Freaky 12v lights flickering and fading out

[RichHog]

So am at the rally in Blanco and my 12V system started acting up (2006 safari FB le). The lights started to flicker and then fade down almost to black, the systems indicator display flashed on off and reset. Fridge and smoke carbon systems went off and on, Sony stereo was off. It was strange as ir
Ts raining and getting cold outside. 110V power fine coming into the trailer. Tried resetting the breakers in the box and lights would come back on to full briefly and then dimming back down. Someone here at the rally said check the store/ use button. Did that no change. Thought that one of my two batteries was bad maybe causing the problem. Was about to give up and accept that the Perallex charger system was going out. Then I thought to just start shutting excess usage down so killed the water heater and remembered that the external running lights were on with an adapter I had built on the umbilical cable. Don't need those lights so went out in the rain to remove the plug. Came back in and light back to normal and all systems solid. So go figure. You never know what can trip up the system.

[ROBERTSUNRUS]

Hi, sounds like you were using more power that the charger/converter could keep up with; And you might have weak batteries too.

[RichHog]

Hi Robert, sounds correct to me. I'm pretty sure one of the two batteries is original (2006 Safari) and the PO only replaced one of them before selling to me. But when the trailer is plugged into AC does that matter? Thought the batteries are in parallel and wouldn't affect the system.

[Melody Ranch]

common error...in vehicles (like my diesel truck) and Airstreams....when you have to replace a battery...you have to replace both in order to have a reliable system.

[Jammer]

Rich

That may not be the end of it.

Problems with terminal corrosion and loose connections usually show up first when current draw is high. I would suggest inspecting all the connections to the 12v breaker box and the busbars in the surrounding area. Airstream uses locking nuts but even so I've had these come loose. The best thing to do is disconnect shore power, batteries, and umbelical so there's no risk of shorts and then put a nutdriver on each one and confirm that it is tight. That would also be a good time to check the battery terminals for corrosion although I doubt if that's the underlying problem.

[DKB_SATX]

The overall health of your batteries aside, I can see how you'd get into the loop you were in. Your converter is producing X amps, and your batteries when charged put out Y (at whatever their current state of health is). You set up in a cloudy, overcast environment, turn on every light in the place plus the usual 12V draws plus run the markers off that jumpered 7-pin gadget, and you you end up with:

X < usage < X+Y.

Your batteries, however, can't supply Y forever, so at some point X + Y' < usage and the lights go dim. While you're fiddling around with breakers and such, the converter is charging the batteries a little, AND there's a little internal charge redistribution in the batteries, so you get short periods of better performance before you fall back into the too-little-current state and things start to dim again.

[ROBERTSUNRUS]

Originally Posted by RichHog

Hi Robert, sounds correct to me. I'm pretty sure one of the two batteries is original (2006 Safari) and the PO only replaced one of them before selling to me. But when the trailer is plugged into AC does that matter? Thought the batteries are in parallel and wouldn't affect the system.

Hi, my trailer is a 2005 year model and I have replaced my batteries twice now. Time for a matched set of new batteries. [unless the new one is only a few months old]

[Ag&Au]

The problem with one good and one not so good battery in parallel is that the stronger battery will dissipate power into the weaker one. This will continue until they have reached an equilibrium. Therefore the end result is two batteries at the level of the weakest one. If the bad one is weak enough, the converter will be expending a significant amount of power trying to bring the bad battery (and the good one) up to the fully charged voltage.

It might be worth while to disconnect the batteries one at a time and see if it works better without one or the other.

Ken

[RichHog]

So let me get this straight. The charger/12V system tries to charge the batteries while operating all turned-on device givng a full charge (with the system plugged in to shore power). But the system is overloaded due to the drain of the exterior lights + internal Halogen lights, + water heater / fridge etc. So it takes out extra juice from the two batteries or in my case 1.25 batteries and after a while depletes them. So the charger get's tired and the system goes to a minus (-) condition causing all systems to begin to crater, the power display to flash as it reboots and the fridge to shut down. Something like that? So partial solution is to throw out both batteries and get a new pair so that there will be more reserve juice when needed?

[Jammer]

I'm not buying it.

The converter in your trailer is new enough that, if working properly, will provide roughly 13.4 volts, regardless of the load. It will work with no batteries at all. Unless you have a battery with a shorted cell, which is possible but unlikely, you should have 12 volts when on shore power.

Electrical problems are nearly impossible to diagnose over the Internet but usually a few simple tests will figure out what's going on.

[DKB_SATX]

Originally Posted by Jammer

I'm not buying it.

The converter in your trailer is new enough that, if working properly, will provide roughly 13.4 volts, regardless of the load. It will work with no batteries at all. Unless you have a battery with a shorted cell, which is possible but unlikely, you should have 12 volts when on shore power.

