Re: (ET) 12V batteries (Was mounting a rotarty invertor?)

[JBR <reinharj frontiernet net>]

You are correct if you are referring to standard 12vdc flooded automotive 
batteries.  But I think some of these guys are using Gel Cells / SLA 
(Sealed 
Lead Acid) which are often well constructed (the 100 AH 12v battery 
probably 
costs about $100), and I think have pretty good discharge current ratings 
(my 
UPS pulls a HUGE amount of current out of the battery - most of its charge 
- 
in 10 or 20 minutes.

On Thursday 31 August 2006 8:31 pm, David C Robie wrote:
> Advice regarding 12V batteries in ET's.  Don't use em except for testing.
>  Have had much exprience with them back when I couldn't get 6's except at
> great expense.  12's are not built for sustained high discharge rates and
> will soon fail internally, usually by shorting out a cell. This puts both
> 2 volts less and a relatively high series resistance into your pack,
> robbing you of power (and often in the middle of a half mowed lawn).
> With the 'series parallel 12' scheme, a shorted cell drags everything
> down by 2 volts and the charger works overtime, never tapers down and
> overcharges the heck out of the rest of them.
> 12's are also built 'cheaply' in many cases more for profit by the dealer
> than for load carrying capacity.  It is well known that the average car
> battery, even in the intermittent duty of starting and regardless of
> slick advertising goes about 3 years.  12V Boat batteries seem to go
> about 2,  as they are often left at a low charge level.   With the 6 volt
> 105 ones, 8 yrs in an ET is not unusual.   Check the recent thread about
> using recycled 6V batteries.  Been there done that still doing it and as
> we 'Swamp Yankees' say,  happy as a clam.
>      Same number of total electrons?  MYGAWSH it must be a tough job to
> count em.
>
> Dave
> Weymouth MA
>