Starter/Battery Cable (How Long?)

[carsy]

Dave, are you using 50mm cable on the earth side as well?

The reason i ask is that i like your idea of a further earth strap to the engine block. But looking on eaby all the ready made earth cables seem to be only 16mm.

[Pink_Floyd]

Alexdaredevilz said:

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

But looking at the size of the cable in BMWs it must be 50 or 70mm in size, much much bigger than the size of the chim ones.

[Alexdaredevilz]

Pink_Floyd said:

But looking at the size of the cable in BMWs it must be 50 or 70mm in size, much much bigger than the size of the chim ones.

I can measure a few tomorrow if you like, any particular make?

[Alexdaredevilz]

Simon says said:

Pink_Floyd said:

Alexdaredevilz said:

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

But looking at the size of the cable in BMWs it must be 50 or 70mm in size, much much bigger than the size of the chim ones.

They certainly are way i see it if the stock cable was such an issue then poeple like Daz, Meatball, Haircut mike would all be suffering with there 15 year old+ cars with there high compression double vale springed motors already just my cents worth but i dont blame you for beefing it up a _bit_

Ahem!

[Simon says]

Sorry Alex, I have ETA now

[Alexdaredevilz]

Simon says said:

Sorry Alex, I have ETA now

That's better!

[ChimpanChampagne]

carsy said:

Dave, are you using 50mm cable on the earth side as well?

The reason i ask is that i like your idea of a further earth strap to the engine block. But looking on eaby all the ready made earth cables seem to be only 16mm.

Yep, the earth will be the same 50mm² cable & as short as possible, I'm aiming for the existing earth on the left hand side of the block.

Carsy, like you say I wouldn't bother with a 16mm² earth cable, it would have an OD of 8.3mm and feel like a bit of string.

My new cables are 50mm² (OD 13.3mm), the originals are 35 mm²(OD 11.8mm), it doesn't sound much until you hold both cables in your hand.

My new 50mm² cable is rated at over 100 amps more than the original 35 mm² stuff, and that's if the original 35 mm² cable was new.

Which it most definitely isn't!

In fact my old skinny cable is proper crispy in places, it has sections with hard spots that are noticeably more rigid than others, in these sections it makes that nasty crunchy sound when you flex it.

I doubt it was delivering anywhere near the 240 Amps a new 35 mm² is rated at, even when cold.

As we all know resistance increases (up to a point) in direct proportion to the increase in temperature.

As the starter motor gets hotter & hotter it's internal resistance will increase & the resistance in my already crispy starter cable will also increase.

It all adds up, and with such a long run of cable that's only rated at 240 Amps there is significant scope for improvement, especially when you consider it's highly likely the starter motor draws 300+ amps.

The other thing that would significantly help would be to shorten the cable.

Sadly I cant see an obvious way of reducing the length of the cable other than converting the car to left hand drive thus relocating the battery to where the pedal box is now

So a bigger newer cable & a better earth it is; lets see what difference decent new cable rated at 345 amps makes during a hot start.

My thinking is it should help a lot.

[Bassfiend]

ChimpanChampagne said:

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.

I'm suprised it's even 35sqmm ... Looking at my positive terminal on the battery on mine it looks more like 25sqmm!

I was considering going a slightly different route when relocating my battery to the boot and instead of running a very heavy cable which is harder to route I was going to run a couple of lengths of lighter cable (25sqmm) ...

...I was a little concerned when I read your early post about using #6 guage cable as that's only 13sqmm.

Phil

[ChimpanChampagne]

Bassfiend said:

I'm suprised it's even 35sqmm ... Looking at my positive terminal on the battery on mine it looks more like 25sqmm!

I was considering going a slightly different route when relocating my battery to the boot and instead of running a very heavy cable which is harder to route I was going to run a couple of lengths of lighter cable (25sqmm) ...

...I was a little concerned when I read your early post about using #6 guage cable as that's only 13sqmm.

Phil

A double run is a great idea Phil, & yes I soon worked out #6 in American Wire Gauge would be feeble.

If you follow the thread you will see I went from 6 AWG up to 70mm², then back down to 50mm² - just thinking aloud as I posted each step, my cable knowledge improving as I went along.

Actually "0" AWG is more like the 50mm² I eventually settled on.

Moving on - I picked up the cables yesterday, the electrical engineer only held black stock which I didn't see as an issue.

To completely remove any potential confusion for a future owner/mechanic I simply wrapped the ends in red tape & fitted the red terminal cover.

Although the photos don't really demonstrate the difference between the cable diameter that well, I can assure you it's significant when you hold both cables in your hand.







I really don't think I could have gone any heavier than 50mm² without making routing them a headache, even at 50mm² it's going to be fun

I'm very happy with the work from the electrical engineer, the upgraded starter cable & additional earth should be a big improvement on the originals.


And finally a bit of extra heat protection where the starter lead runs closest to the o/s exhaust manlyfold.





Fitting tomorrow

Edited by ChimpanChampagne on Friday 9th March 11:06

[Bassfiend]

Oh I'm pretty accustomed to heavy guage cabling ... I spent a significant part of my "yoof" terminating and routing cables with cores the thickness of my thumb for mega car audio installs. You wait till you start trying to neatly route 1/0 and 2/0 AWG cables - I used to have two alternators on my old 200SX, one for the car electrics and one for the HiFi.

Phil

[Goaty Bill]

Bassfiend said:

Oh I'm pretty accustomed to heavy guage cabling ... I spent a significant part of my "yoof" terminating and routing cables with cores the thickness of my thumb for mega car audio installs. You wait till you start trying to neatly route 1/0 and 2/0 AWG cables - I used to have two alternators on my old 200SX, one for the car electrics and one for the HiFi.

