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michael
24-01-04, 17:38
I've just spent an hour or so fitting my new Philips bulbs (cheers Gaz) and drying out the inside of the headlamp on my UK Spec auto in an attempt to save 120 for a while.

Like a goon I had the lights on while doing the drying so that I could see what I was doing (outside house light was right in front of the car but for some reason I didn't bother with that) - anyway after some successful drying out (kitchen roll rolled up and inserted through the hole for the main beam bulb) I realised I'd been out longer than expected and when I tried to put the car window up it was very slow.

I realised the errors of my ways and luckily the car started and I've taken it out for a bit of a blast to get some power in the battery.

Anyway my near escape (I hope) raised a few questions that I was hoping for help with, having never had a flat battery I'm a bit of a novice so excuse me if this is really noddy!

1) From a flat(ish) battery how far would you need to drive to get enough charge in it to ensure it didn't go flat if left for 24 hours?

2) If the worst happened and you got a flat battery miles from home can you jump start an automatic car and if so how?

Timwildman
24-01-04, 17:43
You need to be careful, jump starting with leads from another cars battery. I think some people say it might damage ECU's wipe RLTC memory etc. Using a booster battery like the AA use is the best. But bump starting is a no no.

I would say half an hour of driving would be enough to get the battery somewhere near good, depending if your driving with lights, heaters, and stero blasting..

michael
24-01-04, 17:51
Originally posted by Timwildman
You need to be careful, jump starting with leads from another cars battery. I think some people say it might damage ECU's wipe RLTC memory etc. Using a booster battery like the AA use is the best. But bump starting is a no no.

I would say half an hour of driving would be enough to get the battery somewhere near good, depending if your driving with lights, heaters, and stero blasting..


So you can't push it down a hill, stick it in gear and start it up then :)

I have a battery charger in the house so I can trickle mine if I need to hopefully iy'll be OK, I'll go out for a longer drive tonight just to be sure - the last one was just 15 mins with dipped beam, heater off, heated seats off, no stereo etc.

I'm a bit concerned that a total flat might cause the standard alarm to go a bit weird and I'd need to sort the AVC-R settings out again... actually that reminds me, I really should write those down!

Thanks for the input, just trying to be prepared for the worst, battery is fairly new and obviously I caused this problem with the lights being on so hopefully it won't happen again but it's always useful to have the info to hand if it does :)

Nick@TC
24-01-04, 19:03
Driving while lights/heaters on will make no difference, as you should only get a maximum 1v drop with everything on.
Roughly speaking a vehicle needs a 15 minute run to just to replace the power that has been taken out of the battery upon starting, whether this be idling or actually driving makes no difference as the alternator should put out a constant 13.5-14.5 volts.

You can try bump starting an auto, but it'll probably cost you a new gearbox :)

And yes be very very careful if using jump leads, infact, I personally wouldnt use them after now being in the breakdown trade.

Suprash
26-01-04, 11:02
Why ??? Whats wrong with breakdown leads, many a times have I had to jump fellow members at a meet, due to their heavy tunes ;)

Nick@TC
26-01-04, 14:07
Most available DIY jump leads wont be man enough to carry the power, also bad connections can cause air bags to demonstarte what they do best and its also known for people to fry the ECU somehow.

Suprash
26-01-04, 14:29
Originally posted by NWS25
Most available DIY jump leads wont be man enough to carry the power, also bad connections can cause air bags to demonstarte what they do best and its also known for people to fry the ECU somehow.

Ahh, the rest of it I take with a pinch of salt, but this is worrying...


Originally posted by NWS25
also known for people to fry the ECU somehow.

Gaz Walker
26-01-04, 15:02
Originally posted by NWS25
Most available DIY jump leads wont be man enough to carry the power, also bad connections can cause air bags to demonstarte what they do best and its also known for people to fry the ECU somehow.

I blew my first AVC-R up doing that too.

Gaz.

Suprash
26-01-04, 15:15
So Im guessing if your out and the battery goes flat, disconnect the + ternminals, then jump it off the other car, then reconnect terminals, bet that would stop anything form blowing whilst still being able to use the very handy jump method, yes........

