MB Sprinter Battery Question:

[dlj@salinas.ent]

I have a 2016 Roadtrek CS on a Mercedes Benz Sprinter 3500 chassis. RV Vehicle works great. However, last November it was parked for over a month. When I tried to start it the battery was dead. I tried to jump start it using the correct jumper connections and cables. I got nothing but clicks. I tried a couple of emergency starter units and standard jumper cables. I also tried using a battery charger. Again, nothing. I eventually installed a new battery under the cab floor. It started right up.

Even though I'm back on the road, it is still haunting me that there is a problem jump starting it. Anybody out there run into this problem or have answer?M

[femike99]

Originally Posted by dlj@salinas.ent

I have a 2016 Roadtrek CS on a Mercedes Benz Sprinter 3500 chassis. RV Vehicle works great. However, last November it was parked for over a month. When I tried to start it the battery was dead. I tried to jump start it using the correct jumper connections and cables. I got nothing but clicks. I tried a couple of emergency starter units and standard jumper cables. I also tried using a battery charger. Again, nothing. I eventually installed a new battery under the cab floor. It started right up.

Even though I'm back on the road, it is still haunting me that there is a problem jump starting it. Anybody out there run into this problem or have answer?M

I've had a similar problem, multiple times, with our 2018 Agile. I'm not quite sure what is draining the battery after such a short time of rest.

Anyways, the first time, I called AAA (we now have a AAA RV membership), the truck that was sent did not have a charger robust enough to jump it, and had to tow to the MB dealer for a diagnostic since we're still within the 3/36 warranty period. They put it on a charger for multiple days to bring the voltage high enough to start.

The next time, AAA sent a different service. They had a very large charger; too large to lift up to the vehicle. The cables dangled down to the charger on the ground. This had enough juice to jump the Sprinter.

Since, we go outside at least weekly to start the engine and occasionally take it to the store just to drive it between trips.

[Dogman]

Taking from both stories and understanding there are 3-batteries. Two house Batteries and one chasses battery. Does this one chasse battery seem to be the one in question? When you store the VAN you turn off HOUSE power cutting battery drain from the two HOUSE batteries. Something is pulling power from the one chasses in less than a month.

I have a farm truck and if it sets for a month no battery So I installed a small Solar about 6-inch wide to 2-foot long and sets each day in the sun on the dash. Also hooked directly to chassis battery. I'm wondering if you did this if it would fix your issue. As the RV chassis batters, only work's for the vehicle to start.

But I am wondering what is draining the battery and forget the RV side of the problem. I recall an old friend who had a jeep and he would remove the pos terminal cable when the vehicle was at rest. He said it would set two to three months without an issue.

This is what I have been using, but I got mine from Battery Plus. This is AMAZON. https://www.amazon.com/SOLPERK-Panel...a-738510810936

[JohnnyCLE]

If possible, it is best to call MB Mobile Service if you need a MB Diesel jumped. Most of the Diesels have oversized batteries to crank them.

There is a battery cutoff switch by the accelerator pedal on my 2014 Sprinter. This is supposed to be used when parking the unit for several weeks / months. I have never used it despite parking for periods of 6-8 weeks. Still original battery on 2014 build.

Should not be a problem for the length of time you mentioned unless there was excessive heat, something not charging right, or a parasitic draw. Something to check out.

[avanti]

Originally Posted by JohnnyCLE

I have never used it despite parking for periods of 6-8 weeks. Still original battery on 2014 build.

Should not be a problem for the length of time you mentioned unless there was excessive heat, something not charging right, or a parasitic draw. Something to check out.

That's odd. Before we got our Trik-L-Start, our MY2014 would NEVER last for 8 weeks with the battery connected. Same for our previous T1N. Our Sprinter has very significant parasitic draws from the OEM electronics. I wonder what the difference is between yours and ours.

[JohnnyCLE]

The most extreme case of my parking the sprinter was I drove it down to AZ in late October and parked it at our storage location. Flew back to Ohio to tend to my wife going through cancer radiation treatments. We made it down to our winter home end of March. I had by mistake left the house battery connect switch on so the 8 house batteries were toast and buckled. Sprinter started right up. In a few seconds the battery connect switch lit up and house electronics worked. Obviously the house batteries would not retain a charge.

The only connection point between coach and house that I am aware of is the Smart Solenoid, which evidently disconnected.

I also have left my E320 Diesel for extended periods of time with no issue. It's owners manual discourages any type of battery tender and the electronics block any accessory plug feed.

