Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Reaper]

I have a quick question regarding the actual construction of this monster considering that the motor draws a high amount of amperage. 

I know that this will seem perhaps stupid, but is there anything that I need to know regarding safety when building the electric vehicle?  I was talking to a friend of mine who is a materials science Ph.D and he more or less made me paranoid about the current being drawn off of this thing considering that something in the milliamps will kill you and at best the common household electrical outlet has something like 15 amps.  My brushless Etek will draw 300.

I don't think this is too terribly much of a consideration considering that the wires are insulated and the user should be nowhere near any of the circuitry that current could pass through him, but I thought that I would double check.  Are there any safety precautions that I should know of? 

And I would expand this to any safety issues in general that maybe perhaps some of you ran into.  Seriously, even if the motor ran away while you were charging the batteries (if such a thing is possible)  I want to know about it.  Are there any issues, potentially dangerous issues that you all have run in to?

[Bogan]

yes its the current thatll kill you, but you need a large voltage to generate that current (unless you somehow get one wire on each side of the chest. Physics demo in high school we got a generator, grabbed the output wires one in each hand and got over 100volts, was a bit tingly. But things like wet hands, leaning agains metal etc will probly affect it as well. Personally im not worried bout the electricity, just work on one wire at a time and itll greatly reduce chances of getting shocked, oh and connect the battery earth last of all.

[Reaper]

Connect the battery last... good advice. 

Also someone gave me the idea of putting on multiple cut off switches as well.  Good idea.

[MotoJussi]

Connect the battery last... good advice. 

This is a bit tricky When having plenty of batteries, there's no single place to disconnect the batteries to make the system safe

I thought about this and one thing which might be important is to -not- use vehicle chassis as a ground. It's easy to accidentally have something wrong to touch the chassis. Having two wires connect each other is much more difficult to do accidentally...

Just my 2 eurocents.

[picasso]

Super important not to have anything grounded. Also important to check for ground leaks from cheap parts or broken parts. On a conversion I would even un-ground the 12volt system, but to chase those down can be no fun on modern bikes. For safety I want a big disconnect. Like the one in this pic with the fuse but much much bigger. I have not found a big one yet. But I want something like this on a pull rope or some kind of handle.

[Reaper]

Definitely good ideas.  I am definitely considering employing multiple disconnects in the circuit so that if something goes awry (heaven forbid) I can push a button to shut everything down.

[Bogan]

yeh, ive found it pretty hard to find a good e-stop. High current ones are all bloddy expensive, and not exactly what i want anyway, ive decided to build a custom three stage e-stop/contactor, has a sequential disconect of the motor then the batteries, as well as an electrically operated disconnect of the motor. Should be enough to stop a short circuit from catpaulting me into a tree or whatever, in the unlikely even that my circuit shorts out.