2018 Sprinter Battery Drain

[KenInRockwall]

Is your experience with older or newer CTEK chargers?

[jrobe]

I wouldn’t hesitate to buy NOCO or CTEK chargers. I have had both and have never had a bad one.

[Backcountryguy]

I’ve had the battery tender hard wired now for almost 4 months. It provides a smart charge to the chassis battery while hooked up to shore power and I can also run it off the inverter. The battery is at a steady 13.0V when hooked up. It’s been outstanding.

My build thread shows the battery tender.

[Rockvoyager]

Thought I would respond to this thread as I'm in the middle of my sprinter conversion right now.

I'm definitely not an expert, but I am a solar contractor and do a lot of off-grid work on 80ft plus houseboats. All the posts on parasitic draw are spot on. They aren't just an inconvenience, they are a real pain in the butt. I've seen giant battery systems drained to inverter shutoff in just a few months. Finding these bad guys can be tricky but here are some places to look.

1. Carbon monoxide or any type of detector. They all have a small draw and as was pointed out up thread, it only takes a tiny draw to discharge a battery over time.

2. Cell phone chargers whether AC or DC.

3. Solar charge controllers. I know, I know! That's not supposed to happen but I've seen cheap charge controllers that acted as a load once the sun went down.

4. Stereo systems. Just fixed a problem where a friend wired in a car audio unit to her house battery. It drew .6 amps with the power off and would discharge her battery in less than a week.

Parasitic loads are tricky devils but dealing with them isn't hard. Make sure that you only have one cable connected to each battery terminal. Run each lead to a busbar and connect all your loads to that bus, this way you can test each circuit to determine the guilty party. Put a disconnect switch (like the one up thread) on the positive side and I strongly suggest fusing the hot side close to the battery positive post.

Make sure you have a good meter and be patient. 12 volts won't hurt you but it can do a lot of damage to some really expensive bits.

Now for my questions:

1. Is there a MB battery isolation switch that mounts to that plastic monstrosity underneath the drivers seat?
2. Has anyone added a fuse module to the empty location on the fuse panel and used that for house circuits?
3. The plastic duct going between the passenger and driver's seat has a number of small wires. I'm a little concerned with the idea of running a high amperage circuit in with all the low amp stuff. Anyone have a factory installed second battery under the passenger seat that could share their thoughts.

I've been in the DC business for a lot of years but this camper van stuff is new to me. I'm a beginner here and would appreciate any help I can get.

Brad

[Backcountryguy]

The battery tender solved it all. It’s been hard wired in now for 9 months. Smart charger which keeps the battery on float while plugged in to shore power and also can charge while the inverter is on.