|
|
12-20-2018, 06:40 PM
|
#1
|
Senior Member
City: Blaine
Vessel Name: Slow Bells
Vessel Model: Marine Trader 38
Join Date: Nov 2013
Posts: 327
|
isolator vs battery switch for generator
My generator (Westerbeke 4.4kw) currently has its own start battery, which is only charged when the 115v battery charger is working. So in theory, if I goof and accidentally discharge the main engine start battery and the house battery, I can still start my generator and recharge everything. I'm thinking that it is kind of silly to not to add some charge to the generator start battery while I am mindlessly cruising along for several hours. One option would be to install an isolator in the middle of a new cable connecting the house battery to the generator start battery. Another option would be just a simple on/off switch in the middle of a new cable connecting the house battery to the generator start battery (I could turn it on after lunch, then turn it off at the end of the day). Any thoughts?
|
|
|
12-20-2018, 07:53 PM
|
#2
|
Guru
City: Seattle
Vessel Name: AZZURRA
Vessel Model: Ocean Alexander 54
Join Date: Aug 2017
Posts: 4,308
|
I would use a small AC battery charger/maintainer for your gen battery. This way it’s always fully charged and there is no chance for error. You could use a smart ACR for combining purposes or a DC to DC charger. I would not recommend going with a standard ACR or a manual switch.
|
|
|
12-20-2018, 08:01 PM
|
#3
|
Senior Member
City: Compton
Join Date: May 2016
Posts: 105
|
Quote:
Originally Posted by seattleboatguy
My generator (Westerbeke 4.4kw) currently has its own start battery, which is only charged when the 115v battery charger is working. So in theory, if I goof and accidentally discharge the main engine start battery and the house battery, I can still start my generator and recharge everything. I'm thinking that it is kind of silly to not to add some charge to the generator start battery while I am mindlessly cruising along for several hours. One option would be to install an isolator in the middle of a new cable connecting the house battery to the generator start battery. Another option would be just a simple on/off switch in the middle of a new cable connecting the house battery to the generator start battery (I could turn it on after lunch, then turn it off at the end of the day). Any thoughts?
|
Rather than use an on/off switch I would use a 12V continuous duty relay and tie it into your ignition switch so the relay will be energized with key on and will break the connection when the key is off. You won't need to remember to turn the switch on and off. The relay will be working when you are running the engine and off when the engine is off. 12V relays are cheep. https://www.amazon.com/CONTINUOUS-SO...62773433&psc=1
|
|
|
12-20-2018, 08:25 PM
|
#4
|
Guru
City: Sydney
Vessel Name: Sojourn
Vessel Model: Integrity 386
Join Date: Oct 2011
Posts: 13,329
|
Another way is charging your genset battery via a small dedicated solar panel. A 25W panel with a basic regulator to the 6D/135AH sealed battery has worked well for 5 years. It overcomes the "not running not charging" issue,keeps the genset batt independent, and charged for starting the genset.
__________________
BruceK
2005 Integrity 386 "Sojourn"
Sydney Australia
|
|
|
12-20-2018, 08:38 PM
|
#5
|
Guru
City: North Carolina for now
Join Date: Aug 2011
Posts: 6,348
|
How long do you go not using your generator or being on shore power?
That's the critical question. More than a week or two? Think about it, have you ever left a car for a month without charging? If the battery is not already near death, the car starts right up. Same with generators, as I experienced first hand myself with a boat on the hard and unpowered.
__________________
George
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
|
|
|
12-20-2018, 08:49 PM
|
#6
|
Guru
City: Gibsons, B.C., Canada
Vessel Name: Island Pride
Vessel Model: Palmer 32'
Join Date: Oct 2007
Posts: 4,414
|
If you wish to pursue this I would suggest an oil pressure switch of about 20-25 psi which then operates a continuous heavy duty relay. Then when the engine is running the oil pressure sw. will activate the H.D. relay allowing the gen. battery to be charged.
I'm suggesting a somewhat higher than normal activation pressure so the connection is likely broken when the engine is idling.
I would not use a manual switch. Eventually you will forget, either leaving it on or off.
Caltexfranc has a point also, a good one.
|
|
|
12-20-2018, 09:23 PM
|
#7
|
Guru
City: La Conner Wa.
Vessel Name: Sea Fever
Vessel Model: Defever 49 RPH
Join Date: Sep 2012
Posts: 877
|
Doesn't your generator have a alternator on it that charges that battery? You should be able to let it sit for months without needing a charge. (as long as nothing else is connected to that battery) I just started my generator tonight for the first time in 3 months and it started right up.
|
|
|
12-21-2018, 05:30 AM
|
#8
|
Guru
City: Narragansett Bay
Vessel Model: Grand Banks 36 Classic #715
Join Date: Sep 2016
Posts: 1,857
|
All good advice but post 7 hits it on the head. You may be overthinking this.
|
|
|
12-21-2018, 05:36 AM
|
#9
|
Guru
Join Date: Oct 2007
Posts: 22,553
|
"Rather than use an on/off switch I would use a 12V continuous duty relay and tie it into your ignition switch so the relay will be energized with key on and will break the connection when the key is off."
This is easily done by installing an ignition switch with an "acc" terminal.
