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Discussion Starter · #1 ·
Hey guys

I've got a flat battery and no choice but to jump it:

1. Is this wise
2. Do i need to get a battery fitted at Honda (thinking of immobilizer etc)

Thanks

Sked

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...............Daedalus
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You can jump it no problem, just make sure the key isn't in the ignition when you connect the jump leads.

You can fit the battery yourself no problem, but again, make sure the key isn't in the ignition when connecting to the terminals.
 

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Discussion Starter · #3 ·
Thanks, can you put the key in once its hooked up and charging or do i have to disconnect after a little charge and try to start it?

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Discussion Starter · #4 ·
thanks mpn, I got the car home :cool:

At the risk of sounding totally useless...

I have a new battery ready to install, being a little paranoid about my electrics I just wanted to know...

black/neg/- off first then red/pos/+ >>>take battery out>>>>install new one>>> red/pos/+first then black/neg/- right? of course with key out of the ignition.

I did google it but it's clearly so obvious that no one else has needed to ask it!

If someone can explain to me why you take the ground off first that would be nice as it seems wrong to have the live connected without the ground but I'm sure there is a reason.

I've replaced batteries before but due to reading stuff on here I'm less gung ho about doing it on a car with so much electronics gear :)
 

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Normally it does not. But...
...a thing crossed my mind, in your case you can accidently drop positive terminal and there may be a short circuit - either in your or other car - because many things are grounded in the motor bays!
Without preliminary grounding such an 'accident' 50% does not matter (there is not yet real closed circuit), but vica versa it can more easily cause fire or ultimately blasting of battery, the donor one or 'zombie' one either...
 

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World Traveller
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You can jump it no problem, just make sure the key isn't in the ignition when you connect the jump leads.

You can fit the battery yourself no problem, but again, make sure the key isn't in the ignition when connecting to the terminals.
Probably really silly question, but I've never had to jump a car or anything..
But why no key?
 

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Discussion Starter · #8 ·
Whenever I've done it, I've taken the +ve off before the -ve, and then installed the -ve first before the +ve.

Does it matter? :confused:
Well tbh, it makes more sense in my mind to do it that way but the more I think about it the more complicated it sounds - maybe its because electrons flow -ve (black) to +ve (red) [which just seems backwards anyway] - I'm imagining that electrons can return to the battery if you leave the +ve on until last for this reason - +ve is into the battery and -ve is out of the battery and it is better to have electrons flowing into the battery rather than around the chassis that have no where to go. But like I said, this is an uneducated guess and maybe a load of bullcr*p so don't quote me :)

Anyone who actually knows what they are talking about rather than me guessing like a noob, please step in...
 

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...............Daedalus
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Probably really silly question, but I've never had to jump a car or anything..
But why no key?
It doesn't matter on most cars but for some reason on the Civic, if you connect the battery with the key in the ignition, the immobilser code is wiped from the key.

Which means an expensive trip to the dealer to get it recoded.

Well tbh, it makes more sense in my mind to do it that way but the more I think about it the more complicated it sounds - maybe its because electrons flow -ve (black) to +ve (red) [which just seems backwards anyway] - I'm imagining that electrons can return to the battery if you leave the +ve on until last for this reason - +ve is into the battery and -ve is out of the battery and it is better to have electrons flowing into the battery rather than around the chassis that have no where to go. But like I said, this is an uneducated guess and maybe a load of bullcr*p so don't quote me :)

Anyone who actually knows what they are talking about rather than me guessing like a noob, please step in...
Not sure about +ve and -ve, but I would disconnect the live terminal first, then the ground (the one connected to the chassis) second and vice versa for reconnecting.

Glad to hear you got home in one piece though :)
 

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Discussion Starter · #10 · (Edited)
Not sure about +ve and -ve, but I would disconnect the live terminal first, then the ground (the one connected to the chassis) second and vice versa for reconnecting.
Yeah see that's what I would have expected but the garage that sold me it said the other way around. I know I'm over thinking it but "live" is the red +ve, BUT as the electrons travel -ve to +ve then the thing that it pumping OUT is actually the black -ve so it makes sense to remove the black -ve first as recommended by the garage if you think about electron flow. (EDIT... ah actually, as it's a circuit, then it's going out of the black -ve then following it around then the red CABLE is where the electrons are streaming OUT of hence "live", I suppose if you left it all connected then disconnected the black -ve at the chassis then the loose end would then become the "live" end even though it's black.)

I'm no electrician and I last did physics 15 years ago so I have no idea really but I'd like to know the real reason now that I have started thinking about it. I've changed plenty of batteries but the cars/bikes have always been oldish and not so electronic. I've not had to do it on a nice car before :)

So CTR is sitting still until I find out :)

It doesn't matter on most cars but for some reason on the Civic, if you connect the battery with the key in the ignition, the immobilser code is wiped from the key.

