Surgeguard Transfer Switch failure

[Jim Gill]

We have a 2006 Monterey. A few days ago, I was watching TV with the air conditioner on using 110v shore power. For no apparent reason, I lost the shore power source. Assuming the problem was at the RV park pedestal, I took my digital meter and went out to check the pedestal. Both legs of the 50 amp service checked OK. I shut off the 50 amp breaker, unhooked my power cord, checked for any issues with the contacts, reconnected the power cord and turned on the 50 amp breaker. I was very suspicious when I didn't hear the normal "thumping" sound from inside the transfer switch when the 110v power connection is normally completed. I turned on the gen set to see if I could get 110v into the coach from this source and it was also dead...no power to any 110v circuits. After speaking with the Surgeguard folks, I removed the cover from the transfer switch and checked for input voltage to the switch from both shore power and the gen set...both legs of both input sources to the transfer switch checked OK. But there was no output from the transfer switch. I looked closely for any loose/broken/burnt wires inside the transfer switch box and discovered the failure shown in the attached images. A corner of the printed circuit board and the wire connecting to it had burned...badly!!! When I touched the wire, it instantly separated from the burnt portion of the board.

I have ordered a new transfer switch from Bend and plan to install it as soon as it arrives. My concern is trying to figure out the root cause of this failure. If the connector and circuit board reached their design life and just failed, OK. But if there was some other problem source which caused this failure, I'd like to know this before I install a new switch. I recently had to install new house batteries after a positive post on a 3 year old battery pulled out of the battery and caused a failure in our 12v system. But the 12v and 110v systems on these coaches are separate systems so I'm not certain how a failure in the 12v system would cause a failure on the circuit board of the 110v transfer switch...but I suppose anything is possible.

Any thoughts on this matter would be helpful...thanks in advance.

Jim Gill
    

[Joel Ashley]

Did you email those pix to SurgeGuard for their analysis?

Joel

[Jim Gill]

Joel
Yes, I have already sent them to Shawn in the Surge Guard technical group at the TRC factory down in Florida. He's trying to get a design engineer to take a look at this failure before he provides me with any feedback. Since the fuses which are part of the surge protection part of this unit were not blown, Shawn partially dismissed the possibility of a power surge but he won't eliminate this possibility until an engineer gives it a look. The direct replacement unit is a #40250-RVC...according to Shawn, the only difference between this unit and the original #40250 is that it has a port for an external monitor option.

I'll post the answer I get from Surge Guard as soon as I get it. The new unit arrived a few hours ago...it goes in later today or over the weekend.

Regards,
Jim

[Gerald Farris]

Jim,
I can not see anything that would cause the failure that you experienced, except a connection in the transfer switch that had high resistance. Either the pins on the circuit board did not have a good connection with the connector, or the connection between the pins and the board had high resistance, from an improper or cracked solder connection.

Gerald

[Jim Gill]

Gerald
Thanks for your feedback. I'm a bit more comfortable installing the new transfer switch based on your thoughts that the root cause of my failure originated within the transfer switch box itself rather than from some outside source. After 58,000 miles of bouncing and jiggling down the highway, it would not be surprising that a connector or solder joint or something on the printed circuit board could fail.

I have another question for you. Without any 110v power for the past few days, I've connected a 12 volt, 10 amp trickle charger to my house batteries so that we can live off the 12 volt lights and use the inverter as needed for other things. But when I look at the Magnum inverter screen, the voltage never seems to get above 12.4-12.5 volts. I thought that this screen was measuring the charge in the house batteries and that after almost 4-5 hours of charging at 10 amps, the charge level would be above the 12.4-12.5 level. Once I turn on the inverter, not surprisingly the voltage on the inverter screen drops way off...quickly down to 12.1-12.2 volts. I'm not certain how low I can run the batteries based on the reading on the inverter screen before I turn everything electrical off and leave the charger on for the night. As mentioned before, my Alladin screen is not supplying any electrical info at the moment so other than putting a meter on the batteries, I really don't have an easy way to check the house battery status.

Any thoughts? As always, thanks in advance for your help.

Jim

PS How is it feeling to be "house bound" after all of your years full-timing? We hope you folks are adjusting well to the change.

