Battery disconnect

[Quanyin]

Hi,
We have a 2015 Legend EX. I believe that there is a disconnect switch somewhere for the engine battery. Does anyone know where it is found? We found Peggy with a completely dead battery yesterday, and I suspect we'll be replacing it today. After our upcoming trip, I'll remember to disconnect, if I know where the switch is.
Thanks,
Paul

 

[avanti]

It is not a switch. The ground cable goes through a stud that is located just above the accelerator pedal and can be removed to disconnect the chassis battery. Press the red tab. This is documented in your Sprinter operator's manual.

 

[avanti]

I recommend you install a Trik-L-Start:

http://www.lslproducts.net/TLSPage.html

especially if you park outside. That way, your solar cell will keep your chassis battery topped up--no need to disconnect. Cheap and easy and works great. Just install it across the isolation relay.

 

[Quanyin]

Thanks much. We're off to shop for a replacement battery. The original isn't holding a charge.
Paul

 

[sailquik]

Quanyin,
Which battery died......the engine starting battery, under the drivers side floor board.....or the coach battery (s) bank.
Just above the throttle pedal is a disconnect for the engine starting battery but it's really for emergency use.
You most likely need to find (or have someone find it for you) what is draining the battery (s).
How long way your RV stored that the battery went flat?
Perhaps you need to add a marine type battery selector switch (if not already fitted by the up fitter) so you can
isolate the coach loads from the Sprinter starting systems.
Disconnecting the engine starting battery, and the auxiliary (coach) battery is covered pretty well in your MB Operator's manual
around pages 260-270.
Roger

 

[avanti]

Just above the throttle pedal is a disconnect for the engine starting battery but it's really for emergency use.

I disagree that the chassis battery disconnect is only for emergency use. The 2014 Operator's manual says:

Only switch the vehicle to de-energized using the battery main switch if:
--the vehicle is stationary for a lengthy period
--it is absolutely necessary

I read that list as an "or", not an "and".

Also, Great West vans come with isolation relays (at least mine did) controlled by the "engine running" signal, so unless it is malfunctioning, I don't think that coach loads are part of the problem.

 

[chromisdesigns]

Agreed, not for emergency only. I unhook mine any time the coach is gonna sit for more than a few days. Parasitic and engine computer loads can kill it after a while. I left the door cracked once and came back two weeks later to dead vehicke battery. Flattened it completely.

 

[sailquik]

chromisdesigns,
That's kinda strange.
I wonder if during the RV up fit they change something gets changed in the electronics.
My 2014 can sit for a couple of weeks, and there is no parasitic or engine computer drain on the battery.
Also, if I leave any interior lights on, accidentally, the Sprinter's system will automatically shut them off
in around 7-10 minutes.
Interesting!
Roger

 

[avanti]

My old T1N had significant parasitic loads -- It couldn't last more than a month or so without flattening the chassis battery. After the original battery suffered an early death, I added a knife switch to the positive battery terminal. With that open, the battery would survive the winter without issue.

I have no idea how my 2014 I4 would fair, since I have a Trik-L-Start which keeps it topped up.

 

[Quanyin]

it was the engine battery under the floor board in front of the driver's seat. We had left Peggy unattended (though plugged in) for a several months, but I had not used the shut off by the accelerator. I think the $200 invoice will remind me next time. We're leaving for an trip to Haida Gwaii, and I'm glad this happened here at home.
I reviewed my original post along with the replies, and I'm embarrassed that I made a typo. It's a 2012 Legend EX, not a 2015. Sorry for that.
We went to remove the old and install the new battery, and I'm less than impressed with the engineering. I'm not particularly a DIY person, but I thought removal and replacement of a battery would be a cinch. Not so. We have to return with a Dremel tool to cut a couple of small bolts which protrude from the side of the box so we can remove the battery. I think it's attached to a fuse of some kind.
Anyway, thanks for the informative replies.
Paul

 

[chromisdesigns]

chromisdesigns,
That's kinda strange.
I wonder if during the RV up fit they change something gets changed in the electronics.
My 2014 can sit for a couple of weeks, and there is no parasitic or engine computer drain on the battery.
Also, if I leave any interior lights on, accidentally, the Sprinter's system will automatically shut them off
in around 7-10 minutes.
Interesting!
Roger

