Light weight battery options -Help required

[old-git]

I have now got to the point in the build where I have to decide where to locate the battery. Do I place it at the back to aid weight distribution but with the added weight of heavy battery cable, or place it at the front with less cable but compromised weight distribution?

In order to help me to come to a decision I need to know the smallest battery size and weight I can get away with. This is where I need your help, suggestions and comments.

The car has no unnecessary electrical items. No heater, no ICE, no extra lighting, etc. Only basics. Engine is 2litre 4 cylinder Cosworth turbo using high torque starter and a 50amp alternator. Car will be road legal. If you are new to this forum, have a look at the "At Last!. I have started my car " thread.

Any suggestions as to what would be a suitable battery, bearing in mind that I am looking for lightness and smallness?

[pgarner]

newbies read here
http://www.torquecars.com/forums/f8/...d-my-car-2454/

6kg do you
http://www.xlraceparts.com/lightweig...ries-210-p.asp
was looking at the redtop 25 - 16Ah and 680A cranking
is that enough for you

[old-git]

Originally Posted by [URL

http://www.xlraceparts.com/lightweight-varley-racing-batteries-210-p.asp[/URL]
was looking at the redtop 25 - 16Ah and 680A cranking
is that enough for you

I don't know, that is why I am asking Will it be able to cope with normal road use?

[pgarner]

i would hae thought the alternator would be able to supply for when the engines on as youve said theres no high drainage items on the car.
50 Amps at lets say 13V gives you 650w of usage from the alternatot

headlight 50w
dipped 50w ( cant remember if theres 2 lamps in your setup )
sidelight 5w
taillight 10w
brake 10w
indicators 10w
total 135w x 2 is 270 watts if only 1 headlight bulb then 160w
didnt bother with foglights as i cant see you taking it out in heavy fog.
that drain around 13 amps leaving the altinaor 37 for the charging system, wipers and ecu ( is that all the basics ?)

and a kill switch / isolator or even just remove the +ve terminal when its in the garage.

hope someone will be able to back me up on this as dont want you to go out and spend £120 on a battery then it not be enough

[stamford]

I would recommend giving the guys at Merlin Motorsport a bell on 01249 782 101, website linky they will be able to assist you with the right choice.

[HDi fun]

50 amps should be plenty. Basic cars often used to come with little tiny 30 amp alternators. Given this is effectively one of those from an electrical standpoint I think you'll have ample reserve capacity.

[old-git]

Originally Posted by stamford

I would recommend giving the guys at Merlin Motorsport a bell on 01249 782 101, website linky they will be able to assist you with the right choice.

Thanks, I will give them a call on Monday.

[old-git]

Originally Posted by HDi fun

50 amps should be plenty. Basic cars often used to come with little tiny 30 amp alternators. Given this is effectively one of those from an electrical standpoint I think you'll have ample reserve capacity.

That was what I was hoping, thanks.

[old-git]

Originally Posted by pgarner

i would hae thought the alternator would be able to supply for when the engines on as youve said theres no high drainage items on the car.
50 Amps at lets say 13V gives you 650w of usage from the alternatot

headlight 50w
dipped 50w ( cant remember if theres 2 lamps in your setup )
sidelight 5w
taillight 10w
brake 10w
indicators 10w
total 135w x 2 is 270 watts if only 1 headlight bulb then 160w
didnt bother with foglights as i cant see you taking it out in heavy fog.
that drain around 13 amps leaving the altinaor 37 for the charging system, wipers and ecu ( is that all the basics ?)

and a kill switch / isolator or even just remove the +ve terminal when its in the garage.

hope someone will be able to back me up on this as dont want you to go out and spend £120 on a battery then it not be enough

Normal old fashioned sealed beam 7" round headlamps. As you say, no fog lamps but will fit a reversing lamp.

Thanks for taking the time to work this out.

[waynne]

I've been thinking about this a lot. Would a motorcycle battery be man enough? As far as I know they are 12 volts. You could always keep a booster spare handy for jump starting it at event if the drain is too much.

[old-git]

Originally Posted by waynne

I've been thinking about this a lot. Would a motorcycle battery be man enough? As far as I know they are 12 volts. You could always keep a booster spare handy for jump starting it at event if the drain is too much.

I think the problem is with the torque required to turn over a large car engine compared to a small, lightweight bike lump. Taking it to the extreme, I could line up 8 AA batteries to get 12 volts but the engine wouldn't turn over