brunnhilde said no to trailer winch battery - part 4

this drain valve has irked me since day one as it is totally useless for draining the water boiler

The most expedient way to drain and clean the water boiler is to remove the anode rod which you want to do anyway when winterizing. The drain valve does nothing but to leave another place for freeze damage so it's got to go. Doing so allows me to reclaim a few cubic inches of precious storage in this compartment.

taking advantage of the cool morning before the brutal sun sets in I started to work on the trailer winch power supply now that all the needed parts arrived

I needed to enlarge the hole of the positive cable ring lug so it fits the cutoff switch

I soon realized I only need the binding post for the ground but not the positive one since the cutoff switch doubles as the binding post to transition down the cable AWG; this also eliminates accidentally shorting the +12V now it is not exposed

since this cable pair is quite stiff they dictate the mounting location of the cutoff switch as well as the binding post for ground

this ring lug also required enlarging to fit

every detail matter for quality workmanship down to the orientation of how you fasten the ring lugs to the contact post and the choice of screws to fasten the switch to the cabinet wall

I fed the 10 AWG cables back down to the undercarriage using the same cable shield

While it seems so little were done, all these took a couple of hours since I improvise and design as it went. Original design and work take significantly more effort and time. As always I want my work to be professional, safe, and look as original from the Westfalia factory.

What remains is to route the 10 AWG cable pair in the undercarriage, protect them with cable shields against attack by rodents, and install the Anderson connector. In designing the cutoff switch and ground binding post installation, I left the option to add a small battery in the water boiler compartment so to minimize the risk of draining the Sprinter's starting battery.

It should be note that while it takes a small winch to pull a race car up the gentle ramps onto the trailer, but the energy requires is actually higher than one raise the car vertically. Why? Raising an object vertically of X pounds you raise the potential energy. When you winch the same object up a gentle ramp you incur the same potential energy of raising it, but adding friction of the bearings, differential, tire distortion, rubber friction. Hence a gentler ramp angle actually requires more energy from the battery.