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Trailsweep · 08-24-2022, 12:21 PM

Does anyone know of a high current discontent switch that can be put inline to disconnect the starter from the batterries.

2001 Alpine 8.3 with the 42 MT type starter on it that can draw up to 1650 AMPS holly crap

Reason for this is I had the start stick engaged and had to pull the positive wires which was no fun as the current draw basically was welding the wires as i was pulling them , almost started a fire !!!

wonder if this has started a fire in coaches before . Super scary and would like to prevent this in the future .
any thoughts ? Think this would be an excellent preventive measure as when all the battery disconects are thrown the starter was still engaged and trying to turn the motor over !!!

twinboat · 08-24-2022, 02:04 PM

That happens when attempting to start the engine with weak batteries.
The starter mounted solenoid or the smaller starter solenoid bolted on the chassis internal contacts weld together.

Smack it with a hammer and it will let go.

Unless your in sub zero temps, your starter won't drop that much. Find a disconnect with a high surge rating, like the CAT disconnect.

Old Scout · 08-24-2022, 02:46 PM

Classic risk mgt question--doesn't happen very often but when it does, its serious. Never had the issue but a friend did on his 2005. As a preemptive measure, I switched the power feed to the secondary starter solenoid to switchable power so I could try to kill starter with the chassis bat kill switch vs removing a cable; second, I added a back-up beeper to the secondary solenoid circuit so if secondary welded, I "might" hear the beeper. Never had to test it.

bcbowers · 08-25-2022, 08:10 AM

I added a backup beeper available at most auto parts stores for $12 or so. It alerts me if the solenoid stays connected after starting the engine. This actually happened to me immediately after adding the beeper and saved my starter from burning up. Of course, I then had to hurry and disconnect the hot wire. I like OS suggestion to move the hot wire to the disconnect engine source to allow quick disconnect.

The only drawback I can think of is that turning off the disconnect switch means you’ve killed the engine. If the solenoid is defective then restarting the engine becomes problematic assuming you started it because you need to drive somewhere. I carry a spare Cole Hersee solenoid for this very situation.

Trailsweep · 08-25-2022, 10:18 AM

Twinboat

batteries where @ 100 percent so I can rule that out , could it happen ? Maybe ?
Thinking that the coach just sat for a little to long myself .

I did smack the living crap out of it , so hard I broke the darn Solenoid

Old Scout ,
I would do this but the start is rated @ 1650 AMP s that it could potentially pull ,
will it ? Not sure . Im thinking or a high voltage 600amp rating but wanted to know if anyone knows or something higher rated .

And putting it on the battery disconnect when that disconnect is rated @ 300 amps is a little scary to me

The alarm sounds like maybe a solution or perhaps a dash mounted LED light ?
All I know is that she was pulling some juice . BTW starter is brand new now !
Anyone have any other ideas ?

Old Scout · 08-25-2022, 12:01 PM

Think we are mixing terms here--if the primary solenoid on the starter fails--the only option is to disconnect the cable, or install a hi-amp disconnect. Not sure what the max amp would be--technically, a locked starter with the engine running wouldn't draw the same amp load as when starting the engine. Blue Sea is a common marine source for these types of switches. My experience is limited to the secondary low-amp solenoid--adding a beeper and connecting it to a switchable power source helps but doesnt solve the entire issue.

twinboat · 08-25-2022, 12:19 PM

Quote:

Originally Posted by Trailsweep

Twinboat

batteries where @ 100 percent so I can rule that out , could it happen ? Maybe ?

Thinking that the coach just sat for a little to long myself .

I did smack the living crap out of it , so hard I broke the darn Solenoid

Old Scout ,

I would do this but the start is rated @ 1650 AMP s that it could potentially pull ,

will it ? Not sure . Im thinking or a high voltage 600amp rating but wanted to know if anyone knows or something higher rated .

And putting it on the battery disconnect when that disconnect is rated @ 300 amps is a little scary to me

The alarm sounds like maybe a solution or perhaps a dash mounted LED light ?

All I know is that she was pulling some juice . BTW starter is brand new now !

Anyone have any other ideas ?

There is a good chance that the other smaller solenoid stuck, did you find and smack that ?

How long were you cranking before you realized the starter was cranking on its own. 30 seconds and the volts are below 10 volts.

Trailsweep · 08-26-2022, 12:27 PM

oh ya , smacked that . The coach starts right up and was warming her up and noticed a strange noise and was checking to see where it was coming from .
shut it down to find the starter was still trying to start it !
disconnected the secondary start solenoid and that did not work so that is when I pulled the battery cable
I figured the starter was running for maybe 5-10 minutes . But could have been shorter but was kind of freaking out when the main solenoid started to smoke !checking everything now .figured shes 20 plus years old so.....

Trailsweep · 08-26-2022, 12:33 PM

Old Scout ,
yes that is the solenoid I'm referring to is the main one that can pull the max AMPs but possibly the secondary could be on a switch .
I know this is a very limited issue .? but it could save someone a fire or destroying there coach You can what if it all day but that seemed to be something that could stick and you would not know that if you where not in-tune to the noises that your motor makes ? That is the only reason I figured something was wrong . Sounded to me like a flex plate nut came loose and was coming from the transmission !

I thought , what is that new noise