Need some assistance

[LeBout]

My wife and I are on the road right now and dealing with a bit of an electrical mystery. Here's the situation:

We're currently boondocking and drove about 6 hours to get to our current location. We noticed last night before bedtime that the lights inside the TT were dim, so I checked the control panel and the battery read "empty." (Again, this was after 6 hours of driving.) I have a tester to plug into my pickups RV connection and found that my 12-volt feed from the pickup IS working just fine.

It was late so we went to bed. During the night the heater came on but the fan was running in low mode, which it does if the battery is low.

This morning I began by starting my pickup and letting it run a while. (I left the pickup and TT connected overnight so we wouldn't freeze to death since I knew the TT would draw from the pickup.) Pickup started just fine but then it has a new battery.

My assumption is that the TT battery itself may be bad. (I have a single 12-volt deep-cycle battery that I bought in 2015.) I put my voltage tester on it and it registered just over 10 volts AFTER running the pickup for a bit. Not full by any means, but not down all the way.

I turned off the pickup this morning and pulled out one of my Honda generators and connected it to the TT. This is the weird part. We keep seeing the lights go from dim (about 50%) to full brightness and we hear the heater fan go from low to high all while the generator is running. Could a bad battery be the cause of all that, even when the generator is connected and running?

My plan this morning is to take the TT battery into an auto parts store and have it load tested. Anyone have any comments about our electrical weird behavior?

[opnspaces]

I would open up the circuit breaker/fuse box and find the charge fuses. I'm betting they're bigger than the other fuses, probably at least 40 amp fuses. Pull each one and look for a burnt fuse. You can also pull them and check for continuity with your meter to see if they are blown.

Or find a ground in point near the fuse box and then check each fuse for battery voltage on each side. you'll notice that there are two holes in the back of every fuse right next to the amperage rating that you can poke the positive lead on the meter into, Each hole is the back side of one of the fuse blades. Put your positive lead in a fuse hole and the negative lead to a ground. If a fuse reads voltage on one hole and no voltage on the other hole the fuse is blown. If you get no voltage on either hole it's most likely that your grounding point is no good.

If no fuses are blown check if your charge fuses are reading 13+ volts. If so then your charger is probably good and you likely have a bad circuit breaker on the tongue by the batteries.

Follow the positive lead from the battery to the trailer. If there is a little box with two terminals in the wire it's likely a circuit breaker.


with the trailer plugged in check that the voltage is the same on each post of the breaker. if different like 13+ on one side and battery voltage on the other, the breaker is bad. They are available at any auto parts store for less than ten bucks.

[campigloo]

Glad you’re making progress. Also, run the gen a lot. When we only had two 12v Walmart deep cycles the heater would run fine all night, but that was without any other significant load. Changing your light bulbs to l e d help more than one might think.

[LeBout]

mgirardo wrote:
Get a portable car battery charger and run it off your generator until you get a chance to replace your converter/charger.

Thanks Michael. Most likely while you were typing you're message I was in buying a portable battery charger. Have it connected to the batteries right now.

[mgirardo]

When our converter failed in our Class C Motorhome, we were about 4 weeks into a 6 week trip. We had a bunch of other small issues and I didn't feel like dealing with the converter. It was in a hard to get to place and I just wanted to enjoy the rest of the trip. I bought a car battery charger and used that to keep the battery charged. Once the battery was charged, I left the charger set to 2 amps and that kept the battery charged the rest of the trip. We were on Shore Power the whole time.

We camp seasonally now, but I still bring the battery charger with us just in case. Get a portable car battery charger and run it off your generator until you get a chance to replace your converter/charger.

-Michael

[LeBout]

opnspaces wrote:

I would check the new batteries and converter? If you buy two new batteries they will be charged up and everything will work fine. If the converter is bad your batteries will be low again after a few days. An easy test is to check the battery voltage with the generator off. Then start the generator and check the voltage again. You should see the battery voltage go up to the mid 13v to mid 14v range. If the voltage doesn't change your converter is bad or you have a blown fuse.

I did this test and wasn't happy with the results. My reading with generator off and back on were both low. We have two more days travel to get to our destination. I would hate to ruin 2 brand new batteries. What's my next move?

[opnspaces]

LeBout wrote:
UPDATE: Doesn't seem to be the converter. I took the advice of several on this forum and didn't even ask to test the old battery. I just went ahead and purchased two new 6 volt batteries (Trojan brand) and plastic housing for each. installed the batteries and everything seems to be working good. We've run the heater several times and it's no longer cycling the fan speed from low to high. Thank you for all the help and advice. It's greatly appreciated!

P.S. All this too place in Idaho Falls, Idaho. We are now in Bozeman, Montana on our way to Minnesota. 🙂

I would check the new batteries and converter? If you buy two new batteries they will be charged up and everything will work fine. If the converter is bad your batteries will be low again after a few days. An easy test is to check the battery voltage with the generator off. Then start the generator and check the voltage again. You should see the battery voltage go up to the mid 13v to mid 14v range. If the voltage doesn't change your converter is bad or you have a blown fuse.

[2oldman]

LeBout wrote:
We are now in Bozeman, Montana

brrr

[LeBout]

UPDATE: Doesn't seem to be the converter. I took the advice of several on this forum and didn't even ask to test the old battery. I just went ahead and purchased two new 6 volt batteries (Trojan brand) and plastic housing for each. installed the batteries and everything seems to be working good. We've run the heater several times and it's no longer cycling the fan speed from low to high. Thank you for all the help and advice. It's greatly appreciated!

P.S. All this took place in Idaho Falls, Idaho. We are now in Bozeman, Montana on our way to Minnesota. 🙂

[johntinacamping]

As others have said above, I also suspect your converter is failing. I've been there and done that. I hope that's not your issue, though.

[CincyGus]

2oldman wrote:

LeBout wrote:
it registered just over 10 volts AFTER running the pickup for a bit. Not full by any means, but not down all the way.

That's essentially dead.

Exactly.

Deep Cycle's don't like to be drawn below 50%. Doing so damages and shortens them, reducing the number of recharge/discharge they cycles they have left in their useful life.

Deep Cycle Overview

12v reading is near the 50% mark. 10v is below the 100% discharge rate. The longer a battery stays discharged, the more damage is done to it so get it fully charged asap and then get it load tested. Chances are you will notice a significant decrease in performance (doesn't last as long before falling below 12v now as it did before) if it takes a charge at all.

Sounds like time for a new battery most likely. Good advice on getting a couple and solar if you are going to be doing boondocking. Would also suggest a battery monitor that gives you a voltage reading and not relying on the typical 4 light tank/battery monitor that most RV's come with.

Here is one that many use that are concerned with keeping their batteries in great condition, monitoring closely because they boondock a lot.

Battery Monitor

[pianotuna]

Hi,

Test the output of the converter at the battery. I suspect the converter may be failing. Don't bother with a load test, the existing battery is toast.

[2oldman]

LeBout wrote:
it registered just over 10 volts AFTER running the pickup for a bit. Not full by any means, but not down all the way.

That's essentially dead.

[wanderingaimles]

As a temporary assist, you can connect jumper cables from truck battery to trailer battery when running truck to charge faster when parked. The small lead in the 7 pin plug doesn't carry a high amp load.
Second, if you are boondocking a lot, really look at roof mounted solar. It charges even when you are moving and will do so averaging 4-6 amp rate for each 100 watts of panel you add.

[schlep1967]

It could be your converter going bad also.