Coach power only functioning w/ pigtail

[Voluntaryism]

Hello! I recently purchased a 21' 1986 Toyota Crossman, which my partner and I dubbed "Little Buddy." Little Buddy has treated us well thus far but unlike the other RV I have owned (a Four Winds Hurricane) the coach power does not work unless plugged into shore power via the pigtail.

A post made to this forum by Jake_Womack earlier this year described a similar issue, which other forum readers suggested was caused by a malfunctioning relay or switch. Could that be the culprit in my case as well? Do I need a new switching supply?

The Power Inverter in Little Buddy is:

Series: 6300 A
Model: 6336

My knowledge with electrical systems is slight, so your input is most welcomed. Thanks in advance!

And in case it impacts the responses to the above issue, we also plan to:

- add a generator (Honda - it'll fit well in the vented external storage area behind the drivers seat)
- swap out the current coach battery with an AGM (Optima)
- add an inverter
 

[linda s]

So you do know that only 12 volt fixtures will work when not plugged in. Have you had your battery tested. Might be completely dead. Have you changed all your fuses. They can be bad even when they look OK.

Linda S

[WME]

Well your about develop a first name working affair with a voltmeter. A simple, workable meter (volt, ohm, amp) will run $25 and will pay for itself many time over.

The thingie (tech term) with red and blue wires is the relay.

You get 12v from the battery and 12v from the converter when the rv is plugged in. The relay switches the different 12v in a single 12v out.

When you plug in the relay should make a click/chunk as it switches from the battery to the converter. See what moves and measure the voltage. When the rv is unplugged the relay relaxes and connects the battery. So if the relay makes connect and no voltage comes out then the problem may be just dirty contacts. Clean with emery cloth.

BE CAREFUL WHEN YOU CHECKING A LIVE CIRCUIT, DO ALL WORK WITH THE BATTERY DISCONNECT AND THE RV UNPLUGGED.

 

 

[payaso del mar]

17 hours ago, WME said:

A simple, workable meter (volt, ohm, amp) will run $25 and will pay for itself many time over.

pays for itself even faster if you get the one for $5 on sale at HF.    might be good to get 2, though, so you can check em against each other......    I carry a HF meter in every vehicle; these days, it's become one of your most important diagnostic tools.

both WME and Linda have excellent suggestions for where to start your diagnostics.  I've even heard of corrosion on fuseholder contacts interfering with current flow, so also pull out and reinsert each fuse.

Edited April 29, 2016 by payaso del mar

[Voluntaryism]

Thanks for weighing-in linda, WME, and payaso.

The coach battery does measure a 12.4v charge with a meter.

When the pigtail is connected to shore power there is an audible "click/chunk."

Indeed -- as was suggested, the issue may be fuse-related. When pulling them I noticed that one, and maybe two, are shorted-out (novice mistake for not checking them initially!). I'll get new fuses swapped in and will update here. It'd be nice were the solution such a simple fix. If that's not it I'll continue as suggested -- disconnect the battery and clean the relay contacts with an emery cloth, etc.

[jjrbus]

A fuse can look   good and be bad!  I learned that one the hard way

[Voluntaryism]

A quick update: replacing the two fuses (both 15A) did not by itself address the problem.

And a bit more info: the coach interior lights have power (even when the AC breaker is switched "off") but the two AC outlets in the coach only have juice when on shore power.

Today I'll act on WME's suggestion to watch the relay -- perhaps the contacts need to be cleaned. I'll first disconnect the battery before such a task is attempted. And I'll swap in new fuses across the board in case, as jjrbus noted, they're bad even though they look good.

[Voluntaryism]

Whelp, replacing all the fuses and cleaning the relay contacts didn't do it. Nor did disconnecting the coach battery, cleaning the terminals with baking soda, adding petroleum jelly, and tightening all the connections.

I may have to loop-in someone local with more expertise than myself...

[WME]

You need a volt meter. Start at the battery and measure at all the points from there to the relay and then on to the 12v fuses.

[Maineah]

That is a micro switch type relay system be careful checking it's operation the coil is high voltage and only pulls up when plugged in. If you have no 12 volts lights etc. when you unplug it that is the time to check it, all of the stuff on the micro switch is 12 volt.

