Charging System

[drmmlien]

I have a brand new 16' Bambi (2002). When I am driving, with electrical connect to trailer, I can only charge battery to 11 Volts. Plugged in to campground electricity, it charges to 12.7 volts. The output at back end of my tow vehicle is 13.8 volts. I have talked to local Airstream dealer about this and they say I must have bad connection from tow to trailer. I have cleaned all the contacts. Is there that much voltage drop along umbilical to trailer? Shouldn't converter charge to higher than 12.7 when I am hooked up to electric? I unplugged umbilical and 110 power to trailer when I made my measurements of battery voltage.

[FrankR]

All the numbers mentioned seem OK. The new converters are more carefully regulated NOT to over charge. The tow vehicle charge rate of 13.8 is good. My SWAG [scientific wild ass guess] is that the previous diagnosis is correct. Between the connections of the tow and the battery, there is a poor connection. I understand you have checked and cleaned. I think at the big plug , at either end, or trailer gound, or battery posts connections, the connections are poor.
I'm not familar with late Airstream trailer's wiring systems. Earlier trailers use fuses for ground, connections to battery both from tow vehicle and converter. Spray lots of WD40 on every connection and loosen and tighten every wire screw. On some occasions a poor connection may become hot or warm to the touch. While checking for a poor connection, having a digital volt meter connected within view would be a great asset. I love a good challenge. Come on over. It can't hide from a meter......Frank

[Inland RV Center, In]

Measuring the voltage at the tow vehicle connector, is of little value, unless a load is impressed upon that voltage. If you try that and find that the new voltage reading at the tow vehicle connector has dropped, then you may have a "charge line" wire that is inadequate for the load. Charge line wires in a tow vehicle should be a minimum of 10 gauge. You could also have a corroded terminal or connection at the point of tapping into the 12 volts. The best place to connect your charge line is directly to the battery, through a 40 or 50 amp self resetting circuit breaker. Using a 10 gauge wire will give you a minimal voltage drop. Andy

[davidz71]

I understand that you found 13.8 volts at the tow vehicle receptacle but what about at the end of the cord which connects to the trailer? If it also shows 13.8 volts or slightly lower then you look further down the line. If there is a significant drop at the end of the cord, I would suspect a connection or bad wire. Otherwise, check battery connections and connections within fusebox. Good luck.