Starter/Battery Cable (How Long?)

[Chimpandtonic]

Can someone tell me the length of the starter cable (battery positive to starter motor).

Also it would be helpful to understand where it goes through the bulkhead to the battery?

Many thanks, Dave.

[Chimpandtonic]

The answer is well over 7ft!!!!

Or "Too Fooking Long"



A 2.25 meter run of suspiciously light gauge low amp starter cable that's been on the car for 16 years & suffered thousands of heat cycles from radiant engine heat.

Oh and then there's the earth path back through the chassis; for the poor old starter motor that must be a 15 foot loop!

Hmmmm

And people wonder why these cars suffer from difficulty when restarting hot.

The resistance during a hot start must be enormous

The plan is to make up a new one in some proper marine grade 6awg tinned copper cable & run an additional 6awg earth cable from the battery negative terminal direct to the engine block.

Add my new Odyssey PC1500 battery into the mix and hot start issues should be a distant memory

[carsy]

Never really thought of it like that but yes very good point. Think you`ve found a good solution to the hot start problem many have. So i take it, its going to be an additional earth to the engine as well as the battery to chassis earth.

Where are you getting your new cables made up.

[Chimpandtonic]

carsy said:

Never really thought of it like that but yes very good point. Think you`ve found a good solution to the hot start problem many have. So i take it, its going to be an additional earth to the engine as well as the battery to chassis earth.

Where are you getting your new cables made up.

Funny really when in my opinion the ModWise hot start kit has nothing much to do with fixing the hot start problem.

The Modwise hot start kit is just a relay, it simply masks the fact that the relay in the immobiliser was never quite man enough to to take the amps required to energise the starter solenoid.

The Modwise hot start kit should really be called the immobiliser relay kit.

I believe the true hot start issue is down to having such a long starter cable that was not sufficiently heavy enough to deliver the amps to the starter motor when the cable gets hot.

As we know the longer the cable the more resistance, also the hotter a cable gets the greater the resistance.

When you look at the quality of the cable and how stupidly long it is, it should be no great surprise to any of us that sometimes our cars fail to restart after a quick stop at a petrol station on a hot day.

To answer your question I will be getting some proper 6 awg marine grade tinned cable from a chandler, the type of stuff used on a fishing trawler.

The current earth (battery earth terminal to chassis) lead will stay.

I will just add an additional earth lead in the same 6 awg gauge cable direct from the negative battery terminal to the engine block.

My recipe to a reliable starting TVR is like this:

1) Bypass the Meta immobiliser on the ignition circuit

2) Add a suitably amp rated relay to protect the ignition switch

3) Upgrade the feed to the starter solenoid with a higher amp rated wire

4) Ditch the weedy 16 year old 7ft starter cable with some decent 6 awg marine grade tinned cable

5) Fit an additional earth from the battery negative terminal to the engine block

6) Fit my new Odyssey PC1500 battery

It can only help what is currently a very marginal original set up from TVR.

[EGB]

My following suggestions for re-threading the new cables through the bulkhead may now be old hat. I presume you have found a way. We would all like to know.

Suggest. If renewing the old TVR battery cables for new cables, connect the cut off ends of the battery cables with the ends of the new cables. Need a strong non slip join here (strong finger overlap soldered join),smoothed off with neat tight winds of insulating tape. Ensure no kinks or shoulders. Then gently and firmly pull through the bulkhead with a screwing poking motion !!!

The same procedure can also perhaps be best done with some strong thin cable wire (bowden or sheathed washing line cable) joined onto the old cable ends and pulled through to form a thread lead. This can then be used to pull the new cable through. Again ensure there is a strong no kink smooth join.

[Chimpandtonic]

Hmmmm, getting the new cable in, hadn't thought about that













Only kidding folks

I went for the old Indian rope trick

1) Disconnect battery

2) Remove starter cable from starter motor

3) Cut various cable ties securing starter cable to main square section chassis rail & engine bay wiring loom

4) Attach thin nylon 8ft rope to starter motor end of cable using strong gaffer/duct tape

5) Return to passenger footwell and gently pull the starter cable through the grommet in the transmission tunnel

6) When the rope appears remove from the starter cable leaving the rope in place

When the time comes to fit my new starter cable I will simply tape the starter motor end to my rope and gently pull the rope from under the car.

Because my rope follows the original path of the old feeble starter cable my new cable will end up taking the exact same rout as I gently pull it through.

A few cable ties to secure my new cable and it's job jobbed.

Then off to the Indian takeaway for a chicken tika massala.

See, it's the Indian rope trick

Edited by Chimpandtonic on Saturday 3rd March 21:06

[Chimpandtonic]

Simon says said:

Or you could do none of this stuff and have a car that as spun over like a top for the past 6 years (even when stinking hot) with a 530A cranking batt and a Bosch starter that looks like its been fitted since day dot Of course i could say i am lucky but seeing as i don't believe in luck

Just like the immobiliser relay you could argue it's just a matter of time.

