Battery cable size

sipep

sipep

Senior Member
T6 Guru
Hi all

I have already purchased a 50a dc to dc charger and 100ah lithium battery from renogy.

I am taking the seats out this weekend, to remove the bulk head plates. I thought I might run the cabling from the battery.

I don't intend to do all my own electrics but I could place to cabling ready.. I watched this YouTube video, and he is suggesting 16mm for the battery. Any ideas what length I would need for under the driver seat?

Screenshot_20230912-092444.png
 
Renogy say 6 AWG for up to 5m which is 16mm2 so that looks fine.

This split charge kit details the cable lengths for T5 to under passenger seat, and I think crossing over to driver would be another 0.5mm

If you are not doing the electrics yourself maybe best plan is to put the cable in with a reasonable level of slack either end and then the electrician can do the final routing, trimming and termination with crimps.

If you are taking the advantage to cable while you have the floor out also consider what other wiring you might need - if you are using a DC-DC you are probably better putting in an engine run signal if you have things in bits anyway, but that might need more work to get up into the dash. I don't think the Renogy has the ability to fall back to voltage sensing a smart alternator (which I assume you have if you are going DC-DC?)
 
The engine run signal is just a cable to the fuse box? I think this kit says it consists of 3 meters of red cable. Perhaps I purchase 3 meters of red and black 16mm?

£32 seems a little high but is this the right thing..
MKGT Set of Red & Black Flexible PVC Cable Wire 110A Amp 16mm2 Battery/Starter/Welding (Red + Black Set, 3 Metres) https://amzn.eu/d/bPcfrdf
 
You won't need as much black as you'll be using vehicle ground and anyway the electrician can make those up to suit, they will just need to be local to the ground under the seats that will be accessible. I'd just leave the black to them.

If you want to jink across to the drivers you'll need to run to the passenger seat area and then across so you'll need more. See any number of pictures of stripped out vans around here! I'd play safe and grab 4m, yes 3.5 will likely do it but if it's short and you have to get everything out again...

Engine run is just a signal level line so any reasonable cable will be fine. I think the Renogy might come with some so double check your box but they say 18-16AWG (so 0.75-1.5mm2)
 
Yep, that one.

The twin core one is for voltage sensing to account for voltage drop over the high current charging cables. If you are putting the charger and battery under the same base probably not worth fitting as the drop will be low. If you need the charger under one seat and the battery under the other (space or cooling requirements) then worth fitting if they've supplied them.
 
Thank you very much for all the support.. can you suggest a red 16mm from Amazon please (prime delivery) 4m
 
I would buy your cable from a known cable supplier rather than Amazon, somewhere like RS or a specialist like 12 Volt Planet.

There are far too many dodgy copper coated aluminium cables around the sell it cheap shops and I wouldn't want 50amps flowing through that under my backside...
 
16mm from vehicle battery through bulkhead along to centre console the under rubber mat through to seat base is just over 3m. You'll need an ANL fusexat each end of this run to be on the safe side. Then 16mm for the other positive and negative runs to the Renogy DC DC charger. For convenience, safety sake and the option to charge at over 25A install isolator switches on the Aux positive feed from van battery, solar positive feed and also on the leisure battery feed.

I bought some 16mm from Amazon and some from 12V Planet. I would say the 12V Planet cable was better quality, and a bit more flexible which can be useful.
 
Thank you.


I might take a risk on this one from Amazon, if it comes and it's good I can crack on this weekend... otherwise I will send back. Any thoughts? Link below. Id have to get 5m for £22

Red & Black Battery/Starter/Welding Flexible PVC Cable Wire 110/170/345 Amp 16mm 25mm 35mm by MKGT® (16mm² Red, 5 Meters) https://amzn.eu/d/4stAiA0


Or


Autowiring Automotive Hi-Flex 110 Amp 16mm² Battery/Starter/Inverter/Welding PVC Cable Wire (Black, 4 Metre) https://amzn.eu/d/4Yt6IzK
 
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Opinion differs on isolators, as they add further joints and connections that can heat at 50 amps.

You can still isolate by removing fuses as, logically, you're protecting the same things.

Whatever you choose it's worth making sure your means of isolation is accessible and ideally labelled so others know where it is. If you got with isolation via fuse make sure you have the means to unbolt them, maybe clip or strap a dedicated hex/nut driver nearby.

As an aside unless you have really good ventilation you probably don't want to run the Renogy at 50 amps, many down rate it to 30 amps in the settings.
 
roadtripper said:
Opinion differs on isolators, as they add further joints and connections that can heat at 50 amps.

You can still isolate by removing fuses as, logically, you're protecting the same things.

Whatever you choose it's worth making sure your means of isolation is accessible and ideally labelled so others know where it is. If you got with isolation via fuse make sure you have the means to unbolt them, maybe clip or strap a dedicated hex/nut driver nearby.

As an aside unless you have really good ventilation you probably don't want to run the Renogy at 50 amps, many down rate it to 30 amps in the settings.
Click to expand...
Valid point mate ... you weigh up your options. Easily access to quickly isolate was my need, especially after reading about another forum member and the story of their DC DC charger burning out. For my install removing a fuse means socket set to remove seat base and fuse link.

Spot on ... my Renogy is set to 30A max charge.
 
Thank you everyone for the support, the reason I went for the renogy is I will probably get their invertor (1000) and a flexi solar panel.. I like that I can plug a 230 hookup into the invertor
 
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First cable delivered... let's be honest.. ordered at about 8-9 pm last night and here.before income downstairs.. thats pretty effective..

Anyway.. says 4 meters on packet. Says 16m2 but is it?

PXL_20230916_081920936.jpg

PXL_20230916_081933270.MP.jpg

PXL_20230916_082009141.jpg
 
Also it's the conductive area not including the insulation.

Should be just a touch over 4.5mm diameter.
 
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