[C38] Fwd: Battery Power

Thu Feb 18 08:38:55 EST 2010

Steve,
I have two batteries in my port battery box.  One is a "standard" sized 
deep cell and the other is slightly larger.  Yes, I know I said it is 
good to pair your batteries, but one of mine had a cell failure way up 
in the remote areas of Lake Huron and I had to take what I could get.  
The new battery is a type 27, which required I cut out the lower corner 
of the battery box (not structural).  As I recall, it is a 130 amp hour 
battery (amp hours is a common term used in the discussion of batteries, 
but it is really only an poor estimate of capacity). 
Each battery has its own isolator of course located close to port of the 
batteries. 
I also have a "A or B or Both" battery switch for the wind charger and 
solar collectors mounted just on the settee wall just forward of the 
battery box.  The wind charger has its own regulator and I have an 
additional smart regulator/switch for the 195 watts of solar panels.  
Finally, I have a 2000 watt inverter mounted under the galley sink 
drawer.  I chose that location to reduce voltage drop, which can be a 
problem with the heavy load this inverter can develop. That is also why 
I mounted the wind charger/solar panel switch as close as I could to the 
battery bank.  While I really like what you have done with Blue Seas, 
with central controls all in one place, every foot of heavy cable and 
every switch creates resistance (the math on this is revealing), so I 
went with two control locations.
By the way, it is interesting that we insist on "marine grade" wiring, 
but when you take apart one of these battery switches we find pure 
copper on the better ones and alloys on others!  This a real problem as 
these switches work under load with "arcing" being a problem (another 
resistance issue).  I try to reduce this issue by first turning off 
heavy loads before switching banks.  This is especially important on the 
charging circuit side...

Sorry for the long answer to your short question!  As you can see, I am 
a bit over the top about this!  I do all my own maintenance and 
upgrading, figuring it is better to know these systems when they break 
down in the most remote locations at the worst possible time!

Chuck
Mighty Quinn #114
Great Lakes

Steve Smolinske wrote:
> Bob,
>  
> Like Charles I also isolated the start from the house bank, I used the Blue Sea Systems Dual plus circuit switch, http://bluesea.com/category/1/products/6011  Instead of 1, 2 and combine it only has on and combine settings.  In the on mode the house and start are both operable and isolated from each other so no need to worry which battery switch setting is  house and which is start, just turn it on and forget about it.  The combine gives you the ability to combine both banks in an emergency.   I also have a third bank (33 amps) which is my emergency bank it is wired only to the  tricolor, strobe and VHF/GPS/AIS.  It is also  isolated from the other batteries by its own single bank battery switch, in its configuration the DC subpanel and main battery switch have to be turned off before using or else it would equalize with the other batteries when the switch is turned on.  Its located under the quarter berth just forward of the fuel tank, with the switch mounted just above it.     
>  
> Charles, where do you have your second house bank located?  Im assuming your first is in the battery box under the port sette.  
>  
> Steve
> Peregrine #312
> Seattle
>
> ________________________________
>
> From: listserve-bounces at catalina38.org on behalf of Robert Miller
> Sent: Wed 2/17/2010 3:54 PM
> To: 'Catalina 38 Listserve'
> Subject: Re: [C38] Fwd: Battery Power
>
>
>
> I just ordered a copy of Calder's book.  Thanks, Chuck.
>
> Bob Miller
> "Bolero" #113
>
> -----Original Message-----
> From: listserve-bounces at catalina38.org
> [mailto:listserve-bounces at catalina38.org] On Behalf Of Charles Finn
> Sent: Wednesday, February 17, 2010 3:39 PM
> To: Catalina 38 Listserve
> Subject: Re: [C38] Fwd: Battery Power
>
> Mike,
> If you are reading 10.7... time to get a new battery! Theoretically,
> each cell can provide 2.1 volts, which adds up to a max reading of (6
> cells x 2.1)= 12.6 volts. You might be a bit concerned if you have been
> using the "ALL" setting on your battery switch as battery voltage
> differentials will harm you good battery. This is why many folks
> advocate buying your batteries together.
>
> The best way to figure out which battery is the engine starter is to
> look for the heavy wire going to your starter. Begin at the battery or
> the starter and trace back. My guess is the smaller battery is your
> starting battery as 10.7 volts probably wouldn't turn your engine over
> as that is not the load voltage!
>
> I personally like to completely isolate my starter battery from the
> house bank. I have installed a third battery for starting the boat in
> what was the shower sump, which is right on top of the keel. A good size
> battery fits snugly in the box and is easily strapped in. This way, I
> can use both house batteries without worrying that I have drained too
> much power to start the engine. I even carry a set of jumper cables in
> case the starter battery dies and I have to jump from the house bank.
>
> I highly recommend a book: Boatowner's Mechanical and Electrical Manual,
> by Nigel Calder. I think he is the best at explaining complicated issues
> in common "sense" terms. Sometimes, I have to read it a couple of times,
> but eventually it makes sense even to me! It is always on the boat and I
> refer to it often.
>
> Chuck Finn
> Mighty Quinn #114
>
>
> Robert Miller wrote:
>   
>> If one of your batteries shows 10.70 volts with a voltmeter, it is
>> gone. Put a load on that battery and it will drop lower. Don't know
>> how you are set up but it looks like you can use either battery or
>> both to start the engine. I have four AGMs in my 38 with two 1/2/Both
>> switches. Once I am underway under sail, I set one switch to Both and
>> the other to 1 leaving one battery isolated to start the engine. That
>> leaves 3 house batteries and one in reserve to restart the engine.
>>
>> Bob
>>
>> "Bolero" #113 at Southwestern YC in San Diego
>>
>> ------------------------------------------------------------------------
>>
>> *From:* listserve-bounces at catalina38.org
>> [mailto:listserve-bounces at catalina38.org] *On Behalf Of *therorl at aol.com
>> *Sent:* Wednesday, February 17, 2010 2:40 PM
>> *To:* listserve at catalina38.org
>> *Subject:* [C38] Fwd: Battery Power
>>
>> -----Original Message-----
>> From: Charles <chas at finn.ws>
>> To: therorl at aol.com
>> Sent: Wed, Feb 17, 2010 2:04 pm
>> Subject: Re: Battery Power
>>
>> therorl at aol.com <mailto:therorl at aol.com> wrote:
>>     
>>> I've had trouble lately with my battery not having a full charge when
>>> I go to start the engine. I've turned off all the shore power,
>>>       
>> checked > both battery's with a volt meter and the larger off the two
>> battery's > reads 10.70 volts. Is this enough juice or do I need a new
>> battery. I > was told at one time that a deep cell battery should read
>> at 12.5 volts.
>>     
>>> Also, I can't distinguish the house battery from the engine battery.
>>> To me it would stand to to reason that the larger of the two
>>>       
>> battery's > would be the house battery and the smaller for the engine.
>> But, if I > disconnect the shore power and switch to the number 1
>> battery my cabin > lights will come on. The same thing happens if I
>> switch to the number > 2 battery. Can someone help me out!!!!!
>>     
>>> Mike
>>> Catalina 38 #271
>>>
>>>       
>> Mike,
>> I think somehow you are sending to the wrong email address as it came
>> to my personal account. The correct one is: listserve at catalina38.org
>> <mailto:listserve at catalina38.org>
>>
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>
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