Reply
 
Thread Tools Search this Thread
 
Old 16 April 2012, 07:42   #1
Member
 
Daibheid's Avatar
 
Country: Ireland
Town: Cork
Boat name: Cúr na dDonnta
Make: Excalibur + Zapcat
Length: 6m +
Engine: Merc120TDI,Tohatsu50
Join Date: Jun 2005
Posts: 302
Isolator Switches -Good or Bad?

I always swore these were an essential item - mainly to ensure batteries don't get drained with something like fishfinder or radio left on but also to ensure no accidents with hydraulic Trim and Tilt.

However, given that the usual red keyed one used on boats can be a source of poor contact and frequently not difficult to knock off, I'm sort of having second thoughts. If the battery disconnnects while the engine is running it'll blow something in the charging circuit - most likely the Rectifier/Regulator or the Stator itself and I've seen it wipe both out. I've also just heard of the "Grand Slam" taking out the CDI unit as well for good measure. Stators (alternator in a car) are pretty high output these days to drive fuel injection etc, so if all that power has no battery to go to, it tends to short things.

BTW, the common or garden isolator switch is also IMHO a long way short of waterproof and if you open one you'll see why you never want to mount one in a "catch-water orientation"
__________________

__________________
Daibheid is offline   Reply With Quote
Old 16 April 2012, 07:49   #2
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,650
Yeah, I;ve had to replace two so far in 2 boats..... Current boat has it fitted in a "hatch bucket" - if you go onto a laser sailing website you'll see it in full effect - basically take a standard 3" (or bogger) access hatch for dinghy bouyancy tanks etc.

While buying the hatch, also buy the "bucket" designed to to hold your mars bars etc. Glue / epoxy the bucket in place (the more exopensive ones will latch in). Mount the isolator on the bototm of the bucket, and site the hatch on a vertical surface. The hatches are designed to be watertight, and if vertical, any water that gets in will not puddle i nthe switch. When finished, put the (watertight) hatch cover on. So far so good......

Or buy a really expensive IP68 rated one!
__________________

__________________
9D280 is offline   Reply With Quote
Old 16 April 2012, 09:20   #3
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,019
Quote:
Originally Posted by 9D280 View Post
Yeah, I;ve had to replace two so far in 2 boats..... Current boat has it fitted in a "hatch bucket" - if you go onto a laser sailing website you'll see it in full effect - basically take a standard 3" (or bogger) access hatch for dinghy bouyancy tanks etc.

While buying the hatch, also buy the "bucket" designed to to hold your mars bars etc. Glue / epoxy the bucket in place (the more exopensive ones will latch in). Mount the isolator on the bototm of the bucket, and site the hatch on a vertical surface. The hatches are designed to be watertight, and if vertical, any water that gets in will not puddle i nthe switch. When finished, put the (watertight) hatch cover on. So far so good......

Or buy a really expensive IP68 rated one!
Fit a good quality unit like this Power Store and you cant go wrong.
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 16 April 2012, 10:07   #4
Member
 
Erin's Avatar
 
Country: UK - Channel Islands
Town: A large rock
Boat name: La Frette
Make: Osprey Vipermax
Length: 6m +
Engine: 200 Suzzy
Join Date: May 2004
Posts: 2,869
Agreed, those 'red key' types are notorious for failure. But then, they are a pretty cheap and basic design so it's no wonder. I've always used BEP or BlueSea components and never had a problem. They may still not be waterproof, but at least they are properly designed and are meant to be vapour-proof to prevent explosion risk from accumulated fuel or battery gases.
I would never contemplate a set-up without an isolator switch. If nothing else it means there is no circuit for electrolysis.
Erin is offline   Reply With Quote
Old 16 April 2012, 10:20   #5
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
I've had a Perko (non-keyed) selector switch for 6 years. Like this guy .

