Ryan P. wrote:
On 3/16/2016 6:53 PM, Alex wrote:
Ryan P. wrote:
On 3/16/2016 10:36 AM, wrote:
On Wed, 16 Mar 2016 08:01:41 -0500, "Ryan P."
wrote:

On 3/15/2016 4:22 PM, wrote:
On Tue, 15 Mar 2016 15:54:11 -0500, "Ryan P."
wrote:

On 3/15/2016 2:42 PM, John H. wrote:
On Tue, 15 Mar 2016 11:57:40 -0700 (PDT), Tim
wrote:

"
Without an alternator, though, I'm worried about leaving it
at a slip.
I have an accessory battery, so I'm not worried about getting
stranded, but running lights and a stereo take up juice. "

Why no alternator? I'm not following...

I'm glad you asked that. I was going to do so, but then thought
it might somehow be a
real stupid question.
--

Ban liars, tax cheats, idiots, audiophools, and narcissists...not
guns!

I'm the one asking the stupid questions, I'm sure. I'm the
novice
here, compared to most of you folks.

Okay, I should use the proper terms, I suppose. Its a 1985
Mercury 75.
I do have electric start, but my understanding is that on older
engines, a stator/vr is only to trickle charge the starting
battery, and
only does that at high RPMs?


I was guessing that you had one without a charging system. That
old 75
has a 9 amp alternator in the stator. If it is working, it will keep
your battery up if you are running it fairly often. It will put out
pretty well at anything much over an idle. (I had one)


But can I link that to the "house" battery? If I jump the starter
battery and the house battery together, won't the house battery draw
down the starter?

Battery switch or isolator. BTW don't run in "both" on a battery
switch. Charge one, then the other. It is the only way to reliably
charge 2 batteries if you are not using an isolator and still the best
way. Both is really just an artifact of the "make before break" design
of the switch but it might be useful if both batteries are down and
between them you have enough to kick over the motor. It is the only
real use.


I'll throw a volt meter on the battery and make sure the charging
system is working properly when I take her out of storage in a few
weeks. A battery switch is pretty simple to install... If its really
producing 9amps, that should be more than enough to keep the house
battery alive if I let it charge while pulling kids on the tube or
whatever.



What you need for your application is a battery combiner. I have one on
my bass boat and it works great. It will keep the starting battery
topped off and then switch to the house battery - or in my case the
deep-cycle trolling motor battery. Here's just one example:

http://www.charlesindustries.com/main/battcom.html

Not bad... Just an automatic battery switch, really... For a bass
boat application, or other short-run situations, do you think its
necessary to have a voltage regulator for the deep cycle?


I'm not sure what you are asking. The combiner I have doesn't care if
the batteries are a different size, or type, so there is no need for an
inline voltage regulator. We often make long runs in our bass boats.
The starting battery is only used..for starting so it's quick to get
that one back to full charge. The trolling motor battery - or house
battery in your case - is another matter and benefits from the on the
water charging.