Nick@TC
26-01-04, 17:13
Originally posted by Ashley Willis
So Im guessing if your out and the battery goes flat, disconnect the + ternminals, then jump it off the other car, then reconnect terminals, bet that would stop anything form blowing whilst still being able to use the very handy jump method, yes........


I dont understand what your saying there?? disconnect the + terminal from where??

Gaz Walker
26-01-04, 17:15
Originally posted by Ashley Willis
So Im guessing if your out and the battery goes flat, disconnect the + ternminals, then jump it off the other car, then reconnect terminals, bet that would stop anything form blowing whilst still being able to use the very handy jump method, yes........

Are you on crack today Ash? ;)

Gaz.

Suprash
26-01-04, 17:31
Nope, that wekends only. I mean if you disconect the positive terminals on the battery, then the car is not connected to the power, Im guessing its something to do with the power surges maybe frying the ECU, so if its all disconnected than effectivly the battery is stand alone, so it could be jumped, er-charged, then reconnect the terminals, and start her up, that way causing no problems for things like the ECU........No..... :confused:

SimonB
26-01-04, 17:32
I think people get a bit too paranoid about this. I can't see what the difference is between using a booster bettery and jump leads from another car. I've jumped my car three times now (having no other choice). The last time it did appear to scramble one of the RLTC settings, but I can't see how it can damage your ECU. It's fused after all. Just use some heavy duty leads (mine are Halfords heavy duty ones and can easily handle the current), and connect the negative lead on to the chassis rather than the -ve battery terminal directly like the instructions tell you.

Nick@TC
26-01-04, 17:44
Originally posted by Ashley Willis
Nope, that wekends only. I mean if you disconect the positive terminals on the battery, then the car is not connected to the power, Im guessing its something to do with the power surges maybe frying the ECU, so if its all disconnected than effectivly the battery is stand alone, so it could be jumped, er-charged, then reconnect the terminals, and start her up, that way causing no problems for things like the ECU........No..... :confused:


It can be charged with the terminal disconnected. but cant be jumped that way for obvious reasons................

Most booster packs have on/off switches so you make a good connection before any power goes through the cables. I also jump leads for when my booster pack is low, 12mm cable and plugs into my truck once connected to the car.
If it can scramble your RLTC it can do the same to your ECU.

If/when I leave this breakdown game, I'll be buying myself a booster pack. Money wisely spent.

Suprash
26-01-04, 17:54
Yeah, but if you disconnected the positive terminals, and even the negative terminals, you could then jump the battery with no consequence to any eletrical devices, and then reconnect.

:conf: :conf: Im repeating myself now arent I, I'll shut up...... :(

foodfreak
26-01-04, 18:00
it's also common for the standard alarm ecu to be spiked,
if it is armed when the battery goes flat and you try a jump start.

It's happened to a few people on here now.....

Me included:D
John

Nick@TC
26-01-04, 18:04
Originally posted by Ashley Willis
Yeah, but if you disconnected the positive terminals, and even the negative terminals, you could then jump the battery with no consequence to any eletrical devices, and then reconnect.

:conf: :conf: Im repeating myself now arent I, I'll shut up...... :(


You could jump the battery, but hows the car gonna start?? :D

SimonB
26-01-04, 18:38
Originally posted by NWS25
If it can scramble your RLTC it can do the same to your ECU.



But the RLTC has flashable memory which is sensitive to this kind of thing whereas the ECU doesn't.

As for the disconnected battery thing, the point of a jump start is to provide enough power from the donor car to start yours, not to charge the battery up enough to start your car on its own. Once it's running your car is generating enough power to charge your flat battery up. If you disconnected your battery you would then have to put enough charge in it to start your car, which would take ages.

Suprash
26-01-04, 18:45
You lot are smart 4rses in't ya..... :D

So the donar car isnt suppling the power to the dead battery, mearly through it....

Trig
26-01-04, 20:07
I tried jump starting mine using the normal jump leads but i ended up blowing the big 30amp fuse!! Got a new battery now tho. :thumbs: