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Friday, February 6, 2015

Smoke Gets in Your Eyes

I'm trying to find out what I have to do in order to fix this power issue. When I last parked my trailer I plugged it into a 50 amp shore power source. Then while trying to raise the power jacks in order to unhook the truck, the switch wouldn't work. It was like there was no power at the switch. So I clicked the battery power switch on in order to use the battery power. It worked fine but after raising the trailer I noticed and smelled smoke. It was like a burning electrical smell. I opened the door for the garage and it was full of smoke. After the smoke cleared I'm pretty sure the smoke was coming from the electric motor that raises and lowers the power jacks. After this I started looking into the problem further and noticed one of the electric breakers that controls the power converter was tripped off and it would not stay reset. Then I unplugged from the 50 amp and with the plugin adapter plugged into 30 amp shore power. That seemed to fix everything and I've been running it that way since (about 3 weeks). I have the trailer for sale and don't want to sell it without fixing this issue. Please point me in the right direction. I don't want to call an RV repair dealer because I've been ripped off by them before. Thanking you in advance... Gary S., (Lisbon, OH)

Gary, with all the accoutrements that come with a coach that large, the 12-volt power demand is huge. Some manufacturers fail to let their customers know about the vital importance of having enough battery power to operate all things 12-volt. Plus that battery disconnect switch must be off in order to have 12-volts distributed throughout the coach. I’m not sure how many batteries are in your bank, but it’s doubtful the full load of those landing jacks lifting that much weight can be adequately provided by the converter/charger alone. There may be something internal to the converter that is not allowing it to fully charge the battery bank, but the symptom suggests a low amount of voltage in the batteries. When connected to 30-amp shore power, is the converter still in operation? With less power available, it’s possible the converter/charger is not being powered by 120-volts AC from the shore line at 30-amps service. If you send me the brand and model of the converter, I can delve deeper into that device.

Another thing some RV makers fail to understand is the negative side of the DC system. Be sure the negative cables are greater than or equal to the size/amperage rating of the positive cables. The high current demand of the landing jacks under load could have overheated the motor by a lack of proper grounding. If possible, fully charge the battery bank independently of the converter/charger and see if the jacks operate normally. If so, we can focus attention to the converter itself.

With 50-amp service and the converter operational, is there a voltage increase, as measured at the battery bank? It’s possible the converter is undersized for the 12-volt demands of the entire coach. Adding the high current demand of those landing jacks possibly overheated the motor causing it to smoke. Typically they are protected by an internal breaker so hopefully no internal damage exists. Have you noticed other 12-volt devices with problems? Dim lighting, slow fan speed on the furnace, low water pressure from the pump, etc.? If other devices exhibit problems, I’d focus on the ground cables and all connections, plus the state of charge of the batteries.

Loose connecting points can also cause overheating and smoke. If the problem is dedicated to only the powered landing jacks, then it could be a problem with the jack motor or possibly the converter. Another question; do you have a power management load center? One that sheds loads if power consumption is exceeded? When operating on 30-amp service, some devices cannot operate unless the management load center can make that decision based on load requirements. Sounds confusing, I know. But until we have some specifics about the individual components, we're just guessing.

Send me the specs on the converter/charger and the landing jacks, and how many and what type of batteries are in the battery bank and I’ll dig further. There’s a logical explanation in there somewhere.


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