Upgrading the Factory Leisure Battery set up (+ additions)!

[roadtripper]

If you've ever accidentally touched a spanner between battery terminals you'll know it gets very hot, VERY quickly! So fuse as close to the battery terminal to reduce any unprotected wiring.

Seconded. With a LiFePo I hope the BMS would step in and try and break the load but I wouldn't rely on it succeeding or not being damaged in the process.

I've been in the bay when a mechanic dropped a spanner across the exposed terminals of a 24v truck battery set. The current welded the spanner and quickly heated it to the point you couldn't touch it, by the time a lever was found the batteries were boiling and gassing oxygen and hydrogen which led to a fire. Something you don't forget in a hurry.

 

[peteaufc]

Wiring diagram updated to reflect suggested changes and I've ordered the Renogy Shunt. Hopefully all good to go with the install this week now.

 

[peteaufc]

@TallPaul_S @roadtripper

Probably a really daft question, but asking just to be 100% sure. (did see someone say that there is no such thing as a stupid question when it comes to electrics.

The bolt in the attached picture (circled purple) toward front centre under my driver's seat is my chassis ground, right?

Is it OK to add the grounding cable for the inverter to this, along with the existing grounding wires?

 

[roadtripper]

12v ground or 240v ground?

12v ground is ok, it's normal in a T6/6.1 to have a common 12v ground through the van - I would however suggest the ideal for an inverter is direct wire to the battery or main bus bar as you could be talking 100A+ (that's about twice as much current as your house to give a sense of perspective)

Inverters are only intrinsically safe on the 240v side if both outputs are floating, that side shouldn't be near any chassis connections, not even an earth. This is why it's simplest and safest to keep invert 240v and EHU 240v independent.

 

[roadtripper]

If you have no alternative to use the chassis ground bolt remember that the highest current connections need to go the lowest. An inverter connection will normally dwarf anything else so that should be in the bottom.

 

[TallPaul_S]

@TallPaul_S @roadtripper

Probably a really daft question, but asking just to be 100% sure. (did see someone say that there is no such thing as a stupid question when it comes to electrics.

The bolt in the attached picture (circled purple) toward front centre under my driver's seat is my chassis ground, right?

Is it OK to add the grounding cable for the inverter to this, along with the existing grounding wires?

View attachment 247305

If the chassis ground on the Renogy case, then yeah that's fine straight to that chassis ground point.

The actual main negative cable from the terminal needs to go directly to the battery, or shunt, or busbar though, as roadtripper says.

 

[roadtripper]

Your wiring diagram BTW is the ideal arrangement with all your high current flows going through a negative bus bar and then that bar is grounded to the chassis.

If the chassis ground on the Renogy case, then yeah that's fine straight to that chassis ground point.

Disagree here as this then grounds the inverter, if the inverter has a N-PE link you now have non floating inputs relative to the van chassis and a shock risk unless you take action to install RCDs downstream. Much safer to leave floating and independent.

 

[TallPaul_S]

Your wiring diagram BTW is the ideal arrangement with all your high current flows going through a negative bus bar and then that bar is grounded to the chassis.



Disagree here as this then grounds the inverter, if the inverter has a N-PE link you now have non floating inputs relative to the van chassis and a shock risk unless you take action to install RCDs downstream. Much safer to leave floating and independent.

I think the Renogy 'ground' is just a case ground, but I may be wrong.

 

[peteaufc]

Thanks guys - yup following the wiring diagram I put above, so from the inverter my plan is:

Positive DC (20mm2 cable) to combi fuse holder (with 125A mega fuse), then to battery via isolator switch and 200A mega fuse right at the battery terminal.

Negative DC cable (20mm2 cable) to busbar, with shunt then connecting it to the battery.

The Renogy inverter has a ground cable which I was going to wire to the chassis ground point in my photo with a 6mm2 earth cable - @roadtripper are you saying it would be better not to connect this to that point at all and just have the positive and negative DC cables connected as above?

