Itineo SB740 electrical upgrade

E

Eno

Joined
Oct 25, 2024
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Itineo SB740
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Hi everyone,

Looking for advice, and sharing my experience as I go about upgrading our electrics.

Rough plan is;
Lithium, 200 or 300Ah across two batteries. Use existing trays in the engine bay. Existing wiring is in place, looks likely will need to upgrade. Marked 033 and 035. No other markings.

Solar, 400-800w depending what I can fit in the roof. We've got a fair bit of space. Should I over size the wattage on roof if space, better in poor weather but wasted otherwise?, but limited to a 50 amp mppt?

Confirm existing vehicle to leisure system, upgrade if needed.

Existing Mains battery charger, 20 amps. Swap to lithium profile.

Inverter, unsure at this stage.

Any initial thoughts or obvious gaps?
 
So maybe overkill but gone for 2x 150Ah of lithium, the bigger ones didn't fit in the current mounts.
And a 50 amp b2b with mppt.
Looking at options but tempted by the following.

Eurener Nexa 475W TOPCon Mono Panel Black

475W all black mono panel with 20 year module warranty and 30 year performance warranty.
midsummerwholesale.co.uk midsummerwholesale.co.uk
Should just about fit on some standard fastenol rail.
 
Gone for a couple of 250w panels, 760x1500. They should fit nicely down one side end to end. So 500w installed with space for atleast another 500w on the other side in the future if needed.

Regards mounting, my thinking is aero front mount, then rail (glued) and clamp for mid and rear. Is this sufficient? Should 1500 panel really be supported mid panel as well? The spec sheet wasn't helpful.
 
A few more questions that hopefully someone can help with.
Currently got leisure battery mounts in the engine bay, but they are 2.5m apart and then another 2m to where I could mount the electrics, and potential future inverter.
It feels like I would be better off moving the whole lot closer together if I can figure out where or spend a fortune on cabling?
Maybe the LPG locker, but the missus has her eyes on it for other storage...

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Thoughts on using this space for mounting electrics?

Under 10cm won't interfere with the bed. Reasonable airflow, similar to a cupboard i expect.
Good access to conduit routes.
A bit far from batteries but manageable.
Good access.

Once fitted, cover with thin door. Airflow in bottom and out top.



20250705_212710(1).webp
 
Funnily enough I was working on an electrics upgrade on our SB740.

The final plan was to locate the 2 x 280Ah Fogstar Lithium batteries in the Gas Locker (have moved to an underslung tank so locker is empty), we would also locate the Victron 3000/12 Charger/ Inverter wired into the 240v circuit. Then a Victron Orion 50A B2B, Victron smartshunt and MPPT Solar controller for my 2 x 120W NDS panels also in the locker.
Worked out a cable run for an HDMI & USB cable to go up to either a Victron GX Touch or a Raspberry Pi running Venus OS, with the display going next to the existing control panel.
Got some good advice from the team at Offgrid Power Solutions from RogerIvy
Sadly got made redundant so couldn't go ahead at the time and still refilling the coffers at the moment
 
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I'm sorry to hear that Genear
The gas locker is still on the option list, though the other half is very keen to have it as storage and BBQ locker, with a fold out table. There is a gas quick connect point still in locker following the underslung tank work. We could also still feed gas back in here in extremis (look away Gas regs ppl).
It feels like wasting space up in the engine bay, but a gas locker install would be quite neat and tidy, nice short cable runs...

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Calcs suggest 1500 unsupported on 30mm alu angle might be pushing it, so going for ~600mm spans. Supports at 0 (Join), 600 and 1200. Leave 300 overhang at each end. Still not sure if I should or need to fit an aero mount at the front? Probably not needed but would look better.

Pic showing the panels just fitting in blue, and space for future panels.

1752009302321.webp
 
just a example of what you can do with smaller panels to make highly efficient use of the awkward gaps between skylights etc. Its more expensive and fiddly of course.
This is my 7M long A class . 16 x 50w panels = 800watts. 4S4P configuration as I am 48v.
The perspective foreshortens it, its used only the front half of the roof.

Untitled-1.webp
 
Eno said:
Thoughts on using this space for mounting electrics?

Under 10cm won't interfere with the bed. Reasonable airflow, similar to a cupboard i expect.
Good access to conduit routes.
A bit far from batteries but manageable.
Good access.

Once fitted, cover with thin door. Airflow in bottom and out top.



View attachment 1082196
Click to expand...
hard to tell where you are in the vehicle, is that the bed over the front seats , so you are up against the roof at the front? would not be first choice for any substantial components but probably ok for smaller ones.
 
