Electric Mountain Board

[Shadow555]

Hello,
In order to better explain the idea of ​​my project to you,
here are some pictures of other realizations:


(source: www.instructables.com)

I even find one on evalbum at this address:
http://www.evalbum.com/519

But we realize that it would be much more practical to put an electric motor on a 3-wheel model,
on the single wheel (rear) you can put the engine and the brake without hindering the direction, and moreover that would save a bit of weight!

(source: pyroboynroses, on another forum)

The 3 wheel electric flexboardz:
it is not an electric mountainboard, but an electric flexboardz (powerflex), the steering system is different.


The electric skateboard market is booming
The groundsurf:

Ground surf video
It has the ability to be controlled with any bluetooth 2.0 portable!

Here I am waiting for the electrical parts, from the site electricvehiclesusa.

[Shadow555]

I have something new!

I just bought a wrecked pocket bike,
to, of course, recover parts.

rear wheel with crown, disc brake, chain ...

It is this model, but the color is different:
We can see that the rear wheel mounting bracket is mounted with two axles on the chassis, so easy to adapt to something else.


Voila, I miss more than a steering truck with these two wheels, the two 12v batteries, a "house" board and I am still waiting for my order of electrical parts, I will keep you posted see you soon !

[I Citro]

Well done for this new topic Shadow555

I see that your technical analysis is becoming more and more relevant.
Your choices appear obvious and common sense.

No complaints.

[Shadow555]

Okay, I have a shipping date for the motor and controller ...
but in the meantime, I'll find the rest.

for batteries:

I do not know which batteries to take for the controller, the motor is 24v / 600W and the controller is 40 A for 24 volts.

The sum of the amps of the two 12volt batteries should not exceed 40Ah, right?
If not, the controller will grill, is that right?

I thought I would find two 12v / 18Ah batteries in series, which would make a 24volt / 36Ah block

voila, this is the last point that remains for me to clarify.

[elephant]

It looks amazing, this machine ........ to break the g ... , no ?

[Shadow555]

Agree with you, at first it's going to be tough.
But after a few hours of use, its going to be sensational!

in addition, no risk of crashing into the walls, with the rear disc brake, it's the top

[dirk pitt]

interesting this project.
just a little reminder of physics: do not confuse amperes (A) and amperes-hours (Ah)
you say your motor is 600W. that means that when it is going to force a max (blocked at the stop) it will consume 600/24 ​​= 25A
your controller accepts to pass up to 40A. So far so good. it will never risk to burn out whatever the battery. The motor is the boss: it is he who sets the current according to the difficulty.
A battery is mainly characterized by its capacity (roughly speaking, this is the size of its energy reservoir)
this capacity is expressed in Ah. In absolute terms, this means that an 18Ah battery can provide 18A for 1 hour before being empty (or 9A for 2 hours or 36A for 30mn)
this is where it gets complicated because there is another important characteristic of the battery which is hardly ever indicated, it is its maximum recommended current. indeed, if you discharge each time at 36A for 30mn or at 9A for 2 hours, the battery life will be different and the capacity will also change !! It is as if the size of the tank changes according to the flow coming out of it.
for a lead / gel battery, I would personally advise not to exceed the discharge current in 1 hour or 18A for an 18Ah or 7A for a 7Ah etc.
in addition, a lead-acid battery should never be completely discharged. it is even necessary to avoid exceeding 50% discharge.
beware of your mistake: 2 batteries of 12V18Ah in series, that will effectively make you 24V but 18Ah because, being in series, the current will be the same in the 2 batteries. In // you would have had 12V and 36Ah
hoping to have enlightened you.

[I Citro]

I thought I would find two 12v / 18Ah batteries in series, which would make a 24volt / 36Ah block

dirk pitt went first and has carefully reframed the issue of battery capacities.

To obtain 24V 36Ah with 12V 18Ah batteries, you would therefore need 4 batteries assembled as follows:

A / - 2 batteries connected in parallel, i.e. 24V 18Ah
B / - 2 batteries connected in parallel, i.e. 24V 18Ah

C / - You assemble A and B in parallel, i.e. 24V 36Ah

To summarize when we mount batteries in series, we add the Voltages (DDP in Volt), the intensity of the whole is that of the smallest of the batteries (ex: 18A + 7A = 7A) The small battery heats up and does not can provide +.
When you go up in parallel, you need batteries of identical voltages, otherwise the strongest battery delivers in the smaller one and one ends up with an average tension lower than that of the strongest battery. On the other hand, the currents add up.

We have only talked about lead-acid batteries but there are more and more batteries with different lithium technologies which, in addition to their lightness and compactness, offer an interesting characteristic:
They are capable of delivering more than their rated capacity instantaneously. I mean that a 24V 20Ah battery, capable of providing 20A for 1 hour or 10A for 2 hours can often provide double or triple instantaneously, i.e. 40A to 60A without deteriorating like a lead-acid battery ...

[Shadow555]

Thank you for your responses, I suspected that it would not be so simple

Ok so I have to find two 12v batteries with more amp hours if I want battery life and not too much weight.
Or to find a lithium battery, you know of the site?

As you explain the motor can consume up to 36A, but to start it needs less, so that it does not force.

I can solve this problem with the controller, it has a 3-wire output to connect a 5 Kohms potentiometer (1 to 4 volts).

With two switches and two resistors, I can split in two speeds with different amperage for the motor, one to start and another for afterwards, according to the amps arriving at the motor.

Thank you very much, I did not really understand the principle of the circuit.

[I Citro]

... Or find a lithium battery, you know any sites?

I often receive offers from ebay ...

As you explain the motor can consume up to 25A, but to start it needs less, so that it does not force.

Well no, you can ask him for the maximum when starting, you will empty your battery faster, that's all.

I can solve this problem with the controller. It has a 3-wire output to connect a 5 Khoms potentiometer (1 / 4volt).

You mean 1/4 of a Watt, right?

With two switches and two resistors, I can split into two speeds with different amperages for the motor, one to start and another for after, depending on the amps arriving at the motor.

The speed depends on the voltage you supply to the motor, Amps give power.
I do not know what the potentiometer acts on (voltage, current, or both).
By putting 2 resistors, you obtain 2 operating regimes; a total revs and a limited revs, which you can use when you reach the end of your batteries to manage to get home, but at low speed. I have this on my scoot'elec which has a V1 mode and a V2 mode + a handling mode which allows me to move it on foot without pushing it.