[C320-list] Battery Isolation

[jelliott at landspring.net]

Thanks Jeff.  As usual a picture is worth a thousand words.  I'll digest
this in more detail tonight. The dual house bank idea is interesting; I
may consider it once I master this topic.

Am I to understand that isolators can come with standard Si diodes OR
Schottky diodes,depending on the manufacturer?  I do remember from my
first EE course back in the dark ages that Schottkys had a lower voltage
drop.  So this must alleviate some of the perceived issues with using
isolators (at least as explained by the relay advocates).  I guess I need
to spend some more time with the tech support teams.

I'm picking this up slowly (very slowly) but surely.

Julian


> Julian,
>
> Just to be clear, the alternator is disconnected from the starter and
> wired to the isolator, but the starter is still wired to the same spot
> on the battery switch.
>
> Here is a link to my picture posting site. Click on the wiring diagram.
> The 320 wiring is similar to the 387 except that I have 2 battery
> switches and chose not to parallel the house batteries.
>
> http://picasaweb.google.com/SailCentral
>
> I don't think undercharging is a problem if you use a Schottky isolator
> instead of the typical silicon diode isolator. I spoke to people at
> Xantrex, Blue Sea, Charles, and a few other sources about overcharging
> the start battery. Without going into detail, I'll just say that they
> explained how the resistance of the batteries naturally prevents it from
> happening. Jeff Hare can probably explain it better than I can.
>
> JeffC
>
>
> jelliott at landspring.net wrote:
>> I've found lots of opinions on diode-based isolators vs. relay
>> combiners,
>> and unfortunatley comments tend to follow who's selling them. I've gone
>> back and forth today on which direction is best. Talk of voltage
>> mismatches, under or over charging, etc. is definitely confusing me.
>> Work
>> has definitely suffered...
>>
>> Your installation that routes the alternator-to-starter circuit thru the
>> isolator answers a question I had as to how the banks would be
>> electically
>> isolated.  The literature I've read has not make that clear.
>>
>> Maybe I should just get a folding prop and be happy.....
>>
>>
>>
>>
>>> Good info. I looked all over for a Schottky diode isolator and didn't
>>> find out that Guest made one. It also didn't occur to me that
>>> relay-type
>>> devices could create RF noise. I just found the Guest unit (#2530) at
>>> Pyacht.com for about $140.
>>>
>>> I recently installed a Sure Power Schottky-diode isolator when I
>>> installed a starting battery on my 387. According to several sources,
>>> using an isolator is a better approach than using any of the combiners
>>> or other relay-type devices. The biggest problem with a combiner/relay
>>> is that when the charging device initially starts and the combiner
>>> closes, the depleted house bank can immediately draw a lot of current
>>> from the  starting battery. Some of the devices like the Echo Charger
>>> might not operate that way, but you should check on that before buying
>>> one. The advantage of the combiner is that it is easier to install and
>>> less wire ($$) is required.
>>>
>>> In order to install an isolator you will need to remove the wire that
>>> connects the alternator to the starter motor, and run a #6 wire from
>>> the
>>> alternator to the input terminal on the isolator. Then from the #1 and
>>> #2 output terminals on the isolator you run wires to the battery switch
>>> #1 and #2 terminals, or directly to the house and starting batteries.
>>>
>>> Good luck.
>>>
>>> JeffC
>>>
>>>
>>>
>>> jelliott at landspring.net wrote:
>>>
>>>> I'm learning more... These are relay-based devices; Blue Sea tech
>>>> support
>>>> says they may induce RF noise if installed at the panel vs. at the
>>>> battery
>>>> (not desirable in my case).  Have you experienced this?
>>>>
>>>> The Guest isolators use Schottkey diodes, which induce a load (and
>>>> corresponding heat), but don't suffer the potential RF problem.
>>>>
>>>> As usual, there is a tradeoff...
>>>>
>>>> Julian
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>> The Yandina is the one I used (mine is a WM re-label of this
>>>>> product.)
>>>>> It's
>>>>> as simple as described. The Blue Seas Relay will definitely do the
>>>>> trick
>>>>> as
>>>>> well...
>>>>>
>>>>> Regards,
>>>>>
>>>>> Jon Vez
>>>>> Solstice #582
>>>>>
>>>>> -----Original Message-----
>>>>> From: c320-list-bounces at lists.catalina320.com
>>>>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of
>>>>> jelliott at landspring.net
>>>>> Sent: Wednesday, April 08, 2009 4:09 PM
>>>>> To: C320-List at Catalina320.com
>>>>> Subject: Re: [C320-list] Battery Isolation
>>>>>
>>>>> John,
>>>>>
>>>>> I see WM has a Blue Sea Systems Starting Isolation Charging Relay
>>>>> which
>>>>> seems to do the trick.  Is that what you installed?
>>>>>
>>>>> Also seen similar items from Guest and from a company called Yandina
>>>>> (http://www.yandina.com/NewCatalog.htm).
>>>>>
>>>>> Looks like this fits the bill with a fairly straightforward
>>>>> installation.
>>>>> Almost too simple to be real...
>>>>>
>>>>> Julian
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Julian,
>>>>>>
>>>>>> I have the exact setup you describe. I used a battery combiner from
>>>>>> West
>>>>>> Marine. It's a simple device that you simply wire to each pole on
>>>>>> the
>>>>>> back
>>>>>> of your current switch--one wire to the '1' and the other to the
>>>>>> '2'.
>>>>>> It's
>>>>>> about the size of a match box and takes a couple of minutes to
>>>>>> install.
>>>>>> It
>>>>>> will combine the batteries when motoring via the alternator and
>>>>>> isolate
>>>>>> them
>>>>>> when not receiving a charge. Is the 'easy' solution to this
>>>>>> problem....
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>> Jon Vez
>>>>>> Solstice #582
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: c320-list-bounces at lists.catalina320.com
>>>>>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of
>>>>>> jelliott at landspring.net
>>>>>> Sent: Wednesday, April 08, 2009 10:59 AM
>>>>>> To: C320-List at catalina320.com
>>>>>> Subject: [C320-list] Battery Isolation
>>>>>>
>>>>>> I am in the process of modifying my electrical system, and am
>>>>>> curious
>>>>>> as
>>>>>> to how others electrically isolate the house bank from the starting
>>>>>> battery.
>>>>>>
>>>>>> I have two 4D's under the settee paralleled as my house bank, and a
>>>>>> separate  starting battery located in the port lazarrette.  Both are
>>>>>> connected to independent channels of a Xantrax Truecharge 20.   The
>>>>>> house
>>>>>> bank is monitored with a Link 10.
>>>>>>
>>>>>> The banks are still not electrically isolated; I assume this is a
>>>>>> result
>>>>>> of a common connection to the alternator?  How do others handled
>>>>>> this?
>>>>>> I
>>>>>> understand there are battery isolators that do this?  Any advice on
>>>>>> how
>>>>>> to
>>>>>> "break" this return circuit (if that's the cause) would be
>>>>>> appreciated.
>>>>>> I
>>>>>> am not very interested in adding a second switch which I know some
>>>>>> have
>>>>>> done.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Julian
>>>>>> Polaris #340
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>>
>>
>>
>>
>>
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