It will cut off when the key is being used to start the engine , and of course when the ignition circuit is off.
This is the system used to charge a RV house batteries , seamless and almost idiot proof.
Under $14.00 for a 150A relay seems a good deal, even if a $ 19.00 4 position key switch needs to be installed .
http://www.partdeal.com/wiring-elect...iABEgLDJfD_BwE
|
|
|
12-21-2018, 07:04 AM
|
#10
|
Valued Technical Contributor
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,785
|
Some gensets don't have a 12V charging alternator. The easiest way to charge its starting battery underway and keep it isolated is a battery isolator (diode based) or better a battery combiner like this one from Yandina: Combiner 100 Sheet.
The combiner is a better solution as it doesn't have the voltage drop of the diode type isolator.
A switch would be easy to install but can be forgotten. The isolator/combiner solution is a set and forget solution.
David
|
|
|
12-21-2018, 07:46 AM
|
#11
|
Guru
City: Solomons Island Md
Vessel Name: Fryedaze
Vessel Model: MC 42 (Overseas Co) Monk 42
Join Date: Sep 2011
Posts: 1,721
|
I got rid of our Genset battery to make more room for house bank. We ha twin engines so 2- 4Ds for engines and 8- 6volt for the house. I like the simplicity of an ACR. The engine batts are isolated from the house by an ACR.
You could put an ACR between you engine and Genset battery. This would kelp Genset Bart charged underway and isolate it from engine batt at 12.75volts so it always ready
|
|
|
12-21-2018, 07:50 AM
|
#12
|
Guru
City: Solomons Island Md
Vessel Name: Fryedaze
Vessel Model: MC 42 (Overseas Co) Monk 42
Join Date: Sep 2011
Posts: 1,721
|
|
|
|
12-22-2018, 06:25 AM
|
#13
|
Guru
Join Date: Oct 2007
Posts: 22,553
|
"The isolator/combiner solution is a set and forget solution."
As is the solenoid and key switch , at perhaps 1/5 to 1/10 the cost.
|
|
|
12-22-2018, 07:14 AM
|
#14
|
Guru
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 12,834
|
I also would recommend the simple 120VAC battery charger. To me, the generator is the fallback position. Should something happen and I find the other batteries discharged, I can start the generator with its totally independent battery, and run the main battery charger(s).
I have been extremely happy with these (have2).
https://www.batterystuff.com/battery...arger-rs1.html
Something simple like this would work well also.
https://www.batterystuff.com/battery...-021-0123.html
Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
|
|
|
12-22-2018, 07:28 AM
|
#15
|
Guru
City: Cary, NC
Vessel Name: Skinny Dippin'
Vessel Model: Navigator 4200 Classic
Join Date: Jul 2009
Posts: 5,841
|
Quote:
Originally Posted by Russell Clifton
Doesn't your generator have a alternator on it that charges that battery?.
|
Not all do. Mine has one and I am planning on bypassing it.
__________________
2000 Navigator 4200 Classic
(NOT a trawler)
|
|
|
12-22-2018, 08:26 AM
|
#16
|
Guru
City: Maine Coast
Vessel Name: Tortuga
Vessel Model: Nunes Brothers Raised Deck Cruiser
Join Date: Feb 2015
Posts: 889
|
The spec sheet for the Westerbeke 4.4 kw generator says it has a 12 volt 10 amp battery charging output that you can wire to the start battery.
https://www.westerbeke.com/advanced%20specs/4.4_bcd.pdf
|
|
|
12-22-2018, 08:42 AM
|
#17
|
Senior Member
City: Blaine
Vessel Name: Slow Bells
Vessel Model: Marine Trader 38
Join Date: Nov 2013
Posts: 327
|
Quote:
Originally Posted by TDunn
|
Very interesting. Up until now, I had no idea that existed. Thanks very much.
|
|
|
12-22-2018, 10:32 AM
|
#18
|
Guru
City: La Conner Wa.
Vessel Name: Sea Fever
Vessel Model: Defever 49 RPH
Join Date: Sep 2012
Posts: 877
|
I would think that the alternator is already connected to that battery and you just don't realize it. Turn off the battery charger that is attached to it and take a reading of the voltage at that battery. Start the generator and take another reading of the voltage at the battery. If the alternator is charging the battery it should read about 13.5 volts or so. Don't wait to long to test it. Problem solved. You either need to wire the alternator to the battery or do nothing as everything is working as designed.
|
|
|
12-22-2018, 01:43 PM
|
#19
|
Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,088
|
Quote:
Originally Posted by Tom.B
Not all do. Mine has one and I am planning on bypassing it.
|
Why would you do that?
-Chris
__________________
Chesapeake Bay, USA
|
|
|
12-22-2018, 03:11 PM
|
#20
|
Guru
City: Cary, NC
Vessel Name: Skinny Dippin'
Vessel Model: Navigator 4200 Classic
Join Date: Jul 2009
Posts: 5,841
|
Quote:
Originally Posted by ranger42c
Why would you do that?
-Chris
|
Just so I can be told on an online forum how wrong and stupid I am. :-) lol
__________________
2000 Navigator 4200 Classic
(NOT a trawler)
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Trawler Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|