I don't think Vic is under any illusion that a motorhome builder would have a clue about extra low voltage electrics. The bus we have in at the moment says they didn't have a clue about electrickical at all Believe it or not, Jayco would probably be the pick of the bunch these days regarding their electrical work, still needs a few ideas revised, but better than the average. Plug and play leads with 20 amp cable probably helps a lot, although some of the piggy back joins remind me of the old cartoon about the housewife with all the double adaptors plugged into each other and a chair propping them up with smoke curling up out of the wires going into the house
T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
If we have data, let’s look at data. If all we have are opinions, let’s go with mine. – Jim Barksdale, former Netscape CEO
First trip might be down to your joint so ya can cast your peepers over the blokes elecki work in lieu of a pub lunch for you two
Three possible outcomes:
It's all wrong.
It's ok.
It's better than what I could do.
Sometimes it's better not to ask.
Was the blank bit in between to add more possibilities You know the last one of the three you listed would never happen
Hmm , well passes the first look done right test ...
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T1 Terry
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Merk 4x4 VF30 519 CDI 2020 LWB V6TD 3 ltr 6 wheeler ,Tenorite Grey ... yep, it's not white ...!!!
No idea what that forest of red cables is all about and I'm assuming they are relying on the single cable resetable circuit breakers to provide all the protection. They have at least split the main cables between the two batteries so they won't died after a few weeks/mths, you would be surprised by how many of these multiple 12v battery set ups come in, only weeks or mths old and one battery is already damaged beyond recovery.
There doesn't appear to be a main fuse or battery disconnect of any type, they must be relying on the internal BMS in each battery for low voltage disconnect, but no idea how you would disconnect the battery for maintenance or repair ..... or if everything went pear-shaped and you needed to cut the battery supply to the short circuit. Those 5 cables running from the battery positive have no protection between the battery and the fuse holders, a short in that section would not be good .....
T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
If we have data, let’s look at data. If all we have are opinions, let’s go with mine. – Jim Barksdale, former Netscape CEO
BruceS wrote: ↑Sat Mar 25, 2023 1:55 pm
That's not how I would hook up those two batteries?
But Treence gave it the nod FFS ...!!! ...
So HOW should it be done then ...???
vik...
I think Bruce might have been condensing my previous post but he is on the money there.
If you plan to take it off road over rough country where bouncing and swaying are likely to be involved, those multiple cables with get enough movement to loosen the clamping nuts and start the high resistance joint and the heat generating sequence that will lead to those multiple cables coming from the battery to melt into one mega size conductor and finally find a negative connection, things will get even more exciting from there .....
In our "show and tell" collection, we have lots of examples of what happens when a clamping device loses it's clamping effect, generation that high resistance joint and mega heat, enough to melt fuse boxes with muck metal fuse holders into a puddle and weld 10mm stainless nuts onto 10mm threaded studs and melt to cable insulation a long way up the cable from the terminal .....
T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
If we have data, let’s look at data. If all we have are opinions, let’s go with mine. – Jim Barksdale, former Netscape CEO
BruceS wrote: ↑Mon Mar 27, 2023 12:28 pm
I was meaning the way both takeoff leads are off the same battery with the second one feeding into the first.
Might just be the way I'm seeing it?
Looked like the main negative lead did run parallel with the linking cable to the second battery, maybe I'm not seeing it properly ...... In any case, the two leads should be the same length and go to a common point, with the negative that would be the shunt, with the positive, that would be the mega fuse.
Those single contact resettable circuit beakers suffer from either heat build up that causes premature tripping, or welding the contacts closed so they don't trip at all.
T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
If we have data, let’s look at data. If all we have are opinions, let’s go with mine. – Jim Barksdale, former Netscape CEO
Believe it or not, Jayco would probably be the pick of the bunch these days regarding their electrical work, still needs a few ideas revised, but better than the average. Plug and play leads with 20 amp cable probably helps a lot, although some of the piggy back joins remind me of the old cartoon about the housewife with all the double adaptors plugged into each other and a chair propping them up with smoke curling up out of the wires going into the house 
...
