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12v 26Ah 200A battery - up to the job of keeping in car?
jimmyd - 2/3/14 at 08:25 PM

I really can't get my head around battery spec & requirements for my CVH engine.

During my build I've been using an old battery out of a BMW 318 and it's massive so been thinking what to use. Today I went to get a battery for my ride on mower and when I saw the size I wondered if it was man enough to do the car. It's 26Ah 200A which means nothing to me but certainly started the car when I experimented before cutting the grass.

Physical size is probably a little bigger than a race spec battery and probably 1/4 to a 1/3 of the cost.

So what's the minimum Ah I could use with a CVH engine in a basic Locost i.e no wipers, heater etc

Sorry for what may be a dumb question I ready can't find any real guidance.

Thanks in advance.

J


britishtrident - 2/3/14 at 08:37 PM

ISTR Caterham used 25AH for years --- just by a decent quality one keep charged up.


coozer - 2/3/14 at 08:40 PM

I used a bike battery for my 2L zetec with no problems..


matt_gsxr - 2/3/14 at 11:14 PM

As I understand it there are 2 numbers for a 12v battery.

26 Ah (Amp Hours) so basically the capacity of the battery. In practice this doesn't matter much, as if your alternator isn't generating more current (Amps) than you are using then your battery will go flat however big it is. Although it does relate to how many times you can fail to start the engine.

The other measure is 200A. 200A in this case is the peak cranking current. That is basically the maximum current that the battery can pump out when it is short circuited by the starter motor. This is important because if it is too low you won't start!

In practice the capacity (Ah) and the cranking current (Amps) tend to correlate, and this also correlates with battery weight. The exception is with more exotic batteries ( Odyssey, Red Top, Russbot specials, etc.) where they get lightweight and high cranking performance.

From what I have read 200A is perhaps a little on the low side for a car engine, fine for a motorbike engine.

In terms of lbs/£ an lightweight battery is definitely in the top five cost efficient ways of saving weight.


coyoteboy - 3/3/14 at 12:23 AM

As above, I'd want something a bit better than 2000cca but it might cope. The official starter rating for my v8 is 2.2kW, which is about 185A so smaller would be less, but will your battery always be in tip top condition and when you leave your sidelights on for 30 mins to nip into a shop...


britishtrident - 3/3/14 at 07:30 AM

Measured with dc clamp meter normally at 10c ambient at cold start expect. a 1.4 engine to draw 60 amps and a 1.8 engine to draw 80amps.

These figures are for a Rover K engine.


jimmyd - 3/3/14 at 08:31 AM

Thanks for the replies, very helpful.

J


Smoking Frog - 3/3/14 at 10:46 AM

Seen this 30ah 300cca one, measures 187mm Long, 128mm Wide, 165mm High so not that big. Never had one, so can't recommend.
Caterham battery Banner 53034 supplied dry with acid pack O.E. specification.***

[Edited on 3/3/14 by Smoking Frog]


bimbleuk - 3/3/14 at 12:54 PM

1.6 4AGE - I used 19 Ah bike batteries for 7 years. More than adequate but the car was always garaged so rarely started from stone cold.


jacko - 3/3/14 at 01:05 PM

quote:
Originally posted by Smoking Frog
Seen this 30ah 300cca one, measures 87mm Long, 128mm Wide, 165mm High so not that big. Never had one, so can't recommend.
Caterham battery Banner 53034 supplied dry with acid pack O.E. specification.***


Thats like my battery and had it about 8 years on the indy pinto engine
Jacko