Which means an expensive trip to the dealer to get it recoded.
This also applies for jump starting it would seem from previous posts which is a more likely scenario for having your key in the ignition whilst sorting it out
 

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When my CTR was at Honda last year for its summer health check, they fitted a new battery some Microsoft component under the bonnet (which drains the battery) and a new speedo + dash. As these parts are all on the recall list apparently. But they won't tell you that willingly off course!! So glad it was still under warranty -well worth a £9.99 health check.

Might be worth checking with Honda mate
 

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Discussion Starter · #13 ·
If you remove the - terminal first and then the + terminal you won't risk any short cicuits if you hit any metal parts with the back end of the spanner while removing the + terminal.
deftly put :)

I spoke to an online Honda engineer and yes indeed, remove black -ve first, remove red +ve, remove battery, replace battery, connect red +ve then black -ve
 

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...............Daedalus
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When my CTR was at Honda last year for its summer health check, they fitted a new battery some Microsoft component under the bonnet (which drains the battery) and a new speedo + dash. As these parts are all on the recall list apparently. But they won't tell you that willingly off course!! So glad it was still under warranty -well worth a £9.99 health check.

Might be worth checking with Honda mate
I thought Honda health checks were free?
 

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#MrGrumpy
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If you remove the - terminal first and then the + terminal you won't risk any short cicuits if you hit any metal parts with the back end of the spanner while removing the + terminal.
Makes absolute sense. I guess my way of thinking comes from always wanting to ensure there's a ground in place before doing anything!
 

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I'm looking in to this one cos I'm not 100% sure, but if your civic is a diesel DO NOT BUMP START IT. I seem to remeber something about it damaging diesels. But even if the civic is petrol it is not advisable to bump start any car with a catalytic converter, as neat fuel can get drawn into it rendering it useless. You may not notice the problem until it comes to the MOT and fails.
 

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BELOW TAKEN FROM ANOTHER FORUM ABOUT THE QUESTION OF BUMP START DAMAGE...

It damages the arc springs for one. A DMF is essentaily 2 flywheels together, with no solid connection. When the engine drives the gearbox it transmits power from one flywheel (A) to the other (B) (and then the clutch) by means of springs and friction plates which dampen vibrations. Bump starting makes flywheel (B) drive flywheel (A) by pulling on the springs rather than pushing and this leads to noise and other things. The latest flywheels are very complex (read expensive) bits of kit





There is no "fundamental" reason why bump starting a car will damage any component any more than the usual starter motor starting, but that is with the caveat that the battery actually has enough power to power the engine and fuel systems as normal. And of course, the reason you usually bump start a car is because the battery is flat! If there is insufficent voltage to correctly operate the fuel system and EMS (usually requires >8volts) then the manufacturer cannot warrant what could happen, with things like partial fuel pressure, or stuck on injectors etc, all of which "might" cause damage to your engine.

So to play safe, they recommend you do not bump start the car, but jump start it (which obviously will ensure there is enough voltage for the systems to function). If you had say just a failed starter motor but the battery and rest of the electronics was fine then you could happily bump start your car no issues.

In fact, every time you drive your car you actually "bump" start it many many times, as lifting fully off the accelerator these days results in a zero fuel quantity injected, and the engine is actually not running (turning yes, running no)...... ;-)

Of course, if you have an Automatic transmission, you cannot bump start it, because it relies on hydraulic pressure to engage and hold a gear, and the hydraulic pump is driven by the input shaft, which is not turning (hence no pressure availible) with the engine off.

Manual gearboxes are not damaged by bump starting. Those fitted with oil pumps are really there for cooling purposes and lubrucation under large torque loads, neither of which is an issue for the couple of secs and low load of a bump start (an engine takes about 2kW to start it, my car puts over 150kW through the transmission most of the time without any issues!)

Finaly, DMF's, yes you could theoretically damage your DMF if you continuously bump started it for years on end, but it would be a slow wearing rather than a sudden failure, which would also probably be true to the clutch center plate damper springs.

Editted to add " old cars were of course easy to bump start, as the carb had a nice bowl full of fuel, so you didn't care if the fuel pump worked at key on, and the only electrics needed was about 2 amps to get the coil to fire the sparks, so even with a fairly flat battery that couldn't manage to drive the starter motor, you could get a decent bump start out of it. Modern cars now pull over 30 Amps as soon as you unlock the door (sometimes 100's of amps, no names mentioned LandRover, oopps, sorry.... ;-), so unless your battery is charged, the voltage will sag immediately, and no amount of bump starting will work"
 

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Finally having read up on this now... it appears that you may be able to start your car by Bump starting it, but it also appears that it MAY damage your engine or other components? If you try it and it works fine, then you will obviously think,... What was all the fuss about. But then again it could be... :worms:
 

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#MrGrumpy
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So I guess the bottom line is always try and jump it rather than bump it if you can?

I see a promo poster with "Don't bump it, JUMP IT!" on it. Maybe some kids avoiding drugs and enjoying an outdoor recreational activity for a background image too...
 
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