Unless you maintain them, they will both be dead when you want to use
them. Use a battery switch... start and run on one battery (to charge
it) Then when you stop to play with your toys, switch to the other
battery. When you are ready to go home, try and start on the battery
you used.... if it works.. great... it will charge on the way home... if
not, switch to the other and start the engine to get home and then don't
forget to charge both when you get home.

another option... I have 2 batts on my 17' tender and I use a perm
mounted 2 battery charger so they are both always fresh. They will
last longer and within 2 years, they will have pd for the charger due to
fewer battery replacements.



JimH wrote:
"Bryan" wrote in message
et...

" JimH" jimh_osudad@yahooDOT comREMOVETHIS wrote in message
...

"Bryan" wrote in message
.net...

I'm thinking of adding a second battery to my 18 foot bowrider. I want
to use one battery for the engine and one for the stereo and lights and
air pump and ...

I don't want to lose my engine starting ability due to a battery that's
been run down using accessories.

My first battery is a Marine/RV Cranking type (I can't read the labeling
to know what it's amp hour rating is).

What type should my second battery be?

Thanks


A deep cycle with decent CCA's.


Care to explain your answer or should I just blindly accept your advice?
; ) Oh yeah, and I don't know what CCA's are or maybe I do, I'm not sure.



You said you will be using the second battery for accessories.....that is
what a deep cycle battery is designed for.

You can also combine engine cranking ability with the accessory draw demands
by purchasing a deep cycle battery with a decent CCA (cold cranking amps)
rating.

I would consider a Group 27 deep cycle battery with as high as CCA's (650
minimum) as you can find.

Good links:

http://www.windsun.com/Batteries/Battery_FAQ.htm

http://www.windsun.com/Batteries/Battery_FAQ.htm