I’m trying to figure out a solution so that I don’t have to open my case and plug/unplug the batteries every time I ride. I do have a power switch on my ESC bit I’ve heard that you shouldn’t use that as an on off switch and that you shouldn’t keep your batteries plugged in. My main goal is to have the batteries permanently plugged in and just have an on off switch. Any solution other than the $60 torque boards option?
The cheapest solution that I have found is a big circuit breaker. I picked up a ~$7 60amp AC breaker on Amazon to try. My VESC and Motor just shipped so I won’t be able to test it until they get in next week. Someone else here mentioned that they also used a circuit breaker (more amps than the one I have) and it worked fine as a switch and never switched off unexpectedly.
Keep in mind that I am not really recommending this as I don’t have personal experience using it yet… It’s big, ugly and not designed to be used as a DC switch… but it’s cheap and may be what you are looking for. I was also turned off by the $60 price tag for torqueboards switch…
You could make a loop key. Cheap and reliable. Use the search funtion, you can’t miss.
I’ve tried a number of toggle, rocker, and even slide switches on the power mains. It’s not worth it. I use @torqueboards $60 electronic switch because i don’t really want to build my own, but its the cleanest option. It allows you to keep your mains in place and then the only other thing you have to worry about if figuring out a charging port option. Unless you’re using a space cell, then neither of these things are an issue.
The tiny little slide or pushbutton switches on the ESCs could easily be replaces by a a different, more durable pushbutton switch that could then be mounted into your box. The switch that’s current;y on the ESC may not be able to withstand the abuse of being on the outside bottom of an electric skateboard.
I don’t know why its considered a bad idea to cut power at the ESC while leaving the batteries connected on ESCs that come with outboard power switches. Maybe somebody could enlighten me on this because it makes little sense. It seems like they were designed to work this way.
I don’t like to leave my batteries hooked up to anything if its not on. “soft power” options scare me a little. I like to sleep knowing that my batteries are physicaly air gapped from everything and are not going to catch fire and burn me in my sleep because some 2c Chinese Cap went dry.
So basically the only options are:
Loop Key Big ass circuit breaker $70 DIY switch
I guess I’ll go with loop key. I don’t want to take apart my board everytime I want to use it
@lowGuido I always liked the way you incorporated that! What do you call that circuit breaker? Is it just a “100A circuit breaker” or is it something more specific?
yeah it’s just a 100A circuit breaker.
Look up “hi amp circuit breaker”
One cost me about $40 landed in Oz. They are nice and compact and are soft switching (i.e. no sparking) I had to assemble the PCB and components (which isn’t too difficult) and purchase a SPDT switch from Jaycar (cost about $5 and a few different options). If you were to upload the design to OSH Park or similar and source the parts from Mouser they would work out a fair bit cheaper.
This is what mine looks like finished, ready for connection to two VESCs:
Note that I used fuse wire (3 strands of 16A in parallel) instead of the automotive fuse.
Previous to that I used a loop key in my charge port (wired in series) that worked ok, until I lost my loop key and I didn’t like the sparking.
The circuit breaker option looks good as well, although I would be a bit worried about vibration tripping the breaker and you also need to ensure that the breaker is rated at the correct DC current (house type CBs are rated for AC voltage).
Yeah I’m not big on that soft power setup for the reasons stated above.
My breaker is ugly. But has never tripped in >700km worth of travel.
i had a problem early in with the switch that came with my original Flier-type dual ESC that came from enertion, but it was the push-switch not the circuit that was the issue. Vibration would throw it. I fixed that eventually with a rocker switch, but when i got the one from DIY i didn’t have a problem anymore. I’ve been using it for a year now with zero issue on my terribly paved streets.
my biggest issue with solid state (or soft switching) is that it needs power to work.
don’t get me wrong. its great. those FETs can handle loads of current and they are an elegant hi current switching solution.
but. the way it works is that the switch allows a a connection from the b+ to the gate which in turn allows current to flow across the source/drain on the -ve wire. the switching side (left side in the photo) is ALWAYS live. if I was to use one of those soft switches I would have to physically disconnect my battery every time for piece of mind.
again. 99 times out of 100 there is no issue with leaving the batteries connected to the device, I just dont want to be the 1% a good friend of mine actually burned his whole house down with lipos. I don’t want to play that lottery.
Word to that! I keep my lipos disconnected in a fireproof bag when I’m not riding. It’s a pain, but I sleep better. Not saying everyone should do that, it’s probably overkill!
What can happen when using the little slider or soft ESC supplied switches is that in the soft switch is the cutt off can fail. This will turn on your board, drain your cells below their LVC and possibly cause a fire. On the sider switches like with Castle ESC’s they can wear and eventually the current will bridge in that small area.
Neither are really an issue if you’re in close proximity. But lets say, you’re back from a long day, you don’t have time to recharge your battery after you hit your LVC. You put your gear away and go to sleep. While your sleeping the slider switch fails, drains your battery further and…
So it’s safe to say that the best bet is a disarming switch aka loop key?
I understand your concerns with soft switches and believe you should go with whatever you feel comfortable with. For me I like solid state switches because of the the size, soft switching (no spark) and the ability to use a small form factor switch mechanism.
I think blaming soft switches for LiPo fires is a little far fetched, a LiPo fire would most likely occur in the event of a short circuit within or across the battery pack. With the soft switch design developed by Vedder and Fetcher (the schematic can be found here: https://github.com/vedderb/SparkSwitch/blob/master/Plot/Schematic.png ) it is very improbable a short would develop in the switch across the battery pack. If this somehow did occur (most likely water ingress or something similar) the switch has a fuse which would protect the pack.
I am not so concerned with FETS failing as this would be rare and the worst that would happen is the load may become powered on (as psychotiller mentions) in the event of a source to drain short in which case you may drain your batteries depending on the type of ESC connected to the switch. I have my battery pack connected to a BMS to protect against this and other conditions that are bad for the battery pack.
If you really dont like solid state switches the loop key is a good option as it is cheap, and compact. Having said that it would pay to look at the likes of Boosted, Marbel, Evolve, Enertion etc. and look at what they are using.
Here is what you need to buy cheap high voltage switcher: -car relay 80A (7 euro) -step down converter (6 euro) -waterproof blue led bipolar switch (7 euro)
It cost me in Poland 20 euros.
I dont know why I don’t see more auto relays as switches. Anyone have a good reason why they wouldn’t work well for esk8?