No problems aside from a possible cable to switch connection problem (loosen, clean, tighten, might have fixed, if it was a problem to begin with.)
It is in a fairly protected location (well, the back is protected; the switch side is exposed.)

jky
__________________
jyasaki is offline   Reply With Quote
Old 19 April 2012, 07:10   #6
Member
 
Daibheid's Avatar
 
Country: Ireland
Town: Cork
Boat name: Cúr na dDonnta
Make: Excalibur + Zapcat
Length: 6m +
Engine: Merc120TDI,Tohatsu50
Join Date: Jun 2005
Posts: 302
Looks like we're all still keen on isolators and there are some good ideas there to improve on the standard red key version.
Those Perko ones metnioned by jyasaki are good as they protect against accidental switching off of the battery circuit - presumably with a big fat diode across the switch temrinals. I wonder......
__________________
Daibheid is offline   Reply With Quote
Old 19 April 2012, 10:20   #7
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
There are some that have (I think it's called) a field disconnect circuit that protects the alternator and related bits should it be switched to off with the motor running. Mine doesn't have this.

jky
__________________
jyasaki is offline   Reply With Quote
Old 19 April 2012, 10:58   #8
Member
 
Nathan k's Avatar
 
Country: UK - England
Town: Lyndhurst
Boat name: Airborne
Make: SR4
Length: 4m +
Engine: 40hp
Join Date: Oct 2011
Posts: 216
Send a message via AIM to Nathan k Send a message via MSN to Nathan k Send a message via Skype™ to Nathan k
Had the red key isolator, lasted about 2 weekends. it's rubbish if your out in the rough would often turn off my gps due to it losing connection for a split second.

Don't have a isolator now and I've never had a problem, just remember to turn everything off!
__________________
Nathan k is offline   Reply With Quote
Old 19 April 2012, 11:03   #9
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
I have used a Lucas cut off switch with a fixed knob on my RIB for the last 2 years. I have mounted it facing downwards on my consol with the electrical parts inside the consol and the switch poking out of a downwards facing ledge. I have packed it with silicone grease and had no problems. It is not clearly visible and isolates everything but the radio and GPS's.
See link for picture:
LUCAS BATTERY ISOLATOR SWITCH - SSB106
__________________
Rokraider is offline   Reply With Quote
Old 19 April 2012, 11:11   #10
Member
 
kerny's Avatar
 
Country: UK - England
Town: Ashton-under-Lyne Lancs
Boat name: IMOGEN
Make: Air-Craft 5.4
Length: 5m +
Engine: Suzuki df70a
MMSI: 235087492
Join Date: May 2010
Posts: 7,078
RIBase
Send a message via Skype™ to kerny
I have one of these fitted which does the job.
Liverpool Power Boats
__________________
Member of S.A.B.S. (Lancashire Division)
kerny is offline   Reply With Quote
Old 19 April 2012, 11:27   #11
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,558
DURITE MARINE BATTERY ISOLATOR SWITCH 300 AMP ROTARY OF/1/2/BOTH 0-605-09 | eBay


just purchased one of these my self
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 20 April 2012, 03:04   #12
Member
 
Country: UK - Scotland
Town: glasgow
Boat name: arriba
Make: marlin
Length: 7m +
Engine: suzuki 300
Join Date: Jun 2007
Posts: 315
Ive used these for many years no probs
Absolutely sure your battery is disconnected
Prior to that the isolators were crap
Attached Thumbnails
Click image for larger version

Name:	terminals.jpg
Views:	128
Size:	99.1 KB
ID:	67330  
__________________
never miss an opportunity
dougcrock is offline   Reply With Quote
Old 20 April 2012, 03:56   #13
Member
 
martini's Avatar
 
Country: UK - Channel Islands
Town: jersey
Boat name: Martini II
Make: Arctic 28/FC470
Length: 8m +
Engine: twin 225Opti/50hp 2t
MMSI: 235067688
Join Date: Jun 2005
Posts: 3,028
I don't think having no isolator at all is a good idea on a boat, for fire safety reasons.

