Battery Disconnect Switch Failure

[floydfowler]

I experienced a failure with my house battery switch on my 2001 Holiday Rambler Imperial.

The switch was frozen in the on position so I replaced it with another Guest switch (2102) just like the original one (except red rather than original black, not that that should matter). 

After two trips out ( less than 2000 miles) the new switch has failed in the same way.  The switch is rated at 230 amps continuous but I see that the case has melted around one terminal and the knob will not rotate.   

Yesterday we stopped at a rest area for lunch but had no power to the generator starter. While stopped at a rest area for lunch I tried to start the generator to use microwave but no power to the generator starter so I checked the battery switches. I checked the house and chassis battery switches and found the house switch frozen and when I turned off the chassis switch the engine died and would not restart.  No power on anything, ignition switch had no power as well.  Now I have a real mess and a hungry DW. I jumped  both switches by fastening the lugs together and now everything is working as normal.  Generator starts right up ans does the engine. 

After our lunch we continued on home and I ordered two new switches but I cannot explain the failures. Both nuts on the house switch were tight but I did feel that one on the chassis switch was perhaps not as tight but it was the original switch that may have had thread locker as they were hard to remove. 

Here is another weird note, the drivers side overhead map light was  on and would not turn off while I was without power  but went off  after I jumped the switches!  Switch turns it off and on fine now.

I lost a lot of sleep wondering about this last night and would greatly appreciate any help possible if anyone has experienced a similar issue.

 

 

[richard5933]

I'm wondering if you might have a problem with the chassis batteries. Without them providing power, your using only your house batteries to start, which is probably calling for more amperage than 230 amps.

[floydfowler]

House batteries are one year old.  I failed to mention in original post that while the power was off to the chassis, I was able to start the engine using the battery boost switch but it died when I released it.  The house batteries are not used for starting without pressing the momentary contact battery boost switch.  I was also able to start the generator using the boost switch while I had no power to the chassis.

[jleamont]

1 hour ago, floydfowler said:

House batteries

Check the ground for the house batteries. You have the same coach as us just one year older. Directly behind the battery compartment the negative cables come through the back wall of the compartment and bolt to the frame of the chassis. 

[richard5933]

Sounds like your chassis batteries are not supplying power to the engine or generator starter. That's why things work when you hold the button and die when you release it. Have you checked your chassis batteries to be sure that they are good and that they are charged?

[floydfowler]

Richard, please read my first post. I have isolated the battery cutoff switch as the problem, just wanting to know if anyone has had battery switch problems like mine. Everything works fine when I jump the switches.

[floydfowler]

3 hours ago, jleamont said:

Check the ground for the house batteries. You have the same coach as us just one year older. Directly behind the battery compartment the negative cables come through the back wall of the compartment and bolt to the frame of the chassis. 

Thanks for the tip. I checked the ground terminal and it was very tight. Since you have the same coach, have you experienced any problems with the Pac Brake?

[jleamont]

32 minutes ago, floydfowler said:

just wanting to know if anyone has had battery switch problems like mine

To answer this question, NO. 

I found this photo and it looks like the previous owner did at some point as mine are different. Ignore the solenoid that is circled, I took this photo to help someone identify that.

[jleamont]

30 minutes ago, floydfowler said:

Thanks for the tip. I checked the ground terminal and it was very tight. Since you have the same coach, have you experienced any problems with the Pac Brake?

We have the optional compression brake with the ISL 400, no PAC brake. What issues are you experiencing and which engine and Horse Power rating do you have?

[floydfowler]

Yes, That would be the same problem as mine except I found a replacement with same size and mounting as original.

Sure wish I had the ISL 400, as I have a 350 ISC with pac brake.  I use the exhaust (Pac) brake very frequently and have never had any problem until yesterday going through W. Va. on I-77. We hopped off of I-77 to follow US 19 for a few miles just to enjoy the scenery and encountered very sharp curves and steep grades. Engine lost power and would barely  go any further.  My first thought was clogged fuel filters so I got to the side of the road next to a sheer drop and changed the filters. I learned early on to carry spares as well as a gallon of fuel to fill them. Coach ran fine for a few moire miles and died again on I-77.  I then noticed I had no boast pressure from turbo.  After a few minutes I got it started again and it ran fine until I used the exhaust brake which is attached to the back of the turbine. Short version, I did not use the exhaust brake anymore and engine ran fine all the way home.  I am now trouble shooting the pac  brake to try to find the answer.  I found out  while researching it that you need to lubricate the pac brake but neither the coach or Cumming manuals had any lubrication requirements  for the brake. Disconnected the linkage the arm and vane moves freely. Now about to apply 12 v to the air switch to operate the cylinder so I can check that. 