[jjrbus]

I'll second WME.  Electricity is not my strong point, but with a cheap multimeter and continuity tester and volt tester and the help of the forum I can muddle my way through most things. It is not as confusing as it appears.

 

[zero]

On 2016-05-02 at 11:11 AM, Voluntaryism said:

And a bit more info: the coach interior lights have power (even when the AC breaker is switched "off") but the two AC outlets in the coach only have juice when on shore power.

 

I don't understand the comment about the AC outlets only working when plugged into shore power. How else are they going to work?  Is there some other source of AC power in your RV like a DC to AC inverter?

The coach converter/power-system works like this.  When there is NO AC power coming to it (shore power or generator), the relay contacts stay closed and the "house" battery is connected to the coach. NO electronics involved.  House battery is wired to the converter, power travels through the closed relay contacts, and to a main DC system-fuse that is likely 30 amps.  Then there are a bunch of smaller "circuit" fuses. beyond that. One for lights, one for water-pump, one for furnace, etc.

 

6300 Series Owner/Operator Manual

 

 

 

AC PANELBOARD

 

 

 

When 120 VAC is connected to Power Center via commercial power or AC

 

generator, the 120 VAC circuits are protected by the breakers contained in

 

the AC PANELBOARD.

 

120 VAC circuits may be turned off by flipping breaker to indicate “OFF.”

 

The circuits may be turned on or reset by flipping breaker to indicate “ON.”

 

12 V DC FROM POWER CONVERTER SECTION

 

When 120 VAC is connected to the Power Center via commercial power or

 

AC generator, and the circuit breaker controlling the POWER

 

CONVERTER Section is “ON”, the POWER CONVERTER Section will

 

convert the 120 VAC to 12 VDC and is instantly switched—via the

 

Automatic Relay—into the 12 VDC RV circuits to operate the 12 volt lights

 

and motors. A cooling fan will come on when certain temperatures are

 

reached in the lower section. Equipment limited to operation from 12 volt

 

battery power only—including 12 volt TVs, radios, stereos, unfiltered

 

fluorescent lights—must be connected to the fused battery circuits of DC

 

DISTRIBUTION PANEL or RV battery line.

 

DO NOT connect equipment requiring more than 3 amps to terminal “B”.

 

AUTOMATIC-RESET THERMAL BREAKER

 

A protective Thermal Breaker will “break” the 120 VAC power to POWER

 

CONVERTER Section of Power Center if POWER CONVERTER becomes

 

overheated—by operation above its maximum limit for an extended period

 

of time or obstruction of ventilation to unit.

 

POWER CONVERTER Section will instantly switch 12-volt light and

 

motors to battery.

 

In either case, the Thermal Breaker will reset itself after a period of time,

 

and the lights and motors will again resume operation from POWER

 

CONVERTER Section—only to shortly again “break”. When this occurs,

 

take immediate steps to correct cause of overheating. A portion of RV 12-

 

volt load—lights or motors or both—should be turned off to reduce total

 

load. Also, inspect POWER CONVERTER Section to make certain

 

ventilation is not obstructed.

 

12 V DC FROM STORAGE BATTERY

 

When 120 VAC is NOT connected to Power Center via commercial power

 

or RV generator, the POWER CONVERTER section—via its Automatic

 

Relay—will switch RV battery into the circuit for power to operate 12 volt

 

lights and motors.

 

When 120 VAC is again available, connect it to Power Center. The POWER

 

CONVERTER Section—through its Automatic Relay—will be brought back

 

into circuit.

 

When operating RV 12-volt equipment from RV battery, it is recommended

 

that the amount of equipment in use be reduced—to conserve battery.

 

Gradual dimming of lights and slowing of motors indicates low battery

 

voltage. If 12 volt equipment will not operate from RV battery, check wiring

 

between 12 volt DC DISTRIBUTION PANEL in Power Center and battery.

 

If this line is fused and fuse is “blown,” inspect for overload or “short”. DO

 

NOT install oversize fuse. Make certain battery is fully charged—see No. 5

 

below.

 

The DC DISTRIBUTION PANEL

 

The DC DISTRIBUTION PANEL is located behind hinged door of Power

 

Center. This panel contains circuits with replaceable fuses for protection of

 

RV 12-volt light and motor lines.

