L494 RRS secondary battery install

PhyrraM

Adventurer
I'm slowly building my '17 L494 for exploring/camping/mild "Overlanding". Part of my needs are a second battery. This platform. along with the L405 (I assume), present some interesting problems and advantages. First being that the main battery is already in the back of the vehicle so cable runs are short. Second is that there is already a designed in mounting place specifically for a second battery - because some diesels have an H6 (group 48) as factory equipment.

However, the spot used for the secondary battery is used by either the small start/stop auxiliary battery or the voltage quality module that replaced it on later years. My '17 had the voltage module.

Motor vehicle Automotive tire Steering wheel Gas Automotive exterior



To use the proper location that module needed to be relocated. Luckily, these is plenty of wire to play with. There is a large area just to the right of the factory location, but that void is mostly take up by the storage "recess" in the trim panel. I did find that it fits up behind the upper trim, next to the fuse box. So a few hours playing with the tin snips and a bracket was made that picked up unused factory mounting points.

Motor vehicle Gas Machine Auto part Engineering


Saw Wood Automotive tire Motor vehicle Monoplane


Hood Motor vehicle Bumper Automotive exterior Electrical wiring



After that it was a matter of ordering a few OEM battery hold downs and bolts from Europe and installing an H6 battery.

LR038342 Side hold down bracket
LR038343 Top hold down bracket
LR096355 Long bolt for top hold down (2)

Flight instruments Cockpit Motor vehicle Aircraft Auto part



The battery is just an empty case for now. The largest H6 lithium battery I can find is 50amp-hours. I'm pretty sure I can build a 100 amp-hour battery in the case as a DIY. Next step is integrating a DC/DC charger and distribution fuses. I also want to make a better (probably CAD and CNCed) bracket. It's an OCD thing.

Hopefully this helps or give somebody a few ideas.
 

lvivier

New member
I’m following in your footsteps with my own build! I have a 2015, which has the start/stop battery rather than the VQM.

I’ve found that a 100Ah lithium battery from Renogy fits in this space nicely:

IMG_2721.jpeg

I believe It’s a bit longer and taller than H6, so it will want a custom bracket.

The Renogy part number is RBT100LFP12SH.
 

PhyrraM

Adventurer
I’m following in your footsteps with my own build! I have a 2015, which has the start/stop battery rather than the VQM.

I’ve found that a 100Ah lithium battery from Renogy fits in this space nicely:

View attachment 794055

I believe It’s a bit longer and taller than H6, so it will want a custom bracket.

The Renogy part number is RBT100LFP12SH.
Nice. Looks like a tight fit, but seems to make it. I notice that your model has the parking brake controller in the spot I relocated the VQM to. I believe the parking brake controller was integrated into ABS module in later years, so mine doesn't have it. I'm not sure if it's the camera angle or not, but your fuse block (yellow) looks to be about 1/2" shorter than mine (black). Valuable space it seems.....

I've added a pair of OEM battery cables, mostly to keep the OEM look theme. There is a 500(?) amp MEGA fuse in the OEM positive terminal for safety. The negative terminal is from a Jaguar F-Pace as it had the right shape for that battery in that location. I'm currently in the process of making a bracket to mount a pair of early year OEM MEGA fuse holders - one for the charger and one for the sub-panel to the loads. Progress so far:

53138139368_5dea369ae4_o.jpg

If you could snap a picture of how your MEGA fuse block (at the end of the main battery positive cable) is mounted, that might help me find a spot for mine.

This is what I bought and am trying to use:
Battery positive.jpg
 
Last edited:

PhyrraM

Adventurer
The next phase is done.

I obtained a bracket from an early model with the auxiliary battery for the start/stop system. It's stamped as part #DK62-14N072-AB. It normally mounts the MEGA fuse blocks for the starting battery and the dual battery isolator/relay device. I'm only using the MEGA fuses.

53182895214_9170b6c37f_o.jpg


From there I landed the AUX battery positive lead to the common side of the fuse block and the DC/DC charger output to one of the fuses (yellow wire). Mounted up, it all looks pretty factory.

53182872254_fc39d4dba5_o.jpg


The DC/DC charger input wire was connected to a spare/empty MEGA fuse location in the OEM fuse block (3rd location from the left).

53182091882_077265e918_o.jpg


All buttoned up ready for the trim panels.

53183180618_b52f2bac09_o.jpg

Next up will be a mounting bracket and turn-on signal for the charger and then on to the A/C inverter and other electrical loads and proper switching and fusing for them.
 

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