Always something!

[wolfe10]

Yup, lubing the PacBrake is a routine maintenance item:

https://pacbrake.com/product/c18037-superlube/

[jleamont]

28 minutes ago, wolfe10 said:

Yup, lubing the PacBrake is a routine maintenance item:

https://pacbrake.com/product/c18037-superlube/

Thank you, I was just looking for that link 

40 minutes ago, floydfowler said:

Yes, That would be the same problem as mine except I found a replacement with same size and mounting as original.

Sure wish I had the ISL 400, as I have a 350 ISC with pac brake.  I use the exhaust (Pac) brake very frequently and have never had any problem until yesterday going through W. Va. on I-77. We hopped off of I-77 to follow US 19 for a few miles just to enjoy the scenery and encountered very sharp curves and steep grades. Engine lost power and would barely  go any further.  My first thought was clogged fuel filters so I got to the side of the road next to a sheer drop and changed the filters. I learned early on to carry spares as well as a gallon of fuel to fill them. Coach ran fine for a few moire miles and died again on I-77.  I then noticed I had no boast pressure from turbo.  After a few minutes I got it started again and it ran fine until I used the exhaust brake which is attached to the back of the turbine. Short version, I did not use the exhaust brake anymore and engine ran fine all the way home.  I am now trouble shooting the pac  brake to try to find the answer.  I found out  while researching it that you need to lubricate the pac brake but neither the coach or Cumming manuals had any lubrication requirements  for the brake. Disconnected the linkage the arm and vane moves freely. Now about to apply 12 v to the air switch to operate the cylinder so I can check that. 

Always something!

Here is an thread on PAC brakes;

 

[richard5933]

2 hours ago, floydfowler said:

Richard, please read my first post. I have isolated the battery cutoff switch as the problem, just wanting to know if anyone has had battery switch problems like mine. Everything works fine when I jump the switches.

Sorry if I misunderstood. If the only problem is the switch failing, then there are only two options: Either the switch is not actually capable of carrying the 230 amps it's rated for, or you're pulling more than 230 amps through it.

Battery switches should not melt down during normal use. Ever. Something caused that terminal to get hot enough to melt the housing. Likely cause is either more current flow than the switch can safely carry, or the contacts are not mating properly causing arcing. The high current flow theory was why I asked about the chassis batteries, because if you were starting the engine using just the house batteries you're likely putting more than 230 amps through the switch. If the switch is the weak point, that's where the heat will build.

I've been using Blue Sea battery switches and have not had any problems. That's what jleamont shows in the posted photo above. From comparing pictures I found online of the Guest switch you're using to the Blue Sea, I'd say that the Blue Sea is much heavier duty.

[floydfowler]

Thank you for checking that out.  I will look into that Blue Sea switch. The high heat/amps would seem to indicate a loose connection, possibly inside the switch where I can't get to it without cutting it apart. I plan to do that  after I get everything back together.

I really appreciate all the time and suggestions from this forum.

[bm02tj]

There is also other causes 

draw to high on starter for light plant 

back feed and main starter is drawing off coach battery's instead of just chassis battery's   

[richard5933]

This is the Blue Sea I'm using on my house battery bank. It has a continuous duty rating of 600 amps, and a cranking (30 sec) rating of 1750 amps. It's available with and without the AFD, depending on need. https://www.bluesea.com/products/3000/HD-Series_Heavy_Duty_On-Off_Battery_Switch

Quite a bit more substantial than the switch you had on there, and of course it will set you back a few more dollars and may require new terminals on the battery cable depending on the ring size you currently have.

I don't know the size of your battery bank, so I can't say whether or not this is overkill for you. I try to have the battery disconnect larger than any possible load on the battery bank, and since we are configured to use the house battery bank to run the starter on the Perkins diesel (genset) I used that as my standard. Since you can join your house & chassis batteries to start your main engine, you might want to calculate the max draw based on that load. I'm sure others here will offer other methods to determine the proper battery disconnect size.

