Shore Power Issue

JackinVT

Member
Shore power no longer providing power when plugged in. On board generator 120VAC is fine. Thinking this is a transfer switch issue. Can someone provide the location of the transfer switch on a 2017 CS Adventurous Model RSCM on a 2016 MB Sprinter chassis? Thanks!
 
Last edited:

Philip53

2021 2500 Sprinter 170, 4 cyl gas
Also check the shore power 120v junction boxes for proper wiring & connections. Several here have found problems there, including myself. I had found loose connections with associated burn and scortch marks in those boxes.
 

Hooligan2

Member
Does sound like the Transfer switch. It is placed by RV manufacturer not MB. You may be able to follow the power cord, it will usually go direct to the box.. My Thor Siesta it is under the passenger side bed.
 

JackinVT

Member
Check your 120v breakers first. Would help if you provide Make/model.
Are the 120VAC breakers common for both shore power and the generator? Everything appears to be fine running off generator power. This is a Roadtrek camper, not sure of model as it is a friends, but I will find out. Thanks!
 

Solera2012

Well-known member
Here is an assumption. Shore and generator (supply 120v) feed your panel(s) 120/12v sides, going from your transfer switch, after it recognizes proper input, to the converter, which splits your circuits (120v and 12v).

I am not at all familiar with your units wiring, so hopefully someone here will chime in.
 

WinnieView1

Well-known member
Are the 120VAC breakers common for both shore power and the generator? Everything appears to be fine running off generator power. This is a Roadtrek camper, not sure of model as it is a friends, but I will find out. Thanks!
Correct, they are common. Check the shore power pedestal or outlet, shore power cord, and onboard outlet.
 

bazar01

2008 Dodge Sprinter 2500 170 extended
Shore power no longer providing power when plugged in. On board generator 120VAC is fine. Thinking this is a transfer switch issue. Can someone provide the location of the transfer switch on a 2017 CS Adventurous Model RSCM on a 2016 MB Sprinter chassis? Thanks!
Transfer switch is suspect.
Here is a very common 120V RV wiring diagram.
Both Shore Power (Yellow) and Generator (Green) are inputs to the automatic transfer switch. It's either OR.
Auto transfer switch sends the 120V output (Red) to the power center with breakers to the various electrical loads (Blue).
A digital meter or a 120V AC probe is a must to test yellow and red circuits when plugged to shore power.
The transfer switch should be located inside and very close to the Shore Power receptacle and propane generator outside the van. Start removing rear seat cushion on the driver side and open the wooden base cover and it could be there close to the wheel well.

120V Wiring example.jpg
 

JackinVT

Member
Thanks to everyone for your input and suggestions. I went to take a look at my friends camper. With shore power on there was power at the transfer switch but could not tell what connections went where. Now that I have the transfer switch make and model (Progressive Dynamics PD5110610) that will help. The switch defaults ( normally closed relay contacts) to shore power and the switch relay switches to generator power when present after ~20 seconds. His camper has a generator that runs off the engine serpentine belt, so 120VAC power is available whenever the camper engine is running. Strange thing was I saw no 120VAC at the transfer switch, maybe didn’t wait long enough as I didn’t know about the delay at the time. However I did see the coach battery voltage increase as if they were being charged. Also never saw power at the receptacles. So does the 120VAC possibly get passed through the inverter which may have been off?
 

RT.SS

Active member
Roadtrek wiring schematics differ from year to year and model to model. What kind of inverter you have? Do you have AGM or Lithium’s?

When on shore, you mentioned having 120-VAC at the transfer switch but no 120-VAC at the outlets. If you turn on the generator and everything works, then highly likely that your transfer switch is faulty (possibly the relay contacts are welded shut on generator input). A non-contact voltage tester can easily trace a break in the 120-VAC line.

Your friends Roadtrek is wired differently; the underhood generator is simply a second alternator controlled by Balmar; it has DC output and charges the coach batteries directly. Some RT without a 120-VAC genset come with a transfer relay that serves no purpose, so it can get confusing.
 

JackinVT

Member
Roadtrek wiring schematics differ from year to year and model to model. What kind of inverter you have? Do you have AGM or Lithium’s?

When on shore, you mentioned having 120-VAC at the transfer switch but no 120-VAC at the outlets. If you turn on the generator and everything works, then highly likely that your transfer switch is faulty (possibly the relay contacts are welded shut on generator input). A non-contact voltage tester can easily trace a break in the 120-VAC line.

Your friends Roadtrek is wired differently; the underhood generator is simply a second alternator controlled by Balmar; it has DC output and charges the coach batteries directly. Some RT without a 120-VAC genset come with a transfer relay that serves no purpose, so it can get confusing.
So his generator is not a generator, that is very interesting. The additional alternator is just charging the coach batteries and the 120VAC is from the inverter. I also read in the manual that ”The switchover from shore power to inverter is automatic-the inverter will sense the incoming shore power”, so shore power is apparently fed through the inverter. But now I have no idea what is controlling the transfer switch, nothing????? But it is wired, maybe the inverter is controlling it???? Now I’m beginning to think his inverter was either off or is faulty.
 

irvingj

2015 RT SS Agile (3.0L)
"The additional alternator is just charging the coach batteries and the 120VAC is from the inverter." This is precisely as I understand it on our 2015 SS Agile.

I believe the 120 outlets (except maybe one?) only get their 120V from/through the inverter. In other words, that inverter has to be turned on to get 120V at the outlets -- whether "plugged in" to shore power or not. On our RV, there are two ways to turn on the inverter: either by a switch on the unit itself, or with the remote switch over the sliding door -- which, BTW, is quite confusing in its label's wording.
 