[Gerald Farris]

Jim,
The Magnum panel is reading the house battery voltage at the inverter. This reading will probably be 1 or 2 tenths below the actual battery bank voltage, depending on how much current you are drawing from the batteries at the time. A 10 amp charger will have a lot of trouble keeping up with your electrical usage. Your parasitic draw with just the inverter on and nothing else, will probably be about 5 amps. My rule of thumb is not to go below 12V in the house batteries. In your case, I would start restricting the electrical usage to try to keep it in the range that it is being replaced by your trickle charger when you get to 11.8 to 11.9 on the inverter panel. You may start restricting the usage a little earlier so that you do not need to turn off any of the essentials of life like the TV too early.  

As for the charge rate of your little charger, If it does charge at the full 10 amps that it is rated at, 4 hours at 10 amps is only 40 amp hours. That is a long ways below the capacity of 4 golf cart batteries, and since the batteries do not charge at a 100% efficiency rate. you are a long ways from a fully charged battery bank.

The house is taking a little getting use to. Going from 10 years in a 40 foot coach to a 6 bedroom house is an adjustment. However, it is only a winter base, so we still travel 7 to 9 months a year. I got the outdoor kitchen finished a few weeks ago, so if you are in the Surprise Arizona area (NW Phoenix) sometime in the winter, stop by for a few days (I have hookups for 2 coaches), and we will grill a few steaks.

Gerald    

[Jim Gill]

Gerald
Thanks...everything you said makes good sense and will help us get by until we get the new transfer switch installed.

I still have a couple of questions for you. First, I turned the inverter off overnight and I left the trickle charger on at the 10 amp setting. With little or no electrical draw all night, the inverter voltage reading this morning before I turned on anything was only 12.7 volts. At 10 amps per hour X 8 hours, I would have thought that the battery charge would have been a bit higher first thing this morning. Any thoughts?

Second, before the transfer switch failed, I had to replace all of my house batteries because of a broken battery post. Not surprisingly, this problem was causing all sorts of 12v electrical and charging issues. At one point, when the Alladin electrical status screen was still providing data, it read that the solar panel was putting out 24 volts...no amperage reading but 24 volts!!! Is this possible and should I be disconnecting the solar panel until I can resolve this matter? If so, what is the easiest was to separate the solar panel from the rest of the electrical system?  

The thought of sharing a few steaks with you folks sounds like fun...we'll bring the wine!! We have been parking the coach in Casa Grande during the winter months so we really aren't that far away from Surprise...we could easily run up in our car for an evening. We have a group from the Casa Grande RV park that goes out Jeeping every Friday...some trips hard, some trips not so hard. If you have an interest, you'd be welcome to join us on a trip...I most often have space available in the passenger seat.

Thanks again for you expertise...it's always very helpful.
Jim

[Gerald Farris]

Jim,
The first question has a few variables that need to be answered. The first one is, what is the voltage that the charger is putting out? If the charger is only supplying 13.4 volts or so, the amperage output will drop as the batteries get nearer to fully charged, and I would expect those readings. However if it is supplying 14.4 volts at 10 amps, I would expect a little higher readings. I am also assuming that the charger is really delivering the full 10 amps when the batteries are 75% charged or less, and that it is never disconnected.  

The second question sounds like an error in the Aladdin reading. You solar panel is a 12V panel and as such it will have a maximum power output at around 17V, and have an open circuit maximum voltage of 20 to 22 volts. I do not know of any 12V panels that will produce 24 volts, especially through a regulator. As for disconnecting the solar panel, I do not know where the regulator is on your coach, but you can always disconnect the wires at the panel on the roof. But I would not, especially now when you need all the power that you can get. I would verify the voltage readings with a good digital voltmeter, and proceed from there.

Gerald    

[Jim Gill]

Gerald
Once again, thanks for your help. Hopefully, the new transfer switch will solve our problems and we can be on our way back to Colorado...Roberta is getting VERY homesick!!!
Regards,
Jim

[Joel Ashley]

Jim-

Our coach is a similar model to yours, and just so you can have a clue where it might be (in case you don't already know), the solar control module is high on the rear wall of the bay in front of the curbside rear wheelwell - the one with the bay door hook latches underneath, with Alladin modules and waste tank access, etc.

Joel

[Jim Gill]

Joel
Thanks for the solar panel info. I've been into the bay you described but didn't realize that the solar panel was in this compartment. Good to know in case I need to get at it but as Gerald has already said, for now, I probably need all of the charging power I can get!!
Thanks again,
Jim