Honestly, just look at the length of that cable.

Show it to any experienced automotive electrician and they will tell you it's a bad design & ultimately a problem waiting to happen.

In my case I don't really suffer the hot start problem unless things are pushed to the extreme heat wise.

However, I take an "improve & re-engineer before I break down" approach to maintaining my TVR.

After all it's not like our cars have a fantastic reputation for reliability, which is a shame in my opinion.

The fundamental design of the car is excellent, the execution however left a little bit of scope for improvement.

But you leave it as it is mate, & the very best of luck to you

[EGB]

Chimpandtonic said:

Hmmmm, getting the new cable in, hadn't thought about that

Well done. Chimp and Griff minds, think alike.











Only kidding folks

I went for the old Indian rope trick

1) Disconnect battery

2) Remove starter cable from starter motor

3) Cut various cable ties securing starter cable to main square section chassis rail & engine bay wiring loom

4) Attach thin nylon 8ft rope to starter motor end of cable using strong gaffer/duct tape

5) Return to passenger footwell and gently pull the starter cable through the grommet in the transmission tunnel

6) When the rope appears remove from the starter cable leaving the rope in place

When the time comes to fit my new starter cable I will simply tape the starter motor end to my rope and gently pull the rope from under the car.

Because my rope follows the original path of the old feeble starter cable my new cable will end up taking the exact same rout as I gently pull it through.

A few cable ties to secure my new cable and it's job jobbed.

Then off to the Indian takeaway for a chicken tika massala.

See, it's the Indian rope trick

Edited by Chimpandtonic on Saturday 3rd March 21:06

[Chimpandtonic]

EGB said:

Chimpandtonic said:

Hmmmm, getting the new cable in, hadn't thought about that

Well done. Chimp and Griff minds, think alike.











Only kidding folks

I went for the old Indian rope trick

1) Disconnect battery

2) Remove starter cable from starter motor

3) Cut various cable ties securing starter cable to main square section chassis rail & engine bay wiring loom

4) Attach thin nylon 8ft rope to starter motor end of cable using strong gaffer/duct tape

5) Return to passenger footwell and gently pull the starter cable through the grommet in the transmission tunnel

6) When the rope appears remove from the starter cable leaving the rope in place

When the time comes to fit my new starter cable I will simply tape the starter motor end to my rope and gently pull the rope from under the car.

Because my rope follows the original path of the old feeble starter cable my new cable will end up taking the exact same rout as I gently pull it through.

A few cable ties to secure my new cable and it's job jobbed.

Then off to the Indian takeaway for a chicken tika massala.

See, it's the Indian rope trick

Edited by Chimpandtonic on Saturday 3rd March 21:06

I was going to say that.

Hang on a minute?????

[Chimpandtonic]

Simon says said:

ell I don't have the Meta so that's a start my car come with the Foxguard originally, that was replaced years ago with a Cat 1 system and the starter trigger relay mod I did a few years ago as preventive maintenance (Vauxhall ign switch was not exactly reliable on the sourced from models) Previous me fitting the MegaSquirt I had an earth cable rethink hence lots of extra earth/cables straps fitted.

Edited by Simon says on Sunday 4th March 09:12

MegaSquirt + lots of extra earth/cables straps.

Nice

If it wasn't for the cost, an ECU change & junking the distributor would be top of my list Simon.

[Goaty Bill]

Not to disparage your effort, because it makes perfect sense to me, but I had CB fit the 'hot start kit' on mine a few years back and it killed the problem. As I recall, the main issue was undersized relays (that has started to melt in my case IIRC).

You are absolutely correct I think, the hot start issue is a time bomb that will eventually get you if you leave it long enough. It certainly seems to be age/mileage related, and one thing is for sure, it doesn't improve once it starts happening.

One experience of having to wait 15-20 minutes at the petrol pump after filling up was more than enough for me.

[Chimpandtonic]

Goaty Bill said:

Not to disparage your effort, because it makes perfect sense to me, but I had CB fit the 'hot start kit' on mine a few years back and it killed the problem. As I recall, the main issue was undersized relays (that has started to melt in my case IIRC).

You are absolutely correct I think, the hot start issue is a time bomb that will eventually get you if you leave it long enough. It certainly seems to be age/mileage related, and one thing is for sure, it doesn't improve once it starts happening.

One experience of having to wait 15-20 minutes at the petrol pump after filling up was more than enough for me.

Mate there are two issues with the starter wiring on these cars and they seem to get confused.

ISSUE 1 IMMOBILISER RELAY:

This gives the following symptom - Disengage the immobiliser, turn the key to the start position and nothing, not even the faintest click from the solenoid

This is an immobiliser fault or more specifically the failure of a relay inside the Meta unit.