[floydfowler]

I have done some more checking and found that the max load on the house batteries is 275a (inverter) and it is fused at 300 amps.I normally am drawing 38a with the refrigerator and 140 with ref. and Microwave. All of these loads are well below the 300a fuse.  I have ordered the e-series switch rated at 350 amp continuous and 3/8 posts which should work well. Since my normal draw is less than 40 amps (refrigerator only) I think the switch failure is an internal resistance /high heat problem due to poor design/quality of the sliding contacts and the 350 amp ones will hopefully be ok.  If not, I will send them back to Amazon and get the 600 amp ones.  As a side note, I put my ampmeter on the coach and chassis circuits and confirmed 38a on the house with the inverter (ref only) on and less than 9 amps on the chassis circuit while starting the engine. I had expected higher loads while starting but that is what I had. If I were to use the battery boost switch to combine house and chassis batteries I will still be no where near the 350a capacity of the switches.

Thanks again for taking the time to respond. 

[hermanmullins]

Floyd,

I am not an electrician but drawing 38 amps on the refrigerator seem very high to me. My residential refer. only draws about 5 amps on startup and less then 3 amps when running. Are you sure about those draws? 140 amps with ref. and microwave ? 

Herman 

[richard5933]

1 hour ago, hermanmullins said:

Floyd,

I am not an electrician but drawing 38 amps on the refrigerator seem very high to me. My residential refer. only draws about 5 amps on startup and less then 3 amps when running. Are you sure about those draws? 140 amps with ref. and microwave ? 

Herman 

Herman - are you measuring AC amps at the appliance or DC amps actually being drawn from the battery? To make the AC amps for the fridge the inverter will pull a higher number of amps DC from the battery bank.

Watts consumed will remain the same, but amps will go up or down inverse to the volts according to equation watts = volts x amps.

Let's assume that a residential fridge pulls only 2 amps AC while running. That means 2 x 120 = 240 watts. To calculate the DC draw 240/12 = 20 amps DC, so it is not surprising to see that his fridge is pulling 38 amps from the battery bank. Since the number under consideration is the current flowing through the battery disconnect switch, it's important to know the numbers there. Good job to the OP for doing the homework to find the numbers.

Only 9 amps while starting the main engine? That sounds low - I'm wondering if there is another ground somewhere in the system that caused a false reading? Where did you check the current flow to the starter? If you're using a clamp-on amp meter, perhaps you can check at the starter itself to confirm. Be a shame to go through all this and be working from a faulty number. Assuming that you have a Cummins engine, the smallest starters I see out there at 12v would draw up to 3.3kW, which means far more than 9 amps.

[floydfowler]

Wow, 3300 watts!  I think that would be 275 amps!  I agree that the 8 amps is low and I read it at the chassis battery cut off switch with my clamp on amp meter.  I have a Fluke digital meter as well but the clamp on is too small for  the 2/0 battery cable. I will use the clamp on meter right at the starter but will need to wait until DW gets home to start it for me. The fluke meter can record the highest reading if it would fit over the cable and I could do it by myself.

Speaking of another ground somewhere, here is one other strange fact...while stranded with the faulty battery switches, I had no power to the instrument panel or ignition switch and nothing worked, including the generator which I had been trying to start.  The house battery switch was frozen in the on position.  Now the overhead map light over the drivers seat is on and cannot be turned off!! I never use it so I know it was previously off.   I tried the boost switch which combines both battery banks and the instruments lit up and I was able to start the engine but all died when I released the boost switch.  Now I knew the issue was with the chassis battery switch so I bolted the two leads to the same terminal and bingo, everything worked and the map light was out but would turn off and on with it's switch.  Just how weird is that?

[wolfe10]

Be aware that on start up, particularly when cold there are two large draws:

Starter

Intake manifold heater-- it also takes a lot of amps.

[richard5933]

Sure sounds like a problem with the chassis batteries and/or the chassis battery disconnect switch.

Sounds like the overhead map light is wired in a non-standard fashion - perhaps with a ground switch instead of a positive switch, or perhaps somehow bridging both the house and chassis batteries so it can run on either. I've got a few odd lights like that, including one that for some reason was wired with its ground wire through the 120v grounding system instead of the 12v system (that was fixed immediately).

