Cycle Analyst; Ebike Battery Gauge

October 15, 2012

The Cycle Analyst  is the first digital dashboard and battery monitor originally designed around the specific needs of electric bicycles. However, the flexible setup configurations, wide feature range, and affordable price have also led it to widespread appeal in a range of other EV applications. From the dashboards of MIT’s solar car, to record-breaking electric motorbikes, to small electric trains, powered wheelchairs, and even sailboats and airplanes, the Cycle Analyst has become the e-meter of choice for keeping track of the vehicle’s battery usage and performance characteristics.

You can find the Cycle Analyst on Sale at Luna Cycle here for $99 or the latest V3 version on sale for 129.00. saw a need in the market for serious battery protection and management, for both home-builders and commercial ebike builders, and he devised an effective solution. It is a fully functional piece of technology. It does not have fancy readouts, or a fancy case, it does not have any advertising decals, but it does its  intended job almost flawlessly. Its screen, although not fancy, is perfectly viewable even in direct sunlight, and also when riding at night (it is back-lit).

Cycle Analyst on Home Builds

Cycle Analysts on home builds have really moved forward and enabled the DIY electric bike movement. It makes it possible to use  lithium  batteries without a BMS  (battery management system) which for many DIYers means the fire risky Hobby King LiPo chemistry, which is much safer when monitored with a Cycle Analyst while riding. The Cycle Analyst has a programmable voltage shut off so that if your battery pack falls below a specific voltage (which you determine and program in), it will automatically shut off your system. Suave ebike builders often times will ride without the cutoff feature, but monitor their battery voltage as they ride and decide themselves when to cut it off.

How to Hook it Up?

The Cycle Analyst has two ways to  be hooked up to your ebike.

#1 It can be connected in between the battery pack and the controller by just splicing and soldering its wires to the positive and negative leads coming from the battery. This is fairly simple and can be adapted to any bike, even a turnkey manufactured ebike…the only hard part sometimes is finding the positive and negative leads, which are not always properly labeled.

#2. Buy a controller equipped with a special plug for the Cycle Analyst.  Hot Rod controller-builder Lyen offers this service on any of the controllers he builds. This is a simple plug that literally makes the Cycle Analyst plug and play.

Cycle Analysts on Commercial Bikes


Above you see a Stealth Fighter (read review) with built-in Cycle Analyst. This screen is showing the maximum amperage drawn on the ride (247A on this modified high-performance Stealth) and the minimum voltage of the pack (69.2V).

Stealth Electric bikes is one of the few ebike companies that sells complete electric bikes with a Cycle Analyst built in, and as standard equipment. There are two reasons for ebike companies’ reluctance to do this:

#1   Cycle Analysts are somewhat expensive ($120-$155 retail, depending on features). Ebike companies are gravitating towards cheap cheap Chinese components and are caring less about quality (see our story on Chinese nifty tech).

#2 The big reason: Cycle Analysts really tell you if the battery pack is living up to warranty and sales-claim expectations.  Whereas with traditional cheap Chinese dashboards, actual battery usage is hard to quantify, with a Cycle Analyst you know exactly how long your ebike battery is lasting. If your battery is not up to snuff, and you are an ebike manufacturer, you probably don’t want to offer a Cycle Analyst even as an option. Obviously the $11,000 Stealth Bomber has a great battery pack (LiFePO4, which is known as a reliable battery chemistry) that they are extremely confident in.


Cycle Analyst Version 2 showing voltage of battery (80.9V) speed (0.00 Kph) watts that the motor is burning (-33) and amp hours used on ride so far (0.00), This newly-installed CA was reading negative watts because it was not properly soldered to the controller shunt, an easy fix.


The Cycle Analyst performs the following functions:

1.  Measure volts in the battery pack at rest, or while riding  (the difference is voltage sag, which is temporary).

2.  Measure current flow of amps into, or out of the battery. (into the battery when using regen braking)

3.  Keep track of current flow into or out of the battery relative to time (Amp-Hours).  Like a gas gauge for your battery.

