House battery - Where are you pulling power for DC-DC charger

[Levi]

Hi All,

In short, factory dual battery system is problematic. So I am leaving as factory for a simple dual crank set up (not using EXT at all) and installing an independent house battery (LiPo) with a DC-DC charger (smart alternator ready 3 wire) includes MPPT input. The new system will sit in my canopy, not the cabin (Quartermaster) with alternator charge supply coming from rear seat, via factory rubber boot exit.

I am curious, for anyone else adding a DC-DC charger, where are you drawing the input from?

I’ve got a good mate who’s well versed in this stuff who’s going to educate me on wiring, but like to know ahead where others have connected in.


Cheers,
Levi

 

[Logsplitter]

I have thought of adding a house battery at some point and I was considering using the spare 40amp fused cable, in my battery box that has an ignition trigger wire. This is fed from fuse Fl13.
I have the dual battery and high amp wiring set up.
I haven’t researched this any farther to see if it’s feasible. If it isn’t I figure I could still use the trigger wire if needed and connect fused power directly to the starter battery or spare fuse point in fuse block next to battery, to power the dc to dc charger.

 

[Clark Kent]

I have just ordered an m6 and m8 stud, plus a spare 40, 60, and 80amp ZCase fuse so I can populate the unused 5th slot in the 5 stud Littelfuse holder. My thinking is to tap power from here to a couple of small terminal blocks. One live and one ignition switched. The ignition switched block I would activate via a relay that was triggered from the brown ignition feed wire that was part of the unused air compressor circuit on MY23 vehicles - same as @Logsplitter mentioned above.

The same unused 5th stud could potentially be used to provide power to a DC-DC Charger but the total current draw needs to be evaluated. The 5 stud fuse holder has a maximum current limit of 400amps.

The studs are available from Mouser Electronics.

 

[Logsplitter]

I have just ordered an m6 and m8 stud, plus a spare 40, 60, and 80amp ZCase fuse so I can populate the unused 5th slot in the 5 stud Littelfuse holder. My thinking is to tap power from here to a couple of small terminal blocks. One live and one ignition switched. The ignition switched block I would activate via a relay that was triggered from the brown ignition feed wire that was part of the unused air compressor circuit on MY23 vehicles - same as @Logsplitter mentioned above.

The same unused 5th stud could potentially be used to provide power to a DC-DC Charger but the total current draw needs to be evaluated. The 5 stud fuse holder has a maximum current limit of 400amps.

The studs are available from Mouser Electronics.

Glad you mentioned that. How do you put an extra stud in there. ?

 

[Keato]

Using the spare 40A circuit as suggest by @Logsplitter is a good option if your DC-DC is within its current capacity. Otherwise connect to the starter battery and use an isolated DC-DC, rather than a non-isolated one (recommend Victron). Do not connect to the factory aux battery or the CTek load terminal (which should have been disabled by your dealer pursuant to a mandatory work order if it was one of the early ones before they started disabling them from the factory). Maybe also to add a smart shunt while you are at it.

 

[Clark Kent]

Glad you mentioned that. How do you put an extra stud in there. ?

There is a plastic cover on the back of the fuse holder. Push that out from above (poke a wood pencil through the hole) then the stud can be installed from underneath. The cover clips into place and retains the stud until a fuse and nut is installed. I don't think the new studs come with nuts (eunuchs) so you would probably need to provide a nyloc nut as well as a fuse.

It's probably do-able in situ otherwise you might need to lift the fuse holder off the brackets to get access to the back. Shouldn't need to disconnect everything. Disconnect the battery/ies first.

There's a pic in one of my earlier posts here:
https://www.theineosforum.com/threads/rok_dr’s-exceedingly-unofficial-owner’s-manual-supplement.12415655/post-1333302768