 

If any line is loaded beyond the capacity of its fuse, the fuse will “blow”. A

 

portion of the 12-volt load on the line—lights and/or motors—must be

 

turned off to reduce total load on the line below the capacity of the fuse.

 

Replace fuse with same size fuse. DO NOT install larger fuse than indicated.

 

If this reduction of load on the line does not stop the “blowing” of the

 

replaceable fuses, there may be a “short” along the 12-volt line or at a

 

nonfused 12-volt motor on the line. Check the RV 12-volt line and

 

equipment on the line. Locate the “short” and take the necessary steps to

 

repair it.

 

IMPORTANT

 

If 12 volt lights and motors will NOT operate as indicated above, check to

 

make certain 120 VAC power is properly attached to RV. Also, make certain

 

the AC breakers in the AC PANELBOARD indicate “ON”.

 

5. BATTERY CHARGING SECTION

 

Units with Option C contain an automatic, solid-state Battery Charging

 

Section. When 120 VAC power is connected to Power Center, the Charging

 

Section will automatically “sense” the condition of RV battery. If it is below

 

“full charge,” the Charging Section will start charging the battery.

 

If RV battery has been drawn down quite low, it will be charged at a

 

relatively high amperage rate. If battery has not been severely drained, it will

 

be charged at lower amperage rate. The rate of charge will decline as the

 

battery reaches “full charge”. After battery reaches “full charge”, the

 

Charging Section will drop back to “maintenance” level. It will not resume

 

active charging until battery again falls below “full charge”. If your storage

 

battery cannot be charged as described above, it is possible the battery is

 

defective—see “Battery Maintenance” below.

 

STORAGE BATTERY MAINTENANCE

 

WARNING—Before inspecting or servicing storage battery, read and follow

 

battery manufacturer’s cautions and directions.

 

Your RV storage battery must be properly maintained so it can perform its

 

functions as described in 3& 5. The following suggestions—plus those of

 

battery manufacturer—will help your storage battery:

 

The battery must be in good condition with water at proper level when first

 

installed in RV.

 

When 120 VAC is connected to Power Center, check battery once a week.

 

As battery ages, it will usually need water added more often.

 

If 120 VAC is not connected to Power Center, it should be reconnected to

 

Power Center once a month for 8-12 hours to “recharge” battery.

 

If you store battery outside of RV, a battery charge should be connected to it

 

a least once a month to recharge battery.

 

Do not allow battery to remain in discharge condition—it will become

 

sulfated and not accept a proper “charge”.

 

Some situations which may indicate need for battery replacement are:

 

The loss of more water in one cell than others.

 

Continuous loss of water in all cells—perhaps accompanied by overheating

 

of battery, gassing and extreme bubbling.

 

A marked difference in the specific gravity reading between one cell and

 

others.

 

[Voluntaryism]

Thanks everyone for your input. It appears my own ignorance is cause for this thread.

I had thought -- per the operation of my previous RV -- that coach power to the AC outlets was the norm and thus, that my current Toyota RV was operating incorrectly. In fact, the Toyota electrical system is operating as intended, being that it has only a converter installed, not an inverter.

Thanks again to all for your help. And on a good note -- I have become just a bit more learned about the electrical system and its various components.

[WME]

Aw first baby steps, wait until  plumbing problems arise.

[payaso del mar]

don't feel bad, we all have a learning curve.  I had to learn that item myself....

i'm adding two AC outlets that will be run off the inverter.  tried to find the special orange or red ones that signify something under the NEC (connected to backup power?) but no luck, so I just painted em orange for a reminder that we're drawing battery power when we're plugged into that one.  the other outlet in the box is regular shore-power system.

[RunningMan]

i have the same panel and a 12v Rm2400 Dometic fridge. When i check the the top of the fuse bank i get 12volts.. and i also get that reading on the bottom for each of the three remaining fuse circuits......... except for the fridge circuit.

it only shows 6-7 volts. ive changed the fuse and still no consistent 12v reading.  any ideas?

 

what size/type fuses should be in line for the fridge?   

Edited May 27, 2016 by RunningMan