For example, I once lost an outboard off the back of a boat at speed which left me with a bunch of cables and live wires inc battery cables and fuel hoses hanging in the breeze. The first thing I did was isolate the power at the battery switch, I would've hated to not be able to do that.
__________________
martini is offline   Reply With Quote
Old 20 April 2012, 05:32   #14
Member
 
Oscarguitar's Avatar
 
Country: UK - England
Town: Poole
Boat name: Half Cut
Make: Cobra 8.6
Length: 8m +
Engine: Verado 275
MMSI: 235104619
Join Date: Jun 2011
Posts: 381
Used the BEP unit for 3 years now with no problems. Had to red key ones on a Sunseeker for 7 years and changes them twice, and they were in a really dry well protected position compared to the rib!
__________________
Oscarguitar is offline   Reply With Quote
Old 20 April 2012, 06:19   #15
Member
 
Country: UK - England
Town: Dorset & Hants
Boat name: Streaker/Orange
Make: Avon/Ribcraft
Length: 4m +
Engine: 50Yam/25 Mariner
Join Date: Apr 2007
Posts: 5,551
Risky moment here ....

I've not got one on my Avon ( despite being 'professionally' rigged from new) . I had one on the old boat that was painful due to corrosion when it wasn't looked after before I got it.

My car doesn't have one and it doesn't burst into flames , but of course when you crash a car one of the first things the fire & rescue ( can I call them brigade any more ? ) service do it cut the battery wires under the bonnet ( assuming its located there).

I think they can cause more hassle than is really worth it, but of course in the situations like Martini describes well worth it.

I wonder how many fires start due to dodgy switches etc .....

I'll get my coat .....
__________________
PeterM is offline   Reply With Quote
Old 20 April 2012, 11:27   #16
Member
 
Country: UK - England
Town: Surrey
Boat name: Fugly & Rokraider 1
Make: Pac 22 & Porter 6.5
Length: 6m +
Engine: Ford 250 & jet,DT140
Join Date: Jun 2008
Posts: 681
Quote:
Originally Posted by PeterM View Post
Risky moment here ....

I've not got one on my Avon ( despite being 'professionally' rigged from new) . I had one on the old boat that was painful due to corrosion when it wasn't looked after before I got it.

My car doesn't have one and it doesn't burst into flames , but of course when you crash a car one of the first things the fire & rescue ( can I call them brigade any more ? ) service do it cut the battery wires under the bonnet ( assuming its located there).

I think they can cause more hassle than is really worth it, but of course in the situations like Martini describes well worth it.

I wonder how many fires start due to dodgy switches etc .....

I'll get my coat .....

Stating the obvious..
The problem with heavy electrical cables coming direct from the motor to the battery, means that in the event of any fire whether it is caused by petrol or oil, once the flames get to grips with electrical stuff and a short occurs, the cables themselves short and spread the problem along the length of the vessel to wherever the battery is situated. With the electrics isolated at least it should hopefully be limited to the source of the problem. With a car you can stop, get out and walk to a safe distance and there are likely to be other people about to give assistance.
__________________
Rokraider is offline   Reply With Quote
Old 20 April 2012, 11:36   #17
Member
 
Daibheid's Avatar
 
Country: Ireland
Town: Cork
Boat name: Cúr na dDonnta
Make: Excalibur + Zapcat
Length: 6m +
Engine: Merc120TDI,Tohatsu50
Join Date: Jun 2005
Posts: 302
Quote:
Originally Posted by dougcrock View Post
Ive used these for many years no probs
Absolutely sure your battery is disconnected
Prior to that the isolators were crap
I had these on a rib a few years back and quite liked them. For those who haven't seen them they use a quick lever action to clamp the wires on/off the battery terminals. So you can isolate but not so easily by accident and battery location can make a big difference to their practicality.
The only thing I didn't like about them is they didn't appear well protected against corrosion.
__________________
Daibheid is offline   Reply With Quote
Old 20 April 2012, 14:59   #18
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 60hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 4,128
RIBase
I fitted a Blue Sea M-series switch. Feels solid, seems waterproof, and worth every penny.
__________________

__________________
Is that with or without VAT?
spartacus is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT -5. The time now is 06:42.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.