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Choosing a Battery for your Electric Bicycle

Posted on January 29 2016

Introduction

A recent survey of over 20,000 electric bicycle owners in the Netherlands found that a full 25% were dissatisfied with their battery! The reasons were many and the brand-breakdown is interesting reading. However one trend is clear - not getting enough range or not getting the advertised range is a big source of discontent, even in a market as sophisticated as Holland. So choose your battery wisely and remember - the bigger the better!

Choosing a Battery

This article is about choosing a battery for your electric bicycle, amongst various electric bicycle brands for sale in Australia

The battery is one of the most important components of an electric bicycle. A good battery is one with enough capacity to give you the flexibility to ride as far as you need to between charges. It will last a long time, come with a strong warranty and not to be forgotten - will a spare battery still be available years down the track as it will inevitably need replacing. Without a replacement option, your whole e-bike will lose most of its value!

Choosing a Battery for eZee Electric Bicycles

 

11Ah – 400Wh

15Ah – 540Wh

21Ah – 750Wh

28Ah – 1000Wh

Vertical Pack (11 and 15Ah)

Yes

Yes

-

-

Tall Vertical Pack (21 and 28Ah)

-

-

Yes

Yes

Flat Pack

Yes

Yes

-

-

Downtube Pack

Yes

Yes (14.5Ah)

-

-

Compatible models

All

All

All except e-Rex and Viento

All except e-Rex and Viento

Weight

3kg

3.8kg

5.5kg

5.5kg

Cost

$749

$949-$1299

$1299

$1899

eZee electric bicycles have 4 battery styles (shapes). First you need to check which style your bike uses.

All models except the Viento (folding) and e-Rex (fat bike) use either the Vertical Pack or the Tall Vertical Pack, which slide down behind the seat. This provides 4 different battery capacity choices from 11Ah (400Wh) to 28Ah (1000Wh) and are shown in bold above. Click here to purchase one.

The Down Tube (DT) battery pack is installed onto the drink bottle area and is found on conversion kits, the e-Rex (Fat Bike) and Raptor (dual suspension).

The Flat Pack battery slides horizontally into a purpose built rear rack and is found on the eZee Viento (folding) and conversion kits.

Both the Flat Pack and the DT have two battery capacity options and both can also be used as a secondary battery on standard models. 

Click here to purchase batteries for eZee electric bicycles.

Choosing a battery for electric bicycles with Bosch motors

Choosing a battery for a Bosch bike is a simple affair. There are only 3 sizes (300Wh, 400Wh and 500Wh) but the 300Wh is hardly seen in Australia. So all you have to do is pick the 500Wh if it's available on the model you want or live with the 400Wh if that's all that is offered. The tricky question is whether or not it's worth waiting for the 500Wh batteries to become more widely available in Australia. More info on batteries from the Bosch website.

Bosch Electric Bicycle Battery options in Australia

Choosing a battery for electric bicycles with Impulse motors

The Impulse mid-drive system, made by Kalkhoff in Germany, is quickly making an impact on the Australian electric bicycle market. Gazelle has brought in a line of impulse equipped electric bicycles and Focus and Kalkhoff electric bicycles use Impulse in the Australian market. 

The battery options have more variety compared to Bosch and importantly - they go to a much higher capacity. This is great news but also means more care needs to be taken when selecting a battery size. Similar to the Bosch systems, your choice of bicycle model will restrict your battery capacity options to 1 or 2 choices. However unlike Bosch, the difference in the battery size you end up with can be quite significant. Therefore we recommend you carefully choose your bicycle model taking into account the battery capacity available. 

