The C-Brats Forum Index
HomeForumsMy TopicsCalendarEvent SignupsMemberlistOur C-DorysThe Brat MapPhotos

what is the battery selector switch selecting?

 
Post new topic   Reply to topic    The C-Brats Forum Index -> Electrical and Wiring
View previous topic :: View next topic  
Author Message
BillE



Joined: 09 Jun 2016
Posts: 148
City/Region: Nashville
State or Province: TN
C-Dory Year: 2004
C-Dory Model: 25 Cruiser
Vessel Name: TBD
PostPosted: Tue Jul 10, 2018 10:52 am    Post subject: what is the battery selector switch selecting? Reply with quote

I have the Perko 4-position switch 1,2,OFF, BOTH.

Is the switch selecting:
What is being charged by the alternator?
or, what is being charged by the battery charger?
Or, which battery is powering what?
Or ?

Yes, even after searching and reading many threads here it is still possible to be confused.

_________________
Bill & Sherry, clueless C-Brat newbies
Back to top
View user's profile Send private message Send e-mail
DW



Joined: 07 Sep 2017
Posts: 23
City/Region: Mount Vernon
State or Province: WA
C-Dory Year: 2004
C-Dory Model: 22 Cruiser
Vessel Name: Wicked Pissah
PostPosted: Tue Jul 10, 2018 11:09 am    Post subject: Reply with quote

With a bit of hesitation, let me take a stab at this. The selector switch selects what source of energy is being used. Most setups using this setup will have two batteries. When selecting 1, you select one battery that you decide is either the start battery or the house battery. When selecting 2, you have selected the other battery. When you select "Both", you have selected to use both batteries at the same time, which might make sense if your start battery was low and could not turn over the engine on its own. Selecting "Off", isolates both batteries so no drain on either battery is present. Of course that only applies to loads that go through the switch, which are the majority of the loads. (There are loads, ie bilge pumps, that go directly to a battery and not through the switch).
Common use of this switch would have you select the start battery (1), to start your engine. Then switch to both for charging while underway. Upon shut down, when away from an exterior charge source, switch to the house battery. (2). Again, "Both" might be used if for some reason the start battery did not work on the next attempt to start.
Back to top
View user's profile Send private message Send e-mail
localboy



Joined: 30 Sep 2006
Posts: 3989
City/Region: Lake Stevens via Honolulu
State or Province: WA
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: 'Au Kai (Ocean Traveler)
Photos: 'AU KAI
PostPosted: Tue Jul 10, 2018 12:51 pm    Post subject: Reply with quote

And with the addition of a relay, the switching back/forth can be nearly eliminated as the relay sends alternator charging to the weaker battery and then isolates the starter battery once at anchor.

https://www.bluesea.com/products/7649/Mini_Add-A-Battery_Kit_-_65A

_________________
"We can go over there...behind the 'little one'....."
Wife to her husband pointing @ us...from the bow of their 50-footer; Prideaux Haven 2013
Back to top
View user's profile Send private message Send e-mail
thataway



Joined: 02 Nov 2003
Posts: 15948
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Tue Jul 10, 2018 1:22 pm    Post subject: Reply with quote

Excellent explanations by both DW and Locallboy. I am like to just add a "combiner" voltage sensitive relay, or automatic charging relay, as Localboy suggests, keeping the 1/2/all off switch, and using it to select the primary load which runs off the batteries.

The ACR or VSR, will combine the start and house batteries, once the start battery reaches a voltage of approximately 13.7 volts. They will remain combined as long as there is a charging source, keeping the battery voltage above 12.7 volts (can be a battery charger or the engine generator/alternator. When the battery voltage of the start battery, drops to 12.7 volts the batteries are isolated. Thus there is no chance of running down the start battery.

In some boats I take that a little further, since the biggest draw we have is the refrigerator / freezers, we have a battery, or set of batteries dedicated to that, and they may have their own ACR, which begins to charge the dedicated 3rd bank of batteries when the house battery reaches 13.7 volts.