[Windrat]

I would check to see if there is voltage drop between the alternator and the starter battery. There is a main battery cable referred to as the Y cable that develops a high resistance at the splice point due to corrosion.

I also use a small dash solar panel to keep up with the drain from lock radio and security system draw. For winter storage when my solar is under a foot of snow in Edmonton Ab I have a smart charger that is on a timer hooked up to three deep cycle Marine coach batteries and the starter battery. This has been working great starts like I used it the day before after sitting idle for months

[RossWilliams]

Originally Posted by JohnnyCLE

I also have left my E320 Diesel for extended periods of time with no issue. It's owners manual discourages any type of battery tender and the electronics block any accessory plug feed.

We have left our Roadtrek Etrek parked in mostly sub-zero temperatures for a month and had no problems starting it. Unless the previous owner replaced the chassis battery, it is still operating on the original battery. I didn't use the chassis battery disconnect and there does not seem to be any significant parasitic draw. As far as I can tell, the chassis and coach electrical systems are completely separate so nothing in the coach is going to drain the chassis battery.

My guess is that the problem with jumping was a combination of a truly dead battery and insufficient jumper source. I noticed when I was buying a battery to use as a backup for my cpap machine that some batteries were rated to jumpstart heavier diesels and others weren't. I got one that claimed it would work although I have never used it for that purpose.

[avanti]

Originally Posted by RossWilliams

there does not seem to be any significant parasitic draw.

This is incorrect. There are many nodes on the CANbus, each of which has to listen for a "wakeup" message from the "sleep" state. NONE of them are truly powered down.

I have never measured mine, but typical reports from folks who have is ca .05A. That is 1.2A/day; 8.4A/week. With a typical 95Ah battery, that will get you to 50%SOC in around 5 weeks. This is why MB recommends disconnecting the battery if you are going to park for longer than 4 weeks. (The above assumes we are talking about a NCV3 Sprinter).

If you have solar and park outside, get a Trik-L-Start and forget about it.

[Gastineaurower]

Re main battery charged but nothing but clicks: make sure you house batteries are fully charged. They have nothing to do with cranking the starter, but the electronic ignition in those those Sprinters, once they have been modified for RV use, is collecting data from everywhere. In my 2008 Roadtrek, the info as to whether there is enough juice to turn the starter comes through the house system. If your house batteries are dead or drained it may be telling the ignition system its a no go, even though the main battery is fully charged. The Mercedes Mechanics were completely baffled, bu Poulsbo RV recognized the problem instantly.

[avanti]

Originally Posted by Gastineaurower

Re main battery charged but nothing but clicks: make sure you house batteries are fully charged. They have nothing to do with cranking the starter, but the electronic ignition in those those Sprinters, once they have been modified for RV use, is collecting data from everywhere. In my 2008 Roadtrek, the info as to whether there is enough juice to turn the starter comes through the house system. If your house batteries are dead or drained it may be telling the ignition system its a no go, even though the main battery is fully charged. The Mercedes Mechanics were completely baffled, bu Poulsbo RV recognized the problem instantly.

If this is true on your van, it was wired incorrectly. Standard practice is to isolate the systems with an air gap relay, so no interaction is possible. The isolation relay is supposed to be activated by the "D+" terminal of the EK1 strip (located under the driver's seat). This terminal is activated by the Sprinter's electronics only AFTER the engine is running and producing power. (There are more exotic systems that involve solid-state relays instead of air gaps, but they are all designed to work the same way.) With a proper setup, you should be able to start your engine even with a totally deal coach battery.

[Gastineaurower]

Well, it happens and Mercedes tried to charge me over $1k and never did figure out the problem. It obviously was was not the first time the RV dealer had seen the problem, either.

[avanti]

Originally Posted by Gastineaurower

Well, it happens and Mercedes tried to charge me over $1k and never did figure out the problem. It obviously was was not the first time the RV dealer had seen the problem, either.

It could happen if your isolation relay failed closed. You are right that it might take an RV guy to recognize the problem.

[Belzar]

I've needed jump after leaving van unattended for 3+ weeks in dead of winter. My portable 1000 amp jump starter didn't work and the jumper that the tow driver had in his truck didn't work either. He went back to shop and got a fully charged heavy-duty jumper and van started right up.

[avanti]

Note that if you use the provided disconnect terminal (down by the accelerator pedal) as per the manual, your Sprinter can sit happily for many months without significant battery loss. You can easily make it through a winter and start right up in the spring. Just be sure to follow the directions about giving the systems time to cycle down completely before doing so. Don't succumb to the temptation of "warming her up" during the storage. Just let it sleep.