Battery cable size.

[twin wheel camper]

Is 40mm battery cable heavy enough for a di? Mine need remade because of a bad connection at the battery terminal it’s getting hot and turning over slowly, if I flex the cable when someone is trying to start it turns much quicker so it’s time to make up new cables
So will 40mm battery cable be ok or should I go higher? It’s not a hard engine to start normally but these cold mornings it’s started to really struggle.

[bambi mk 1]

Put two 40mm cables each end of the battery

[twin wheel camper]

Is that really needed? Surly 40mm would be ok? If bigger is needed I’d probably put a single larger cable on, maybe 70mm but that seems a bit of a overkill

[jamie182]

bmw e46 or e36 battery lead. go to a scrap yard and get one its very high quarterly and its inside the car so will be like new condition. the e46 320d has 70mm2 i think and the 330D touring(estate) will have 120mm2 cable it is completely overkill but will 100% be enough for a Di.
cause the cable is around 4M long there will be loads left over if you ever wanted to do twin battery's.
70mm2 is what i would use.

[twin wheel camper]

Good idea that with the battery in the boot the cable would be good.
But unless the car is completely gutted it would be a pain to get it removed with the interior still in the car.
The cable isn’t that expensive on eBay so will most likely just buy a couple of lengths and make some up.

[jamie182]

It's not to bad to get out of an e46 just disconnects on the bulkhead just above the pedals few trims and you can just pull it into the boot maybe 20 minutes, my local scrap yard normally chargers me a tenner (I have been going there since I was a kid ) maybe a bit more at a normal scrap yards
I have got the ebay cable in the past difference is night and day ebay will more than likely be Chinese rubbish. I have made jumpleads in the past the bmw battery cables seem so work much better. You can feel it, Chinese cable of the same size doesnt feel as heavy, lower grade of copper I would imagine.

[DodgeRover]

I used super flexible welding cable about 75 mm sq - cheaper than battery cable too

[blizard]

DodgeRover is right, welding cable is the best option
Why?
Welding cable is usually made of pure copper, a lot of starting cable has a lot of alu in it, witch will increase resistance.
You never have too thick cable, too small can get very hot (resistance)

[Jim Archer]

Solder the terminals.

Hold the the flat of the terminal in a vice, slosh some Bakers Flux on at both ends with a small paint brush, warm with a torch til the flux starts reacting and the shite starts coming out, more flux, so it cools and pulls it into the wire voids, heat til the solder will run into the cable at the far end, keep feeding it in til you see it wick out the other end of terminal. Let it cool, then dunk in boiling water til muck stops coming out, then dunk in WD-40/Plusgas etc.

Fit cables to van, and hope engine mounts are good as starter motor now tries to spin motor upsidedown.

Jim