_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
Back to top
View user's profile Send private message Send e-mail
gulfcoast john



Joined: 14 Dec 2012
Posts: 392
City/Region: PENSACOLA
State or Province: FL
C-Dory Year: 2010
C-Dory Model: 255 Tomcat
Vessel Name: Cat O' Mine
Photos: CAT O' MINE
PostPosted: Tue Jul 10, 2018 4:33 pm    Post subject: Reply with quote

BillE,
Everyone was once a newbie, and they learned from others.
A PO may have already installed a VSR since they are cheap, easy to put in, simplify ‘switchcraft’ and mitigate against the most common switchcraft errors that lead to dead batteries on the water.
A few additional comments I hope may be helpful:
The 110v battery charger outputs will be wired directly to the positive studs of the batteries. (Neg goes to a common ground bus bar). When the shorepower and charger are ON, both batteries will be getting charged regardless of the Perko switch position. As above, think of the Perko as selecting the SOURCE of 12v power on the boat.
There are likely fuses on those outputs at the charger. There should also be fuses within 7 inches of the battery. Mine didn’t have those, perhaps the standards changed. If you need those, Blue Sea MRBF are simplest to wire.
https://www.westmarine.com/buy/blue-sea-systems--1-terminal-stud-fuse-block--9368895?recordNum=33
An additional change to standards is that now yellow wire is used for 12V Negative (will be black wire on older boats).
The ‘BOTH’ position on the Perko switch is equivalent to what Blue Sea and some other switches label as ‘COMBINED’ you may have read about. You’d think there would be a standard, but no.
Items which SHOULD be direct wired to a battery (these are not affected by the Perko switch position) include any bilge pumps, CO detectors, and (often) stereo memory. A PO may have also installed a N2k network with sensors with parasitic loads and goodness knows what else.
Get a mulimeter (I like Fluke) and test around the boat.
Have fun learning how things work! Happily, it’s a never-ending quest.
John

_________________
John and Eileen Highsmith
2010 Tom Cat 255, Cat O' Mine
Yamaha F150, LXF150
Back to top
View user's profile Send private message AIM Address
BillE



Joined: 09 Jun 2016
Posts: 148
City/Region: Nashville
State or Province: TN
C-Dory Year: 2004
C-Dory Model: 25 Cruiser
Vessel Name: TBD
PostPosted: Tue Jul 10, 2018 4:48 pm    Post subject: Reply with quote

----"Have fun learning how things work!--"

Well, some of it is fun. But boats get really hot in the summer and crawling around and under trying to trace a rat's nest of wiring is a bit less than fun!

I have also discovered that just "doing stuff" on a boat--in the water--- uses some neglected muscles, and I is sore! It is also more tiring than doing the same job on land, as one is always keeping their balance and reacting to the shifts.
Should be good for me!

Thanks to all for the helpful replies.
Back to top
View user's profile Send private message Send e-mail
ssobol



Joined: 27 Oct 2012
Posts: 1318
City/Region: Leesburg
State or Province: VA
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
PostPosted: Tue Jul 10, 2018 6:19 pm    Post subject: Reply with quote

FWIW, the manual for my Guest battery charger said that the charger should not be operated with the battery switch set to BOTH. Any other position was ok.
Back to top
View user's profile Send private message
thataway



Joined: 02 Nov 2003
Posts: 15948
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Tue Jul 10, 2018 9:04 pm    Post subject: Reply with quote

ssobol wrote:
FWIW, the manual for my Guest battery charger said that the charger should not be operated with the battery switch set to BOTH. Any other position was ok.


That is correct, because at least some battery chargers will sense each battery individually, and then apply the appropriate charge. If you have combined batteries, you will have a "average" and the charge will not be ideal. The combiner does the same thing--and there is an argument to turn off the combiner when using the battery charger.

I am toying with buying a lithiumFE PO4 battery, to be dedicated to my refer/freezers. If I do so, that battery cannot combined when charging or discharging with lead acid or AGM batteries, because of both the different charing characteristics, but also the discharge characteristics.
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    The C-Brats Forum Index -> Electrical and Wiring All times are GMT - 6 Hours
Page 1 of 1

 
     Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum



Page generation time: 0.0636s (PHP: 62% - SQL: 38%) - SQL queries: 25 - GZIP disabled - Debug on