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Replaced My Boost Switch Solenoid

June 30, 2015, 04:37:16 am

My boost switch has not worked for a long time. I bought a new Cole-Hersee solenoid and replaced the old one with it. When I checked by battery banks (I normally keep two plug-in meters installed in the two 12-volt receptacles on the dash. They both read 12,8 volts. I had planned to use the boost switch to check the boosted voltage, but they were already the same!
 
I had removed the Positive battery leads from each of the battery banks and opened the circuit breaker for my shore power plug. After turning the circuit breaker back on, they were now different, The house battery was reading about 14.1-14.3 volts; the chassis battery was reading about 13.3 volts.
 
With the boost switch turned on, they both went to about 13.8 volts, if I recall correctly. So, I have solved my boost-switch-not-working problem!
 
I have attached before and after photos. OOPS! I just realized I had mounted the solenoid upside down, relative to the original! Something about leaning over the foot of the bed and dangling washer and nuts to get the wires secured. (I did brush them and put Corrosion X onto the wire terminals, before reinstalling.
 
The first question is does it matter which position the solenoid is installed? Should I redo them to get the crimped-on plug on the bottom as the one I replaced, or did I luck into a symmetrical situation? (If I do have to remove the cables and replace them, I will definitely lay a pillow or something over the end of the bed as I lean over. It is not comfortable for short people to dangle across the two wooden partitions at the foot of the bed.)
 
Is it okay to use Corrosion X on cable connections?
 
Thanks to everyone for sharing their own experiences with us wide-eyed novices,
 
Trent

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Re: Replaced My Boost Switch Solenoid

Reply #1 – June 30, 2015, 08:15:50 am

Actually, the way you installed the new solenoid is the "normal" orientation, judging by every one I've seen.  I don't think it matters which end is "up", as far as function goes.  Corrosion X is good stuff...works great on any battery cable.

Easy way to check boost solenoid (or any solenoid switch):  Check voltage on both big lugs with multimeter - one is hot, one is not.  Then activate the control circuit (boost switch, in this case) - now both big lugs should be hot (showing the same voltage).

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Re: Replaced My Boost Switch Solenoid

Reply #2 – June 30, 2015, 08:21:49 am

The reason the solenoid is mounted the other way is so the contact is not resting on the spring.  That way the spring stays fresh and the solenoid doesn't fail to an "ON" condition.

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Re: Replaced My Boost Switch Solenoid

Reply #3 – June 30, 2015, 08:25:25 am

CorrosionX has a 36,000 volt dielectric rating.  Spray it on live circuits below that voltage for corrosion killing and protection.  Very good for circuit boards and electric connections on boats operated in salt water.

Excellent for motorhome connections that are in harsh environment outside of living space.

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Re: Replaced My Boost Switch Solenoid

Reply #4 – June 30, 2015, 09:09:04 am

Are there any special mounting instructions for solenoids?
Electromechanical solenoids should be mounted on a non-vibrating surface such as a fender well or firewall. They should not be mounted on a surface that vibrates such as an engine, as this may reduce the lifetime of the component.

Continuous duty solenoids should be mounted in an area that has ventilation, as the coil circuit normally generates heat. Our research shows that it might be best to mount the solenoid dimpled end down. Electromechanical switches can over time build up deposits due to arcing. By orienting your solenoid as recommended, deposits will have a tendency to fall to the bottom, clear of the contacts, thus prolonging the life of the solenoid.

Electronic solenoids such as 48785 are much more rugged, because they have no moving parts. They also will stand up to an incredible one million On-Off cycles!

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