Dual batteries not charging on the road

sheandIinluv!!! · 12-31-2014, 07:40 PM

We have a 2012 Jayco Jay Flight Swift SLX 145RB Travel Trailer with two new Optima 12V batteries, wired in parallel. Two different tow vehicles (each with factory 7-pole plugs properly wired and tested to be putting out 14V to the charge wire) are not charging the trailer batteries when traveling. When we charge the batteries at home with a 110V charger, we have to disconnect the two batteries from each other and from the trailer in order to fully charge them. Fuses inside the trailer's power center and in the tow vehicle check out okay.
Are there other modifications required in the circuit or in the power center (WFCO ULTRA III Power Center Model WF-8735P) when a battery is added?

Can anyone help us diagnose the problem/s?

**Mustang65** · 01-01-2015, 08:57 AM

It sounds like you may be discharging the batteries lower than the 12VDC level (which is the 50% level), and it takes a lot of Amps/time to bring a discharged battery(s) that have been drained below 12VDC and get them up to 100% charge. How old are the batteries? Have they ever went below 10.5VDC or to 0VDC and how many times? What is the voltage on each battery, without any load/charging device on them? What is the Ah rating of each of the batteries? In your case the batteries will not fully charge using the TV system as the charging wire from the TV is to small to carry a large charge.

By indicating that the home 120VAC charger will not charge both batteries at one time means, the charger may not be supplying the required output the batteries need, you discharged them below the 12VDC level, or one or both of the batteries may have a bad cell or more, not sure if you have sealed batteries but the water level may be down if you have FLA batteries.

Your TT's charger is capable of 35 amps so it is OK for (2) 12 volt batteries or 6 volt batteries if they are kept above the 12VDC level.

Just my thoughts,
Don

RedHorse1 · 01-01-2015, 11:33 AM

Does your TT have a battery isolator? When connected to the TV do you see 14V at the batt's?

sheandIinluv!!! · 01-01-2015, 02:50 PM

Thanks Don--the wiring on both the TV and the TT are factory wiring. The TV was ordered with the heavy duty two package and the Jayco plug is the factory molded plug and wiring.

We do have a battery isolator and an inline switch to turn the batteries off when the trailer is stored at home. The Optima batteries are brand new BLUETOP 12V Type D34M and are fully charged each time we bring the TT home. They have never been discharged more than 25% and are kept fully charged by a "Battery Tender" while in storage. Our problem is when we leave home with fully charged batteries and run the refrigerator, on battery, 200 miles to a campground, the batteries are one or two bars down, on the monitor, when we get to our destination. The charge from the tow vehicle, seems to either not be reaching the batteries, or isn't keeping pace with the refrigerator draw, which is only 2.0 to 3.0 amps per the manufacturers approximate electrical load ratings. We bought this trailer used less than a year old and have experienced these problems the four times we have used it since. The first two trips we had a single Interstate Deep Cell Battery and the tow vehicle was a new 2013 Toyota Tacoma. The battery went completely dead while towing and the dealer said the battery was bad. Interstate replaced it with a new one and it went dead while towing during the next use. The battery shop in town fully charged it overnight and it quickly discharged in camp. We made it through the hunt with the use of a spare battery and came home and bought the two new batteries sited above. Our problem is not at home or with chargers or tenders at home. It seems to boil down to discharge while towing. We have no problem when the trailer is hooked up to 120V at home or in a campground with hook-ups. We suspect the power center is faulty on the 12V charge circuit????? Any ideas?

sheandIinluv!!! · 01-01-2015, 02:57 PM

To RedHorse1--We do have and use a battery isolator and we have not put a meter at the batteries when hooked to TV and running. Will test this.

**Mustang65** · 01-01-2015, 05:01 PM

Is there a possibility that the battery isolator is improperly hooked up?

Try this, if you have a volt/ohm meter that has an amp meter also (usually allows for 10 amp tests) pull the 30 amp main fuse at the battery. I am assuming that you have the fuse that plugs into the plastic case, so pull the 30 amp fuse. Disconnect your shore power, turn off your fridge and lights so the only load should be the CO detector, radio circuit and the fridge electronics.... Take the meter, set it for Amp reading and CAREFULLY connect your meter leads to the contacts in the fuse holder Positive lead on the battery side of the fuse holder and negative lead on the TT side of the fuse holder. This will give you your TT's drain without any heavy loads. My TT was less than 1 amp. If you find that you have a larger drain you will need to pull all your 12VDC fuses and plug them in one at a time, monitoring the drain when plugging each of them in, to isolate the circuit.

If you do not have a large drain on the battery, connect your meter to the fuse holder and have someone turn on the fridge to see what the drain is.

Let us know what you find.

You can check the TV's charging amps by shutting everything down in the TT, along with the shore power and with your meter (on amp setting) plug it into the TT's main fuse holder (no fuse installed) with the Positive lead toward the TT and negative lead toward the battery. It would probably be good to hook up the TV prior to starting this test. Then start the TV and you should get a reliable Amp/charge reading. It will be better to try this test on the TT batteries when they are not at a full charge.

You can also check the TV's charging voltage with the TT hooked up, with the TT main fuse out (isolates TV from batteries). Start your TV, hooked up to TT. Now set your meter to DC Volts, ground the black lead and connect your red lead to the TT side of the main fuse holder contact. This will give you the approximate voltage that your battery would be receiving from the TV.

GOOD LUCK and keep us informed,

Just my thoughts,

Don

sheandIinluv!!! · 01-01-2015, 05:46 PM

Don,

Thanks again for your thorough reply. We do have the equipment and the know-how to do these tests. We will do them and get back to you. Right now our only hindrance is the weather. Our low's are running in the two digit negatives with our highs at around 3 degrees above. Weather permitting, we will work this list of test and let you know. THX

Jimw606 · 01-02-2015, 06:49 AM

My 2011 Ford has a spot for a Battery Charge relay in the fuse box.

Sorry, I missed the 14v at the connector.

Look for s fuse under the trailer on in the storage area. Just a guess.

RedHorse1 · 01-02-2015, 08:08 AM

Quote:

Originally Posted by sheandIinluv!!!

Don,

Thanks again for your thorough reply. We do have the equipment and the know-how to do these tests. We will do them and get back to you. Right now our only hindrance is the weather. Our low's are running in the two digit negatives with our highs at around 3 degrees above. Weather permitting, we will work this list of test and let you know. THX

Double digit AND negative!

xkuzme1 · 01-02-2015, 10:02 AM

Here was my idea to add to the capacity of my 184BH. I kept the group 24 on the tongue. Then, when needed I bring along a solar generator that I built. It is really just a tool box with batteries in it. I have mine so that it can be charged with solar easily. I can also charge with while driving, or via a battery charger.

http://www.jaycoowners.com/forums/album.php?albumid=635

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