TheSkoolieLife.com Episode 28:
Adding a kill switch to the
It was a challenge last winter to start the bus, and it’s only gotten
worse this year. Even in the milder weather the batteries seem to
drain if the bus is idle for a few days. I’ve had the bus in to the
dealership to diagnose related issues, and learned how difficult
(and therefore expensive) it can be to find the cause of such a
My brute force way of dealing with the issue has been to open
the battery bay on the outside of the bus, and use a socket
wrench to disconnect the negative battery terminal while the bus
is parked. This has been a nuisance, and not entirely effective (I
think because the batteries were getting old.)
I’d heard of truckers using a kill switch to disconnect the battery
when parked. I decided on that solution.
Given the large current that passes through the battery cables
especially when engaging the starter, the kill switch needs to be
designed to handle the current. So do the cables.
It’s counter-intuitive, but electrical cable gauges use smaller
numbers as cables get thicker. House wiring is typically 14 or 12
gauge. To handle the heavier current that a dryer needs, you’d
use 8 gauge wire. For the kill switch I used wire smaller than 0.
4/0 to be exact. At about $24CAD per linear foot for each of red
and black cables, I paid the dealer more than it would have cost
from other sources. The sticker shock led to me place the kill
switch as close as possible to the starter batteries, while still
inside the passenger compartment.
Last winter I found that, on several occasions I had to recharge
the starter batteries using a typical battery charger plugged into
the generator. In addition to the kill switch, I also added positive
and negative bus bars in the bus interior. That means I can now
charge the starter batteries from inside the bus.
Finally, when I start wiring the bus interior, I’ll be able to easily
hook up this Renogy DC-to-DC charger that will allow the
alternator to charge the house batteries when the bus is running.
To see how I made the kill switch assembly, click the image
below and watch episode 28 on my YouTube channel. And while
you’re there, click the Subscribe button so you don’t miss
Copyright 2023 TheSkoolieLife.com