Mysterious Electronics - 2007 19' Bambi

[rmax1]

We have neglected our Bambi this summer and she seems to be paying us back in spades via miscellaneous electrical problems, that i hope are all related to bad batteries.

We knew the batteries were going bad almost within the first year of owning the trailer. We bought it new off the dealer lot in spring of 2008. Problems with two blown Goodyear tires this summer taught us that even though the Bambi was new to us, it was still a 2007 trailer.

Our second trip this summer was dry camping in a national park. We thought we'd be able to get at least 2 days/nights out of our known weak batteries but were surprised to only get part of one night. We knew that when batteries fail, furnace fails as well, but we were surprised to notice that at weak battery level, the furnace smelled a bit smoky inside before failing.

Current symptoms--I am currently parked at our house, connected to a 30amp outlet I had professionally installed in our garage. The battery positive terminal is disconnected, which i presume should take the batteries completely out of the electrical loop. But even with the batteries disconnected, the battery disconnect switch near the door in "use", there isn't nearly enough power in the Bambi.

With just the front lights on, if I turn on the system monitor the battery light flickers between green and yellow. if i run the system monitor test the front interior lights will dim as the LEDs flash. If i turn on the water pump, the lights dim and the pump barely turns over. If i turn on the radio, there is an audible hum in all the speakers. If i turn on the lights in the back of the trailer, the lights flicker and the radio turns off and then back on.

I have plugged a tester into the 30 amp outlet at the house and measure 120Volts. I plugged a tester into the outlets in the trailer and read 120 volts/60 hertz.

If I turn the battery disconnect switch at the door to "store" the lights get dimmer, the radio turns off and on, the hum gets much louder, battery level indicator is pegged at yellow. My understanding that with the switch in "store" no power is directed to the batteries for charging (and the battery is disconnected anyways).

So presuming that the power from the house is correct, what could be giving me the low power symptoms in the trailer? Before the batteries went completely dead, connecting to shore power at a previous campsite seemed to give full bright lights, no diminished water pump, and no hum in the radio. Could the OEM electrical cable from the house to the trailer be going bad?

Is there a method to test the condition of the converter/charge system in the Bambi? I have read a lot about the ongoing discussions about efficiency of the OEM converter/charger and batteries. I expected to replace batteries, but not have to replaced the converter also.

Equipment - Parallax 7300 Model 7355 Converter Charger; original Green top Interstate Batteries

thanks for anyone's input.

[KenS]

We have a 2005 19' with similar electronics, including the Parallax 7355. It is my understanding the Parallax should be able to run all systems when plugged into 30amp shore power with or without the battery. Therefore, there may be a problem with Parallax or the electrical system. However, bad batteries are notorious for causing problems and confusing electrical diagnosis.

A note about the battery disconnect switch - In our trailer, the switch does isolate the battery from the system (with the exception of LPG alarm). However, the indicator light stays lit if the the trailer is plugged into shore power.

~ Ken

[Skater]

Similar to what KenS said: If the batteries are shot, they can 'drag down' the entire electrical system. Disconnect them entirely and see if the converter can handle the camper alone. If it can, it's probably okay; if not, it's probably time for a new one.

[ROBERT CROSS]

My electrickely deprived observation....the P-lax is shot and most likely ruined the Interstates.

This is a cheep method for a more accurate reading of electrik's.

Ask me how I think I know.

lewster....where are you??

Bob

[Silver Goose]

By removing the batteries from the circuit you've taken the most likely culprit for your symptoms out of the loop. Be sure your red battery cables aren't grounding out. A weak short may be placing a high load on the converter. I would expect a fuse or breaker would trip with that much load, but weird things can happen.

Yes the Parallax will provide power to run the trailer without the batteries installed. Look at the 12v fuse panel. Are the connections tight? You will see 2 lugs with a large gauge red and white wires attached. This is the output to the battery bus. It is common to the 12v converter output. Put your meter on them. With the converter on, you should read something around 13.5 - 14 volts.

Is the hum coming from the converter section ( bottom half of the Parallax )? Or the 110 v breakers? Or the battery isolation relay ( located close to the battery compartments )?

Try resetting the 110v breakers, to be sure the one feeding the Parallax is giving it 120v...

You said you had good 12v ( bright lights, strong water pump ) at the campground plugged into shore power, but not when plugged into shore power at home. Did I pick up that you are using an extension cord between the garage and the trailer? Normally, an extension works fine to run small loads like the converter. Find a way to take the extension out of the equation. Maybe if an RV park is nearby, they might let you plug in briefly to test your power.

