Hoping you guys can help me. Ive got a 2013 class c Coachman on a Ford E450 super duty chassis. The truck battery, alternator, volt reg have been checked professionally several times this last week at three different battery stores. The battery is dated at 11/17, so it is almost 4 years.The truck battery will discharge overnight. It will go from the 12.7v to 8.0 or lower over night and the truck will not start in the morning. I have made sure to turn everything in the truck off (radio, cell phone cable, interior lights, key in correct position, etc) and it still does it. I can jump start truck and drive and battery charges ok. I can charge battery back to spec voltage and it will start and run.While charging yesterday, we noticed a "ticking" sound coming from under the steering wheel area. Could not locate the source of sound. I could hear ticking sound, both if engine was running or off. I tried to pull one fuse at a time to see which circuit would stop the ticking but could not do all the fuses as some were too big for my puller to extract. I disconnected neg terminal and ticking stopped. I have left it disconnected and charged battery. It is holding voltage while disconnected. So, Im confused. What is drawing down the truck power? This has only started in the last week. Previously, it has been very reliable and worked fine. If I charge the battery and disconnect from truck it will stay charged to spec voltage overnight.Any thoughts or ideas would be greatly appreciated.

From The Internet:A malfunctioning diode in the alternator can create a parasitic drain on a car's battery. Diodes should allow current to pass in only one direction, but a bad diode will keep the charging circuit open even when the engine in not running, allowing the battery to go dead. This often happens overnight.

thanks trailrider.so the fix is to r&r the alternator? or can it be checked while on board?

You are talking chassis under your class C motor home?In that case there is other items. Do you have electric step? It has some draw.Carbon dioxide detector, has draw from chassis batteryCharge relay from battery control center could be holding in so you are using power from chassis battery.Yes, a diode in alternator. It should show up on a proper alternator test.To test your self, disconnect and insulate the large wire on alternator. If battery stays up, replace alternator.

mharrel wrote:thanks trailrider.so the fix is to r&r the alternator? or can it be checked while on board?If it was the alternator, I doubt you would here a ticking sound coming from under the dash.. Diodes generally when they go bad, short or open, ticking sound would not come from that.Ticking would mean something like a motor running or a relay opening and closing.2013 Fords often had wiring harness issues, one real bad one is there is a harness on the driver side which has a connector that the pins get damaged from the vibration caused by applying and releasing your parking brake. Ford decided it was a good idea to solidly wire tie one side of the connector directly to the parking brake assy.. The fix to prevent damage to the connector was to remove the wire tie and tie the connector and cable to another wire harness above the brake assy..One other wiring harness issue has been moisture getting into several of the wire harness connectors at the rear of the vehicle.. On trucks those connectors are above the spare tire..It will be difficult to isolate where the drain is coming from, so many over the top complex computerized systems and some fuses are in and around the engine compartment along with inside the cabin..

Starting offYank the cruise control fuseYank the windshield wiper stalk fuseYank the main Accessory fuse

Truck Battery discharging overnight | Good Sam Community

Dusty_R
Explorer
Oct 02, 2021
Sort of a fix.
Get a Battery Disconnect Switch, and put it on the engine battery, open it when engine is not being run.
mharrel
Explorer
Oct 02, 2021
e.nblethen :
thanks for the help.
yes, it's the chasis (truck) battery not the house battery.
no, no electric stairs

is the carbon dioxide monitor able to disconnect from power to check to see if that is problem?

would the "charge relay" be in the fuse box. it looked like there were a bunch of relays in there.

thanks for your ideas.
MEXICOWANDERER
Explorer
Oct 02, 2021
Starting off

Yank the cruise control fuse
Yank the windshield wiper stalk fuse
Yank the main Accessory fuse
Gdetrailer
Explorer III
Oct 02, 2021
mharrel wrote:
thanks trailrider.
so the fix is to r&r the alternator? or can it be checked while on board?

If it was the alternator, I doubt you would here a ticking sound coming from under the dash.. Diodes generally when they go bad, short or open, ticking sound would not come from that.

Ticking would mean something like a motor running or a relay opening and closing.

2013 Fords often had wiring harness issues, one real bad one is there is a harness on the driver side which has a connector that the pins get damaged from the vibration caused by applying and releasing your parking brake. Ford decided it was a good idea to solidly wire tie one side of the connector directly to the parking brake assy.. The fix to prevent damage to the connector was to remove the wire tie and tie the connector and cable to another wire harness above the brake assy..

One other wiring harness issue has been moisture getting into several of the wire harness connectors at the rear of the vehicle.. On trucks those connectors are above the spare tire..

It will be difficult to isolate where the drain is coming from, so many over the top complex computerized systems and some fuses are in and around the engine compartment along with inside the cabin..
enblethen
Nomad
Oct 02, 2021
You are talking chassis under your class C motor home?
In that case there is other items.
Do you have electric step? It has some draw.
Carbon dioxide detector, has draw from chassis battery
Charge relay from battery control center could be holding in so you are using power from chassis battery.
Yes, a diode in alternator. It should show up on a proper alternator test.
To test your self, disconnect and insulate the large wire on alternator. If battery stays up, replace alternator.
mharrel
Explorer
Oct 02, 2021
thanks trailrider.
so the fix is to r&r the alternator? or can it be checked while on board?
trailrider
Explorer
Oct 02, 2021
From The Internet:

A malfunctioning diode in the alternator can create a parasitic drain on a car's battery. Diodes should allow current to pass in only one direction, but a bad diode will keep the charging circuit open even when the engine in not running, allowing the battery to go dead. This often happens overnight.

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