Electrics setup advice

[Coatesy69]

Hi all.
I've just bought a 2018 T6 Kombi with twin sliders.
I want to install a basic setup with the leisure battery under the passenger seat and the heater pipe under the driver seat.
The seats are factory swivels.
I know I will need to lay the battery on its side.
If you would be so kind to have a look at the diagram I've botched together and let me know if this setup would work.
I'm unsure of the correct wire size and fuse size.
I emailed Fogstar regarding the battery and whether I would need a battery shunt as the battery has a built in monitoring system.
They said the Victron shunts are more accurate than their own system so it was up to me if I wanted one.

Thanks for looking,

Regards,

Graham

 

[TallPaul_S]

Fogstar are correct, a shunt will be more accurate than the batteries own BMS - the fogstar batteries can't read draws under 1a. I have a constant 0.4/0.5a draw as I have a Cerbo GX and a 4g router powered on.

This is my battery BMS and Victron smart shunt reading at the same time - the shunt is the correct reading:




As for your wiring:

No need for an isolator between the starter and DC-DC. If you want the option of turning off the DC-DC manually, use the remote port and a switch wired to it.

Fuse the SB feed at both ends, it's not a must but it makes sense for the long cable run and potentially 2x power sources.

If you can, swap the Orion TR for the newer Orion XS. It runs cooler, is smaller and more efficient.

Run 16mm² on all the cables from SB to the Orion and both outputs on the Orion.

Add a main system fuse next to the positive battery terminal, and (optional) a main isolator switch just after this.

 

[Coatesy69]

Thanks for replying.
You say to turn the DC DC charger off, use a remote switch.
Would I need to turn this off for any reason.
You also say to run a main fuse next to the positive battery terminal, is this the leisure battery you are referring to.
If a fuse did blow for any reason, is there a way to find which one it is or would I have to check each one in turn.
Would this setup work for a couple of days off grid camping.
Also, would the heater drain the battery too much if left on for a few hours.

I'm a complete novice at wiring so excuse me if I ask stupid questions.

Regards,

Graham

 

[roadtripper]

You say to turn the DC DC charger off, use a remote switch.
Would I need to turn this off for any reason.

Because a DC-DC charger can put a high 30A+ load on the starter battery as soon as the ignition is on some people like to have the option.

For instance if you know the starter battery is likely to be low as the vans not moved for a fortnight, or if you want to put the ignition on to listen to the radio while parked up.

 

[roadtripper]

You also say to run a main fuse next to the positive battery terminal, is this the leisure battery you are referring to.
If a fuse did blow for any reason, is there a way to find which one it is or would I have to check each one in turn.

Yes, fuses protect the cable from overheating in the event of a fault so they should be sized to the cable and as close as possible to the source of the voltage.

If you fuse the supply cable from the van at both ends you would normally fuse the remote and harder to get to end by the starter battery slightly higher so any general fault will blow the lower one by your leisure system. The factory wiring for this uses a 100A at the starter and 80A in the van as an example.

 

[roadtripper]

Would this setup work for a couple of days off grid camping.
Also, would the heater drain the battery too much if left on for a few hours.

Likely if the diagram covers all your loads.

The way to work it out is to take the capacity of your battery (105Ah) and work out how many hours a day you are running your loads to get a power budget. For instance if your TV draws 2.8 amps then 2 hours will use 2.8 x 2 = 5.6Ah from the battery.

A battery isn't a fuel tank you empty and refill, draining a battery dead causes damage. For lithium aim to only discharge regularly to 20% so your usable capacity will be about 80Ah.

For your compressor fridge it won't run all the time and most people find using a figure of a third of the draw works for this sort of estimation - so assuming it runs for 20 mins every hour.

 

[roadtripper]

If you are fitting main bus bars wire the heater positive feed to the bus bar. I know the instructions normally say to wire direct but this is because they need permanent power and must not go through a switch panel - wiring to your main bus bar will be fine and much more organised.

 

[Coatesy69]

Thanks for all your detailed replies. It's a lot to take in.
I've amended the diagram to I think is what you mean. Could you please let me know if this is the case.
You say that the DC DC charger puts a high load on the starter battery when the ignition is on.
Does this mean every time the stop start works, it puts the strain on each time or just on initial engine start up.

Regards,

Graham

 

[roadtripper]

You still need the battery master fuse on the 16mm2 feed to the busbar.

Don't worry about the load during stop/start, it's intelligent if there is a high load it wont stop (or will restart) just the same as if you have the Aircon on or a heated window.

I would check the fuse and cable requirement in the Orion XS manual - 60A seems a little low for a 50A charger.

 

[TallPaul_S]

60-70a is the fuse recommended by Victron for the Orion 50a.

And don't worry about the strain when starting the engine, there's a delay before it starts charging, it'll wait for a minute or so before it starts pulling any amps from the SB - if you're using engine shutdown detection then you can set this delay.

Would this setup work for a couple of days off grid camping.
Also, would the heater drain the battery too much if left on for a few hours.

Diesel heaters use the most when they're getting up to temperature, once running they don't use that much power.

I would say you'd be able to get 2x days off grid with that set up, remembering that if it's really warm and the fridge is working hard then you won't be using the heater, and if you've got the heater on then the fridge won't be working as hard!

 

[roadtripper]

60-70a is the fuse recommended by Victron for the Orion 50a.

In which case I'd fuse at 70A at the starter battery end and 60A at the other

 

[Coatesy69]

Thanks for all this.
Just one more question.
So I will need a 70a fuse at the starter battery,
60a fuse at the Orion,
60a fuse at the Orion going to the busbar and a 60a fuse at the leisure battery going to to the busbar.

Regards,

Graham