Wilbrett

New member
After ensuring that I had good 120 vac at the charger inverter input, I learned from the manual on mine that there were trimmer adjustment pots for fine tuning the sensitivity. Simply turning the dials in 1 turn and back to their original setting solved my similar symptoms
 

RT.SS

Active member
It really depends on what inverter you have and how it is wired, RT made so many modifications in there later models with addition of Etrek/ Ecotrek/ UHG/ and 24-volt system. It’s probably the reason why the manuals for the later models does not include wiring schematics.

The PowerStar 2-3 Kw inverters are wired before the main breakers, it needs to be “On” to bypass the shore power into the main breaker/panel. The smaller Tripp-Lite inverter is wired differently, it is a branch circuit from the main breaker and only powers two I20-VAC outlets.

Yours has a generator that requires an ATR; the ATR is not controlled by anything; it has its own logic board and auto switches to generator input when 120-VAC is detected in the generator input. If you tell us what kind of inverter/charger you have, we can probably figure out or narrow down what's wrong.
 

JackinVT

Member
0
It really depends on what inverter you have and how it is wired, RT made so many modifications in there later models with addition of Etrek/ Ecotrek/ UHG/ and 24-volt system. It’s probably the reason why the manuals for the later models does not include wiring schematics.

The PowerStar 2-3 Kw inverters are wired before the main breakers, it needs to be “On” to bypass the shore power into the main breaker/panel. The smaller Tripp-Lite inverter is wired differently, it is a branch circuit from the main breaker and only powers two I20-VAC outlets.

Yours has a generator that requires an ATR; the ATR is not controlled by anything; it has its own logic board and auto switches to generator input when 120-VAC is detected in the generator input. If you tell us what kind of inverter/charger you have, we can probably figure out or narrow down what's wrong.
The generator is apparently just an additional alternator that charges the coach batteries. I need to get back to the camper, a friends, to determine the make/model of the inverter. I’m confused by the transfer switch as initially I thought it switched between shore power to generator power. But with no actual generator what is it switching? Unless it switches between shore power and inverter power. However based on what I read in the manual the inverter itself senses shore power and switches itself. Now that I know more based on everyone’s inputs here hopefully things will become clearer when I determine which inverter is actually installed.
 

RT.SS

Active member
@JackinVT
Lol. I got confused I thought you were asking about your Camper and just comparing it with your friends camper.

After re-reading above posts, it appears that your friends camper has the 12-VDC Underhood Generator and not the 120-VAC Propane generator. As I’ve mentioned above, there are RT models that came with a transfer relay without a propane generator. The ATR was there for the optional propane generator but since there was none, it serves no purpose, it doesn’t do anything.

RT models with an Underhood Generator/Alternator typically have a larger inverter (2-3 Kw) and possibly Lithium batteries (Ecotrek). The larger inverter is located beneath the rear sofa bed, and it has an integrated LCD display that should display any error codes. If the inverter is turned off, if there is a fault, or if the 12-volt kicker battery is bad or severely depleted, the inverter will not bypass shore power (granting the inverter was updated and connected to the charge side of the Ecotreks). We need more information about your friend's RV, such as whether it has AGM or Lithium batteries and what type of inverter it has.
 

irvingj

2015 RT SS Agile (3.0L)
Ditto RTSS -- mine has the newer (?) PowerStar 3KW inverter located in the back right, under sofa; no propane generator but with the UHG alternator, four 6V VRFLA coach batteries and 300W of solar -- so my comments are based on my unit's set-up. It seems there were a lot of "experimental" interim-type electrical systems back in 2015-2018 -- I've yet to see another set-up like mine. Hope I've not confused the issue.
 

JackinVT

Member
@JackinVT
Lol. I got confused I thought you were asking about your Camper and just comparing it with your friends camper.

After re-reading above posts, it appears that your friends camper has the 12-VDC Underhood Generator and not the 120-VAC Propane generator. As I’ve mentioned above, there are RT models that came with a transfer relay without a propane generator. The ATR was there for the optional propane generator but since there was none, it serves no purpose, it doesn’t do anything.

RT models with an Underhood Generator/Alternator typically have a larger inverter (2-3 Kw) and possibly Lithium batteries (Ecotrek). The larger inverter is located beneath the rear sofa bed, and it has an integrated LCD display that should display any error codes. If the inverter is turned off, if there is a fault, or if the 12-volt kicker battery is bad or severely depleted, the inverter will not bypass shore power (granting the inverter was updated and connected to the charge side of the Ecotreks). We need more information about your friend's RV, such as whether it has AGM or Lithium batteries and what type of inverter it has.
His camper has four AGM batteries, I’ll know better tomorrow as to what inverter he has Installed.
 

JackinVT

Member
Ditto RTSS -- mine has the newer (?) PowerStar 3KW inverter located in the back right, under sofa; no propane generator but with the UHG alternator, four 6V VRFLA coach batteries and 300W of solar -- so my comments are based on my unit's set-up. It seems there were a lot of "experimental" interim-type electrical systems back in 2015-2018 -- I've yet to see another set-up like mine. Hope I've not confused the issue.
Actually your setup sounds the same. Although he has recently replaced his four AGM batteries, however everything had been working fine since that time. Do you happen to know if your transfer switch is functional with NOT having the optional propane generator, and/or it is wired like it’s functional maybe to accommodate the option?
 

Top Bottom