Batteries relocated to boot

[anthropoidape]

Hi,

I know a couple of you have relocated your battery to the boot of your Stag. Just wondering if anyone has a photo of the battery in its new location. Also curious as to whether you opted to run the cable under the car or through the cabin, and why. My instinct would have been to run the cable through the transmission tunnel but it's pretty crowded in there and it's all rather close to the exhast. I am not sure I *need* the space in the engine bay but I think that overall it could be an improvement in getting the engine bay nice.

Anyone got time to fill me in on their approach? I am debating this option at the moment, as I have stripped my engine bay fairly substantially in order to paint it. It's getting a good clean up and looking darn good so far actually!
Here's a teaser ;)



(Yes, it's a Rover V8 not a stag V8, stroked to 4.2 litres and now injected. )

Cheers,

Jason

[volospian]

I'm thinking of moving my battery to the boot as well, but I haven't even started to consider the technicalities of it, so I'll be keeping an eye on this thread. Personally I'd think of running it through the cabin to keep it protected from any wear and tear in the tunnel. The last thing you want after doing that is a damaged cable.

The battery box is fairly well corroded anyway, but I want to move mine to remove all that weight from over the front wheel. I haven't decided whether it's best in the middle of the boot, or over on the passenger side (to balance the weight of the fuel tank a bit more). If it's not hijacking the thread too much, anybody wish to comment on the balance of the Stag (as long as it doesn't turn into an "American cars are so much better balanced than your Brit cars" thread :D)

[anthropoidape]

Good point; I was mainly thinking of front-rear balance but I guess left-right balance matters too. For what it's worth, the cable on a Jag XJ-S runs through the trans tunnel (I once missed it with a self-tapping screw by about 1mm, battery still connected, when I was young and careless!), which is what made me think along those lines. However, the closeness of the exhaust is much less of an issue on that vehicle.

Other than the routing and the exact position in the boot, I don't think the technicalities are too challenging; currently a cable goes from the battery to a bolt on the firewall which then feeds the starter motor, fuse panel etc. It should simply be a case of having the same cable (but longer) come from the other end of the car! Having said that, I am still hoping for input from others on this question :)

[AlanChatterton]

Bear in mind that if you do this, you will need to use a much heavier grade of cable (thicker) to reduce the voltage drop due to the length of the cable.

When people convert a 2000/2.5 to Stag or Rover V8 the common thing is to relocate the battery to the boot, to avoid the Stag problem of having to remove the PAS Pump to get to the battery! Surely, not having a huge heavy battery in the front nose corner can only improve the balance?

However, where in the boot to put it is a different matter. You either have to loose the spare wheel and put it in the wheel well, or surface mount it in a battery box in the already smallish boot.

Does anyone know how much room is below the hood frame when its folded down? It always seems to me that the storage "bin" behind the rear seats it far deeper than it needs to be. I wonder if it could be mounted down there? Especially if you use of of those "gel" type batteries which are about half the size of a normal one?

[anthropoidape]

Interesting. I have no trouble getting the battery in and out with all engine ancillaries in place on my Rover V8. Having to remove the power steering pump to get to the battery is an amazing idea! Is that true of all standard stags?

[Richard B]

Yes it's true; Friday afternoon design job.

[Lewis]

I've got my battery boot mounted but there are several things you've got to consider:

- It has to be run inside the car, unless you've got a supply of armoured cabled

- The extra drop you get through the distances. If you've already got a weak electrical system or poor starter, this'll exacerbate the problem unless you get a massive high-powered battery

- You need large diameter cable. 25mm square preferably

- You'll need something to retain the battery in the boot as well and to shield it from loose objects. It can actually take up a suprising about of space :)

About all that springs to mind at the moment :)

If it works, you've got it in the bay and all is hunky dory, I'd leave it as is. Hell, how often do you have to get at it?

[thescrapman]

[quote by=AlanChatterton link=Blah.pl?b=stag,m=1181101753,s=3 date=1181123950]
Does anyone know how much room is below the hood frame when its folded down? It always seems to me that the storage "bin" behind the rear seats it far deeper than it needs to be. I wonder if it could be mounted down there? [/quote]

You can certainly get quite a substantial quantity of wine in teh hood well.

:-)

Colin

[shenderson]

My battery is in the boot too, mounted in a cradle behind the LH wheelarch.  It does take away some luggage space but does not prevent access to the spare wheel.

