Battery

[twinstacks]

Guys the battery tray in my berlinetta seems very small. I have a big heavy duty diesel battery that has a fair kick in it and was wondering if anybody has fitted the battery in the boot and run a main cable along the floor to the starter motor ? Would the voltage drop be to much ?

Many Thanks

[greyV8pete]

Re: Battery

The battery in my Rover V8 Hunter is in the boot. It is a Varta D59, link below for details. It has always had this model battery fitted and it turns the V8 over no probs. The previous one lasted 10 years! You will need a decent cross section of cable to minimise voltage drop. No idea what my cable is but it does the job! Peter.

https://www.batterymegastore.co.uk/product/varta-blue-dynamic-d59-car-battery/

[scott h]

Re: Battery

When I first built my V8 powered Berlinetta in 1993 the battery was put in the boot due to lack of space in the engine bay. I used heavy duty cable and had no problems during 18k miles of use. When I rebuilt the car the battery was again located in the boot, although this time the engine is a 2l 16v.

An alternative would be one of the latest high tech lightweight batteries that are just as powerful but smaller in size.

[twinstacks]

Re: Battery

Thanks guys. Does anybody have an idea as to what size and type of cable I need to run from battery to starter motor ?

[h_m_cumming]

Re: Battery

This any help

[scott h]

Re: Battery

Depends on the starter motor. Find the power of the motor then use the formula:
Current (amps) = Power (watts) ÷ Voltage.
Then add say 50% extra amps for safety, and that will give you the amps that the cable needs to carry. Probably the 170 amp cable below would do but you can see there are other choices.

https://www.vehiclewiringproducts.co.uk/p-1030-battery-starter-cable

[twinstacks]

Re: Battery

Thanks. I take it that it’s better to be to high a rating rather than to low a rating ? I am not sure what the amps of the starter is. It’s a new one if that’s anything to go by.

[scott h]

Re: Battery

Yes if the amps required by the starter is greater than the amp capacity of the cable then the cable will melt! You should be able to find the power of the starter on google.

[ggrum]

Re: Battery

One way would be to check the max cold cranking current of the battery and choose a cable x-section to match. I think a typical value for a car is around 300 to 350A. From the table above this would imply using a nominal conductor area of around 95 sq mm which is approx 11 mm diameter. Personally I think this is a bit larger than necessary and is probably a continuous rating and will be quite expensive but would be safe.

[HairyDave]

Re: Battery

A simple answer would be, to ask an auto electrician or supplier. They could then provide the cable etc.

[daveghunt]

Re: Battery

Just to support the above
Bentley fit the batteries in the boot, that's with a 6ltr W12. (similar VW / Audi installations)
If my memory is correct they where about 12mm dia, a right sod to route through the cabin!
good luck Dave H

[twinstacks]

Re: Battery

Thanks for every bodies help. Why is the battery tray on the Berlinetta so bloody small !