Some sort of hybrid...
"A dual or starting marine battery is a compromise between a car and a
deep cycle battery that is specially designed for marine applications.
A deep cycle or dual marine battery will work as a starting battery if
it can produce enough current to start the engine, but not as well as a
car battery. For saltwater applications, AGM or gel cell batteries are
highly recommended to prevent chorine gas."
http://www.marine-electronics.net/techarticle/battery_faq/b_faq.htm
I think I saw the word "starting" on the battery as well. Not sure;
don't remember.
I guess I'll look for an RV deep cycle then.
When I do find my RV deep cycle, would a regular cheap battery charger
(such as is used for charging car batteries) properly charge a deep
cycle battery as well?
Thanks,
Michael
Andy answers:
Yes. The battery chemistry is the same but the deep cycle battery
will have internal plates of a different thickness...
If you can charge the battery at a lower rate , say 2 to 6 amps, it
will be better . Since you are using if for campling, I assume you
will be using it on weekends and have the entire week to charge it.
That is a good scenario....
Buy yourself a hydrometer. They cost 3-4 bucks and give a reading
of the specific gravity of each cell . They are the very best
indication
of the state of charge of the battery. If you do a google on "lead
acid
batteries" you should find a wealth of data on what the readings should
be..... Make sure your battery allows you access to each cell. Sealed
batteries do not. You need this capability to maximize the battery
life.
Do NOT use battery terminal voltage to determine state of charge. There
are many reasons why this is inaccurate.
There are two really good ways to ruin a lead acid battery. The
worst
is to leave it in a discharged state. The other is to overcharge
it......
The SG hydrometer will tell you the battery condition after the
camping trip, and you can put on the slow charger, and every day
take a reading till you get to a fully charged state......Then you can
disconnect it, or use a "float" charger. One is sold by
www.harborfreight.com for about 6 dollars..... It isn't very good for
charging , but for maintaining the charge to counteract the
battery self-discharge ( aka leakage)..... Some battery chargers in
the 2-6 amp range have this capability built into them.....
By the way, there are two uses for marine batteries. One is for
starting a big boat motor. They deliver a big slug of current just
like in a car, and used the boat's alternator to recharge, just like
a car.
The other is to run a trolling motor at 3 to 15 amperes for 10 or
15 hours. They are NOT made to deliver massive slugs of current
and are deep cycle type...... The fisherman uses the motor
to ride around drinking beer all weekend
while he pretends to fish , and then goes home and puts
it on a small charger until the next weekend...
These two goals are almost opposites. A battery that is claimed
to do both jobs is optimum for neither.... However, a deep cycle
battery MIGHT give enough of a current slug to start a big motor,
but the internal heating could buckle the plates. Best to use
a battery suited to your operation , and RV batteries are not
ambiguous.....
Andy in Eureka, Texas
