A little help. Please

Sounds like this would best be left to a competent auto electrician as poor car accessory wiring is often the cause of fires.

Hi Dave, Good point, but it can be protected with inline fuses, it's the modern car has so much shit put into them.

Regards .

Micky.

Whilst that's true it makes no difference as regards connecting accessories to the car electrical system if you know what you're doing. As regards 'messing the brain' it would be a poorly designed vehicle that couldn't cope with a flat battery or battery change.

Thing that worries me is that you say you have no knowledge of car electrics - and the wiring and connector types that are suitable are likely very different to the ones you're possibly familiar with - and you're doing this as a presumably paid for job rather than on your own car.

Of course correct fusing is important - but then you've still got to consider the wiring before the fuse.

The following random thoughts might help:

If you connect any electrical system to a car battery, it will discharge if the engine isn't running. You need to calculate the load you are adding, and make a judgement as to whether the vehicle's system can cope.

If the vehicles are "real" taxis, there may well be provision for this; lots of areas of the country already have taxi CCTV. It might be worth asking the manufacturers.

Most modern vehicles can cope with losing the battery feed; there will be a procedure in the owner's handbook for the relearning process caused by the loss of some ECU settings. This usually involves driving in a varied manner, and sometimes an extended period ticking over.

If the vehicles are under warranty, your work may well invalidate that.

Most modern vehicles use multi-plexed electrics. These may cause problems if you need signals from other parts of the vehicle to connect to the CCTV.

If you only want a 12v ignition-switched feed, and the electrical load of what you are adding is very small (less than 1A), it might be possible to use the ignition-switched radio feed.

If you need a permanent non-switched feed, it might be possible to use the feed to the cigarette lighter. If you do this, the users *will* leave things on and flatten the battery! Some vehicles only have this feed enabled when the ignition switch is in the first position or above.

The solution you use will be vehicle-dependent; there won't be a "one size fits all" answer.

HTH

Chris

Hi Chris, I think I will leave it alone, it sounds to deep.

Thanks Man.

Kind Regards.

Micky

Which cars does this apply to? Neither of mine - all that's lost is the radio memory. Even after reasonably extended battery disconnection. Surely the engine ECU has to learn any changes in sensor inputs pretty quickly to be of any use?

Pretty much anything with an ECU.

Things like auto window often also need resetting.

The ECU has a base setting where the thing will run. In order for new optimum values to be learnt, a short period of varied driving is needed.

Current Fords specify a five mile drive. My Focus idles too fast during this time, but drivability is otherwise fairly normal. Some VAG vehicles need longer to relearn, including idling until the fan cuts in.

Chris

Chris Whelan gurgled happily, sounding much like they were saying:

That's a bit of an exaggeration, since every petrol car built for at least a decade and a half, and many for a big chunk longer than that - together with every diesel for damn near as long - has had ECUs for injection and/or ignition. I'd suggest that learning ECUs were fairly uncommon until relatively recently.

Adaptive auto-boxes can often need an extended period to "re-learn" your driving style.

Some Saabs benefit from a periodic wipe of the ECU memories followed by an "adaptation run" - read "thraping the living arse off it" - if you want to get the maximum boost possible.

That would certainly contradict my (mainly Ford and VAG) experience.

Certainly it was more necessary with my '92 Escort than with the Focus.

When I use the A/C in the focus, the changes to the mapping reduce power, and also make it run slightly jerkily on the over-run. This continues for perhaps a day or two after I've turned the A/C off.

I am so familiar with the car after nearly ten years that if someone else drives it, the next time I use it I could tell whether or not the A/C has been used.

Chris

Both mine have ECUs. One of them several.

Crap design, then, if user options are lost with power.

As I said it should react to sensor inputs quickly - or it's not much use.

Good grief. Idle speed should be constantly monitored and adjusted instantly. Like during a cold start.

Seems to me those designers are either cost cutting or don't know their job. Non volatile memory is hardly new.

[...]

It wouldn't necessarily be advisable to store trim settings.

Imagine the situation if a sensor had been slowly failing until it went out of range. You replace the sensor, (having disconnected the battery first). If you then start up and the settings based on the old sensor were used, drivability could well be worse than the base settings.

Chris

You turn it off?

Why would you want to do that?

I'd run a relay off the switched feed for the radio to power the CCTV system and so that the CCTV cuts off and draws no power when the ignition is off (obviously with the live feed to the relay would need to be fused, you can buy combined relay and fuse holders), and wire everything with non insulated crimp terminals (ie, the kind you slide a boot over after crimping, rather than the plastic coated s**te), using a proper crimp tool. I've found Vehicle Wiring Products to be very good (they're on the web, use google), and if you ring them, they'll be able to tell you what tools to use with what terminals etc. Attach everything everywhere with cable ties - stick on cable tie holders can be handy.

I would expect as a CCTV engineer you will already have a basic understanding of wiring and electronics. A car shouldn't present any unusual problems compared with any other DC system, barring vibration and the potential for wires to repeatedly flex / chafe (ie, door openings, through the engine / cabin bulkhead, but usually there are a load of grommets to route through). The only way you will knacker things, IME is by getting polarities wrong or routing wires where the insulation will fail and zapping sensitive components. Obviously you would be advised to use car spec wire and ensure that everything is heavy enough to cope with the power being pulled by the CCTV.

Usually the worst that will happen through removing the battery is that the radio will need its security code re-entering - check the driver has this before you start...

One thing to note is that you may well be able to buy a readymade loom designed for something like a car audio amplifier or rally spotlights.

See above ;-)

Chris

You call yourself an engineer! What a joke, you can't even spell "sourced". Do yourself a favour and get someone who knows what they are doing to fit it. If you don't even know a taxi has a battery in it you have a long way to go. I wouldn't go putting your company name on messages when you appear thick and unable to do anything without asking in a newsgroup. You might find people avoid your company.

That's true, but the early stuff could only be rewritten 10's of times before it died.

I know this because I had a custom printer driver which set a laser printer up differently depending which computer was printing to it - worked fine for about a week then killed the laser. Which was a very expensive thing to do at the time. Oops

Thanks for the help Ian, why is there alwwwats noe.

CAN YOU SPELL WANKER.

mICKY

fORGOT TO MENTION YOUR WEIF CASEHED THE CECK, NCIE LOBw BOJ . she said it was nice to have an a veraAeg dcik so what is yours? again spell WANKER

In message , Adrian writes

You'd suggest wrong then. Learning ECU's have been around for at least

20 years that I know of on mass market cars like the Rover 800 series and Ford Sierra IIRC so not exactly uncommon.