Electrical problems are nearly impossible to diagnose over the Internet but usually a few simple tests will figure out what's going on.

I think where you're getting lost here is "regardless of load." I may well be wrong about what's going on in RichHog's trailer, but if you throw enough load at a converter it'll eventually be unable to carry it all. If you have no batteries and put 50 amps of load on a 40 amp converter (distributed across all the fuses/breakers so that nothing but the main is overloaded) it'll either blow the main or brown out, and brown out sounds like what RichHog described.

(This assumes that the theoretical 40-amp converter is really only capable of outputting 40 amps.)

[TouringDan]

DKB

It should not be to hard to figure out the total amps being used when all the lights and the refrigerator are on. If there are 12v electrical problems then step one would be to make sure that the fridge and water heater are operating on propane. Then only the lights are on to provide the 12v load. This is another reason to switch to LED's. It will cut the power consumption (current load) by about a factor of 10.

Dan

[ventport]

How about the "converter" that you made and was plugged in the umbilical cord to run your exterior running lights. You also said it was raining out. I bet that water got into the plug in "converter" that you made an was shorting out.

[RichHog]

The exterior lights were on over 24 hrs continuously, I left them on during the day. They were turned on by using a Male plug connection as would connect to the TV with the pins connected on the back and a housing over it. Weather temps low 50's and raining Sat. night. I turned off the water heater and then disconnected the exterior lights. After doing that everything ran fine, lights and Sony DVD player/sound was fine. Other issue is the one old/ one a year and a half old battery.

[Ag&Au]

Originally Posted by RichHog

So let me get this straight. The charger/12V system tries to charge the batteries while operating all turned-on device givng a full charge (with the system plugged in to shore power). But the system is overloaded due to the drain of the exterior lights + internal Halogen lights, + water heater / fridge etc. So it takes out extra juice from the two batteries or in my case 1.25 batteries and after a while depletes them. So the charger get's tired and the system goes to a minus (-) condition causing all systems to begin to crater, the power display to flash as it reboots and the fridge to shut down. Something like that? So partial solution is to throw out both batteries and get a new pair so that there will be more reserve juice when needed?

That is pretty much correct. When you are connected to shore power and everything is functioning normally, the batteries contribute nothing to the powering of the load. As far as the converter is concerned the batteries are an additional load. Depending on the design of the converter, one of two things will happen when the converter reaches its maximum output. Either it will shut off in one of several ways, or it will produced a reduced voltage. Either one of these will cause the batteries to provide some or all of the power to the loads. However until this point is reached the converter will see the batteries as just a big resistor. If one or both of the batteries are bad, they will present less resistance to the converter and therefore will draw more current and take a bigger share of the available power.

In my last TT, I placed a large marine battery selector in the circuit. It had 4 positions, OFF, 1, 2, and BOTH. When I plugged into AC I would leave the switch in the BOTH position for 24 hours to assure the batteries were fully charged, and then took them out of the circuit by switching to the OFF position. If the trailer was parked for an extended period, I would switch back to both for a day every couple weeks or so. I have not done that yet in my current trailer, but plan to soon.

The one thing to remember out of all this is that one bad battery left in the circuit will eventually cause the other battery to go bad also.

Hope this helps,

Ken

P.S. I am not saying that a bad battery is definitely causing this problem. There are too many variables. The whole setup needs to be thoroughly checked out with a multimeter before one can be sure.

[Jammer]

Originally Posted by DKB_SATX

I think where you're getting lost here is "regardless of load." I may well be wrong about what's going on in RichHog's trailer, but if you throw enough load at a converter it'll eventually be unable to carry it all. If you have no batteries and put 50 amps of load on a 40 amp converter (distributed across all the fuses/breakers so that nothing but the main is overloaded) it'll either blow the main or brown out, and brown out sounds like what RichHog described.

(This assumes that the theoretical 40-amp converter is really only capable of outputting 40 amps.)

::shrug:: Converters are generally sized to run everything in the trailer at once and still have considerable capacity to charge the battery or run accessories. I don't know what model converter the Safari has and I haven't measured or added up the loads. Usually the furnace and the water pump are the two large loads with the lighting and electronics (fridge control board, water heater board, stereo, tank monitor, smoke, co, and gas alarms, and possibly the thermostat) being relatively smaller.

Clearance lights typically draw 1/4 amp each, tail lights 1/2 amp, so for a typical setup with 16 clearance lights and two tail lights the running light circuit will draw around 5 amps. Less for LEDs.

I know with my trailer if I go around and turn on the stereo and all the lights including the exterior compartment lights and the running lights, and run the furnace, the converter will keep up. The voltage might drop if the water pump then kicked on.