Fitting a rear battery (in boot)

[snowathlete]

The petrol model has a battery in the boot, with it's own tray and clamp to hold it. And a pipe to vent fumes. I want to fit a battery in the rear of my diesel model (not linked to the main battery/electrical system). Anyone able to tell me anything helpful about it?

 

- photos from a petrol model?

- part numbers?

- where that vent goes?

- whether the bolt holes are present on all models already? I don't want to drill holes in the car really, so it may kill the idea if the holes aren't already present

[gianthotdog]

Why do you want to fit a battery in the rear?

[snowathlete]

47 minutes ago, gianthotdog said:

Why do you want to fit a battery in the rear?

dashcam

[TLV]

Do you intend to install a second battery? I doubt battery management approves. Or relocate the current battery to the trunk for the dashcam? Wiring it as is makes more sense.

[snowathlete]

26 minutes ago, TLV said:

Do you intend to install a second battery? I doubt battery management approves. Or relocate the current battery to the trunk for the dashcam? Wiring it as is makes more sense.

 

Not quite either. I 'm thinking of installing a second, separate, battery in the boot; completely isolated from the main battery and the car's electronics. I may introduce one small caveat to that later, but essentially I'm not talking about linking the two batteries in parallel. Even if the battery regulator was happy with that set up - and I agree that it probably wouldn't be! - you'd probably need to fit a more powerful alternator to charge two batteries like that.

 

This will be an isolated battery in the rear, the only things connected to it would be a solar panel via a controller and a dash cam. But if I do this I want to do it properly and make sure the battery is secure and can vent gas properly.

[williamshatnerspants]

Would a small LiPo battery be an easier/cheaper/lighter option? Thinking something along the lines of an RC battery.

[snowathlete]

6 minutes ago, williamshatnerspants said:

Would a small LiPo battery be an easier/cheaper/lighter option? Thinking something along the lines of an RC battery.

 

I wouldn't want to use LiPo because they don't like heat and have other drawbacks, but a Li Fe would be a good choice, even though they are heavier, but as I already have a spare LA battery available that's the main reason why I'm going for that.

[jafo]

@snowathlete

 

How long do you need the dashcam to work ? A Week ?

 

I've left few times my dual camera dashcam for at least 12h overnight - forgot to turn it off - and no problems in the morning starting the car.

[gianthotdog]

Is it really necessary to fit a second battery?

 

are you trying to crack a walnut with a sledgehammer?

[snowathlete]

16 minutes ago, jafo said:

@snowathlete

 

How long do you need the dashcam to work ? A Week ?

 

I've left few times my dual camera dashcam for at least 12h overnight - forgot to turn it off - and no problems in the morning starting the car.

 

Ideally I'd like a system I don't have to think about, i.e continuously powered. But I don't want to connect to the main battery. I've had problems with power drains as it is and these cars have a lot of draws on the battery. I don't think I will achieve my aim quiet, but I should be able to get fairly close with a decent solar panel connected to its own battery.

 

In parking mode we're talking about something like 300mA draw. 300mA over 24 hours is 7.2A. For someone who drives often enough, and long enough, such as an hour commute to work each day, it's not going to be an issue probably but I do too many short journeys.

[snowathlete]

11 minutes ago, gianthotdog said:

Is it really necessary to fit a second battery?

 

are you trying to crack a walnut with a sledgehammer?

 

It's a bit OTT maybe, but I figure, why not?

[MikeHig]

How well will a solar panel work inside the car? I thought they had to have direct exposure. Or do you plan to fix it on the roof bars?

[jafo]

@snowathlete

 

First, you need to think - and maybe tell us so we can help you better - how long / often and why you need the dashcam to record ?

 

Are you looking to record whole parking time when you are at work ? Maybe would be better to park somewhere else ?

 

Solar panel can be a magnet for thieves. 

