Hi Roadlou and Paul.
See if this helps some as TV battery charging the TT coach battery can some times be tricky pending a few things.
A few things 1st.
1 As others have stated the battery switch if you have one needs to be on.
2 Do you know if your 7 wire TV receptacle actually is putting out voltage on the battery terminal? Some TV’s need a fuse installed to make that pin hot. Yours may or may not even be working.
3 On the newer Sunlines and maybe even the older ones, they have a fuse, generally 30 amp, in the TV charge line to the battery. This protects the TV if a short comes in the camper wiring circuit. It needs to be good.
Once past these 3 things comes the battery itself. Depending how far drained the battery is, the odds are not in your favor it will recharge off the TV by what you said you used the battery. If it is deeply discharged, odds are it will not come up unless you put it on an actual battery charger. If you are below 50 to 60% charge you might be in that requirement.
Part of the problem is the small 30 amp rated wire used in the 7-wire plug. On the TV battery it has very heavy cables capable of 60 plus amps in some cases to the TV alternator so it can put a level of charge to a discharged battery some if you drive long enough and the battery is in good shape.
But with that little 30-amp wire some 30 feet away, the voltage and current may not be high enough to recharge a deep discharged battery.
Here are some comparisons on time. I have a higher end 3-stage convertor I upgraded to on the TT. This Progressive Dynamics convertor can put out 60 amps of power at 14.4 volts to quick charge a 125-amp hour battery in 2 to 3 hours to about 90% IF it started out at around 10.5 volts which is about 50% discharged. If this bigger battery is even more discharged, it takes even longer. This larger 125 amp hr battery is bigger then most. You probably have a group 24, 85 amp hour battery unless you know it is bigger.
To go from 90% to 100% my charger then drops down in voltage and power and it takes about 15 hours to reach full 100% charge. That is if you are after a full 100% charge. Most RV chargers stop in the 90 to 95% range which is still good, but technically not 100% full charge. The newer 3 stage chargers get you higher.
The TV charging system cannot reproduce this to your TT if your TT battery is deeply discharged in most cases.
Check your battery for water, put it on a charger and try bringing it back to life. Ideally do not drain your battery down to below 50% (about 12.06 volts) before recharge while using it. It will last longer if you do not heavy drain it and recharge.
See this web site The 12 volt side of life
It is helpful in explaining a lot of these battery type questions.
Hope this helps.
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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