Finally get the DC to Dc charger working today. While memory is fresh, want to write up the steps leading to this after many hours of searching in this forum. This forum has been so helpful l. It has lots of info but scattering around. So hope this will be somehow consolidate some of the info I collected.
1. power tapping points (positive connection). Depends on your sprinter setup, there are 3 places one can connect positive line. The first one is in the battery compartment. The so called F150/1. In my set up, I need to build a bus bar to connect two studs and then use a midi fuse. Also requires me to add line in the battery compartment. This was my original plan but I eventually decide not go this route and leave the battery compartment alone. See picture 1 and 2.
the 2nd option is the F150/4 bus bar (3 rd picture). Position 6 in my van is live and fused (80A) so it fits my purpose and this is where I connect to.
3rd option is to use the F150/5. If you have an aux battery, you may have this set up. I don’t have this one.
2. Ground connection. This one takes me a long time. There are at least one under driver seat but one needs to remove many items to access. Also, it will share with 3 other lugs. I eventually decide not to use this ground bolt. The ground bolt I used is the one for securing seat base and located in the lower left corner of the seat base. I do have concerns of using this one as it is for seat securing seat base. The easy access wins at the end.
3. D+ line. This is connected to the first stud in the EK1 box.
4. driver seat removal. It is actually OK just to loosen the 4 bolts and lean the seat to a support backwards, no need to remove it completely by disconnecting the wires.
5. Picture 4 shows its working.
6. in the future, I might still add a switch to the d+ line so I can manually turn the charger off. Right now, it can be turned by the breaker to the house battery.
now can move On to plumbing, etc.