First help question, 12vdc, X20E

[Mtbiker70]

Hi all. So, while going through things on our new to us Jayco Feather Lite X20E hybrid trailer, I started looking around at the electrical system. I was 99% sure the battery was dead as it hadn’t been plugged in or charged in 2+ years and upon investigation, the battery was already 6 years old. So while cleaning and getting to know our trailer, I had it plugged into our home AC outlet using the included adapter, shore power. I had not removed the battery and we ran the AC and fridge/lights without any issue. I could push the little battery check button while on shore power and all lights we indicate full, assuming that since on shore power, the battery was being trickle charged. Didn’t matter much as I was going to replace it anyway, which I did yesterday. Unplugged from shore, then tried to run lights and slide off battery, yeah, nope, dead. Figured as much. Went to RV parts place and bought a deep cycle marine battery. Plopped it in last night, and nothing. Strange. Thought that maybe the RV place sold me a dead battery so I checked with multi-meter, read 12.4. Hmmm, maybe it is a bit low is all. So, pulled battery back out and hooked up to my battery charger. Set it for 2amp slow deep cycle charge and let it go all night. This morning, little green “fully charged” light was on, so a little while ago, put it back in the trailer, checked voltage (13.1) and guess what...still nothing. Started looking at fuses now. The 30amp blade fuse wired into the positive cable is good as are all the blade fuses in the power panel.

I have not checked the inverter as the trailer has one side jacked up while my tire store owner neighbor is fixing me up with new rubber. I didn’t want to go walking around too much while balanced into jack stands and floor jacks (I blocked it under the drums and lowered the feet)

Is there a fuse somewhere in between the battery and the power panel? I’ve checked all the connections I can without crawling under anything (on jack stands).

Is it possible that they sold me a bad battery? I did find this taped to the back of the battery, but it is showing a full charge currently.

[Puddle Pirate]

Sort of looks like a bad battery report to me?

[Murff]

Check wiring junction box and make sure all connections are tight.

Murff

[Jagiven]

I am not farmilar with battery reports,

But a few things you can check;
Do you have a battery disconnect switch? OEM ones usually are installed in the cargo hold close to the tongue. Often it has a red switch. If there is an aftermarket disconnect switch, it could be anywhere. Usually near the tongue.

Check your fuses. There should be one at the battery and two in the fuse box. One is for the load. Another for reverse polarity.

Do you have a miltimeter? Measure the voltage battery, with the shore power connected and disconnected. If the inverter is charging the battery you should get a reading of about 14.6 volts. If it is not, it should read 12.6 volts (fully charged battery). If you only have battery charge reading look for a fuse. Battery disconnect switch, or a short (broken wire). You could have a bad ground wire. Check the ground wire from the battery, and make sure it has a good clean solid connection to the frame. A multimeter is good here too.

[JFlightRisk]

The tag makes me suspicious that it might've been replaced from another RV. You can always take it to Auto Zone, and they'll test it for free. If it tests bad or marginal, you may have been given a take off battery, and need to go back for a brand new one.

[RedHorse1]

1) You say the fuses are good, did you check with a VOM? I’ve had fuses that looked good but were not. (Fuses are probably good since things work on shore power, exception might be the reverse polarity fuses)
2) have you searched for a battery disconnect?
3) With battery installed and shore power disconnected test for 12V at the fuse panel (maybe at the reverse polarity fuses). Check for 12V at cable fm battery at back side of power panel.
4) Disconnect batt n check for good ground (ohmmeter neg batt cable to frame) - (again lights work on shore power so prob not this)

As I’m tapping this out I’m starting to suspect the batt+ to converter is the culprit.

I’m pretty much echoing what’s already been suggested but just putting my thoughts down.

Good luck and keep us informed! And welcome to JOF!

[Mtbiker70]

Update: So I took the new battery and had it load tested, auto parts store guy said it checked out fine. Voltage was 12.7, started at 97%. After the load test, amps and voltage were still 12.7, battery was at 91%. So, even if I have a bad battery, it’s good enough to probably run the lights, etc.

Ohm’d the ground with my multimeter. I don’t know what the numbers meant, but there were numbers that ranged between 2.4 and 2.8 with red lead on the negative battery cable and the black lead on a clear/clean portion of the frame. My numbers might have been off....I had a gin & tonic and also slept 6.5ish hours since I checked it. But, pretty sure the ground is good.

I again checked all the fuses I could find, this time with the multimeter making sure it had continuity between the blades of the fuses. Everything checked out.

So, this evening, my plan is to disconnect from shore power, connect the battery and test the 40 amp blade fuse hole labeled “reverse polarity”. I’m assuming that if I have 12v there, that I’m getting power to the panel. I’m also assuming that this fuse is to protect the system from someone hooking the battery up backwards? I can see how that could happen as I almost did it. Wasn’t that I was looking at the wrong colors of the battery cable, but that the previous battery posts we’re opposite the new battery posts. I’ve hooked up plenty of batteries over the years, but was a bit surprised that it would have been that easy to misconnect. Anyway...if I have no power at the fuse, then my plan is to once again disconnect the battery and pull the power panel out and investigate. Hopefully it’s easy enough to either trouble shoot or even replace any parts that might need changed.