Yes, it's over the front bed.
I may look under the drivers seat too.
 
ian27 said:
just a example of what you can do with smaller panels to make highly efficient use of the awkward gaps between skylights etc. Its more expensive and fiddly of course.
This is my 7M long A class . 16 x 50w panels = 800watts. 4S4P configuration as I am 48v.
The perspective foreshortens it, its used only the front half of the roof.

View attachment 1086658
Click to expand...
That's a lot of solar. Looks like still got space for more!

ian27 How have you fixed the panels, looks like some aero profile and then just metal angle? Glued to roof and bolted/screwed to panels?

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Eno said:
That's a lot of solar. Looks like still got space for more!

ian27 How have you fixed the panels, looks like some aero profile and then just metal angle? Glued to roof and bolted/screwed to panels?
Click to expand...
yep. it was a deliberate choice to fill the front as much as possible using small panels to "tile"
I could fit another 1000W or so at the back (with larger panels as less stuff in the way) if I chose to. at the moment I see no need, and I prefer to have the back unused for roof rails (windsurf board on roof) and possible future aircon.

the fixing is all done using 50x50x3mm aluminium angle. following more or less the methods of this
I saw no need to have the alloy angle along the whole length of the panels. I have 2x 100mm lengths on each side of panels that are by themselves (on a 600mm panel side) and 200mm lengths across the join of adjacent panels. The alloy angle is bolted to each panel using 14mm M5 torx head button flange machine screws drilled through the vertical part of the panel frame. Flange head for load spreading, torx for "avoid head stripping as much as poss even at awkard angles". 1x washer and nyloc nut on the outside. 3 bolts per 100mm. Careful not to torque them too much as the frame is thin aluminium ( I tried using my bike torque wrench which goes down to 1nm, but even that was too much).
the base of the alloy angle is stuck to the roof using CT1, with 2mm tile spacers in there to give the required thickness of bonding. there's no mechanical fixing to the roof.

the white plastic angled mounts at the front are the ones that are widely sold, I didn't want to use those as the main panel mounting system, they are there purely to help with airflow when driving they don't hold the panels to the roof. you can see one segment is missing as I ended up with two slightly different types and one of them doesn't fit properly, I need to get another or take a saw to it.
 
Eno said:
Yes, it's over the front bed.
I may look under the drivers seat too.
Click to expand...
under driver and passenger seats are the usual places for this kind of thing. you will find the seat unbolts and you can remove it completely (there are guides to this on here somewhere)
 
Thanks for all the guidance and input. With the gas finished it's time to pick up the electrics again.
Picked up some domestic solar fixings going cheap on Facebook marketplace. These have been glued to the roof and then panels clamped to them.
Should enable me to remove them easily when needed.
I've moved them forward from the original plan, used the old tv aerial hole for cable gland. Leaves the rear free for future things...



20250818_192744.webp
 
An eventful day.
Solar panels up, wired in, cable ties to tidy up the wiring. Just need one hole to finish.
I'll be able to do this in situ, no need to lug the panel off the roof...
Didn't fall off the ladder but did slip with drill and nicked the back of the panel.
:swear:
20250820_093618.webp
I've got it down and inspected it. I think it's OK. A Blob of silicone to be safe.

On the plus side,
2x lithium successfully in the engine bay, bus bars in the electrical bay, b2b under the drivers seat, and almost all working.
20250820_185739.webp

It's not reading the starter battery voltage accurately, probably because the battery is a chassis return only. So hopefully a good sized cable from the negative to starter battery will fix this and stop the alternator charging cutting out.
D+ signal is coming from the existing nord control box, so I think it's working, does mean it needs to be on.
Lenny HB does this make sense?
 
Yes, your B2B needs the D+ signal to work (however contrived)

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First time I've seen this thread, yes it does make sense what you are a saying about the earth's.

I don't think having Lithium's in the engine compartment is a good idea, one thing Lithiums don't like is high temperature & it can get very hot under the bonnet after the engine has stopped.
 
Too late now. Specs note it may stop working if temp gets too high, have to see how it goes. 🫣

Running cable to the vehicle battery negative has fixed the alternator charging.
 
Eno said:
Too late now. Specs note it may stop working if temp gets too high, have to see how it goes. 🫣

Running cable to the vehicle battery negative has fixed the alternator charging.
Click to expand...
High temperature is the one thing that really shortens the life of lithium batteries, that's why EV cars have cooling systems for the batteries.

Even though it may be a PIA I would move them.
 
Thanks Lenny HB
I agree, it wasn't something I had really considered.
Given its less than a week now till we head off, we're going to live with it. Will keep an eye on it.
Hopefully be fine, if we get just this trip out of then lesson learnt.
It's been added to the list of things to consider for v2 if/when that happens.
 

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