I've attached a pic of the Renogy wiring diagram from their manual.

BTW, after your previous advice, I am keeping 12v and 240v completely separate and won't link it to the inverter when I install my EHU.

 

[roadtripper]

I think the Renogy 'ground' is just a case ground, but I may be wrong.

Either way you only want to connect it in a grounded system with downstream protective devices? And an inherently safe floating output inverter shouldn't be grounded as that makes it unsafe as there is now a return current path.

You want to be either left diagram or right diagram, grounding the inverter puts you in the unsafe middle diagram.



(Diagrams from the highly recommended Victron Wiring Unlimited reference)

I do wish all inverter vendors published a schematic showing their wiring and protective devices arrangements, many do not leading you on a bit of gamble safety wise. I've seen cheap inverters link N-PE to DC 0v input making them the unsafe middle situation with the user not knowing unless they test continuity with a meter.

 

[roadtripper]

The Renogy inverter has a ground cable which I was going to wire to the chassis ground point in my photo with a 6mm2 earth cable - @roadtripper are you saying it would be better not to connect this to that point at all and just have the positive and negative DC cables connected as above?

It depends. If the manual is 100% clear that the out also has RCD protection then that is a safe thing to do.

The correct answer entirely depends on the internal wiring of the inverter and as @DXX says Renogy are not always very clear on that (whereas Clayton has a clear schematic of all the flows and relays for instance)

 

[DXX]

I live in my van for months at a time off grid and last year I found the USB cable to charge my electric toothbrush, the last conundrum. Everything I use can be charged from the vans 12v system. Mains voltage systems and the associated appliances just eat into the living space.

 

[roadtripper]

They might be using the US term "GFCI" instead of "RCD" - I can only find what looks like the US manual which mentions a yellow GFCI indicator.

For a true GFCI/RCD I would expect a test button to use you can prove it's functional, it doesn't seem to have that. It just says restart the inverter if the light is on.

I would suggest a direct question to Renogy support of "are the inverter outputs RCD protected?"

 

[TallPaul_S]

Yeah it is very unclear and the instructions don't help at all, there's barely sentence in the manual regarding the ground connection!

 

[peteaufc]

Battery, DCC50S, shunt, busbar and combi fuse box all fitted in (along with the amp and ducting for Webasto heater). Was tight, but hopefully all good. (Battery isolator switch on the front of the seat base, beside the existing 12v blade fuse box)

I haven't put the inverter in yet, but cabling ready to give it a try too.

I just need to get the seat back on and hookup the airbag/heated seats before I reconnect the starter battery to test the DCDC charger. Everything else seems to be working as it should.

@TallPaul_S the only wire I haven't used from the 100A relay is the ground wire that went into it. Am I correct in saying that it doesn't need to be wired in to the negative busbar?

 

[TallPaul_S]

Battery, DCC50S, shunt, busbar and combi fuse box all fitted in (along with the amp and ducting for Webasto heater). Was tight, but hopefully all good. (Battery isolator switch on the front of the seat base, beside the existing 12v blade fuse box)

I haven't put the inverter in yet, but cabling ready to give it a try too.

I just need to get the seat back on and hookup the airbag/heated seats before I reconnect the starter battery to test the DCDC charger. Everything else seems to be working as it should.

@TallPaul_S the only wire I haven't used from the 100A relay is the ground wire that went into it. Am I correct in saying that it doesn't need to be wired in to the negative busbar?

View attachment 248206

You removed the split charge relay completely, right? If so then yeah that ground wire is surplus to requirements.

Mine was removed completely along with the ground stud under the seat and the std ground stud to battery wire.

 

[peteaufc]

Yup, snipped the split charge relay out. Wired the positive cable from it to the DCC50S, along with the Ignition signal.

I used the ground stud under the drivers seat (pointed out a few posts back in an image) for the cable to the negative busbar.