On the Gazelle Impulse model you can choose a Gold (416Wh) or upgrade to the Platinum (482Wh) battery for $300. On the Focus and Kalkhoff models there are choices from 11Ah (400Wh) to 17Ah (612Wh)

Electric bicycle battery options for Gazelle e-bikes in Sydney

Battery Capacity - making sense of Ah, Wh etc

Most manufacturers have their own batteries but they're not all equal in terms of capacity and expected lifespan. Their capacity is most commonly rated in Ah (Amp-hours), such as eZeebike's 36V 21Ah battery. Increasingly the energy capacity is stated in Wh (Watt-hours) and this is probably the best way for standardisation. For example the eZeebike 36V 21Ah battery can also be stated as 750Wh. Bosch e-bikes favour the use of Wh when rating batteries and offers 300Wh, 400Wh and 500Wh electric bicycle batteries. Some manufacturers simply name their batteries. Gazelle electric bicycles have used Bronze, Silver, Gold and Platinum to distinguish their battery choices, in increasing order of capacity. This is handy when you are just considering a purchase within one brand, but doesn't tell you what the capacity really is for easy comparison with other brands and the capacity of each 'colour' differs according to model, even amongst the Gazelle brand.

Battery Range - so how far do they go?

Of course in everyday life these numbers are completely unfamiliar. What's a 15 Amp-hour battery anyway? Technically this means it can provide 1 Amp of electric current for 15 hours, but 1 Amp is not enough to move an electric bicycle, so 5 Amps for 3 hours is getting more realistic for a leisurely day trip, or 15 Amp for 1 hour for the speed demons commuting at full speed.

Most people don't like technical details, so manufacturers are pushed to simply state how far the rider can travel with the different batteries on offer. That is after all, what we are basing our purchasing decision upon. Unfortunately, this is where it gets quite tricky for electric bicycles. A car can be tested on its fuel efficiency based on a standardised trip (city driving or open highway for example) and the weight of the vehicle is already known (the passenger is negligible) and the fuel is the only energy source available. And if it gets the range wrong by 100km out of 500km, it doesn't much matter, you'll still make the next petrol station. Compare that to an electric bicycle. The weight of rider + vehicle can vary by up to 100% between users. There is no standardised route for such a test. The speed you choose to go compared to another rider can easily affect the energy requirement by 300% thanks to aerodynamics. Finally, there's two energy sources, the battery and the human and no-one is measuring the human. What you end up with are wild guesses and let us give you a hint - we haven't seen any manufacturers who are guessing low. They tell you how far it 'could go', not how far it 'will go'. 

The best attempt we have seen to get real life results under consistent testing is done by Electric Bike Reviews. They did not test different bikes at the same speed or same human input as some bikes go faster than others or require more human input than others. Instead they put each bike on maximum assistance for a consistent rider and route and published the average speed, the riders heart-rate and the range achieved. The faster the ride, the lower the range for a given battery capacity.

So what to do about it from a consumer's point of view? First of all, get the the biggest battery available for the bike you want - nobody complains about having a battery with too much range. And remember, battery capacity will decrease over the years so you need to start day 1 with spare reserves! Figure out how far you want to go on a charge and if the retailer cannot recommend a battery that they can guarantee will go the distance, then request a long test ride so that you can find out for yourself. Also check what your options are if you find out that you need a bigger battery within a day, a week or a month of purchasing your electric bicycle. If there's no bigger battery available for the model you want and you cannot test whether it will make the distance you need, then it's not a smart buy.  

You can do all of this and more at Glow Worm Bicycles. If you're not convinced that we can find you an electric bicycle to do all your heart's desire, we nominate you for the 14 day electric bicycle challenge!

 

 

 

 

 

 

 

 

 

 

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2 comments

  • Kay Braggett: June 07, 2018

    I have an eZee sprite bike which has operated perfectly but during the last couple of rides the orange battery light has come on earlier and more frequently. On two recent occasions after riding 24 kms the red light has come on just as I have reached home.
    Does this mean that the battery is wearing out or is it possible that it is not being fully charged?
    Previously the orange light only came on when I pedalled up a very steep hill. Once I reached the top of the hill everything returned to normal – i.e.. the green light stayed on until I reached home.
    Do I need to get the battery checked?
    Should I continue to ride my 24 kms and just see what happens on future rides?
    My bike is about 5 or 6 years old.

  • Richard: June 07, 2018

    We have Ezee Sprint and Street bikes (from Gloworm). I notice there is a branch cable in the rear rack area. Can this be used to attach a second battery? If so what type?

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