Replacing Battery Interconnect Solinoid

[subtroll]

My 2004 National Tropi-cal electric systems appear to be working property except both Chassis and Coach batteries remain isolated from each other. AC sources(shore and generator) charge coach batteries fine but do not charge chassis batteries. Engine alternator charges my new chassis batteries fine.

Have located the Battery Interconnect Solenoid (out of the way behind a circuit board) and measure chassis battery voltage on one side and coach battery voltage on opposite side (~1 VDC difference). Measured 12 VDC on one control terminal indicating solenoid is energized but not connecting batteries. (I assume solenoid is normally open and closed when energized.) Believe that also confirms that whatever relay actuates the relay is OK.

Looks like replacement will require both sets of batteries and AC power to be disconnected and I don't know what solenoid to order. Looks to be similar to Battery disconnect relay in another compartment. Think I'll wait until my road trips are complete this year before replacing it.

Any suggestions?

[phays]

Sounds like you have an insulated coil solenoid since you have two small terminals. The Cole Hersee would be a great replacement. However you might consider the 24213. It has silver alloy contacts not copper as the earlier one referenced.

I purchased one from from Cole Hersee 24213 Solenoid

[tropical36]

subtroll wrote:
My 2004 National Tropi-cal electric systems appear to be working property except both Chassis and Coach batteries remain isolated from each other. AC sources(shore and generator) charge coach batteries fine but do not charge chassis batteries. Engine alternator charges my new chassis batteries fine.

Have located the Battery Interconnect Solenoid (out of the way behind a circuit board) and measure chassis battery voltage on one side and coach battery voltage on opposite side (~1 VDC difference). Measured 12 VDC on one control terminal indicating solenoid is energized but not connecting batteries. (I assume solenoid is normally open and closed when energized.) Believe that also confirms that whatever relay actuates the relay is OK.

Looks like replacement will require both sets of batteries and AC power to be disconnected and I don't know what solenoid to order. Looks to be similar to Battery disconnect relay in another compartment. Think I'll wait until my road trips are complete this year before replacing it.

Any suggestions?

You might first test it further by actuating your dash switch. If nothing happens, have someone hold it in, while you check for voltage on the coil terminals.
Also there should be voltage on the coil terminals, when one of the battery banks reach full charge.

[211kevinrichard]

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[subtroll]

This is our 15th season with this rig and AC shore and Generator have always charged both batteries. I'm using a maintainer now until I replace the solenoid.

[camperguy99]

Yes that's good advice. But my Trombetta would click and slam the contacts shut but they were so gunked up with black plastic that it was still an open circuit. Filing the contacts made the connection good but I destroyed the housing getting to the contacts! Hello new White Rodgers 15V solenoid. Works great!

[wolfe10]

Yes, if you got 12 VDC between the two small terminals with the dash switch ON, then the solenoid is bad.

If you do not have 12 VDC between the two small terminals, disconnect the one that should have 12 VDC positive from the dash switch and use a small jumper wire (small gauge is fine) from either large lug that is over 12 VDC to the small positive terminal. You should hear the solenoid click and read the same voltage on both large terminals.

[TNGW1500SE]

subtroll wrote:
.... Chassis and Coach batteries remain isolated from each other.

I'd bet that's normal operation. My RV did not charge the starting battery when pluged into AC. It came from the factory that way. I just added a battery maintainer to "fix" it.

[subtroll]

Great inputs.

Since my batteries remain isolated and my boost function doesn't work (watched voltage readings when boast switch activated),I'm assuming my relay needs replacing. My relay has four posts, two labeled coach and chassis batteries and two control terminals. 12VDC on one terminal.

[ILVMYGT]

Here is another option for the solenoid.

PAC PAC-200 200-Amp Relay Battery Isolator

https://www.amazon.com/PAC-PAC-200-200-Amp-Battery-Isolator/dp/B000CEBXRS/ref=sr_1_3?ie=UTF8&qid=1529542126&sr=8-3&keywords=PAC+PAC-200+200-Amp+Relay+Battery+Isolator

On my coach that solenoid has 2 functions. One it is the boost relay and second it combines the coach and chassis batteries when the coach is running. They provide power to the solenoid and then ground it to activate it. When the engine is running the ground is through a oil pressure switch. The Boost switch just provide a ground circuit.

On my coach the battery charging circuit is separate from the boost/combine solenoid.

[wolfe10]

D.E.Bishop wrote:
While tbat brand has fouur studs, that isn't always the case. Neither of my rigs have had an isolated stud. Both were grounded through the solenoid case.

Percussion persuasion is not recomended, you appear to have found your problem, trust you meter and your gut.

Yes, some solenoids are grounded through the metal body of the solenoid. If so, and it is not being screwed into clean metal, just run a wire (small gauge is fine, since it only carries a few amps) to a good ground. Same as you would if the solenoid has two small terminals (one being for ground). Said another way, makes no difference-- electrically they are the same.

Agee that percussion persuasion is not a "fix". But, it might get him through getting the chassis battery charged this time.

Another work around is to label the wire(s) on one of the large lugs and ADD THEM to the other large lug. Electrically the same as if the solenoid is working/continuity.

[subtroll]

Thanks for the excellent suggestions.

[Mandalay_Parr]

Make sure that the ground side of the solenoid control is good.

[D_E_Bishop]

While tbat brand has fouur studs, that isn't always the case. Neither of my rigs have had an isolated stud. Both were grounded through the solenoid case.

Percussion persuasion is not recomended, you appear to have found your problem, trust you meter and your gut.

[wolfe10]

It needs to be a CONSTANT DUTY solenoid. Probably 200 amp.

May get it to work short term by "percussive persuasion". Give it a light, sharp rap with the plastic handle of a screw driver. That will sometimes free them up for a time or two.

Here is a common one: http://colehersee.com.au/product/spst-12v-200a-continuous-duty-solenoid/