[TR] battery summary

[nwolf at u.washington.edu]

On Sun, Sep 21, 2008 at 6:54 AM, <dorpaul at bellsouth.net> wrote:
[...]
>I wonder if batteries that are sealed are maintainence free (even though 
>they are not called 'maintainance free' ?
[...]
>Also, recently there was an email saying something about 'vented
>batteries'...What are they?

Hi Paul
   The two main categories of car batteries are Vented and Valve-Regulated.
   "Vented" batteries are the ones you see all the time with caps on top, prone to occasional leaks and sometimes in need of topping up.
   "Valve-Regulated Lead-Acids" (VRLA's), also known as "Recombinant" batteries, are supposed to recombine any H and O produced during charging, so that they don't have to vent under normal operation.  They are also referred to as "Sealed" batteries (though they have pressure-relief valves), or "Maintenance Free" (though you still have to keep them charged).  AGM's, including Optimas and Exide Orbitals, are VRLA's.

-Nick Wolf
'62-ish TR4
Seattle