Currently in Costa Rica and the house battery (AGM deep cycle) is not getting enough charge to last through the night. I have a 135w solar charging it through the day but only getting a reading of 12.15 from the terminals. With the car running, this does not change. My understanding is that if the truck (F350) was pushing current through to charge the battery then it should read around 13.5 - 14.2. Took it to a battery fellow here and he seems to think the battery is ok, just not getting a full charge. It has enough to work the lights at night but by morning we are in trouble. This has only been a recent development and I drive on some terrible roads. The camper is a Lance 1010.I need some pretty urgent help as getting RV repair down here is pretty tough and not many places to plug in overnight.Thanks

If it used to work, could be a fuse. What is the charging system from the truck -- stock? Your install?

Just some initial brainstorming here...Is there charge voltage at the 7-pin?Is there a good ground between truck and camper?

Disconnect the battery from the circuit completely, and then see what voltage you have on the charging wires that would normally be on the battery. If the voltage is now normal from the truck and from the solar cells, the only thing that it can be is a bad battery with one cell shorted out.

Just a point of information, batteries PULL current from the charger and the charger PUSHES voltage to the battery.Voltage drops in a circuit due to current increasing so if the battery is bad it will be pulling max current (yet never charging) and thus showing the low voltage. How many amps does your solar charge controller show as being produced?

Use a volt meter to measure the seven way connector on your truck to see if voltage is present. Put the ground lead of your tester on Pin#1, and the positive lead from you meter on pin#4. If you have 13+ volts DC with the truck running, the problem is with the trailer's battery, wiring or connections. If you do not have 13+ VDC at the seven way pins with the truck running, you need to trouble shoot the truck.Jim

Battery not charging from the truck | Good Sam Community

12 Replies

Kayteg1
Explorer II
Feb 24, 2016
Also ground of Ford sucks.
I track the big wire from rear outlet going 1/2 way under the bed when it was bolted to side of the main frame.
With minimal corrosion the huge bolt made no connection.
Driftwood132
Explorer
Feb 24, 2016
Under the hood on drivers side is a fuse block under a plastic cover that is where a 30 amp fuse for the charging circut is. The manual will tell about it or the plastic lid will show the location of it. Also the engine has to be on before the relay will engage the charging circut .
When I first bought my truck it wouldn't charge ,F250 it didn't charge the house battery after a little reading the manual I found the problem , no fuse . like other reply check the plugs and wires under the truck there is a couple of connections between the front to the back . if you have a meter or a simple light you can find the problem.
Kayteg1
Explorer II
Feb 24, 2016
Check the voltage on the plug per pictures above.
The 7-pins are high maintenance items and often need cleaning or adjustment.
If you have no charging power on the truck side - check the fuse.
30 amp can be blown when you connect deeply discharged battery .
On my F250 I had PO putting automatic breaker for the circuit.
ticki2
Explorer
Feb 24, 2016
marksgone wrote:
Currently in Costa Rica and the house battery (AGM deep cycle) is not getting enough charge to last through the night. I have a 135w solar charging it through the day but only getting a reading of 12.15 from the terminals. With the car running, this does not change. My understanding is that if the truck (F350) was pushing current through to charge the battery then it should read around 13.5 - 14.2. Took it to a battery fellow here and he seems to think the battery is ok, just not getting a full charge. It has enough to work the lights at night but by morning we are in trouble. This has only been a recent development and I drive on some terrible roads. The camper is a Lance 1010.
I need some pretty urgent help as getting RV repair down here is pretty tough and not many places to plug in overnight.
Thanks

It seems from your statement the battery is not charging from the truck OR the solar ( 12.15v). I would first check all connections and any fuses . Even if the fuses look good check both sides for any voltage drop . If the truck charge line is not working the solar should still charge the battery , or both are not functioning . Good luck .
kohldad
Explorer III
Feb 24, 2016
Check voltage at end of cable to verify the circuit is good. Then connect, disconnect, wiggle, repeat a couple of times as it may be nothing more than a bad connection. If this temporarily solves the problem, then clean the connectors when you get a chance.

May also be necessary to put a slight strain to one side. Should not have to do this, but I had a regular 7-pin connection custom wired and was only getting 1A charge through it. By putting a bungie on the input cord and holding it to one side, I'm now able to get about 20A through it. Contacts are clean, just loose if I don't use the bungie.
Shadow_Catcher
Explorer
Feb 23, 2016
X2 Bedlam and jumper cable.
My worry is however that you have taken the batter below the 50% depth of discharge and done permanent damage.
Bedlam
Moderator
Feb 23, 2016
For temporary fix, run jumper cables between the truck and camper batteries while the engine is running. This will charge the camper faster than the OEM thin gauge wire.
TucsonJim
Explorer II
Feb 23, 2016
Use a volt meter to measure the seven way connector on your truck to see if voltage is present. Put the ground lead of your tester on Pin#1, and the positive lead from you meter on pin#4. If you have 13+ volts DC with the truck running, the problem is with the trailer's battery, wiring or connections. If you do not have 13+ VDC at the seven way pins with the truck running, you need to trouble shoot the truck.

Jim
Steve_in_29
Explorer
Feb 23, 2016
Just a point of information, batteries PULL current from the charger and the charger PUSHES voltage to the battery.

Voltage drops in a circuit due to current increasing so if the battery is bad it will be pulling max current (yet never charging) and thus showing the low voltage.

How many amps does your solar charge controller show as being produced?
Artum_Snowbird
Explorer
Feb 23, 2016
Disconnect the battery from the circuit completely, and then see what voltage you have on the charging wires that would normally be on the battery. If the voltage is now normal from the truck and from the solar cells, the only thing that it can be is a bad battery with one cell shorted out.