It is not unusual for the original batteries to be in poor condition from the start. The trailer has likely set for awhile in the dealer's lot with the batteries completely run down and they often never recover from that. The Parallax converter has a reputation for overcharging the batteries if left in the Use mode for extended periods. It is possible that some bad condition in the batteries has taken out the converter. If you find the converter is bad, replace it with a better one before you get new batteries, but since they are at least 4 years old and in question, replace them also. An Intellipower PD4655 is a direct replacement for the Parallax, it is made in the USA, has a good reputation, and won't cook the batteries. It can be found for about $200. There are other choices also.

[Silver Goose]

Some additional info about the Use/Store switch; many find it, particularly the red light confusing. The switch toggles a relay located near the battery compartment. In Use mode the batteries will provide power for the 12v circuits inside the trailer and they are connected to the output of the converter. In Store mode, the batteries are isolated from the converter and the interior 12v circuits. The batteries do remain connected to the LPG detector, tongue jack and breakaway switch.

In Use mode, the red light is on. In Store mode, the light is also on if the converter is providing power or the tow vehicle charge line is providing power to the trailer. Otherwise, it will be off.

The relay draws power only when it is being transferred from one state to the other. Some notice an arc or pop at the switch when they operate the switch and may also hear the relay transfer. If the 12v power is marginal, it is possible to notice a momentary dimming of the lights while the relay is drawing current.

[Silver Goose]

Originally Posted by randf

...If i turn on the radio, there is an audible hum in all the speakers...

The hum is usually associated with an AC component or significant ripple from the output of the converter. This was expected with the ancient linear power supplies that required a battery to regulate and smooth the output. Modern converters use smaller more efficient components that use high frequency switching circuits that don't require a battery and their output contains negligible ripple.

[rmax1]

Originally Posted by YankeeDoodle

By removing the batteries from the circuit you've taken the most likely culprit for your symptoms out of the loop. Be sure your red battery cables aren't grounding out. A weak short may be placing a high load on the converter. I would expect a fuse or breaker would trip with that much load, but weird things can happen.

Yes the Parallax will provide power to run the trailer without the batteries installed. Look at the 12v fuse panel. Are the connections tight? You will see 2 lugs with a large gauge red and white wires attached. This is the output to the battery bus. It is common to the 12v converter output. Put your meter on them. With the converter on, you should read something around 13.5 - 14 volts.

Is the hum coming from the converter section ( bottom half of the Parallax )? Or the 110 v breakers? Or the battery isolation relay ( located close to the battery compartments )?

Try resetting the 110v breakers, to be sure the one feeding the Parallax is giving it 120v...

You said you had good 12v ( bright lights, strong water pump ) at the campground plugged into shore power, but not when plugged into shore power at home. Did I pick up that you are using an extension cord between the garage and the trailer? Normally, an extension works fine to run small loads like the converter. Find a way to take the extension out of the equation. Maybe if an RV park is nearby, they might let you plug in briefly to test your power.

It is not unusual for the original batteries to be in poor condition from the start. The trailer has likely set for awhile in the dealer's lot with the batteries completely run down and they often never recover from that. The Parallax converter has a reputation for overcharging the batteries if left in the Use mode for extended periods. It is possible that some bad condition in the batteries has taken out the converter. If you find the converter is bad, replace it with a better one before you get new batteries, but since they are at least 4 years old and in question, replace them also. An Intellipower PD4655 is a direct replacement for the Parallax, it is made in the USA, has a good reputation, and won't cook the batteries. It can be found for about $200. There are other choices also.

YD--i am able to park the trailer close enough to the garage, so am using the same electrical cable (no extensions) that i would use at a park.

so at home connected to shore power and with both leads off the batteries, i get the same low power indications (dim lights, low water pump output).

[edit--i might add, that with the poor shape of the batteries, when attached to the TV and off shore power, all lights are dim and the powered tongue jack is verrrrry slow]

can i "safely" assume that there is an output problem with the converter? I'll take a look at some of the other troubleshooting ideas sent to me by lewster to hopefully prove one way or another about the converter.

thanks for everyone's comments here. please keep the ideas coming!

[rmax1]

Originally Posted by ROBERT CROSS

My electrickely deprived observation....the P-lax is shot and most likely ruined the Interstates.

This is a cheep method for a more accurate reading of electrik's.

Ask me how I think I know.

lewster....where are you??

