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

 

[Levi]

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.

View attachment 7921112
View attachment 7921111

Thanks, didn’t know about this one.

 

[Levi]

Thanks m

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.

Thanks mate.
My dc to dc is 40amp, so may be better connecting direct here as you mention.

 

[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.

Received these studs and z-case fuses from Mouser today. Ordered and shipped from Mansfield TX on Feb 9. Arrived Feb 16 in my small village a very long way away. FedEx. Not too shabby at all.
If you're shopping for z-case fuses in Australia then SWE-Check is a very good option and are slightly cheaper per fuse but they don't stock the mount studs and Mouser had free freight so they won this time.

 

[TheDocAUS]

Received these studs and z-case fuses from Mouser today. Ordered and shipped from Mansfield TX on Feb 9. Arrived Feb 16 in my small village a very long way away. FedEx. Not too shabby at all.
If you're shopping for z-case fuses in Australia then SWE-Check is a very good option and are slightly cheaper per fuse but they don't stock the mount studs and Mouser had free freight so they won this time.

View attachment 7921523

Australians can also source the LIttelfuse 5 stud busbar, but not individual parts from Swe Check. I bought mine there and used it for parts. But I wanted a spare busbar, so not for everyone.

Fuses can be bought individually, and they are not cheap.

 

[Skydance]

Can anyone advise me which fuse in the rear compartment can be used for a D Signal wire (alternator charger). Needs to come on only when the car is started (alternator charging), not just when the ignition is on. Thanks.

 

[Znarfgh]

Do you have the C-Tek Smartpass between your 2 batteries?

If so, you could use a C-Tek DC-DC charger and connect that to the Smartpass with 2 bus bars and use the output for the second battery which would then be isolated from the main. You could replace the second battery with a Lithium and just run a power cable to the rear. I'm not sure about the existing connections but you mate might work that out for you.

I have left the factory system in place until my warranty runs out and use a battery box with a built in DC-DC charger where the power input comes from the spare bus bar - as others have said you'll need to get another fuse and stub.

 

[Skydance]

Do you have the C-Tek Smartpass between your 2 batteries?

If so, you could use a C-Tek DC-DC charger and connect that to the Smartpass with 2 bus bars and use the output for the second battery which would then be isolated from the main. You could replace the second battery with a Lithium and just run a power cable to the rear. I'm not sure about the existing connections but you mate might work that out for you.

I have left the factory system in place until my warranty runs out and use a battery box with a built in DC-DC charger where the power input comes from the spare bus bar - as others have said you'll need to get another fuse and stub.

Sorry for the misunderstanding, I should have explained more clearly.

I have a BLUETTI Charger 2 which requires a D+ signal to tell it to turn on/off, I plan on using a fuse tap to hook up. I’m looking for the nearest fuse to the rear of the vehicle which powers on/off with ignition live only for neatness and avoid running to the front.

Alternatively, I can pull a wire to the 15 amp 12v front or rear fuse outlet in the cockpit fuse outlet.

 

[Clark Kent]

You had me going down a rabbit hole there!
I was looking for a source that is active at alternator voltage (>13v) but not at ignition on (~12v).
If you have the Smartpass the output terminal facing the aux battery qualifies. The Smartpass cuts in at >13.1v which is higher than battery voltage. You could use that as your D+ signal or any of the ignition switched circuits in the interior electrical centre (fuse box).
Candidates are FI13 Spare (compressor) but it has a battery and ignition feed so check it first, or the heated seats fuses F121 and FI22. I don't have the heated seats option but the fuses are still fitted and the heater circuit is ignition switched. There's plenty of others. You just need to put a test light between earth and a fuse. If you have no power with the key OFF but power with the key ON it's an ignition switched circuit. Stay away from vehicle control circuits.

The Bluetti D+ has the same purpose as the red wire on the Smartpass. It tells the Bluetti (or the Smartpass) when the alternator is charging. With a smart alternator the alternator output is regulated and switched on and off by the ECU so devices like chargers need to look for a voltage increase at the battery to know the alternator is actively charging.

 

[WaterOx]

Are the "Run crank -" fuses (F135, F137, F140) switched based on engine running vs not running? I would think these would be candidates for the D+ if that were the case??

 

[Skydance]

You had me going down a rabbit hole there!
I was looking for a source that is active at alternator voltage (>13v) but not at ignition on (~12v).
If you have the Smartpass the output terminal facing the aux battery qualifies. The Smartpass cuts in at >13.1v which is higher than battery voltage. You could use that as your D+ signal or any of the ignition switched circuits in the interior electrical centre (fuse box).
Candidates are FI13 Spare (compressor) but it has a battery and ignition feed do check first, or the heated seats fuses F121 and FI22. I don't have the heated seats option but the fuses are still fitted and the heater circuit is ignition switched. There's plenty of others. You just need to put a test light between earth and a fuse. If you have no power with the key OFF but power with the key ON it's an ignition switched circuit.

The Bluetti D+ has the same purpose as the red wire on the Smartpass. It tells the Bluetti (or the Smartpass) when the alternator is charging. With a smart alternator the alternator output is regulated and switched on and off by the ECU so devices like chargers need to look for a voltage increase at the battery to know the alternator is actively charging.

View attachment 7922347

You can tell I’m no electrician. You have explained it far better than I have.

I don’t have a twin battery or smart pass but I do have heated seats. So I’ll have a look at this fuse and use a meter. Thank you.

 

[Clark Kent]

Are the "Run crank -" fuses (F135, F137, F140) switched based on engine running vs not running? I would think these would be candidates for the D+ if that were the case??

Quite possible. I don't know enough about their function. I'll test them later today.

 

[Znarfgh]

Sorry for the misunderstanding, I should have explained more clearly.

I have a BLUETTI Charger 2 which requires a D+ signal to tell it to turn on/off, I plan on using a fuse tap to hook up. I’m looking for the nearest fuse to the rear of the vehicle which powers on/off with ignition live only for neatness and avoid running to the front.

Alternatively, I can pull a wire to the 15 amp 12v front or rear fuse outlet in the cockpit fuse outlet.

I used the yellow wire on the 40A circuit for the trigger wire on the DC-DC charger and the +'ve and -'ve for the compressor.