Battery Boost Solenoid or Battery Isolator?

[rphcampers]

Hello

I have an 01 Monaco Signature. When I tried to turn on the lights, none of the 12 volt circuits in the house worked. The only thing that seemed to operate at all was the fantastic fan in the bathroom... but only ever so slowly. I have already bypassed both solenoids controlled by the "salesman switch," so the only thing left to try was the large battery boost solenoid. It did "clunk" when the batt boost switch was pressed on the dash. I used some jumper cables to "jump" the batt boost solenoid, and everything worked again. Now, I don't even need to jump the solenoid and everything seems to work fine. House batteries are good. Chassis batteries are good. Could this mean the Cole Hersee solid state battery isolator is going bad? Could it be the large batt boost solenoid right next to the battery isolator? I thought that those just broke rather than working intermittantly, since they're electronic... Any ideas or suggestions out there? Am I missing something? Anyway, I would like to replace the large batt boost solenoid. I tested it and, even though it "clunks," it doesn't seem to be connecting. There are no markings on it. Does anyone know what the part number might be? It's 200amp continuous current rated at 1000amp "spike." Thanks so much for any info!

Matt

[Robi.1014]

Matt,
Your "...The only thing that seemed to operate at all was the fantastic fan in the bathroom... but only ever so slowly" says that your "house" was only getting a few of the 12VDC from your house batteries. So something in the electrical path, from your house batteries (which you say are good...did you put a voltmeter on them?) to the 12volt lighting fixtures is failing. Let's not blame it on the battery-boost solenoid just yet.

Suggest checking for good continuity across the house battery-cut-off switch in the battery bay, and take a good look at the large fuse that is also there. Bad wiring or bad ground is distinct possibility.

[KIX]

In my opinion you have dirty contacts in the boost solenoid. I think you will continue to have the problem intermittently until you renew the solenoid or disassemble it (if possible) and clean the contacts.

[distaff]

This is odd. The isolator relay should have nothing to do with your coach batteries powering the coach unless the coach batteries are dead and the only power to the coach is from the chassis batteries. If this is the case you may have some logic in the isolator circuit that will prevent the relay from closing if it doesn't see a voltage (or enough) on either side.

I say this because the relay circuit does not stand between your coach batteries and your coach circuits. You can remove it and you will have power on both sides unless you have dead batteries. You may also have a bad cut off switch.

Did you check your voltages at the coach batteries?

[lonestarace]

Originally Posted by rphcampers

Hello

I have an 01 Monaco Signature. When I tried to turn on the lights, none of the 12 volt circuits in the house worked. I have already bypassed both solenoids controlled by the "salesman switch," so the only thing left to try was the large battery boost solenoid. It did "clunk" when the batt boost switch was pressed on the dash. I used some jumper cables to "jump" the batt boost solenoid, and everything worked again. Now, I don't even need to jump the solenoid and everything seems to work fine. House batteries are good. Chassis batteries are good. Could this mean the Cole Hersee solid state battery isolator is going bad? Could it be the large batt boost solenoid right next to the battery isolator? I thought that those just broke rather than working intermittantly, since they're electronic... Any ideas or suggestions out there? Am I missing something? Anyway, I would like to replace the large batt boost solenoid. I tested it and, even though it "clunks," it doesn't seem to be connecting. There are no markings on it. Does anyone know what the part number might be? It's 200amp continuous current rated at 1000amp "spike." Thanks so much for any info!

Matt

Sounds to me like 1) the jumper job to bypass your 2 saleman switch solenoids wasn't done correctly; 2) bad battery connection(s); 3) dead batteries.

It is not your Cole Hersee battery isolator. They are just a 1 way electrical check valve that prevents current from flowing from one battery bank to another. Its only energy source is the alternator. They can fail as a open or closed curcuit. Neither case will cause your problem. If the isolator has failed as a closed curcuit then both battery banks are connected to each other when ever the battery cut-off switches are on. You might want to test it? Ask me how I know. I turned off my chassis battery cutoff switch and was still able to crank the Cummins 500.

Your battery boost solenoid can be taken apart and rebuilt.
12 Volt DC 500 amp continuous duty relay replaces Delco 1119865CD, 9-865CD

[georgetown350]

I agree with lonestarace. No way its the solenoid....... I would take all your battery cables off and clean them and then test the house batteries........

[rphcampers]

