Jump to content

Battery disconnect switch


Chuck H
 Share

Recommended Posts

I'm wanting to change out the chassis battery disconnect switch in the batteries rrb because yesterday when I turned it on it felt a little harder to turn than usual. What I have found is on the back of that switch it gives the amp specs. which states that it is 345 amps INTERMITTENT. I found a new switch on Amazon that says it's 345 amps MOMENTARY. Can somebody please tell me if I can use this new switch and/or what the difference between the two are. Thanks in advance!20220831_224056.thumb.jpg.3e4c3fb5d985888469a19ea44b39085b.jpg

Link to comment
Share on other sites

I replaced my chassis and house batteries with the 600 amp heavy duty marine switches. They both failed internally shortly after I purchased my coach.  
The footprint was somewhat larger, but I didn’t have to change the cables.

Link to comment
Share on other sites

This switch is a heavy duty switch which I’ve used for several years. I think you’ll find it has a high continuous duty rating:

Blue Sea 9003E E-Series Master Battery Switch Single Circuit ON/OFF

  • Like 1
Link to comment
Share on other sites

First.  Judging a switch from how it turns on or off, unless you have intermittent electrical issues may not be a valid test. 
 

Second. A shot of contact cleaner never hurts.  If you want to do the proper, IMO, preventative maintenance. Do this

Use a VOM and measure the voltage ACROSS the cables.  Or, you can, assuming you have a good ground, measure the voltage on each to ground.  Direct measurement across the switches two terminals or on the cable terminals is the mast accurate as grounding one side can lead to variability.  ZERO volts is good….as it should be.  There are many “rules” of thump, but if you get close to a tenth or 0.1 VDC….you have resistance.  Most say LESS THAN 0.05 VDC.

Now, my old “fix” where you might have some internal galling on the shaft.  Disconnect the battery. Hit the switch with a short, very short shot of WD-40 from the “straw” nozzle aimed at where the switch shaft is.  NOT SILICONE. Then cycle it a few times The WD-40 is a kerosene based lube that displaces any water (NASA invention…Water Displacement).  Some will then use ELECTRONIC, not electrical, cleaner….really short blast to remove any residual or non volatile WD-40.

DO that….then  cycle….then hook up battery.  Measure the voltage drop.  If less than 0.05….good to go.

I am biased for the Blue Seas.  The one recommended is the stock one on my Camelot.  The picture caption is WRONG.  Price is correct.  You do NOT have an AFD style switch….just a plain vanilla ON/OFF.  Now remember,  300 A Is a heck of a load.  The Salesman solenoid is only rated at 80 A. You only put 100 A back into the battery charging from the inverter and that drops off drastically.  The 300 A Chassis Battery switch does NOT switch off the chassis battery to the starter. That is directly cabled.  The Chassis switch turns off the other loads, save power to the ECM & TCM and some other low draw items.

EDIT….Frank, in a later post, brings up an issue.  The Dynasty and above have a DIFFERENT switch.  The Blue Sea 9003E is the most common for us lower end MH.  If your old switch is in the Dynasty or above, it will have two smaller wires.  That is an AFD style. The Blue Seas switch for that replacement would the AFD version….the 9004E.  It has the two additional terminals.

I would NOT just “connect the two sensing wires”….I would purchase the right version….plain if only two posts….not small wires or AFD if the OEM switch has the sensing circuit.

Monaco was inconsistent in how they hooked up the inverter.  Mine goes through a 300 A fuse and not the House switch.  Some DID, I believe, go through the House  Switch.  Look at yours on the prints.

Investigate and verify.  If the switch is bad, replace….and you have 2 choices.  Don’t judge it by feel unless you need pliers to turn or have downstream issues.

B8F113B2-2891-4130-9D00-2135AE2DF9FC.png

Link to comment
Share on other sites

1 minute ago, throgmartin said:

The Blue Sea switch is the only way to go. Have never seen one fail.

The choir gives you a BIG  A>M>E>N.  I carry a spare 300.  I put in a 2 battery selector switch for my hydraulic slides as I have an illusive House Feed that has about a 0.5 VDC DROP….BUT a next door neighbor 200 A Chassis feed does not.  So I keep the slide on the Chassis….works great.  Blue Seas answered a couple of simple questions and has great tech support….

Hard to beat!

Link to comment
Share on other sites

9 minutes ago, Tom Cherry said:

The choir gives you a BIG  A>M>E>N.  I carry a spare 300.  I put in a 2 battery selector switch for my hydraulic slides as I have an illusive House Feed that has about a 0.5 VDC DROP….BUT a next door neighbor 200 A Chassis feed does not.  So I keep the slide on the Chassis….works great.  Blue Seas answered a couple of simple questions and has great tech support….

Hard to beat!

I wont install any other type of switch on a customers coach. I do not want the liability. The factory switches are junk and a fire hazard. My OEM switch failed, nearly fried my inverter and melted to the point that when I took it off it fell apart in my hands. I lost track of the OEM switches we have replaced. We buy the Sea switches by the case load.

Link to comment
Share on other sites

9 hours ago, Tom Cherry said:

First.  Judging a switch from how it turns on or off, unless you have intermittent electrical issues may not be a valid test. 
 

