Felix E Posted March 29, 2004 Share Posted March 29, 2004 OK, I've had it with this feature. The immobiliser has eaten batteries in the past and is now getting through fuses in the battery conditioner at a rate of one every ten days. Can anyone tell me how to switch it off? Hopefully this is not too difficult. Best Regards, Felix. Link to comment Share on other sites More sharing options...
Luke Beaumont Posted March 29, 2004 Share Posted March 29, 2004 Tricky. I was going to suggest battery master switch, but don't these allow a trickle of current through to keep the ECU memory alive & the immobiliser going? If they don't then it would achieve your aim, but the ECU would have to do whatever learning it does from scratch every time. Link to comment Share on other sites More sharing options...
CharlesElliott Posted March 29, 2004 Share Posted March 29, 2004 No, BMS cuts off everything, including the immobiliser and ECU (well, it depends how it's fitted of course, but on my 2004 Academy race car the only thing connected to the positive side of the battery is the BMS). Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
frankyknuckles Posted March 29, 2004 Share Posted March 29, 2004 ECU would have to do whatever learning it does from scratch every time I remove my BMS during the week when my car is sitting in the garage doing nothing, does it matter that the ECU has to re-learn? Build Diary Link to comment Share on other sites More sharing options...
charlie_pank Posted March 29, 2004 Share Posted March 29, 2004 Is it more important to have an fast-learning or knowledgeable ECU? What is knowledge etc... I had a EU3 ECU for a while and always removed master switch when it was left anywhere including home. Never really noticed problems with having to re-learn what kind of engine etc... Besides the first 10 mins is just the warm-up right? Link to comment Share on other sites More sharing options...
Felix E Posted March 29, 2004 Author Share Posted March 29, 2004 Many thanks. Looks like a battery c/off switch is the way to go. Best Regards, Felix. Link to comment Share on other sites More sharing options...
Chris W Posted March 29, 2004 Share Posted March 29, 2004 Felix The immobiliser has eaten batteries in the past and is now getting through fuses in the battery conditioner at a rate of one every ten days The immobiliser only draws about 40mA so it won't drain the battery if you have a conditioner fitted. Also, there is no reason why the immobiliser should blow the conditioner fuse. The fuse is probably about 1 amp, so it's an order of magnitude larger than the immobiliser current. Under what conditions does the fuse blow? BTW the BMS can be wired to allow ONLY the immobiliser and ECU to run with the BMS in the OFF position. Chris 2003 1.8K SV 140hp see it here Link to comment Share on other sites More sharing options...
Nifty Posted March 29, 2004 Share Posted March 29, 2004 My immobiliser was responsible for drawing down my battery when it went faulty. Did not immobilise, light stayed green constantly. Haven't prized it open yet...may do that now..but it may well be carrying more current it faulty. Mine was a Vecta, easy to remove. Not sure of the later ones. Keep off the straight and narrow 😬 Link to comment Share on other sites More sharing options...
inspector71 Posted March 30, 2004 Share Posted March 30, 2004 What sort of immobiliser unit have you got? Older k series engined Caterhams have the Vecta unit (separate and under the dash after market product) armed with a small "key" you insert into the dash. Newer ones immobilise in the Rover MEMS ECU unit (linking with a lucas 5AS immobilise) armed with a remote "blipper" key fob. The Vecta type isolates things like the fuel pump (i think) and can be bypassed. The newer type immobilises in the ECU and cannot be defeated by your local Rover dealer. I had to get a replacement Rover MEMS ECU from Rovers approved ECU refurbisher and request that the unit was not coded. Cost me £200 and i had to give them my existing ECU. regards Peter H Link to comment Share on other sites More sharing options...
Felix E Posted March 30, 2004 Author Share Posted March 30, 2004 Chris thanks for your reply, I not from your other thread this morning that you too have fitted a ciggie lighter socket for a Draper conditioner - snap. The car is a 2003 KSeries with the Rover MEMS immobiliser system and there are two fuses in between the conditioner and the battery, one either side of the ciggie lighter. It is the 5A fuse on the battery side of the lighter that keeps blowing, not the 1A fuse on the conditioner side. This surprises me, how can the bigger fuse blow but not the smaller one? Best Regards, Felix. Link to comment Share on other sites More sharing options...
Chris W Posted March 30, 2004 Share Posted March 30, 2004 Felix I do have a Draper and I do have a ciggy socket on my 7. However I don't use the two together as I fitted a dedicated small battery connector from Maplin for the Draper. My cig socket runs a map light. On your 7, the 5A fuse on the ciggy socket blows but the 1A fuse on the conditioner survives. Sounds impossible doesn't it? But, what I suspect is happening is that as you plug the conditioner ciggy plug into the ciggy socket, the centre pin on the socket is somehow touching the plug's negative connection which is also simultaneously touching the socket's negative outer, thereby putting a direct short across the battery positive and negative and hence the 5A fuse blows. The 5A fuse is doing exactly the job it was designed to do. It shows the importance of putting a fuse in line because, if it were not there, the whole cable behind the dash would receive an enormous current, overheat, melt and the insulation would start to smolder. Smoke, panic etc. Ah, but why does the conditioner's fuse not blow as well or instead? Well, the conditioner has a resistance in its output circuitry which limits the normal charging current to a value of about 100mA or so in order to just keep the battery topped up and to enable it to be left safely connected 24x7. If the output of the conditioner is shorted, the current will be much greater but still limited by the resistance to just under an amp. So, strange as it may seem, the conditoner's output fuse will not blow as its value (1A) is actually higher than the conditioner's short circuit current. The 1A fuse is to protect against a possible internal failure in the conditioner whereby the output current is not limited. If the cig socket fuse keeps blowing, it would suggest there is a misalignment fault on either the socket or the plug. Is the centre pin of the socket screwed in tightly or can it move a bit? I am not a fan of cig sockets in general which is why I fitted a dedicated conditioner plug and socket. In case you're interested, I used Maplin parts JG04E and JG05F @ £3.78 the pair. The Maplin site is here Chris 2003 1.8K SV 140hp see it here Edited by - Chris W on 30 Mar 2004 20:12:32 Link to comment Share on other sites More sharing options...
Frying Pan Posted March 30, 2004 Share Posted March 30, 2004 Chris I followed your advice in an earlier posting and bought the same connectors, with an in-line fuse and wired it direct to the battery. I routed the wire into the cockpit and tie-wrapped the connector underneath the steering column. In this way, I can 'kill' the car using the battery master switch and still easily connect the Draper (although I normally don't bother and plug it in with the car live). Works fine for me Guy See some pictures of the build here. Collected on March 1st! Link to comment Share on other sites More sharing options...
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