New Battery Cables

Today’s job was to replace the battery cables, I was suffering from the infamous hot starting issues that these cars can have from the undersized battery cables. They are tiny for the amount of amps they carry from the battery in the passenger footwell to the starter motor in the engine bay. I was also getting lazy cranking despite having replaced the starter motor previously.

Additionally, I have taken the opportunity to replace the alternator cable and earth straps and relocate the mega fuse TVR decided to locate under the engine and is prone to cracking with vibration giving no indication that it has failed until your battery is flat.

First things first, I took the drivers side front wheel off to replace the engine to chassis battery lead. You can see here that the cable is deteriorated and tiny. I will be replacing the cables with 50mm2 cable and crimped terminals. I bought a cheap crimp tool from Amazon, professional grade not required here, as this will probably be the only time I ever use it.

I didn’t have any suitable size heat shrink tubing unfortunately, so I resorted to electrical tape, although looking at the old cable, electrical tape is an upgrade on what was there before. I cleaned up the chassis grounding point as it was rusty, coated it in copper grease, fitted a new nut and washer and that was that done.

Next was the starter and alternator wiring. I had decided to give the starter and alternator their own dedicated wire here, again in 50mm2. I removed everything I needed to get to the alternator cable. I found some burned wiring here, seemingly at some point someone had connected to part of the loom with a scotchlock which had melted and shorted out. I couldn’t see what these cables were supposed to be used for as nothing appeared disconnected. I soldered a couple of fly leads onto them and routed them up to the back of the alternator in case I came across what they were for in the future.

I removed the old alternator wire that went down the front of the engine block and to the mega fuse, I didn’t want to leave anything behind for someone to find in the future and wonder what it was for. Then removed the cable from there to the starter motor and then back to the battery box. I fitted a new starter cable from the battery to the starter and rebuilt the alternator end.

Next I made up a cable to go from the alternator to the battery, may seem a little overkill, but I saw no harm in it. I refitted the mega fuse holder on top of the drivers side rocker cover inline with the cable so checking or replacing this fuse doesn’t mean having to crawl underneath the car anymore, an absolutely absurd design piece from TVR. The rest of the cable goes through the bulkhead to meet up with the battery and starter motor feed too.

Next was replacing the negative cable that goes from the battery to the chassis, this is located just underneath the dashboard on top of the transmission tunnel. Again making up a 50mm2 cable here replacing the original cable. Interestingly all of the battery cables that I removed had “16mm2 welding cable” printed on the sheathing, strange.

I bought some new heavy duty battery clamps with bolts on the end for the cable connections as the original clamps were soldered onto the cables, and there was little point trying to remove them as they wouldn’t fit the new larger cables anyway. I connected the new starter motor and alternator cables along with the fuse box supply cable and the feed for the amplifier. It was at this point I realised that whoever fitted the amplifier hadn’t fused the supply cable, so I fitted an inline blade fuse holder here.

All back together and it was time to test and go home, another job done, the car is turning over at a proper speed now, most pleased.