Moved battery to boot

[lotusandy]

After considering it for a year or so I have just completed relocating the battery to the boot.

I adopted a slightly different approach to others that have also done this as I felt that locating the battery in the bottom corner of the boot would make getting the roof panel in even more difficult & was slightly concerned about the consequences of being shunted in that area, the battery is not at all protected.

My approach was to shell out for an AGM battery which I felt would be sufficiently small to locate on a wooden platform directly above the fuel tank, in this location it does not suffer form either of the 2 disadvantages that the other method of location do.

The battery I used was a Odyssey PC925 from http://www.odysseybatteriesonline.co.uk although it only has a capacity of 28 AH (roughly half the TVR original) but as it has extremely low internal resistance due to the technology used it has massive cranking power, it turns the engine over slightly faster than before, I removed the fuel pump relay & there was sufficient power for it to turn the engine over after 2 minutes of cranking which is more thasn enough for me.
These batteries also have the advantage that they are suitable for cars that are laid up for extended periods.

I ran 2 new battery cables using 40mm flexible cable to the starter & the original earth point, this cable is a fair bit larger than the original.
I also relocated the fuse box to the cubby hole behind the passengers seat, which is a far more sensible place to have it, no cables needed to be extended, although I did have to unwind the entire loom & make a few adjustments.
The fuse box is held in place with an extended version of the original housing.

The ECU is now located on a plywood panel that is fixed using the original mounting holes for the battery & fuse box, I also properly mounted the fuel pump relay & the other additional one in the same area, it is nice not to have these item rattling around anymore.

I have attached a load of photos that explain the project from start to finish.


The battery tray


Tray in position


Finished installation


The beginning of untangling the loom!


Fusebox housing


Wiring in position


Fusebox in position


Completed installation


ECU and relays in position

Andy

[lotusandy]

The racing 40 battery is speced to give a Cranking current rating of 1100 Amps this is far higher than the standard 072 type batttery that typically has a CCA of 650 Amps, the battery I am using has a CCA of just 380 Amps, but this is more than enough to spin the engine over wether hot of cold. I am sure you could get away with a slightly smaller one.

Bear in mind that the CCA is a measure of how much current the battery can supply at -17 deg C, it is somewhat unlikley I will be trying to drive my Chim at that temperature!
I have no idea how much current the starter motor actually draws though, but I would take a guess at 200 - 250 A
I am not sure why a hot engine would be more troublesome to turn over though I would have thought the hot thin oil would make it much more easy.

I picked mine on the basis of an educated guess & the fact that they are speced for the Morgan V8 cars.

Andy

[lotusandy]

Adrian@ said:

Sorry, but which side did the new battery wires run down TIA.
Adrian@

The positive runs from the battery along the floor next to the transmission tunnel, then I drilled a hole in the floor just by the front seat mount to pass the cable under the gearbox, then along the chassis rail to the starter motor.
The negative cable just runs along the tunnel and up to the existing eart point.

Andy

[lotusandy]

daveparry said:

So now that you have had this Mod for a while have you had any problems with it or are you as happy as a pig in poo!

Dave

Very pleased with it!
My wife can now actually fit in the passenger seat with some degree of comfort.
The battery I used was a slight gamble as it is so small, but has proved to be excellent under all conditions, I have just started the car (first time in 2 weeks) and the battery turned the engine over just a fast as it does in the summer, despite it being 1 deg C at the moment..

Andy

[lotusandy]

To make it really easy you could just chuck the standard battery & its box in the bin and then fit the same battery that I used, it would gain you a fair bit of extra room without all of the hassle.
The only professional I know that might be able to help is Dan at Taylor TVR nr Maidstaone, but due to the time involved I expect it would be somewhat expensive.

Andy

[lotusandy]

Dave - I just un-wound the mess of a loom that was in the footwell, it was quite a tight fit to get it to reach to the new fuse box position, but there is just enough length in the wires as you can see in the photos

Andy

[lotusandy]

Mark,

I got the battery cables from here - http://stores.ebay.co.uk/kojaycatvehiclewiring the will make up battery cables to your spec.
The lengths I used are below,
Red cable Length 3M termination M6 end 1 M8 end 2
Black cable Length 2.6M termination M6 end 1 M10 end 2

The M6 ring ends go to the battery, the other ends go to the earthing point (M10) on the chassis and the starter motor (M8)
The Red cable was a little short, so I woul fo for a 3.5m lenght if I did it again.

Other bits were bought from Polevolt or vehicle wiring products.

Andy

Should have told you the cable size!
40mm 300 Amps BATTERY STARTER CABLE

Edited by lotusandy on Sunday 25th July 16:19

[lotusandy]

From memory I ran the live back from the starter motor then crossed the transmission tunnel under the gearbox, then drilled a hole by the front of the passengers seat then back past my new fusebox location & up and back to the battery location.

The 40mm refers to the cross sectional area of the conductor, so this means the cable conductor is about 7mm dia, the overall dia is about 12.5mm.

[lotusandy]

Dimensions here.. http://www.odysseybatteriesonline.co.uk/odyssey/ot...
Yup would be perfectly feasible to move the fusebox & use the PC925 battery in the existing place, although you would need a new smaller battery box.

Andy

[lotusandy]

Pacman1972 said:

Hi Andy,

On the verge of ordering one of these batteries.
Now you have it for a while has the lower capacity caused any grief or do you need a trickle charger or cut-off to prevent it draining too quickly?

Hi Steve,

The smaller battery capacity has made no differnce at all since i fitted the smaller battery, I do use a trickle charger in the winter & I often don't use the car for 2-3 weeks, but then This is just a habit going back to my Caterham days..

Andy

[lotusandy]

Dickie Dastardly said:

Evening all,

Sorry for resurrecting an old thread however I am in the midst of fitting a battery (same as the one used by lotusandy) into the boot.

The one area I am still concerned about is the routing of the battery cables. To run from the boot into the passenger foot well then follow the old routing would require some 5mtr of +pos cable which seems extremely long. I notice from some of the comments that tyre tread came to a similar conclusion. Again apologies for the repetition but if the following could be clarified it would be very appreciated -

1. From the boot what route did the positive cable to the starter motor take?
2. What route did the negative cable take, was the original earth point at the front of the transmission tunnel used and if not what point was used for earthing.
3. There are smaller twin constant live feed cables from the battery to the back of the fuse box (on my car these reach an in-line fuse block just before the fuse box) - what route did these take and was the cable size also increased.

Any advice or photos would be great to put my mind at rest,

Thanks
Richard

Richard,

I routed the positive cable along the floor by the side of the transmission tunnel on the passengers side, then I drilled a hole through the floor under the seat and fed the cable along the chassis to the starter motor terminal, this ensures the shortest length of cable.

I ran the negative cable along side the positive, then up to the original negative chassis point, but there is no reason why you could not attach it to any other good point on the chassis.

I extended the 2 cables that go directly to the fuse box with some cable around 10mm sq, you could replace them with 1 but I had some suitable cable lying around so I did both.
I'll see if I've some photos later if that would help.
Think I answered most other questions you may have over the history of this topic have a read through..
Andy