A quick check and balance...

[Simpo Two]

Now that rain has stopped, I've put some time in on the knotty problem of how best to connect a battery conditioner to a 2007 DB9.

It needs to be quick and easy to connect and disconnect, so I headed towards the front of the car. The official +ve terminal was obvious for the +ve point, but where to attach the -ve? Inspecting the forward area of the engine bay revealed a number of possible locations, but were they electrically suitable? I got the multimeter out and worked on the principle that if I got 12V between the official +ve terminal and any other point, that would do, at least for the low current a battery conditioner puts out.

The other question was a route for the cable from the fixing points to the outside front of the car. I pondered the idea of unscrewing the big grey metal panel that covers the radiator, and cautiously removing one bolt, I found that it was screwed straight into a metal frame which connected to the rest of the structure. Maybe this bolt could be my -ve terminal? But it had a black coating that didn't look very conductive... anyway, with a bit of fine sandpaper and the multimeter, I refitted it and confirmed that it did indeed make a 12V circuit with the +ve terminal. Hooray! Two terminals, and close together.

Now how best to connect the conditioner wires... in the end I made two (rather crude, but I'm not a metalworker) brass tags - and this is what they look like in situ:



(incidentally those marks on the grey panel were there when I got the car - not my doing!)

At this point something inside me said 'Am I about to do something really stupid?' - so before I go any further, I'd welcome your thoughts on whether this is a genius solution, or doomed to disaster.

NB The cable is a 12' SAE cable which will be cut in half, the cut ends being secured to the car and the conditioner, and the plugs joining the two halves at the radiator grille: https://www.amazon.co.uk/dp/B01N7CEV00

[westhumbler]

I'm not sure if it's the same in an 07 DB9, but my 05 has a plug in the rear right hand corner (vertical face behind the rear seats) in the boot that you can simply connect your conditioner to.

[Simpo Two]

There is, and that's what I currently use - but then there's a wire coming out of the boot and running the length of the car towards the garage. Not great for regular use. This is about a quicker more convenient answer, as I intend to use the conditioner most of the time. I plan to fit a waterproof box to the garage wall for the conditioner (so I don't have to open/close the garage door every time) and then there will just be a lead about 4' long to plug into the grille area. No need to open the boot, or the garage, or unfurl an extension lead.

[john ryan]

I have a Ctek plug on short wires attached where you show. Simple matter to connect and disconnect at will.

[Simpo Two]

john ryan said:

I have a Ctek plug on short wires attached where you show. Simple matter to connect and disconnect at will.

Ah that's good to hear, thanks. Where did you route the cable? I think over the top of the grey panel looks poor, but I might be able to feed it down the LH side underneath the panel without having to remove it.

[john ryan]

I open the bonnet, but I guess it could appear between the grille slats if a mounting could be fabricated

[Simpo Two]

john ryan said:

I open the bonnet, but I guess it could appear between the grille slats if a mounting could be fabricated

That's the plan - because there's a brick wall on the passenger side so getting to the bonnet catch is a pain. Current plan is to cable-tie the end between the slats and just prise it out when needed - but the first thing is to get the cable run.

I thunk there's a fair case, for a car that only lasts 10 days if not used, to have a connector on the outside - after all EVs have them...!

[Phuketpaul]

I installed a magnetic charging connector behind the front number plate, this is connected to the plus charging point at the front of the engine bay and the negative (earth) to one of the screws under the slam panel.

The slam panel is very easy to remove and you can then run the cables more neatly.

The advantages over the boot charging point are:

It's at the front of the car and I drive into the garage.

If I forget to disconnect it just pulls off easily.

Photos to follow

[Simpo Two]

A cable hanging out of the boot, and an extension lead and battery conditioner shoved under the car really weren't a long term solution. So yesterday in a surge of bravado I set about the large grey panel with a torx bit, eased it away and was surprised to find there's just a big space underneath. I was expecting it to be packed with fans, wires and other hazardous things.



It was now very easy to find a good, safe route from terminals to grille:



A cable tie secures the cable to a vertical in the grille. The SAE connector is a nice wedge fit between the slats. The red wire is slightly obvious but it will do:



This 'overspray' caught my eye. Is this normal?



And with the cable secure, it was a simple matter to connect the terminals. A small notch in the side of the +ve housing allows the cable to exit. I may move the -ve connection to the underneath of the panel if it ever stops raining as it's a bit unsightly, but it works:



And while the 18 bolts were out, as they looked a bit tatty, I took the chance to spray them black again.