Dealer said engine computer never goes to sleep if a door is cracked. Keeps waking up and drains the battery

 

[sailquik]

Chromis,
I didn't know that, but don't think I'll leave a front door open and kill the battery just to find out.
Not sure why a front door would be any different than the side or rear doors and I know it shuts the
interior lights off because I've had it do this when working in the back of the Sprinter.
Roger

 

[DHowie]

I recommend you install a Trik-L-Start:

http://www.lslproducts.net/TLSPage.html

especially if you park outside. That way, your solar cell will keep your chassis battery topped up--no need to disconnect. Cheap and easy and works great. Just install it across the isolation relay.

Where is the isolation relay located on the 2012 Legend? Also, where is the fusable link from the alternator to the house batteries located? Thanks for your help.

 

[avanti]

Where is the isolation relay located on the 2012 Legend? Also, where is the fusable link from the alternator to the house batteries located? Thanks for your help.

Not sure about 2012, but in my 2014 Legend the relay is mounted in the engine compartment on the driver's side sidewall. The connection to the chassis power system is under the vehicle at the point where the Sprinter Y-cable connects to the starter battery. (There is a terminal underneath the battery compartment.) There is a self-resetting circuit breaker (not a fusible link). It is also located under the vehicle, near the battery compartment.

For purposes of installing a Trik-L-Start, it can all be done at the relay in the engine compartment. I just mounted it on the wall, next to the relay.

 

[DHowie]

Not sure about 2012, but in my 2014 Legend the relay is mounted in the engine compartment on the driver's side sidewall. The connection to the chassis power system is under the vehicle at the point where the Sprinter Y-cable connects to the starter battery. (There is a terminal underneath the battery compartment.) There is a self-resetting circuit breaker (not a fusible link). It is also located under the vehicle, near the battery compartment.

For purposes of installing a Trik-L-Start, it can all be done at the relay in the engine compartment. I just mounted it on the wall, next to the relay.

Thanks for this. The isolation switch on my Legend is where you said it would be. I replaced it with a new one and my coach batteries are again being my charged by the alternator. It's funny, I could distinctly hear the old isolation switch (solenoid?) slamming closed when I put the ignition in the run position, which made me think it was working. It wasn't. The new one sounds the same to my ear, but it works.

 

[starrider]

Not sure about 2012, but in my 2014 Legend the relay is mounted in the engine compartment on the driver's side sidewall. The connection to the chassis power system is under the vehicle at the point where the Sprinter Y-cable connects to the starter battery. (There is a terminal underneath the battery compartment.) There is a self-resetting circuit breaker (not a fusible link). It is also located under the vehicle, near the battery compartment.

For purposes of installing a Trik-L-Start, it can all be done at the relay in the engine compartment. I just mounted it on the wall, next to the relay.

Avanti, One question about installing the trik l charge. When I installed mine across the relay it slammed shut like the engine was in the run mode. Is that normal? Thanks for the help

 

[avanti]

Avanti, One question about installing the trik l charge. When I installed mine across the relay it slammed shut like the engine was in the run mode. Is that normal? Thanks for the help

No, that does not sound normal.

You didn't connect all three wires to the relay, did you?
Yellow and blue go to the two "battery" connections of the relay. But the black wire goes to GROUND, not to the "activate" terminal of the relay.

 

[starrider]

No, connected up per the diagram. blue to starting battery and yellow to the house batteries on the relay. Black to ground

 

[avanti]

If I understand your description properly, it means that you somehow applied +12 to the "activate" terminal of the relay. You could do this by shorting that terminal to one of the "battery" terminals. I guess it could also happen if you connected yellow or blue to "activate". Any chance that you mixed up the relay terminals? "Activate" is typically the "middle" terminal in a 3-terminal relay. That one should NOT be connected to the Trik-L-Start. That is really the only possibility I can think of. If you are connecting nothing to "activate", what you describe seems impossible.

 

[starrider]

Thanks for the insight. I did not connect anything to the activate post. I will try this again tomorrow.I was going to say I am very good at wiring stuff up but this has me backing down. Again thanks. I'll repost tomorrow