Chassis battery not charging

[PhilNDenise]

I had a problem previously that the house batteries would not charge from Cummins generator or engine alternator, but would charge from shore power. they replaced the Trombetta relay under warranty a little over a year ago. Now the chassis battery does not charge from shore power or Cummins generator, but does charge from engine alternator.
I checked the Trombetta relay, I have 12volts on the control contact, the solenoid is hot indicating it is activated but I have a difference of .9 volts on the main terminals.
Is it possible that the relay is bad again?

[PhilNDenise]

any ideas?

[YC1]

Yes it is. Any component can fail at any time. You should not have almost 1 volt difference.

Disconnect the control wire and let the solenoid cool for a few minutes. Then touch the wire back on and off several times to make the contacts hammer on and off. Reconnect and measure again.

Now go online and buy the silver contact one to replace it. Take the old one apart and inspect the contacts. Post a picture of them. Clean the contacts and put it back together to use as a spare.

[Steve70605]

I have replaced mine 4 times in past 1.5 years. A major issue with the Trombetta is it is a 12VDC rated contactor (designed for golf carts etc). It is not rated to take the higher charging voltages (as much as 14.4 volts) continuously. So the relay starts to degrade and has less pull in torque and the contactors fail prematurely.

One way to prevent early failure is to install a switch so the contactor is not activated if you are leaving the unit plugged in to shore power all the time. Running the unit once a month will maintain the chassis battery. You can turn on the switch when you will be driving the unit to connect the batteries.

I also replaced mine with this unit: It has a 15VDC rated coil.

https://www.mouser.com/ProductDetail...tH1I0Etg%3D%3D

FWIW

[H2odiverski]

I just went thru the same exact scenario. Ordered silver contact unit and hope that it lasts longer than a year.

[YC1]

Steve, If you had to replace yours that often you must have other issues. There are thousands of these in the field. Yes they fail but four in 1.5 years very strange.

My chassis battery would be dead as a hammer in one month without turning off the battery switch without being charged.

My humble experience and 50 yrs.

[PhilNDenise]

I disconnected the control wire and let it cool. I then engaged the relay at least a dozen times. I had the meter on the chassis battery contact and the meter never flinched a bit during the process. The contacts must be gone entirely. I have ordered a new one that has silver contacts, but it has the same model number as the one I have. Meanwhile I have to hook up the battery charger before we leave on Sunday as it is not charging now.

[YC1]

Originally Posted by PhilNDenise

I disconnected the control wire and let it cool. I then engaged the relay at least a dozen times. I had the meter on the chassis battery contact and the meter never flinched a bit during the process. The contacts must be gone entirely. I have ordered a new one that has silver contacts, but it has the same model number as the one I have. Meanwhile I have to hook up the battery charger before we leave on Sunday as it is not charging now.

Pile the wires together with a nut and bolt but wrap them carefully of course.

[PhilNDenise]

I ordered a new relay from Ebay Thursday afternoon and received it this morning by priority mail. Free shipping. Before replacing it I did another test, this time I had only .2 volt difference in contacts. After I turned off the switch for the chassis battery and house battery, the control terminal was still at 12 volts and engaged. This time I had 0 volts on the chassis battery contact but 12 volts on the chassis battery contact. Evidently the contacts were completely gone. I guess that explains why I had .2 V difference one time and .9 V on another. I was just reading the state of charge of the chassis battery. Anyway, replaced the relay and had 12.8 volts on one contact and exactly 12.8 on the other contact. I took apart the relay to check the contacts and one was completely burned to the point of no contact.
Does anyone know the specs on these relays? The Trombetta site is useless.
I ordered (114-1211-010) and they sent me a (114-1211-020-02). Is there a difference in specs. It was identical size and mounting brackets and color and appears to be working.

[PhilNDenise]

Originally Posted by PhilNDenise

I ordered a new relay from Ebay Thursday afternoon and received it this morning by priority mail. Free shipping. Before replacing it I did another test, this time I had only .2 volt difference in contacts. After I turned off the switch for the chassis battery and house battery, the control terminal was still at 12 volts and engaged. This time I had 0 volts on the chassis battery contact but 12 volts on the chassis battery contact. Evidently the contacts were completely gone. I guess that explains why I had .2 V difference one time and .9 V on another. I was just reading the state of charge of the chassis battery. Anyway, replaced the relay and had 12.8 volts on one contact and exactly 12.8 on the other contact. I took apart the relay to check the contacts and one was completely burned to the point of no contact.
Does anyone know the specs on these relays? The Trombetta site is useless.
I ordered (114-1211-010) and they sent me a (114-1211-020-02). Is there a difference in specs. It was identical size and mounting brackets and color and appears to be working.

"0 volts on the chassis battery contact but 12 volts on the chassis battery" I meant to say "but 12 volts on the house battery"

[revflyer]

The 020 has silver contacts, I replaced my 010 for the same reason as you. I've been running the 020 full time for 10 months with no more problems.