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2travel · 08-25-2015, 03:55 PM

My 2007 Winnebago 33V has no 12 volt power when shore power is disconnected. The batteries are charged and have 12.65 volts. The house lighting will not come on and the generator will not start. Connecting to shore power does give me house lighting. I suspect the ATS but can't figure how that would prevent voltage from getting to the generator starter supply. I can't find any schematics showing how the coach batteries are distributed to the coach and generator starter.

gemert · 08-25-2015, 05:01 PM

Sounds like a battery connection issue. While on shore power 12v is probably coming from converter/inverter. When on battery, it's not probably due to a bad connection, bad ground or corrosion. Look at the ends going to the frame or at the "other end" of the 12+ connection. I am not an expert so take my advice for whats it's worth! Good luck.

RandyKathyM · 08-25-2015, 05:10 PM

Also make sure your battery disconnect switches are on.

nothermark · 08-25-2015, 05:13 PM

The relay activated by the storage switch is open or broken. Check the switch then check the relay.

2 Stroker · 08-25-2015, 05:21 PM

May be the switch by the door. May have turned it off on the way out.
2 stroker

gemert · 08-25-2015, 05:31 PM

He said that 12v works on shore power. That would not be the case with the salesman switch off or that relay bad. Just saying. At least on mine and the ones I've heard of but like I say, no expert here.

shiggs68 · 08-25-2015, 07:18 PM

Quote:

Originally Posted by 2travel

My 2007 Winnebago 33V has no 12 volt power when shore power is disconnected. The batteries are charged and have 12.65 volts. The house lighting will not come on and the generator will not start. Connecting to shore power does give me house lighting. I suspect the ATS but can't figure how that would prevent voltage from getting to the generator starter supply. I can't find any schematics showing how the coach batteries are distributed to the coach and generator starter.

Your 12vdc power from the battery has nothing to do with the ATS.

When on shore power, your 12vdv is being supplied by your Converter or Inverter/charger. When no shore power, it comes directly from the coach battery thru the battery cutoff solenoid. That could be suspect. However, usually the generator starter does not go thru that solenoid.

My guess would be that the negative battery cable has a bad ground connection.

Point is to check all cable connections on both ends of each.

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mgscott4 · 08-25-2015, 08:14 PM

Sounds like to me that there might be a DC circuit breaker in the Battery Control center (or Bird) that needs to be reset. Once reset, it will allow the 12 volts from the batteries to supply the coach. The converter is supplying the 12 volts when o n shore power.

2travel · 08-26-2015, 08:11 AM

Thanks for all the replies. I checked the battery switch by the door and found it to be bad. Seems like things are working properly now.

beenthere · 08-26-2015, 10:58 AM

I really think that the 12v power is always thru the batteries weather shore or gen or none...the shore power just activates a switch to charges the batteries but the 12v actually comes straight from the battery...and its the switching that actually does the shore or gen or none power.. the batteries are obviously being charged when plugged in or they would be dead....so my Opinion is its in the switching or solenoids. jeff

doorfx · 08-26-2015, 11:49 AM

You can disconnect your batteries and still have full 12 v power. The converter is providing the power.

beenthere · 08-26-2015, 02:26 PM

you may be right..i had a long discussion with my son a few ur well many years ago when he was going to school for electrical engineer. but I not him...I thought I remembered him explaining the bird and ems systems and the convertor was for dc to ac power and charging 12v batteries. like mine up to 130 amps hr....so the way I remembered it was as batteries charging you still get the power from the batteries if properly wired and switched. but hey I never tried unhooking batteries and using unless it then uses the charger portion as supplying power.. jeff

shiggs68 · 08-26-2015, 04:42 PM

Quote:

Originally Posted by beenthere

you may be right..i had a long discussion with my son a few ur well many years ago when he was going to school for electrical engineer. but I not him...I thought I remembered him explaining the bird and ems systems and the convertor was for dc to ac power and charging 12v batteries. like mine up to 130 amps hr....so the way I remembered it was as batteries charging you still get the power from the batteries if properly wired and switched. but hey I never tried unhooking batteries and using unless it then uses the charger portion as supplying power.. jeff

The Converter or Inverter/charger is designed to supply the 12vdc needs of your RV using the battery as reserve capacity for large loads like jacks and slide mechanisms. It also maintained the battery charge level when capacity is available and shore power is applied.

DC to AC power is from an Inverter which is normally found in a motorhome. And in some cases a combined Inverter/Charger.

Most trailers have a Converter which converts the 120vac to 12vdc as explained above.

Hope this clears up your understanding.

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nothermark · 08-26-2015, 04:53 PM

Quote:

Originally Posted by beenthere

you may be right..i had a long discussion with my son a few ur well many years ago when he was going to school for electrical engineer. but I not him...I thought I remembered him explaining the bird and ems systems and the convertor was for dc to ac power and charging 12v batteries. like mine up to 130 amps hr....so the way I remembered it was as batteries charging you still get the power from the batteries if properly wired and switched. but hey I never tried unhooking batteries and using unless it then uses the charger portion as supplying power.. jeff

The simple fact is the converter can be wired to either side of the battery disconnect relay. On our first MH there was no 12 VDC even when plugged in because the converter charger was connected to the battery. On our current MH plugging in gives 12 VDC so everything works but the battery is not charged unless I turn on the salesman's/storage switch.