Talk:Electric Nickel Board

Proposal Evaluation

Structural robustness of 3D printed parts

As shown in our 3D Printer wiki page, our 3D printer uses PLA and can print parts of up to about 7x7x11 inches. It is unclear to me how you will jigsaw a collection of small, and weak, plastic pieces to get a robust scooter capable or carrying a human and the weight of the electrical parts (which is not irrelevant in this case). Similar projects rely on a wood or metal foundation. Your proposal must provide a clear explanation on how to solve this problem, otherwise you will probably have to use a different material as foundational support.

Safety of electric system

You are currently quoting a 150W motor, a 1KW motor controller, and a 7Ah lead-acid battery.

First, if you try to pass 1KW through a 150W motor you will create a fire. Your controller cannot be rated for more power than the motor, and your controller must include a safety trip mechanism that is within the safety range of the motor.

Second, lead-acid batteries are dangerous to manipulate since they might leak corrosive and toxic liquids. For this reason they are usually installed is casings that are reasonably safe from puncturing or scratching. I do not understand how you will mount this battery in your scooter, but if there is a risk of the battery hitting the floor at high speed then you have the potential to create a highly unsafe scenario.

Third, this is a very low resistance battery with high capacity. That is the most dangerous combination in terms of handling and operation, leading to potentially risky situations when inappropriately handled. In other words, this is not a beginners battery, so unless you have experience using dangerous devices like this one, you will have to choose a safer battery.

Battery recharge

Your budget does not include a battery recharger. Lead-acid batteries can be recharged with constant voltage (i.e. using a standard power supply) over long periods of time (usually overnight). That being said, the low resistance of this battery means that you will need a special power supply, as none of the ones available in the lab can handle this amount of power. My guess is that a 100W recharger will be way beyond your current budget limit.

In short, this is a thorough proposal, but there are significant safety and design issues that remain to be solved. In its current form, I don't think it is possible to complete this project in a $150 budget. Moreover, I will not authorize the use of possibly risky devices, such as low-resistance batteries or high-power controllers, until all safety precautions are explicitly detailed in the proposal.

This proposal should be improved before Friday September 23 at 5pm.

-- Humberto 00:13, 19 September 2016 (CDT)