You can prove this (like I did) by putting a test meter on the starter solenoid feed wire with the immobiliser disengaged and the key in the start position.

In my case there was a solid feed from the ignition switch, but zero current exiting the immobiliser on the starter solenoid side.

The problem had to be inside the Meta immobiliser unit.

The hot start kit is just a relay that masks the fact that the immobiliser relay TVR originally used to energise the starter motor solenoid is inadequate.

This immobiliser relay often starts to show it's on the way out when the car gets hot, that's because the resistance in the entire system goes up dramatically when it gets hot.

To solve my problem permanently I bypassed Meta immobiliser on the ignition circuit only and added a relay back in to protect the ignition switch, this completely solved my immobiliser related starting issues.


ISSUE 2 STARTER CABLE & EARTH:

This gives the following symptom - Disengage the immobiliser and turn the key to the start position, the car fails to start but you hear a faint click from the starter solenoid

This typically happens on a hot restart, say after filling up with fuel on a hot day.

The solution in my opinion is to upgrade the feeble and very long starter cable with better quality higher amperage battery cable.

Further improvements can be obtained by upgrading the earth path, a short lead from the battery negative terminal direct to the engine block should be all it needs.


So the way I see it there are two issues that are getting confused & mixed up.

I have totally solved the immobiliser relay one but am still in the middle of sorting the inadequate starter/earth cable issue.

With both issues sorted and a decent battery in the mix it should be 100% sorted.

Well that's the theory anyway

[Goaty Bill]

Yeah, I saw the size (and price ) of that battery you are putting in.

Maybe you should choose 'ChimpandChampagne' next

[ChimpanChampagne]

Goaty Bill said:

Yeah, I saw the size (and price ) of that battery you are putting in.

Maybe you should choose 'ChimpandChampagne' next

I like that

[SILICONEKID340HP]

What size cable are you useing ?

[ChimpanChampagne]

SILICONEKID340HP said:

What size cable are you useing ?

Don't know yet Daz, I want to pay a visit to the nice folks at Danka batteries round the corner from me to see what they suggest.

I will get them to advise me & make up the cables.

Tempted to go with 70mm2 tinned marine grade stuff, but I need to see how flexible it is.

At the end of the day, bigger is better.

How about some of this



Seriously though, this may help.



The cable on the left is 50mm2 rated at 345 amps & similar to what TVR used.

The cable on the right is the 70mm2 stuff I hope to use, rated at well over 400 amps it should be just the job if I can squeeze it in

Edited by ChimpanChampagne on Sunday 4th March 18:10

[ChimpanChampagne]

Looks like the 70mm2 cable is going to be overkill, it's tricky to get hold of & very inflexible so routing it would be difficult.

In the end I went for 50mm2, the difference in size from the original cable is significant (similar to the above photo).

I found some good quality tinned cable at a local electrical engineer who builds & re-winds industrial motors, it's flexible enough to route (just about) and is a massive step up from my weedy original starter lead.

In fact the electrical engineer took one look at my original starter lead and laughed, he identified it as 35mm2 and then condemned it as highly inadequate given the application & it's significant length.

He then gave me a lesson on voltage drop and amperage lost over a given length, apparently there is an equation you can use.

Double the length of the cable divided by the amps drawn by the motor & some other stuff that went over my head

Anyway, apparently it all supports my gut feeling that the starter lead is too long, or at least not really man enough for it's length.

The other thing I learnt is that decent tinned 50mm2 battery cable is not cheap

I can see now why our local travelling community has been borrowing all the train power cables of late.

Edited by ChimpanChampagne on Wednesday 7th March 16:37

[David Beer]

The hot start mod is only on the solenoid circuit, not the starter wiring. No matter how heavy the starter cable is, it will not effect the solenoid engaging. The relay is placed so the TVR wiring only has to turn the relay on, it can do that! The range rover cable to the solenoid is fine.

[ChimpanChampagne]

David Beer said:

The hot start mod is only on the solenoid circuit, not the starter wiring. No matter how heavy the starter cable is, it will not effect the solenoid engaging. The relay is placed so the TVR wiring only has to turn the relay on, it can do that! The range rover cable to the solenoid is fine.

I understand that perfectly David.

I'm not talking about solenoid function, the point of the post is to highlight the potential failings of a rather light weight 16 year old seven & a half foot long starter cable cable.

It wont matter how good the feed is to the solenoid, if the starter itself doesn't receive enough amps you've got problems.

I cant think of many cars with a starter cable over 7ft long, or even half that long come to that.

And for very good reason.

It has to be a weakness that can be improved with some better cable and an additional earth from the negative battery terminal direct to the block.

[Alexdaredevilz]

ChimpanChampagne said:

I cant think of many cars with a starter cable over 7ft long, or even half that long come to that.

Bmw's volvo's merc's are all over 10 ft (battery in boot)