Tony_C Posted March 15, 2021 Report Share Posted March 15, 2021 Hello all, anyone ever seen / fitted one of these to your TR, any merit in fitting to original +ve earth side-screen car? Appreciate better, more complex and therefore more expensive options are available... However, as I’ve got this to hand, I’m tempted to try.. would those of you in the know also fit the (10amp) inline fuse...always carrying a few spares in glove box an or door pocket? Thanks in anticipation Tony Quote Link to post Share on other sites
RobH Posted March 15, 2021 Report Share Posted March 15, 2021 Yes I've had one of those on a car Tony and it works just fine as a quick means of isolating the battery. Also a modicum of security if you unscrew the screw-down part entirely and take it with you when you leave the car. Slightly easier than taking the rotor arm. The fuse is only necessary if you have some powered device which gets upset by complete loss of volts - any attempt to start the car with the connection removed will blow the fuse. Quote Link to post Share on other sites
ed_h Posted March 15, 2021 Report Share Posted March 15, 2021 Yes, These can be put on either positive or negative side of the battery, but it's better to put it on whichever side is connected to the body (usually negative these days). Ed Quote Link to post Share on other sites
Waldi Posted March 15, 2021 Report Share Posted March 15, 2021 Hi Tony, if you also install it to avoid draining the battery, you should not install a fuse, since then the battery will still be drained. I am planning to install a switch that I can reach from inside the cabinet (through the bulkhead) but this is so much easier to do. So is on my list of things to do... Cheers, Waldi Quote Link to post Share on other sites
WWT338J Posted March 15, 2021 Report Share Posted March 15, 2021 The negative side is probably safer because the isolator device has exposed metalwork. The battery voltage is low so the risk is not elective shock but the potential risk of something else in the engine bay making inadvertent contact with the isolator and causing a short (such as the battery hold down clamp). It's also worth remembering that with time some oxidation of the isolator contacts may occur. If you try and start the engine the starter motor will be sluggish as if the battery is flat. The cure is to unscrew the isolator and then tighten it up again. David Quote Link to post Share on other sites
Tony_C Posted March 15, 2021 Author Report Share Posted March 15, 2021 Thanks Rob, Ed, and yes Waldi, that was also my original idea (I got scared last year when setting up the carbs and ignition, draining the battery when the starter motor jammed in - first time I’ve ever had that in all the years of old cars). This really should only take’5 mins’ to fit (and I won’t fit the fuse) basis any time I’m fiddling the bonnet will be up anyway and no need to find place to poke cable through bulkheads. Much appreciated all Quote Link to post Share on other sites
Tony_C Posted March 15, 2021 Author Report Share Posted March 15, 2021 9 minutes ago, WWT338J said: The negative side is probably safer because the isolator device has exposed metalwork. The battery voltage is low so the risk is not elective shock but the potential risk of something else in the engine bay making inadvertent contact with the isolator and causing a short (such as the battery hold down clamp). It's also worth remembering that with time some oxidation of the isolator contacts may occur. If you try and start the engine the starter motor will be sluggish as if the battery is flat. The cure is to unscrew the isolator and then tighten it up again. David Thanks David, all good and valid points Quote Link to post Share on other sites
ntc Posted March 15, 2021 Report Share Posted March 15, 2021 Ever wondered why the key is red ? It should be on the positive lead Quote Link to post Share on other sites
Tony_C Posted March 15, 2021 Author Report Share Posted March 15, 2021 2 minutes ago, ntc said: Ever wondered why the key is red ? It should be on the positive lead That’s what I had fitted on my 71 built, negative earth Elan Sprint.... However, if you look carefully at the photo, it’s blue and only (properly) fits on the negative battery lug.. Quote Link to post Share on other sites
RobH Posted March 15, 2021 Report Share Posted March 15, 2021 9 minutes ago, ntc said: Ever wondered why the key is red ? It should be on the positive lead It should be in the earth lead for the reason David outlined above. Far too exposed to be on the live side, whichever polarity that might be. Quote Link to post Share on other sites
ntc Posted March 15, 2021 Report Share Posted March 15, 2021 I can have seen to many of that type fail and always remove them Quote Link to post Share on other sites
Tony_C Posted March 15, 2021 Author Report Share Posted March 15, 2021 Fail in what way? Quote Link to post Share on other sites
ntc Posted March 15, 2021 Report Share Posted March 15, 2021 9 minutes ago, Tony_C said: Fail in what way? Poor contact and early erosion you really do get what you pay for . Quote Link to post Share on other sites
peter clarke Posted March 15, 2021 Report Share Posted March 15, 2021 A big plus of fitting in the bulkhead is ease of operation (every time i park my car) and speed of operation. With smoke eascaping from under the dash do not panic....just find the key ...get out of the car...open the hood....isolate the battery. Quote Link to post Share on other sites
ed_h Posted March 15, 2021 Report Share Posted March 15, 2021 (edited) One thing to realize about the common terminal mounted battery isolators under discussion is that despite the misleading color of the metal, these are not made of brass, but pot metal with a brass finish. There may be exceptions, but ive never seen one. Ed Edited March 15, 2021 by ed_h Quote Link to post Share on other sites
Geko Posted March 16, 2021 Report Share Posted March 16, 2021 They don't last long: the plastic knob and insulator disintegrate due to wear&tear, heat/cold. A gizmo that should be treated as such. Stay away Quote Link to post Share on other sites
Steves_TR6 Posted March 16, 2021 Report Share Posted March 16, 2021 26 minutes ago, Geko said: They don't last long: the plastic knob and insulator disintegrate due to wear&tear, heat/cold. A gizmo that should be treated as such. Stay away That was my experience too. Quote Link to post Share on other sites
DaveR Posted March 16, 2021 Report Share Posted March 16, 2021 I have used at least one for over 20 years without any problems. I agree fit in the negative lead and only use a fuse if you have to maintain a supply to electronic equipment you may have fitted. But remember if you do have electronic equipment that needs a constant supply it will drain the battery over time. Dave Quote Link to post Share on other sites
stuart Posted March 16, 2021 Report Share Posted March 16, 2021 10 hours ago, peter clarke said: A big plus of fitting in the bulkhead is ease of operation (every time i park my car) and speed of operation. With smoke eascaping from under the dash do not panic....just find the key ...get out of the car...open the hood....isolate the battery. On a sidescreen car thats not a quick option. by the time you locate the "T" key and get the bonnet open and propped it`ll be too late. Stuart. Quote Link to post Share on other sites
Lebro Posted March 16, 2021 Report Share Posted March 16, 2021 As fitted to mine access under glove box Bob. Quote Link to post Share on other sites
ianc Posted March 16, 2021 Report Share Posted March 16, 2021 Using Vaseline on the terminals and the screw thread of this Dis-Car-Nect device will assist in preventing corrosion. And one should apply a smear of Vaseline to the terminals of the battery for the same reason. Ian Cornish Quote Link to post Share on other sites
ntc Posted March 16, 2021 Report Share Posted March 16, 2021 Wait till you do a battery drop test though one and watch it self destruct Quote Link to post Share on other sites
Lebro Posted March 16, 2021 Report Share Posted March 16, 2021 ? Quote Link to post Share on other sites
RobH Posted March 16, 2021 Report Share Posted March 16, 2021 ?? Quote Link to post Share on other sites
Hamish Posted March 16, 2021 Report Share Posted March 16, 2021 22 minutes ago, ntc said: Wait till you do a battery drop test though one and watch it self destruct I had to look that one up. not sure it’ll work with our car batteries tho Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.