Here's where I got the starter data: https://www.newindo.com/pdf/MxTbrochure.pdf

I had to take somewhat of a stab in the dark on which you had on the engine, but these are pretty common diesel engine starters.

[floydfowler]

5 hours ago, richard5933 said:

Herman - are you measuring AC amps at the appliance or DC amps actually being drawn from the battery? To make the AC amps for the fridge the inverter will pull a higher number of amps DC from the battery bank.

Watts consumed will remain the same, but amps will go up or down inverse to the volts according to equation watts = volts x amps.

Let's assume that a residential fridge pulls only 2 amps AC while running. That means 2 x 120 = 240 watts. To calculate the DC draw 240/12 = 20 amps DC, so it is not surprising to see that his fridge is pulling 38 amps from the battery bank. Since the number under consideration is the current flowing through the battery disconnect switch, it's important to know the numbers there. Good job to the OP for doing the homework to find the numbers.

Only 9 amps while starting the main engine? That sounds low - I'm wondering if there is another ground somewhere in the system that caused a false reading? Where did you check the current flow to the starter? If you're using a clamp-on amp meter, perhaps you can check at the starter itself to confirm. Be a shame to go through all this and be working from a faulty number. Assuming that you have a Cummins engine, the smallest starters I see out there at 12v would draw up to 3.3kW, which means far more than 9 amps.

Here is a little more data.  Shore power off, inverter on, inverter monitor shows 38 amps. House battery cable at cutoff switch shows 38 amps with clamp on ammeter. Refrigerator AC cord plugged into ac outlet shows 4 amps on each individual ac wire (fortunately the two wire cord was split just before the plug in to the control panel). The wires going to the two ac heater elements in the ref. boiler each show 2  amps per heater.  4 amps x 120 volts = 480 watts.  480 watts / 12v = 40 amps. pretty close. 

[floydfowler]

1 hour ago, richard5933 said:

Sure sounds like a problem with the chassis batteries and/or the chassis battery disconnect switch.

Sounds like the overhead map light is wired in a non-standard fashion - perhaps with a ground switch instead of a positive switch, or perhaps somehow bridging both the house and chassis batteries so it can run on either. I've got a few odd lights like that, including one that for some reason was wired with its ground wire through the 120v grounding system instead of the 12v system (that was fixed immediately).

Here's where I got the starter data: https://www.newindo.com/pdf/MxTbrochure.pdf

I had to take somewhat of a stab in the dark on which you had on the engine, but these are pretty common diesel engine starters.

I have a 2001 Holiday Rambler with a Cummings 350 ISC  8.3L engine.  talked with Cummings and learned that my starter is a Delco-Remy 41 MT.  They were unable to give me the normal starting amperage.  In preparing to read the amperage at the starter I found the starter has three large cables connected to the solenoid so I suspect the started is wired directly to the batteries and the starting current does not all  flow through the battery cut off switch. Could be just the solenoid coil is going through the switch and not the main load. I will check the amperage at the chassis battery next.  I can't find a wiring diagram in my manual that shows the starter wiring but I will check each of the three wires to the solenoid  separately.  I am still leaning toward defective internal switch contacts causing the resistance and high heat. 

[dickandlois]

1 hour ago, floydfowler said:

I have a 2001 Holiday Rambler with a Cummings 350 ISC  8.3L engine.  talked with Cummings and learned that my starter is a Delco-Remy 41 MT.  They were unable to give me the normal starting amperage.  In preparing to read the amperage at the starter I found the starter has three large cables connected to the solenoid so I suspect the started is wired directly to the batteries and the starting current does not all  flow through the battery cut off switch. Could be just the solenoid coil is going through the switch and not the main load. I will check the amperage at the chassis battery next.  I can't find a wiring diagram in my manual that shows the starter wiring but I will check each of the three wires to the solenoid  separately.  I am still leaning toward defective internal switch contacts causing the resistance and high heat. 

What you described is what I might expect to see.

This is some information on your year HR that might help.

  Rich

Starter Wiring.pdf 2001 Holiday Rambler VIM Trans.pdf Rear Run Box Wiring.pdf Starter Wiring.pdf