[snowathlete]

2 hours ago, MikeHig said:

How well will a solar panel work inside the car? I thought they had to have direct exposure. Or do you plan to fix it on the roof bars?

 

It should work. I don't think it'll be a problem because solar panels just require photons so as long as there is visible light. Not sure how well it will work yet. What you don't want is shadow, but the way that we happen to park is pretty ideal for minimizing that. There is a lot of unknown at this stage though to be honest, it's pretty experimental at the moment.

[snowathlete]

16 minutes ago, jafo said:

@snowathlete

 

First, you need to think - and maybe tell us so we can help you better - how long / often and why you need the dashcam to record ?

 

Are you looking to record whole parking time when you are at work ? Maybe would be better to park somewhere else ?

 

Solar panel can be a magnet for thieves. 

 

I don't park in a bad place, but I just want the peace of mind from having a dashcam recording, but I don't want any hassle to go with it, problems starting the car, or having to charge a power bank up all the time.

It's possible that a solar panel would seen as something to steal. They're really not expensive nowadays, not for the sort of size you can fit in a car, but someone might wrongly think they're valuable I guess.

[jafo]

@snowathlete

 

It's not about solar panel cost - it's about all the hassle of broken window or damaged door and premiums. 

 

And you still haven't answered the question - how long do you need your camera to work

 

I do two or four 5-10 miles trips a day - so probably less than others and like I've said - even after 12h of camera working - no problems with starting the car.

 

Maybe it would be much cheaper / better if you just buy bigger and better main battery for your car ??

[Russ77]

Just to chuck something into the mix.......  If the dashcam will be recording constantly for peace of mind, unless you can make it completely covert (which might make any evidence from it questionable if it went to court as it could be classes as CCTV which will require warning signs as it's being used in a public place) or you the footage is going to be streamed/uploaded to cloud storage, there's a risk that any thieving scumbag would take the camera if they chose to break into your car so there wasn't any evidence.

 

I'm sure you can get "security" camera systems for cars which would be more adept at what you're trying to achieve here but personally I don't think a dashcam is the way to go and adding another battering isn't without it's own set of risks/considerations.

 

If it's purely a rear dashcam you want/need then taking a switched live feed from the internal fuse box and running a cable to the rear of the car would be so much cheaper and easier to do

[snowathlete]

2 hours ago, jafo said:

@snowathlete

 

It's not about solar panel cost - it's about all the hassle of broken window or damaged door and premiums. 

 

And you still haven't answered the question - how long do you need your camera to work

 

I do two or four 5-10 miles trips a day - so probably less than others and like I've said - even after 12h of camera working - no problems with starting the car.

 

Maybe it would be much cheaper / better if you just buy bigger and better main battery for your car ??

 

That's not what I meant, what I meant was their not worth nicking because they aren't valuable.

 

I want it to run continuously, or as close to that as I can get.

 

A bigger battery perhaps would have been a good idea, not sure there is much room to fit much bigger in the engine bay but I literally just bought a brand new Bosch AGM battery so I don't really want to upgrade it.

 

Myself, having had battery problems and the massive hassle of a car not starting in the morning, I just want to leave my main battery alone. That's why I'm looking for an independent system.

[snowathlete]

Interesting though it is, discussing the pros and cons of my idea, does anyone know any of the answers to my original questions?

[langers2k]

You're going to need to learn to google better if you want to do this as I doubt anyone else has...

 

I believe only the 3.6l petrol had a rear battery as they ran out of room in the engine bay. Looks like the battery tray part number is 3T0804869/3T0804869A/3T0804869B depending on year.

 

Here is an image of one fitted I found online:

 

Still, such a large battery seem very excessive for the amount of power a dashcam will use.

[snowathlete]

2 hours ago, langers2k said:

You're going to need to learn to google better if you want to do this as I doubt anyone else has...

 

I believe only the 3.6l petrol had a rear battery as they ran out of room in the engine bay. Looks like the battery tray part number is 3T0804869/3T0804869A/3T0804869B depending on year.