The main battery cable is from a Rover P6B (V8) which is the correct spec. and length, and runs inside the car along the transmission tunnel.  There is also a special insulated stud (also from a P6B) that passes through the bulkhead in the driver's footwell, where the Stag has an appropriate sized hole blanked off, to connect with a short cable to the starter motor.

I mounted the washer and expansion bottles in the space vacated by the battery so I can now access the RH spark plugs.

Further weight distribution (and steering feel) gains can be made by swapping the PAS rack for a manual steering rack from a 2000/2.5.  This works well with a Rover V8 conversion because with the lighter engine there is less weight on the front wheels so the steering is not too heavy (even on 215/60 tyres).

With all these mods, the front/rear  weight distribution of my Stag approaches 60/40.

[wakaday]

I had one that I fitted in the area behind the back seat so it sat below the folded hood. It only used up space that wasn't doing anything. I used a battery tray from something like to A Nissan Bluebird that I bolted to the floor and levelled off with Brackets. I ran the cable through the inside of the car along the inner sill with good stong insulated P clips and didn't have any problems with it.
I did a similar set up a few years ago with another Bluebird tray when I did the same thing on my TR7V8 but that went in the boot.

[volospian]

That sounds like a good plan then! Was the battery particulrly small?

[wakaday]

If you remove the rear seat back and drop the hood, its surprising how much space is back there.

[anthropoidape]

That sounds promising! Not just for the battery but there are a couple of other things I would like to put somewhere out of the way...

I'd still like to see some photos of rear-mounted batteries if anyone has any handy.

[wakaday]

There is a good deal of space in the Hood Well for an LPG tank should anyone go down the gas road.

[anthropoidape]

wakaday wrote:

There is a good deal of space in the Hood Well for an LPG tank should anyone go down the gas road.

I've been thinking about that myself. I am not sure the miles I do justify the cost, however...

[stoutgoose]

I HAVE RELOCATED MY BATTERY TO THE HOOD WELL.  THERE IS PLENTY OF SPACE FOR A STANDARD BATTERY.  I USED HEAVY GAUGE FLEXIBLE CABLE FROM THE STUD BY THE CLUTCH PEDAL, RUNNING IT ALONG THE INSIDE OF THE FLOOR-PAN, UNDER THE REAR SEAT AND UPTO THE BATTERY.  THE EARTH IS CONNECTED LOCALLY AT TWO POINTS VIA BOLTS.

I MADE A LEVELLING PLATE FROM ALUMINIUM AND SCREWED THAT ONTO THE FLOOR OF THE HOOD WELL.  THE BATTERY SITS IN A TR6 BATTERY TRAY AND IS HELD IN PLACE BY TWO BRACKETS BOLTED TO THE BOOT BULKHEAD.

I'VE HAD NO PROBLEMS WITH VOLTAGE DROP OR POWER ISSUES.

I'VE COVERED THE TERMINALS WITH RUBBER, BUT WOULD IDEALLY LIKE A BATTERY COVER.  ANY IDEAS WHERE I CAN OBTAIN ONE OF THESE?

THE PHOTOS I'VE TRIED TO UPLOAD ARE TOO BIG, SO I'LL TRY EMAILING THEM.

[anthropoidape]

stoutgoose wrote:

THE PHOTOS I'VE TRIED TO UPLOAD ARE TOO BIG, SO I'LL TRY EMAILING THEM.

Here they are:









I have to admit to absolute amazement that the soft-top still fits into the cavity. I am really going to have to pull the back seat out and investigate just how much room there is in there.

[volospian]

anthropoidape wrote:

I have to admit to absolute amazement that the soft-top still fits into the cavity. I am really going to have to pull the back seat out and investigate just how much room there is in there.

You and me both, that looks like it fills the bay quite full. Does stoutgoose unzip the rear screen when stowing the hood?

Hmmm, not convinced on that solution, but I suppose it depends on just how much time the hood is spent down.

/Edit: Could you use smaller batteries? Maybe 2 or 3 12v bike batteries in parallel or something?

[DJT]

How much difference to balance will moving the battery have? The battery weighs, what 10-15Kg tops? The Stag weighs around 1300 Kg. So the battery accounts for less than 1.5% of the Kerb weight. The difference between a full and empty fuel tank is more than this.
If you have a Rover engined Stag, you have already moved a considerable weight out of the engine compartment, for which you must have changed the front springs to compensate.
Seems a lot of work for negligible benefit. IMHO.