Bob

i just picked up a "kill-a-watt" device to monitor/measure electricity usage in order to save money. i think it will measure the same things you are showing in the photos. (BTW -- kill-a-watt devices are cheap these days, about $20 or so on amazon)

[Silver Goose]

Originally Posted by randf

i just picked up a "kill-a-watt" device to monitor/measure electricity usage in order to save money. i think it will measure the same things you are showing in the photos. (BTW -- kill-a-watt devices are cheap these days, about $20 or so on amazon)

Yes, the Kill-A-Watt will display line voltage and frequency of any 110v outlet it's plugged into. It can also display other values most of don't use on a regular basis. One handy feature is you can plug in your microwave or toaster into it and find out how many watts or amps it pulls.

[KenS]

It might be a good idea to re-check the 30amp outlet at the house. There two types of 30amp outlets which are very different and there have been reports of even seasoned electricians installing the wrong type. This is usually because 30amp outlets in homes are typically installed as 220v circuits for dryers, whereas 30amp outlets for trailers are unique to the RV industry and installed as 110v curcuits.

Plugging into a 30amp/220v outlet can cause serious problems and damage, depending on what trailer circuits/devices were in use at the time.

[rmax1]

Older thread, an update and the mystery remains.

I finally replaced the original batteries and at the same time added a Perko battery isolation switch (As described by forum member Phoenix.) The Perko switch install went pretty smoothly due to his great instructions.

But things don't seem to back to "normal" as I expected it to be and as I remembered from the first couple of trips when the Bambi was new.

So I'm sitting in the Bambi right now, attached to shore power (a 30 amp plug installed in my garage). The Perko switch is in the "both" position. The battery disconnect switch at the door is in the "use" position, red light is on. Lights are bright, water pump turns at normal speed, stereo sounds normal-no audible hum as previously noted last fall. Voltage as read on a kill-a-watt device plugged in to the outlet is showing 117-119 volts.

If I reach over and put the battery switch to "store", all the lights dim, the radio dies, then returns to on. If I turn any additional light on, the radio dies, then returns to on. Voltage shows 119.5-120 volts. If I turn the built in system monitor on, there is an audible hum on the radio, and the coach lights dim as the LEDs flash on the system monitor. The battery indicator is initially green, then goes to amber. If I turn off coach lights, amber light goes back to green. Radio hum mostly goes away.

If I go flip the Perko switch to off, battery switch still in store, conditions stay the same as the previous paragraph.

With the perko switch to off, battery switch back to use, a huge hum comes over the radio, lights are bright, voltage is right at 120 V. There are occasional pulses of sound that correspond to lights flickering. System monitor shows battery as amber. If I turn off the lights, the hum goes away, battery light returns to green.

Pulling the shore power plug and the Perko switch still at off, all power goes away in trailer as expected.

Shore power still off, Perko switch to 1, 2, or all, all lights strong, no audio hum, battery light green. Flipping lights on or off there is no dimming, radio doesn't die. Voltage on kill a watt is blank. Water pump spins ate normal speed.

So in my amateur electrician mind, the batteries are working fine. but the strange dim lights, slow water pump, radio flickering, while on shore power that I had last fall still exists when I thought the old batteries were the problem/weak link to my electrical woes.

Can anyone solve this mystery given a rather wordy and long winded description? We are planning on going to a full hookup camp site next week for a week. Can I trust the shore power via the converter? Can intrust the converter (original parallax 7355) to not fry my new batteries?

Thanks to the battery/electrical pros out there!

[ROBERT CROSS]

randf,
"Thanks to the battery/electrical pros out there!"

No Pro, but the P-Lax 7455 was one of the first items I replaced, after overcharging the OEM Interstates.

This is what I'm using now, give them a call, great customer service.

Do you have an output voltage reading on the P-Lax?

Bob

[mefly2]

If your new batts were charged by the selling dealer and not by your converter, I would hazard that you have a bad converter ... one which will not even supply a modest amount of current to your AS. Have you checked the delivered 12vDC inside the AS? If your batt voltage drops down with use and does not recover overnight with shore power, that would indicate a converter problem as well.

[rmax1]

I bit the bullet and took the Bambi to a local dealer. The OEM converter/charger wasn't charging and the converter side was only putting out about 8 or 9 volts (dim lights).

Since we were leaving for a big Disney camping trip, we bit an even bigger bullet and had an off the shelf 3stage charger installed on the spot. But it supposedly will take care if our new bluetop optima batteries and the Perko battery switch I installed (thanks Phoenix)

Wallet a bit lighter but springs maiden voyage was successful.

[ROBERT CROSS]

Good move....

Be thankful it was undercharging and not frying.

Bob