Edited by Simpo Two on Tuesday 3rd January 14:03

[leman600]

That overspray is over the barcode sticker taboot. Defo not expected.
The bolts you sprayed (I did mine) are probably the best value part you can buy for an Aston. I was shocked how reasonable they are and they'll be better than our sprayed temp solution.

[SHIFTY]

I had the same "overspray" on my Vanquish.

It was only when the car went into X K Engineering for a minor paint correction that I found out that the car had been rear ended before I purchased it and the whole car had to be repainted by the same company.

Moral to me is never to trust a car salesman.

[Phuketpaul]

Simpo,


Did you put a fuse into the positive cable near where you connected to the car positive jump connector because if the cable gets trapped or frayed,since its connected almost directly to the battery it could easily overheat/catch fire.

Simpo Two said:

It was now very easy to find a good, safe route from terminals to grille:

Edited by Simpo Two on Tuesday 3rd January 14:03

[Simpo Two]

Phuketpaul said:

Did you put a fuse into the positive cable near where you connected to the car positive jump connector because if the cable gets trapped or frayed,since its connected almost directly to the battery it could easily overheat/catch fire.

Interesting. I did ask for input in the opening post but nobody said 'add a fuse'. Do you mean that the lead or the battery can catch fire? The conditioner has a (probably) 13A fuse of course, if that's relevant.

If connected via the boot socket, does that have its own fuse in the car? Perhaps I need the equivalent one of those. What type/ampage please?

[Phuketpaul]

The wire is more likely to catch fire than the battery as its only a thin wire and the current that would cause the battery to catch fire is much greater than the current that would cause the cable to melt/burn.

The fuse value depends on the maximum current of your conditioner/charger, mine is 8 amps so I used a 15 amp fuse. Should be as close as possible to the jump start connector.

Yes the boot socket does have its own dedicated fuse already.

This fuse is irrelevant of the conditioner having a fuse, this is to stop the battery shorting to the body whether the conditioner is connected or not.

Edited by Phuketpaul on Tuesday 3rd January 21:58

[Simpo Two]

Phuketpaul said:

The wire is more likely to catch fire than the battery as its only a thin wire and the current that would cause the battery to catch fire is much greater than the current that would cause the cable to melt/burn.

The fuse value depends on the maximum current of your conditioner/charger, mine is 8 amps so I used a 15 amp fuse. Should be as close as possible to the jump start connector.

Thanks very much, I'll look into it tomorrow. This is the unit: https://airflow-uk.com/product/car-battery-conditi...

[Phuketpaul]

This looks pretty low current, so I would use a 5 Amp fuse, the same as the boot conditioner socket has.

[Simpo Two]

Phuketpaul said:

This looks pretty low current, so I would use a 5 Amp fuse, the same as the boot conditioner socket has.

According to the label on the back of the conditioner, it outputs 1.5A. The new cable I fitted in the car is considerably thicker than the one coming from the unit.

When you say ' Should be as close as possible to the jump start connector' I presume you mean near the grille - and it will have to be inside for weatherproofness.

NB Someone commented that the overspray could have been from a nosejob for stonechips rather than an accident. Either way, nothing I can do about it. Though if I do take the panel off again I could give it a rub with cellulose thinners.

[Phuketpaul]

Simpo Two said:

According to the label on the back of the conditioner, it outputs 1.5A. The new cable I fitted in the car is considerably thicker than the one coming from the unit.

When you say ' Should be as close as possible to the jump start connector' I presume you mean near the grille - and it will have to be inside for weatherproofness.

I mean as near as possible to the positive jump start terminal that is already under the bonnet - the reason for the fuse is in case the wire gets damaged or shorts, so the closer to the terminal the better as the unprotected length will then be as short as possible.



I connected mine to the underneath of the +ve terminal and the fuse is just inches away on the the bar that runs across the engine bay.



I then ran the cables around the edges of the area under the slam panel, and used a bolt for the earth under the slam panel



All hidden from view (obviously not bolted down yet though.



And this is the magnetic charging point under the front numberplate

[Simpo Two]

Phuketpaul said:

I mean as near as possible to the positive jump start terminal that is already under the bonnet - the reason for the fuse is in case the wire gets damaged or shorts, so the closer to the terminal the better as the unprotected length will then be as short as possible.

OK, easy enough.

Phuketpaul said:

And this is the magnetic charging point under the front numberplate

A nice solution. But my car, and most DB9s it seems, don't have number plate plinths so I'd have to attack the bumper instead. Now that I'm a bit more confident I might have another look, but access seems difficult and I'm certainly not taking the front off!

Edited by Simpo Two on Wednesday 4th January 12:22