Second. A shot of contact cleaner never hurts.  If you want to do the proper, IMO, preventative maintenance. Do this

Use a VOM and measure the voltage ACROSS the cables.  Or, you can, assuming you have a good ground, measure the voltage on each to ground.  Direct measurement across the switches two terminals or on the cable terminals is the mast accurate as grounding one side can lead to variability.  ZERO volts is good….as it should be.  There are many “rules” of thump, but if you get close to a tenth or 0.1 VDC….you have resistance.  Most say LESS THAN 0.05 VDC.

Now, my old “fix” where you might have some internal galling on the shaft.  Disconnect the battery. Hit the switch with a short, very short shot of WD-40 from the “straw” nozzle aimed at where the switch shaft is.  NOT SILICONE. Then cycle it a few times The WD-40 is a kerosene based lube that displaces any water (NASA invention…Water Displacement).  Some will then use ELECTRONIC, not electrical, cleaner….really short blast to remove any residual or non volatile WD-40.

DO that….then  cycle….then hook up battery.  Measure the voltage drop.  If less than 0.05….good to go.

I am biased for the Blue Seas.  The one recommended is the stock one on my Camelot.  The picture caption is WRONG.  Price is correct.  You do NOT have an AFD style switch….just a plain vanilla ON/OFF.  Now remember,  300 A Is a heck of a load.  The Salesman solenoid is only rated at 80 A. You only put 100 A back into the battery charging from the inverter and that drops off drastically.  The 300 A Chassis Battery switch does NOT switch off the chassis battery to the starter. That is directly cabled.  The Chassis switch turns off the other loads, save power to the ECM & TCM and some other low draw items.

Monaco was inconsistent in how they hooked up the inverter.  Mine goes through a 300 A fuse and not the House switch.  Some DID, I believe, go through the House  Switch.  Look at yours on the prints.

Investigate and verify.  If the switch is bad, replace….and you have 2 choices.  Don’t judge it by feel unless you need pliers to turn or have downstream issues.

B8F113B2-2891-4130-9D00-2135AE2DF9FC.png

On many Monaco coaches, these are simple on/off battery disconnect switches.  But when you get into Dynasty and above models, the Cole Hersee battery disconnect switches also incorporate a separate low amp sensing switch.  Monaco used this to signal the circuit board to not engage Big Boy if one of the battery switches are shut off.  So, if you are replacing the OEM battery cutoff switch on models with a sensing wire, be sure to use a replacement switch with an AFD option.  The internal Alternator Field Disconnect switch is what Monaco used to signal the circuit board controlling big boy that one of the battery switches was turned off.  If one of these sensing wires is not properly connected to the correct replacement switch, Big Boy will not engage when it's supposed to engage.

Screenshot_20220905-141632.png

  • Thanks 1
Link to comment
Share on other sites

So I tested across the cables and measured 0.1VDC. Switch seems to be operating smoothly now all by itself with no contact cleaner but will be doing that anyway. Will be using Blue Seas as spares anyway, just not real confident on the reliability of these 20yr. old switches. Thanks to you all for the education. You guys are wealth of information. 

Link to comment
Share on other sites

35 minutes ago, Chuck H said:

So I tested across the cables and measured 0.1VDC. Switch seems to be operating smoothly now all by itself with no contact cleaner but will be doing that anyway. Will be using Blue Seas as spares anyway, just not real confident on the reliability of these 20yr. old switches. Thanks to you all for the education. You guys are wealth of information. 

Install a new switch.  I would figure out how to mount it.  The 0.1 VDC means the contacts are arced.  That will then give you issues.  You need to also consider doing both.  The House is more critical.  When you have a faulty House switch, the voltage drops.  Then motors such as your slides, will pull higher current….and then damage them.  I would do….the old adage….a stitch in time.  Otherwise, you can do major damage and also be frustrated.  The Chassis is a concern as your high current items such as headlights will pull higher current.  Also, a faulty chassis battery will cause your alternator to work harder and your house batteries to be charged a little less.

Your call…

Link to comment
Share on other sites

On 9/4/2022 at 9:58 AM, RBRODDER said:

Do yourself and your coach a BIG favor and get rid of those switches. Install the ones recommended above by Blue Seas.

Here are photos of the switches you have now. They are RV coach destroyers.

Safe travels.

Marinco BEP Switch.jpg

BEP Failed Battery Shut-Off Switch-1.JPG

BEP Failed Battery Shut-Off Switch-2.JPG

Edited by Dr4Film
  • Like 1
Link to comment
Share on other sites

 I'll be switching to the Blue Seas switches as you all have suggested. So am I understanding this correctly that the 9003E switches will be ok to replace the original Marinco-Guest switches with?

Link to comment
Share on other sites

41 minutes ago, Chuck H said:

 I'll be switching to the Blue Seas switches as you all have suggested. So am I understanding this correctly that the 9003E switches will be ok to replace the original Marinco-Guest switches with?

Qualified YES.  If there are only TWO Large Cables….and NO smaller wires on the switch.  If there are two smaller wires, also….then it is the 9004E.

Link to comment
Share on other sites

3 hours ago, Chuck H said:

Am I also to assume the house batteries switch is the same specs. as the chassis switch?

Yes….your old switches should have a current rating or you can look it up.  Very few were 600 A.  Most were 300A.  House versus chassis is not an issue, unless it is a high end….and they MAY have had a higher current.  Yours is like mine.  Plain vanilla.  I have the 9003E….and they are great.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...