Lotus Elan

Fuses again

PostPost by: Robbie693 » Thu Jul 01, 2010 9:35 am

Hello,

I know this was discussed amidst another thread recently but I thought I'd start a new one to get some opinions.

I was at Paul Matty yesterday and asked about what ratings the fuses in the dash (late S/130) should be. They agreed it was unclear from the manual and said that they fit 35A fuses in all positions..

Does this sound a bit high?

Also, could someone explain to me - when a fuse has a continuous and a blow rating, what's the difference to one with just a continuous rating? And are they marked with both?

Thanks

Robbie
User avatar
Robbie693
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1615
Joined: 08 Oct 2003
Location: UK

PostPost by: steve.thomas » Thu Jul 01, 2010 9:46 am

Hi Robbie,
I also have a late 130/S with the 4 fuses in the dash. Mine are all 35amp except the 2nd from right when viewed from driver seat (not sure if that is referred to as number 2 or 3) - this one is 50amp ! From the wiring diagram this seems to protect stop lights, reverse lights, fog lamps and battery gauge so it sounds too high to me, but having recently acquired the car I haven't found if there is some reason for this......
Cheers
Steve
steve.thomas
Second Gear
Second Gear
 
Posts: 107
Joined: 24 Jun 2010
Location: Gironde, France

PostPost by: robertverhey » Thu Jul 01, 2010 10:59 am

Clearly for those times when you hit the brakes while reversing in the fog, while checking the battery gauge
robertverhey
Fourth Gear
Fourth Gear
 
Posts: 781
Joined: 20 Feb 2007
Location: Sydney Australia

PostPost by: billwill » Thu Jul 01, 2010 12:40 pm

A continuous rating of a fuse is the maximum current it can take continuously, It can exceed that a bit but the fuse will deteriorate over time.

The blow rating would be the current which will melt it quickly.
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
billwill
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 4721
Joined: 19 Apr 2008
Location: London UK

PostPost by: neilsjuke » Thu Jul 01, 2010 2:59 pm

Pull the fuse and check current with a dc ammeter / multimeter with every thing on and go for the next fuse up do take the 50 amp out way to high ,A white 35 amp was rated as 17 amp continuous.
Neil
neilsjuke
Third Gear
Third Gear
 
Posts: 369
Joined: 29 Oct 2007
Location: Kent

PostPost by: gerrym » Thu Jul 01, 2010 4:35 pm

I agree with Neil, that 50A fuse must be way too high.

Do you have any idea how thick a wire has to be to carry 50A with over heating and possibly starting a fire?

Regards
gerrym
Fourth Gear
Fourth Gear
 
Posts: 894
Joined: 25 Jun 2006
Location: Aberdeen Scotland

PostPost by: terryp » Thu Jul 01, 2010 7:12 pm

I have 4 x 25amps!

Surely someone should know what they should be!

Terry
terryp
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1660
Joined: 29 Nov 2007

PostPost by: Galwaylotus » Thu Jul 01, 2010 8:10 pm

The purpose of a fuse is to protect the wiring downstream. If you can determine the wire gauge and look up the amp rating, you're well on the way to determining which fuse to use.
Mechanical Engineer, happily retired!

'67 S3 SE FHC

See Facebook page: W J Barry Photography

Put your money where your mouse is, click on "Support LotusElan.net" below.
User avatar
Galwaylotus
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1357
Joined: 01 May 2006
Location: Galway, Ireland

PostPost by: Robbie693 » Fri Jul 02, 2010 9:09 am

Thanks everyone,

Yes 50A sounds scary!

So, I'll try as Neil suggests and take the fuse out and measure the current. Just have to figure out which accessories run through which fuse..!

Once I've found out the current draw, should I be using continuous fuses or continuous/blow fuses?

Cheers

Robbbie
User avatar
Robbie693
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1615
Joined: 08 Oct 2003
Location: UK

PostPost by: neilsjuke » Fri Jul 02, 2010 9:52 am

Turn every thing on with the engine running pull the fuse and put the ammeter on and go for the next nearest car glass fuse are rated at the max blow

Continuous...........blow or fusing what you will have marked on the fuses
1A ..................= fuse 2A
2.5A................= fuse 5A
5A...................= fuse 10A
7.5..................= fuse 15A
12.5................= fuse 25A
17.5................= fuse 35A

50A WOULD BE OK FOR ABOUT THREE ELANS TOTAL current drain
Neil
neilsjuke
Third Gear
Third Gear
 
Posts: 369
Joined: 29 Oct 2007
Location: Kent

PostPost by: Robbie693 » Fri Jul 02, 2010 1:39 pm

Thanks Neil, very helpful.

Would the reading be the same with the fuses in and just measuring across the contacts?

Robbie
User avatar
Robbie693
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1615
Joined: 08 Oct 2003
Location: UK

PostPost by: alan71 » Fri Jul 02, 2010 2:53 pm

No, you need to take the fuse out to measure the current.

Alan.
alan71
Second Gear
Second Gear
 
Posts: 222
Joined: 15 Jul 2007
Location: UK

PostPost by: billwill » Fri Jul 02, 2010 2:53 pm

Robbie693 wrote:Thanks Neil, very helpful.

Would the reading be the same with the fuses in and just measuring across the contacts?

Robbie


Er, no.

To measure the current, your amp meter takes the place of the fuse, so that ALL the current flows through the meter.


Just putting two prods across the fuse, will not have the right effect, most current will flow through the fuse and only an indeterminate (*) portion through the meter, so it will show an incorrect reading.

(*) depends on the resistance of the fuse and the resistance of the meter, neither of which you will know accurately.
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
billwill
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 4721
Joined: 19 Apr 2008
Location: London UK

PostPost by: neilsjuke » Fri Jul 02, 2010 2:54 pm

No the current need to flow through the meter
Neil
neilsjuke
Third Gear
Third Gear
 
Posts: 369
Joined: 29 Oct 2007
Location: Kent

PostPost by: neilsjuke » Fri Jul 02, 2010 3:00 pm

So thats a no three times then
:lol:
neilsjuke
Third Gear
Third Gear
 
Posts: 369
Joined: 29 Oct 2007
Location: Kent
Next

Total Online:

Users browsing this forum: No registered users and 7 guests