Moved battery to boot
Discussion
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
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
Nice job. 
Was there a way you calculated the effect of the low internal resistance in an Odyssey battery?
Did you calculate it was equivalent to a normal battery of some higher CCA, or was it just an educated guess that it was sufficiently powerful?
How well does it cope with a hot engine?
I was looking at a battery swap using an Odyssey Extreme 40 battery. This will fit into the original battery box and give 45AH.
As it's smaller than the original battery, the battery box could be cut and shut, increasing legroom by about 80mm.
The only thing is, I,ve been told by someone with experience of using smaller than standard Odyssey batterys in racing TVR's that hot starting can become uncertain.
He said that as mine is a tuned 500 and would therefore take more power to crank than a standard 400, it might run into similar problems.
Has anyone else tried a 45AH and what was the result?
Was there a way you calculated the effect of the low internal resistance in an Odyssey battery?
Did you calculate it was equivalent to a normal battery of some higher CCA, or was it just an educated guess that it was sufficiently powerful?
How well does it cope with a hot engine?
I was looking at a battery swap using an Odyssey Extreme 40 battery. This will fit into the original battery box and give 45AH.
As it's smaller than the original battery, the battery box could be cut and shut, increasing legroom by about 80mm.
The only thing is, I,ve been told by someone with experience of using smaller than standard Odyssey batterys in racing TVR's that hot starting can become uncertain.
He said that as mine is a tuned 500 and would therefore take more power to crank than a standard 400, it might run into similar problems.
Has anyone else tried a 45AH and what was the result?
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
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
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.Adrian@
The negative cable just runs along the tunnel and up to the existing eart point.
Andy
ekim said:
what is the advantage to doing this?
Ease of access to the fuses and relays which usually require the adoption of a pose usually only taken by a vet performing an intimate examination of a cow to change...ekim said:
why is the battery in the footwell a big problem, am i missing summet?
Restricted legroom when you're a big fella...Phil
Can't believe that anyone thinks that the original set-up in the footwell is a satisfactory installation. The ECU and relays aren't even fixed down FFS. Metal parts lying around on top of a car battery. IMHO it is THE worst of a host of "unusual" TVR installations.
The fusebox behind the seat and the battery in the boot looks an excellent job to me and I may attempt it myself.
Phil
The fusebox behind the seat and the battery in the boot looks an excellent job to me and I may attempt it myself.
Phil
Pau1 said:
Nice install, but what happens when you get a flat battery and you can't pop the boot open via the solenoid anymore...
A myriad of possibilities and options...Simplest probably being Accumate / Optimate into the ciggie socket to just kick enough current into the system to be able to spring the boot.
Otherwise, battery charger to back of alternator is another possibility or the fitment of an Anderson connector somewhere handy would also do the job...
Phil
Having done this for a customer.....he had seen this post ...I put the battery further across into the wheel arch so that it did not encroach on any space in the boot, I had previously moved the space-saver to the later central position as on the later cars and moved the fuse box out of the foot well to behind the seat, on this car I found the re-positioning of the relays etc. a little easier as the car had the battery box that had been mounted off the floor and further into the wheel arch, which when removed left a nice little area that I could mount things onto flat board and face them forward into the space...when the car is back in I will post a picture or two.
Adrian@
Adrian@
Adrian@ said:
Having done this for a customer.....he had seen this post ...I put the battery further across into the wheel arch so that it did not encroach on any space in the boot, I had previously moved the space-saver to the later central position as on the later cars and moved the fuse box out of the foot well to behind the seat, on this car I found the re-positioning of the relays etc. a little easier as the car had the battery box that had been mounted off the floor and further into the wheel arch, which when removed left a nice little area that I could mount things onto flat board and face them forward into the space...when the car is back in I will post a picture or two.
Adrian@
How big a job (read that as "How much would it be likely to lighten the pocket by") is that then?Adrian@
Would be nice to sort out that rats sh*t of wiring in the footwell and get a bit more legroom...
Phil
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