[C38] Cruising without inverter

[les]

There are many kinds of inverters out there.  

One of the most popular does what you say yours does.  It performs both
the charge and inverter operation.  It is connected in parallel with the
engine charging system (alternator/regulator).  However, if you are
relying on the charging capability at the dock, you will want to check
if the inverter is working in that instance.  

The next time you tie up, before you connect AC power, check the voltage
on the battery terminals.  It should be somewhere between 11.5 and
12.73V, depending on the state of charge.  Wait about 1/2 hour, and you
will probably see it drop.  This is because you likely used the engine
to get into the dock.  Write down the number.  This is the state of
charge of the battery.  There is a nice table on the Trojan website that
you can print to show the state of your battery in terms of charge
percentage.  More about that in a minute.  

Now plug in the shore power cable.  It should rise.  Depending on the
battery type, to about 13.x volts.  The x is due to the slight
differences in AGM (absorbed glass mat), wetcell, or other technology in
the battery case.  You will want to make sure when you change batteries
that you either keep the same kind or that you set the charger
appropriately (and the alternator regulator as well) to the setting for
the new battery type.)  If you see the voltage rise you know the battery
charger is still working on your inverter/charger.

Back to the battery charge percentage... Batteries wear as they are
used.  The wear causes the state of the acid to change.  A float gauge
will show you the state of the fluid in wet cell batteries.  As it ages,
the acidity (PH number is a measure of acidity) changes and the float
will change how high it rides in the fluid.  The total battery capacity
changes as a result of this change (and somewhat due to other changes.)

The voltage measured earlier will reflect the state of the total
capability in percent.  

To give you a concrete example:

		new battery     1 year old      3 years old
capacity	120AH            110AH          90AH
measured        12.73v            12.73v          12.73v
avail cap      120AH            110AH          90AH
measured        12.1v            12.1v          12.1v
avail cap       60AH             55AH           45AH

This is for a deep cycle battery that is very heavily discharged each
cycle.  The deeper you discharge the battery or the higher the current
you draw, the faster the battery looses capability.

Checking the cycle specs on the batteries you have will help you choose,
and also keeping in mind the necessity of having the charger systems,
solar, alternator and AC all set properly.  Most have a simple switch
that says AGM or some thing like that on one side and wet cell on the
other.

Here is the link to the Trojan User manuals and other information.
http://www.trojanbattery.com/Tech-Support/TechSupport.aspx


Regards,
Les H        
On Tue, 2011-10-18 at 06:37 -0700, Patrick Harpole wrote:
> Larry,
> First of "thanks" for you response.  Great community we have
> My inverter tops off batteries when I am plugged into shore power.
> Patrick
> 
> I assume it will run fine without inverter
> 
> 
> ----- Original Message ----- 
> From: "Larry Malmberg" <Larrypi at roadrunner.com>
> To: "'Catalina 38 Listserve'" <listserve at catalina38.org>
> Sent: Tuesday, October 18, 2011 6:04 AM
> Subject: Re: [C38] Cruising without inverter
> 
> 
> Patrick, I'm a little confused here.  Inverters convert, usually, DC to AC
> or AC to DC.  That said, I would suspect your alternator will keep you
> batteries charged as long as you run the engine to keep them topped off.
> 
> 
> 
> 
> 
> 
> Best regards,
> 
> Larry Malmberg
> Team Hassle
> 
> 
> -----Original Message-----
> From: listserve-bounces at catalina38.org
> [mailto:listserve-bounces at catalina38.org] On Behalf Of Patrick Harpole
> Sent: Tuesday, October 18, 2011 5:35 AM
> To: Catalina 38 Listserve
> Subject: [C38] Cruising without inverter
> 
> My inverter needs repair.
> Can I sail without it, that is, does the engine of a generator or alternator
> to keep batteries topped off?
> Patrick
> 
> 
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