Phil

You have got to be the only TVR owner who would actively try to drown the engine music with the noise from his stereo!

[Bassfiend]

LOL - bloody impossible since I swapped my standard exhaust with ChimV8's sleeved one ...

http://www.youtube.com/watch?v=SthbMswkef4

Phil

[EGB]

Bassfiend said:

LOL - bloody impossible since I swapped my standard exhaust with ChimV8's sleeved one ...

http://www.youtube.com/watch?v=SthbMswkef4

Phil

AMAZING, AMAZING !! Drowns the Church bells, frighenes off cats and dogs. kills budgies. old ladies loose their b...ocs, drowns cop sirens, and a lot more.

[ChimpanChampagne]

UPDATE

Fittted my new heavy duty starter cable and additional earth last weekend.

I can't claim it was an easy job getting the cables through the grommet & routed nicely even with my helper rope in place.

After much struggling it all fitted in there very well, new Odyssey PC1500 battery in place and topped off with a BatteryBrain.

http://www.pistonheads.com/xforums/topic.asp?h=0&a...

All that remained was to arrange a nice hot start test, which came sooner that I expected after a run into London left me idling in horrific Finchley Rd traffic on Wednesday evening.

Turned the engine off after idling for quite a while only to see the line of cars up ahead had started pull away, typical

A perfect hot start test, this is just the scenario where the car would typically refuse to crank until it had cooled for 5-10 minutes.

Typically this would also generate much honking from the cars behind as they could see their only chance to move slipping away as the Muppet in front frantically tried to start his TVR.

Grrrrrrrr

So how did this all play out with the new cables?

Turn the key & pray.........

And she starts first time! in fact it cranks like never before

Success, hot start problem completely eliminated, just as I had predicted that thin guage 7.5ft starter cable was clearly the issue.

[carsy]

Good result Dave. Touch wood ive never had the hot start issue but this will be yet another upgrade i will do at some point in the future. A good sensible upgrade in my opinion.

[Goaty Bill]

Bassfiend said:

LOL - bloody impossible since I swapped my standard exhaust with ChimV8's sleeved one ...

http://www.youtube.com/watch?v=SthbMswkef4

Phil

Try harder Phil, I just know you have it in you.
Just look at the size of that boot (not to mention all the space behind the seat), and think of just how big the pre-amp, amp and woofer could be

[Bassfiend]

Goaty Bill said:

Bassfiend said:

LOL - bloody impossible since I swapped my standard exhaust with ChimV8's sleeved one ...

http://www.youtube.com/watch?v=SthbMswkef4

Phil

Try harder Phil, I just know you have it in you.
Just look at the size of that boot (not to mention all the space behind the seat), and think of just how big the pre-amp, amp and woofer could be

LOL - don't tempt me GB ... I did once build a sub box with a pair of 21" drivers!

(I will add quietly that it sounded ste and it was just that the guy wanting it built had seen these 21" drivers and *HAD* to have them but hey ... not my money!)

My current (forgive the pun given the subject of this thread) is I'm trying to build a good mains regenerator ... my domestic mains is incredibly noisy and makes my HiFi hum so I have two options.

1) Get two 1kW motors and a fairly heavy flywheel, drive one motor from the mains and have that drive the flywheel and the driveshaft of the second motor and then take the nice stable generated mains feed from the second motors terminals and drive teh HiFi from that.

2) Build a solid state mains regenerator which would *EFFECTIVELY* be a 1,000 watt power amplifier that is capable of driving an obscenely low impedance load with a stable 50Hz sinewave and then you simply power the HiFi from what you would class as the speaker terminals of the amp ... there's a 300 watt one in a cupboard at work that is a back burner personal project for one of the guys at work and I'm trying to get him motivated into attacking it again.

Phil

[roseytvr]

Sorry to resurect this David (CoD/CoG) but can you remember what length of cable you eventually settled on for the Starter live and earth? A good read by the way!! Thanks

[ChimpOnGas]

roseytvr said:

Sorry to resurect this David (CoD/CoG) but can you remember what length of cable you eventually settled on for the Starter live and earth? A good read by the way!! Thanks

Ian I responded to your PM immediately last night.

I see you have an NHS email address which will have some strong spam filters & junk mail settings.

Check your email again, and your junk, I have just re-sent what I sent you yesterday.

If it's still going to junk mail & auto deleting you will need to provide me with an alternative address that accepts emails from Hotmail.

Dave.

[ChimpOnGas]

ChimpOnGas said:

roseytvr said:

Sorry to resurect this David (CoD/CoG) but can you remember what length of cable you eventually settled on for the Starter live and earth? A good read by the way!! Thanks

Ian I responded to your PM immediately last night.

I see you have an NHS email address which will have some strong spam filters & junk mail settings.

Check your email again, and your junk, I have just re-sent what I sent you yesterday.

If it's still going to junk mail & auto deleting you will need to provide me with an alternative address that accepts emails from Hotmail.

Dave.

The answer to your question:

"What length of cable you eventually settled on for the Starter?"

Is: 2.2 meters

But I strongly recommend ripping out your old cable & measuring it, this way you can be 100% sure it will fit your car.

I take no responsibility if you get a cable made up at 2.2 meters only to find it's 10-15mm too short.

A TVR is a handmade vehicle and measurements like this can vary from car to car.

Take the old one out first & measure it, I expect you'll get the same 2.2 meter figure as I did, but it's certainly not guaranteed.