E-Bikes Battery Details for Dummies

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One of the novelties of the market for the 2016 season have been the larger capacity batteries has presented, Bosch with new capabilities 500Wh regarding 400WH of the 2015 models and the coming to market Rotwild and Bulls with 518 Wh & 489Wh battery respectively. But beyond that have more capacity know what all those little numbers that carry the batteries?



E-Bikes Battery Details for Dummies


Volts, Watts, Amperes, Watts-hour?



I must confess that although small did my first steps with electricity and electronics, little remained of the times, and to explain it, I had to review concepts, see it if I can explain the complex tad easier:


Volts (V)



Volts are a voltage magnitude, voltage or potential difference. It can be technically defined as the electrical potential difference between two points. "Potential difference" is the key to understand this concept. A textbook example: if a waterpark I throw myself from a slide, the higher is the slide, more I have potential difference.

An important concept, the voltage is not consumed. The Volt is not a unit of energy, but tension, ie potential energy, which will determine consumption are Amperes consumed (then we meet our friends Amperes).
Now the definition, to gross, not at all academic, colloquially, between you and me, to understand ...: Volts to an electric motor for all practical purposes would amount to something like the displacement of an internal combustion engine.

More than one cast hands to the head, because I do not think it's a definition for unorthodox, but hey, I think it's good simile for all we place ourselves. I will justify myself:

We all know thanks to marketing the cubic capacity of an engine puts us in the power that can develop an engine, and that means that, two cars of similar category (weight, efficiency, aerodynamics, etc.) will have greater acceleration capacity and speed the largest displacement tip because develop more power. If?
Well, the cubic capacity of a battery or ability to develop a power for their "potential difference", one might say, simplifying a lot, measured in volts. The batteries of electric bikes are normally batteries 24V, 36V, 48V ... A more volts = more power capacity.

The typical battery in most electric bikes is 36V, such as riding Bosch and Yamaha. You can find exceptionally 24V and in some models of S-Pedelec 48V. More than 48 V used to be rare. In addition, a small detail: the human skin can isolate a discharge of up to 40-45 volts, so a "chopped "more than 48 V can become dangerous.


Ampere



They are a magnitude of current or power. Is the number of electrons circulated by a cable. If you want an electric motor put an accelerator so we have to change is the range of amps that deliver to the engine, more electrons more chicha for the engine.

Ampere-hour (Ah)


"Ampere-hour" is a unit of electrical charge that expresses the capacity of a battery. This amount does not define an energy consumption that we saw corresponding to the amount of amperes to circulate through a circuit, but its reserve them .

11 Ah battery means you can give a current of 11 Amperes during a 1 hour or 1.1 amps for 10 hours.
Continuing with the analogy of combustion engines, the "Ah" would become our fuel reserve.
The more hours of Ampere will have greater power reserve and greater autonomy will be obtained with the electric bike. While this statement is true, something else would be real autonomy applied only considering this factor.

Different engines that get different ranges with the same Ah autonomy may be due to many factors, and to continue with similes, a Hummer and a Smart does the same Km with 10 liters of gasoline. Thus, the final autonomy depend on many factors such as engine efficiency, the weight of the tandem bike-rider, the slope of the terrain, the degree of assistance to put the bike and that put us (the Turbo is very addictive) aerodynamics, tire pressure ... and endless more. the list of factors, tends to infinity.


Watt-hour (Wh)




We arrived at the key issue is the hot topic in the marketing of e-MTB's with the emergence of batteries 500 Wh 2016 with respect to 400WH 2015, and for which Agotare my car similes.
To understand the Watt-hour, I am forced to explain that are Watts . And it is now when my car is stuck the simile, because the CV and Watts this time: they are magnitudes with equivalence. That is, both are magnitudes to measure the same thing: power.

If we understand from where the Watts perhaps we will see clearer. Watts are the result of applying the following formula: Voltage [V] (or potential power to develop) x Ampere [A] (intensity of that current) = a Watts [W] (power output). If the output power (Watts) or the maximum speed of an electric bike passes over the allowed (250 Watts and 25 km) the e-bike is classified as a moped which by law requires insurance, registration, etc.


So now if the key fact justifying the previous tirade: the Wh , which are the energy unit. That would be summarized in the ability to deliver a certain power over a period of time.

In this way, if consumption continuously 200 W (power) for 2 hours (time), I will have consumed an energy reserve totaling: 200W x 2h = 400 Wh (energy).

The Wh out dela formula: Volts x Amp-hours = Wh. The amount of energy stored in a battery, or watt-hours (Wh), provides a way to compare batteries with different voltages and Ah.

For example, two bikes can have both 480Wh battery but will have 24 Volt 20Ah (24V x 20Ah = 480Wh) and the other 48 Volt 10Ah (48V x 10Ah = 480Wh). Both bikes as they will have a similar energy available on board, and if their engines have an exact performance, both have the same energy capacity, but higher voltage may accelerate faster and develop more powerful, though that will involve consuming more energy.
Therefore, the limitation of the Pedelecs 250W is purely electronic, often a single motor with a higher electric power delivery, give much better performance.


Summary



I hope your effort to get here was worth it, and now when we talk about batteries we can at least know that we are talking about exactly.


Blog, Updated at: 2:28 AM

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