I’ve gone through at least 6 different types at this stage I think. Although I am sure that luna were responsible for 3 of those re brands. Never been a hazard type fail though just go to turn on and nothing or go to turn it off and everything.
Definitely been the main fail point with all my builds so far.
Perhaps @YUTW123 can clarify. i’m really interested to know 
, and i’m reallying hoping the answer isn’t “pcb layout”.
afaik, you need a separate chip for pre-charge, maybe @b264 can chime in.
I was always under the impression that a resistor is needed. Like an anti spark connector. Something to slow the initial charge.
Disclaimer; I have no actual knowledge and am winging it.
@b264 Get off the girlfriend and help us out here.
Technically (and please call me stupid if I’m wrong) the vedder/fechter design does do a pre-charge, but using the mosfet in the ohmic region. I believe doing it this way is very sensitive to other parameters in the system, like the size of the capacitors and voltages, so they tend to blow up.
The newer designs are using a separate circuit for the pre-charge stage, using timers or MCUs, and sometimes a mosfet in the ohmic region, sometimes a big resistor.
Or a controlled dV/dt slew rate to keep power dissipation within the MOSFET’s SOA.
I don’t see any precharge circuit. If they post a schematic, we could be sure.
Those mosfets will not be able to handle those kind of currents because of their SOA… It’s based on basic vedder switch also its XT60 connector so kinda limits current consumption
I assume this is the Maytech pictured above without the heat shrink?
It has 9 five star ratings that mostly don’t look faked.
Give them time. lol
It looks like the generic switch that always goes pop eventually. They always state the maximum peak values and not the continuous rating. The thing I like about the maker x is that they do state the continuous. My set ups while over that amp rating in the settings don’t pull that kind of current in everyday riding. @Kug3lis XT60 is capable of a lot higher than the name suggests too but yes I would have liked to see XT90 on there.
I posted pic before in builder forum regarding this switch mosfets they will not be able to handle current at all…
EDIT: They changed description… 
Yeah thanks for that. I thought it was yours lol. Couldn’t find it on your site tho…
Well I will see for myself very soon. Might be some magic stuff in there. Who knows? I just want a switch that works. Not a lot to ask. I don’t ask for much. I need a couple of heatsinks actually. Are you still doing the focbox dual that bolts through the enclosure?
@YUTW123 any comments? Care to share if there is indeed a precharge circuit??
Of course, there is indeed a precharge circuit！！
Otherwise it won’t work！
Inrush limiting is not a precharge circuit. A precharge circuit limits the inrush with a discrete resistor and not by slowly turning on the FETs.
But of course if you posted a schematic, we could be sure. Until then, I don’t see the parts for that.
3 resistors, a capacitor, a diode, and some FETs does not have a precharge circuit, but looks extremely similar to an inrush limiter.
I use these and like them better than anything else that I’ve built with. I run them with 13s, but my system’s burst-current never exceeds 100A. So I don’t know how they’ll do on some of the super-powered dual-drive systems. They are really nice and compact. Also, they’re cheap, so replacing one won’t break the bank. The button that they sell the switch with sucks it, but it can be replaced with any 5-pin latching pushbutton that you find on Amazon. These are worth a shot for the price. I have one with well over 100 miles on it. I look forward to seeing how they work out for others.
Maker X also goes by Free RC Hobby on Alibaba. Check them out there. They are making some interesting esk8 toys.
Thats good to hear because ive just got mine. Tiny little things but no conventional pre charge afaik
Wasn’t going to do 12s with them but maybe I will now. Would have been happier with xt90 but ive run 12s batteries with 60’s with no drama. If it lasts more than 3 months it wins. Nothing else has.
I don’t know what the magic trick is that makes them work without a precharge, but I think It has something to do with the 5-pin button. I read about this in an old thread on another forum. I’m trying to find it. Maybe someone with more expertise understands how the concept works.
The biggest thing to prolong their life won’t be less or more voltage, but it’s all about how many farads of capacitance you connect. An old VESC 4.12 usually has three times 680 microfarads, for example. Two of them, twice as much. (4 millifarads) That’s the number that is really hard on these types of circuits.