Thanks to everyone for all of the ideas... The one thing that has me puzzled is that one day all electrical items inside the coach worked fine. The next day, I went to turn on an interior light and nothing happened. I continued to try inside circuits from other lights, to fans, to water pump, etc and nothing worked. Then, I manually jumped the boost solenoid, and everything started to work again. Now, without the solenoid jumped, everything continues to work as it should. The "salesman switch" solenoids were bypassed a while ago, so I don't believe the problem lies there. I checked... all connections are clean and tight. Though I did not actually check voltages on house or chassis batteries, the engine cranks without difficulty and the interior lights are bright. I checked for the PRESENCE of power on both poles of the battery isolator and the tester glows bright. As far as jumping the boost solenoid... I don't believe that had any direct effect on solving my problem. When I did that, I had not educated myself on exactly how that system functions. Since then, I have read up on coaches with BIRD style systems that use a boost solenoid to charge the second battery bank when the first is charged, and coaches with a solid state isolator like mine. I wonder if my jumping the solenoid somehow "shocked" another electrical component in the system resulting in the lights coming back on. Before they came on, plugging the coach into shore power and running the generator had no effect. Could it have been an issue with the switch that changes between power sources? Maybe not because mainly 12V systems were effected? The only additional piece of info (possibly helpful?) is that I noticed my battery isolator (which looks to be original) says max alternator amps 160. The alternator in my coach was replaced in 06 and it's a 200 amp alternator. Could this have somehow damaged the isolator and lead to this problem? Anyway... I'm getting long winded. If anyone has any additional ideas or suggestions, please share. Thanks a bunch

Matt

[ahicks]

I can share one thing with you. Some of my biggest headaches have been caused by wayward grounding issues. When you're troubleshooting, you can't afford to ignore that potential! Between those, and erratic connections of all types, there's never a dull moment!

[georgetown350]

As mentioned that solenoid either connects all the batteries together or keeps them separate. Thats it very simple. So all you did with those cables is temporally connect all the batteries and the fact that you gained instant power as a result of this implies that the solenoid was indeed working as it should to keep the batteries isolated. So with the cables you connected all your batteries which would give you the power you need in case the house batteries were flat or the ground you need in the case of a poor ground. After taking the cables off you still have power which puzzles you, well poor grounds work in mystery ways. Rest assure that your problem is only temporally solved. Find that bad ground, dirty connection or bad battery.

[distaff]

Matt,

Lets look at this from a functional perspective. You lost 12v to the coach, but you had 12v for the chassis. The isolator relay cross connects the coach and chassis 12v systems. If in your coach 12v system you have a bad connection, dead cell on a battery, or a bad fuse you will see a complete loss of 12v power. If you force the isolator relay to close you will have connected the coach to the chassis 12v system.

This may help you eliminate a couple of possibilities - it clearly won't be a bad ground because when you close or jump the isolator relay you are only connecting the +12v side. You may also still route through the main fuse, so it is probably not a fuse, but you need to look at how the power is routed. Last, it probably is not the salesman solenoid because the power from the chassis side does not usually bypass that connection, but again, study how the power routes.

Probably a dead short in a battery, a failed cut out switch, or a bad connection at the battery. Get a voltage meter and check the voltage on your coach batteries.

[lonestarace]

Here is a link to the battery isolator you SHOULD have in your Signature.
http://www.google.com/url?sa=t&rct=j...ya3ro6wzyju3tw

The cables coming off it go to: center post=alternator; 2 outer post= the battery cutoffs for the 2 battery banks. Here is what your cabinet should look simular to.

Below is the cabinet of our 2000 Signature Caesar.

I've modified it in several ways. 1) I added 2 cooling fans above the isolator; 2) added a thermal snap switch(120f on, 105f off) to automatically turn on and off the fans; 3) an indicator light to visually let me know when they are on or off; 4) Installed a Trik-L-Start battery maintainer when the factory unit went bad.

These heat sink type battery isolators can and do "fail". When they fail closed curcuit each battery bank is always connected to the other. They can "fail" so that the battery banks and alternator are never connected to each other(open curcuit). But this ISN'T how they "normally" fuction. "Normally" it ONLY lets current flow from the alternator to each battery bank via one way(diodes) separate paths.

The battery boost solenoid(LARGE) is a way for you to temporarily connect one bank to the other.

In the same compartment, there are 2 small solenoids that are opened and closed by the salesman switch by the entrance door for the house 12v system.

Get a multimeter and start checking everything for voltage and resistance. Also trace the cables between the battery cutoffs and the battery isolator.

I hope this helps?

[rphcampers]

I assume the genset uses 12V chassis power to start. When the power was out in the "house," I started the genset to see if that would help. The genset started with no problem, but still no house power. So... that seems to imply that there was chassis 12v power, but no house power. The way the power was out, then suddenly came back on, seems less like a ground or battery cell (which may lead to dimming or loss of some circuits - more gradual, not all or nothing) and more like a circuit breaker. Would it be logical to investigate one of the four 80 amp auto breakers for the house (located bottom left in the high power panel pictured in the previous post)? Would there be breakers located elsewhere I should investigate? Thanks...

Matt

[rphcampers]

I should also point out... when the house lights were out I tried plugging the coach into shore power. That didn't help... still no lights. But... I noticed that the green battery maintainer LED was not lit. Once the circuit came back on (after jumping the boost solenoid), the battery maintainer LED came back on. I'm assuming power is fed to the maintainer from the converter via the house batteries? Could this be another clue to a "broken" house battery circuit? Does that make sense... because I sort of confused myself...

Matt

[lonestarace]

From your last 2 posts, I'm thinkin 1) either a bad connection at your "house" disconnect switch, or 2) a bad "house" disconnect switch.

It sounds like your chassis battery(s) are powering the house 12v system since you have jumpered over the bat boost solenoid.