Dave

[shenderson]

It's probably worth finding a way to remove the rear seat back with the hard top in position otherwise gaining access to the battery, e.g. for jump starting, will be a pain!

Steve

[anthropoidape]

taylormoran wrote:

How much difference to balance will moving the battery have? The battery weighs, what 10-15Kg tops? The Stag weighs around 1300 Kg. So the battery accounts for less than 1.5% of the Kerb weight. The difference between a full and empty fuel tank is more than this.
If you have a Rover engined Stag, you have already moved a considerable weight out of the engine compartment, for which you must have changed the front springs to compensate.
Seems a lot of work for negligible benefit. IMHO.

Personally, I thought the advantage of moving the battery to the rear was more to do with gaining a little space in the engine bay, which I feel is actually a little crowded. It does seem to me that the boot is a better place for the battery, since I'd want to have fairly ready access to it, but it is still interesting to note that there is a bit of room in the soft-top cavity there.

[anthropoidape]

shenderson wrote:

It's probably worth finding a way to remove the rear seat back with the hard top in position otherwise gaining access to the battery, e.g. for jump starting, will be a pain!

Steve

I agree, but perhaps it could be made accessible via the boot...

[volospian]

taylormoran wrote:

How much difference to balance will moving the battery have? The battery weighs, what 10-15Kg tops? The Stag weighs around 1300 Kg. So the battery accounts for less than 1.5% of the Kerb weight. The difference between a full and empty fuel tank is more than this.
If you have a Rover engined Stag, you have already moved a considerable weight out of the engine compartment, for which you must have changed the front springs to compensate.
Seems a lot of work for negligible benefit. IMHO.

Dave

It depends where the weight is as to how it affects balance. The battery overhangs the front wheel by a foot or so. It is also about left\right balance as the driver, battery, fuel tank, dials, pedals, steering column, etc. are all on the same side of the car.

The battery may be 1.5% of the kerb weight of the car, but imagine a nice 50/50 weight distribution. The effective weight over each tyre is quartered. That means around 325kgs should be over each wheel.

However, the Stag isn't anywhere near 50/50, (according to this (http://www.staggering.info/index.php?f=data_home&a=5) it's more like 76/24 but we'll assume 70/30) so the weight on the front wheels should be more like 450kgs each, but even then the balance is not correct left/right with the weight of other items, such as the pas pump, steering column, steering rack and so on. Because of this there may be a left/right difference of 48/52 which could put around 437 over one side and 473 over the other. Now removing 15kg from that heavy side goes some way to redressing that balance, (especially if you then add that 15kgs to a lighter place. Placing it on the other side of the car, while not addressing any front/rear balance would remove 15k from the heavy side, and add 15k to the light side, leaving the figures more like 452/458. In fact, I wonder what t he left/right balance would be like on a LHD car, as much more weight would be over the left hand side, leaving the petrol tank and battery on the RH side would maybe balance things out)

If you reduce the weight over the front by slapping in a Rover lump, the weight of the battery would be more pronounced as it would be a larger percentage of the weight over each wheel.

OK, so the figures aren't accurate, but it's a rough explaination. You also have to include leverage as well. If a 50kg weight is totally equidistant between the two wheels, then it's distribution is even, but if you move it, say a third of the way across the car, the weight distribution is increased on the "shorter" side, with less weight effecting the wheel further away. If that weight is then extended outside of the vehicle (or in the case of the battery, forward of the wheel), it's effect on balance is increased. Imagine a battery on a pole sticking out 6 feet from the front of the car. although the battery would still weigh 15kgs, its effect upon the balance of the car would be much greater.

At least that is how I understand it, but I may be wrong. Perhaps Davesideways or somebody would like to comment?

[Sam Russell]

If you try to use two smaller batteries, they must be in series not parallel, as they will not be balanced.  The same current must go through both.  You will need to use two 6v batteries.  Trucks use 2 12 volt batteries in series, and so have 24v electricks.  Both batteries must be the same type.

[stoutgoose]

The reason for relocating the battery in my case is that I have fitted a Rover lump.  At the same time I cut out half the O/S front panel including the battery tray in order to fit a huge radiator that would make a good effort at cooling the car, rather than that ridiculously small affair fitted by Triumph.  This has resulted in the engine running at a constant 80 degrees with no heart-in-mouth moments when the ambient hits 25 degrees plus!

I do unzip the rear window when lowering the hood.  It all seems to fit in there somehow!