Charlie/Betty Burke wrote:
8<
> Our customer's experience with Optima batteries has not been all that good.
> While their construction makes installing them very flexible, their capacity is
> quite limiting. When you go shopping be sure to compare Reserve Capacity Minutes
> (RCM) for different deep cycle batteries. You will find the Optima is at the low
> end of the scale. RCM is kind of the EPA mileage for deep cycle batteries. It
> defines a rate of discharge for a given length of time.(25A per minute). While
> one would rarely use a battery at that rate it gives a basis for comparison. An
> Interstate Group 27 battery (what Airstream currently uses) has an RCM of 160
> minutes.
>
> Charlie
Hi Charlie,
I'd be interested in specific details of problems your customers have
encountered. Optima batteries are very popular in off-roading circles,
because the deep-cycle battery can be used for starting, and the extra
demands of winching and auxilliary lights (which are critical for night
driving in forrests and the desert) are often best handled by a
deep-cycle. Further, I have friends who've run Optimas for years as
starting and winching batteries and have participated in multiple
competitions where the batteries were worked very hard winching, etc.
Also, are your customers using one or two Optimas? Placing two in
paralell doubles the RCM.
Admittedly Optima batteries have an RCM of 120, which is, indeed, less
than the Interstate Group 27 battery's 160. However, Group 27 batteries
are 12 1/16" x 6 13/16" x 8 7/8" = ~718ci (from
http://www.rtpnet.org/~teaa/bcigroup.html -- I was unable to find
Interstate's claims for dimensions on their web site). The Optima
yellow tops are 10" x 6 3/4" x 6 3/4" = ~ 455ci That yeilds ~ 0.223
RCM/ci for the Interstate, and ~0.264 RCM/ci for the Optima. Thus, the
Optima has an 18% better RCM/ci rating. But, it doesn't stop there.
There is the matter of what can actually be made to fit. Since fitting
two group 27 batteries in the rear of my trailer is nearly impossible,
if I use one, my RCM capacity will be limited to 160. Since I can fit
two optimas easily, my RCM will be 240. That difference is 33.3%.
That's why I chose Optima over other battery types.
C
To unsubscribe or to change to a daily Digest, please go to
http://www.airstream.net/vaclist/listoffice.html
If replying back to this message, please delete all the unnecessary original
text from your reply.