4.  Compute the watts and watt hours (amps times volts per time) that the system is using in real time as well as totaling accumulated watt hours.  (Like a power gas gauge). (read our story on watt hours)

5.  Measures MPH, or k/h, as well as odometer functions, trip distance, recharge cycles, etc.

6. Control the limit of amps or volts that a battery controller will allow a battery and motor system to expend. This feature of the CA is used on Stealth ebikes for example. It is a very powerful tool to adjust the energy limit parameters of your ebike system battery controller. It gives you full control of the battery and motor system relative to limiting amps and volts to be expended by the motor. This is really the central value of the CA for home built ebikes as well as production ebikes like the Stealth that have committed to it use in their design.  The Optibike does not let us set these parameters other than the 250W Eco Mode switch.

The Cycle Analyst comes in 2 different sizes. A large screen (as above) and a standard model like below which is now somewhat outdated.



The arrows on the Cycle Analyst allow you to cycle through 6 different screens to get bunches of critical information. Most users only use 2 0r 3 of these screens. Above you see an example. This shows how many battery cycles you have gone through, the total amp hours you have burned through, and the total miles you have travelled on the bike.


The above screen show the watt hours used in a trip (see our story on watt hours). This trip I had a battery that was rated for 900 watt hours, but it dies around 668 watt hours, letting me know that this battery is not up to 100% even though  I have less than 100 cycles on the battery. When use a Cycle Analyst, there is no question about the health of your battery and whether or not it’s performing up to factory specs.

At the start of every ride, I hold down the right arrow button which resets the odometer and starts calculating each trips battery usage.

Also notice that I averaged 21 watt hours per mile. This is with pedaling a lot, and travelling on a relatively flat Southern California paved bike-way (by the beach!). I do like to travel at full throttle and average a fast speed. 20 watt hours per mile is what we consider typical usage for this type of riding. (read our story on watt hours) has recently announced their new V3 Cycle Analyst (read complete report), which adds a completely different display screen, temperature sensing, and torque sensing capabilities…included in the feature set of the Cycle Analyst for a few more dollars. This unit is showing a lot of promise in its testing phases.

The V3 CA also has a DC outlet providing a convenient place to hook up a headlight.

Although this is not a review per say, I can say that the Cycle Analyst is one of the most innovative and useful pieces of ebike technology every devised, and I would call it an essential for any serious electric bike rider. I personally own five of them and have one of the new V3 Cycle Analysts on order.

It is also refreshing that China has not managed to duplicate the Cycle Analyst, although they have tried with some half-ass efforts. None of the other dashboards on any commercially available bikes come even close to the functionality and accuracy of the Cycle Analyst.

If you own a turnkey commercial bike, adding a Cycle Analyst will be worth the purchase price just to warranty check your battery…make sure you are getting those precious amp hours you paid big money for. As a bonus, you will have the most accurate battery gauge on the market. You will be able to tell within 1/8 of a mile when your battery pack is going to die.

The only challenge is installing the Cycle Analyst on a commercial bike, but any skilled ebike technician should be able to do this task, or you can do yourself if you get some help from the nice forum members on Endless Sphere.  The manual which accompanies it is excellent as well.

Once you have a Cycle Analyst installed you will really start to understand your ebike, and the nature and characteristics of its battery.

Eric has been involved in the electric bike industry since 2002 when he started a 6000 square foot brick and mortar Electric Bike store in downtown San Francisco. He is a true believer that small electric vehicles can change the way we operate and the way we think.

  • Farfle

    you might want to correct amp hours to what hours mate, a 900Ah battery is a little on the big side for an ebike : )

  • Velias

    What about the speedict…?

    It uses your android phone for a wireless bluetooth interface.
    Way fancier graphics, unlike the cheesy primitive cycleanaylst user interface/graphics.
    Don’t know anyone that has one though.

    • ElectricBIke

      The speedict is a good product as well. If you are concerned with aesthetics it is definitely better.

  • Richard Graham Poster

    I bought the cycle analyst for my ebike only to get torque sensor function and although it is very functional, its physical design is terrible. It feels like it was designed by a 16 year old in his bedroom, in between DND sessions. It is BIG, clunky, has terrible graphics and the myriad of extra wires sprouting from the bottom is unwanted on my build. I am definitely on the lookout for somehing more elegant but just as functional.

  • Paul Sammons

    Thanks for this article!