----- Original Message -----
From: <stantr6@bellsouth.net>
To: <triumphs@autox.team.net>
Sent: Tuesday, October 29, 2002 9:23 PM
Subject: Battery rating
> List,
> What rating battery should I get for a TR6 ?
> Owners manual says "capacity at 20 hour rate - 57 amp. hour"
> What does that translate into as far as how batteries are rated today ?
> thanx,
> Stan
Stan-
I'm chiming in a bit late on this, but I'm behind on my mail.
Amps/hour is an older method to rate a battery. It is not used much any
more. It meant that it would take 20 hours at 57 amps until the battery
would drop to 1.75 volts per cell, or 10.5 volts total. Most batteries now
are rated in cold cranking amps (CCA); this rating is acheived by applying a
load to the battery for 30 seconds at 0 F and the battery does not drop
below 1.2 volts per cell (7.2 volts total). 7.2V is about the minimum
voltage most ignition systems require to operate. The CCA number is the
amount of load applied. The higher the number, the stronger the battery.
Beware of the cranking amps (CA) number however. Those sneaky marketing
types will often put the CA number in much bigger print than the CCA number.
The CA is rated at 32 F and is a bit tainted, especially for us northerners.
The CCA number is the best way to judge a battery's power. The weight of the
battery is another good way to judge the battery's power, the heavier it is,
the better it will be.
Hope this clarifys it a little better.
Tim Hutchisen
71 TR6- 475CCA
80 TR7 Spider-525CCA
86 Dodge slant 6- 875 CCA- ready for winter!
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