wind conditions)
-Weight
-# of stops
-Hills
-Temperature
-Motor/wheel (mid drive vs hub, windings RPMs and what it's optimized for)
-Speed (kinda factored with the other stuff already with wind resistance and motor)

Way to many things to factor, it's best to find someone with similar conditions and good data logged to compare.

What I'll share that may help is:

-It's all about "watt-hour" (Wh) which is voltage X amp-hour (Ah) to determine the real size of a battery.
Going from 24 volt to 48 volt at the same Ah roughly doubles the battery size (if same chem) because you're basically taking 2-24V batteries in series.
Going from 48 volt 10Ah to 48 volt 20Ah also roughly doubles the battery size (if same chem) because you're basically taking 2-48V batteries in parallel.
This means a 48V 20Ah battery is around 4 times bigger/heavier than a 24V 10Ah battery of the same chemistry. This is something to consider given the ability of a bicycle to hold the weight and size, as well as removing it. Some guys are lugging around 40lbs in batteries.

-So to calculate how much battery you need, you have to figure out your Wh consumed per mile, which all of the above things are a factor of.

Per your other thread, you want throttle only @ 20mph for 33 miles, I'd assume you want at least 30Wh/mile which takes you to at least a 1kWh battery. But I"m kinda guessing with a little theory and data.

The closest thing to your needs I can think of is the newest Juiced Rider bike:
http://www.juicedriders.com/
It's 48V 22Ah = (1056Wh) and I believe does 20mph by throttle.
However, the battery is not removable like you wanted. In theory this could pull off 33 miles of <20mph throttle, but I never count on it until proven.

As for weight of the battery, it depends on the chemistry. The one on my S10 is just under 7 lbs and is 612Wh (36V 17Ah)

 

[JoePah]

Ok, so I am hearing that the estimate of mileage given by the batteries is exaggerated. Can experienced riders give feedback on what to REALLY expect from batteries, despite their claims of what mileage they provide? My commute is 33 miles. I am definitely willing to do SOME pedaling, but am hoping for big assistance from the e-bike. I have seen a number of batteries which state they have a 70 mile distance. Would such a battery not even realistically provide 33 miles, if it is performing at 100% capacity?

How heavy are the batteries, and how much do they cost? Is it impractical to carry a second battery?

Don't spend any more money than necessary upfront... Buy the bike with the largest battery and range possible. The Stromer Platinum battery 36v14ah runs around $700, and weighs close to 9 lbs... It can easily give you 40 miles in Eco mode, assuming there aren't too many hills.

A better choice is to buy a eBike conversion kit from someone like CellMan.. He can sell you much larger battery pack to start with, and of better quality, and for less money... All these ready to ride bikes have huge markups at every level, and you pay the price for mediocre bikes.

If you know anything about bicycles, test ride and buy the bike that suits your need the best (like a Trek or Specialized commuter bike), then buy a nice kit from Cellman for around $1300, with a huge battery.

 

[George S.]

Cellman = em3ev.com

There's a certain amount of luck. More is better. You'll draw it down less. When you get to 80% capacity it still might be 'enough'.

 

[opimax]

I wrote what i get , Joe Pah gets much more . I don't think I ever saw 40 per battery and if i did I was being very conservative. I dont remember if Joe has an Elite or Platinum, Elite will supposedly get a little more...the point though goes towards "your mileage may very" A LOT.

 

[Brambor]

yeah. My wife got almost 60 with running on eco and pedaling slow (her normal cadence). She doesn't weigh much and the trail was mostly flat. I made a post about the trip where we both pedaled 57 miles on both of our bikes. I have totally babied mine by switching to regen when going downhill etc... but she was just pedaling on ECO and didn't worry about it at all.

I haven't really given this info in this thread because the intent was to go fast at 20mph with SOME pedaling. At those requirements my mileages are irrelevant.

 

[calvin]

Two miles per amp hour. If you don't weigh much, are on the flats, with no head wind, and you sip at the battery, and you pedal moderately and if your bike is not a cruiser style, you will get more miles per amp hour, perhaps much more.

 

[PowerMe]

Soooo... my bike has a 12 ah battery. 12 x 2 = 24 miles range? My eBike's range (according to Easy Motion) is 30 mi up to 60 mi.

 

[J.R.]

Soooo... my bike has a 12 ah battery. 12 x 2 = 24 miles range? My eBike's range (according to Easy Motion) is 30 mi up to 60 mi.

That's probably the right average, if you add all the variables in. I have 16ah battery and average 35 miles +/- on a charge. I did do 42 miles the other day but all was almost perfect (except hills), 52F, no wind and I pushed. I think I could have done 45-50 miles because I had a fair amount of charge left.

 

[calvin]

Soooo... my bike has a 12 ah battery. 12 x 2 = 24 miles range? My eBike's range (according to Easy Motion) is 30 mi up to 60 mi.

Go for a long ride @ about 18mph, note your range. Include your weight and other parameters. For accuracys sake, try throttle only and no heavy pedalling! I'll betcha you get about 24 miles total.