 

Here is an image of one fitted I found online:

 

Still, such a large battery seem very excessive for the amount of power a dashcam will use.

 

Thanks for that. Can't see where the tube vents to unfortunately. 

Looks like the interior panel is different as well, which makes it more of a pain than I had thought.

 

You might be right that a smaller battery is a better way to go. Even though I already have a LA battery handy it might be that buying a smaller battery makes more sense. It depends because I'm not sure how efficient the panel will be in real use, especially in the winter. My husband thinks it will produce a surplus of energy in the summer, but a shortage in the winter and of course the energy is not constant, any battery will have to store enough energy while it's light, to run the camera when it's not.

 

I think we'll have to test the panel out in position once it arrives in the post and see what we have to work with before deciding what to do.

[jafo]

@snowathlete

 

?!?!? Why do you need 24/7 surveillance ?!?! 

[TLV]

Your solar idea seems flawed. Find a specific panel first and then explore your options. If it's small enough to be conveniently placed in the car without getting in the way, it'll most likely barely power the camera in ideal conditions and the UK is not exactly known for sunny weather. What's worse, there's a number of reasons to avoid parking your car under the sun.

 

Few cars have solar panels as an option and they're mostly used for ventilating the car without bothering the battery. They're just not capable of doing much else besides running a fan.

[bigjohn]

On 22/03/2018 at 13:14, snowathlete said:

The petrol model has a battery in the boot, with it's own tray and clamp to hold it. And a pipe to vent fumes.

 

My petrol has the battery under the bonnet but it's only the 1.4tsi. Presume it must be the v6 monster that has the battery in the boot.

 

Rather than solar panels why not consider a "SPLIT CHARGE RELAY PCT VOLTON ZR1220" which is designed to charge a leisure battery in a caravan, except in your case in the boot. Make sure the battery is a deep cycle one  - you can also find some compact ones designed to fit in small

spaces(eg boats etc ) . If you have towbar fitment you probably already have the relevant electronics.

 

I used to run a twin battery setup on a Passat years ago to run 12v  coolbox (for a while) and lights when camping. Plugged my tent into the second socket on the tow bar. Had to tie a duster around my steering wheel to remind me so I didn't drive off with my tent in tow!

 

 

 

 

Edited 23 March, 2018 by bigjohn

[superbdreams]

20 hours ago, snowathlete said:

Interesting though it is, discussing the pros and cons of my idea, does anyone know any of the answers to my original questions?

 

Not definitively but I looked into this quite exhaustively.

My plan was to have the boot battery charged when the main battery was full, there are devices made (for caravans/force vehicles) for this purpose.

The drawback apart from cost which I would have paid (iirc £130 ish) was cabling through the car.

A sealed lead acid standard battery was going to be my choice and fitted where the 3 litre superb is, in the left boot compartment.

 

I fitted a dashcam from new but because of my constant flat battery problems I also fitted a hidden switch so I could shut it down overnight, the blackvue battery magic device fitted did not help because as you know from your own experience, the car drained the battery overnight anyway and the camera just exasperated this.

On a side note the camera paid for itself twice by catching a hit and run driver and alerting me to the damage caused to my vehicle by blade group.

 

As of now with my car somehow fixed, I have often forgotten to shut down the camera and still the car starts the next morning.

I urge you to pursue your efforts to cure the drain and then just fit a dashcam with a low voltage shut off switch.

 

If it helps, I decided to throw money at a dashcam and have the best, I bought a twin camera system from blackvue with wifi.

Very disappointed!

The sd card needs formatting regularly and if you don't the date and time jump forward years (Samsung are more reliable in it than sandisk)

The wifi is a joke as you cant transfer any files via it.

The rear camera often gives a psychedelic picture despite being sent back under warranty with no fault found.

Picture quality is good but other much cheaper cameras are as good, probably better by now.

Gps, route map,parking mode and incident recording are all excellent.