Furnace draws down aux battery when plugged into 110

[tpnysted]

I have my right plugged into 110. My furnace draws the battery down, motor slows down and won't ignite. All 110 accessories work. Shouldn't the furnace be running on stepped down power from the converter? That's the way I read the operation manual. Any ideas of what is wrong?

[BFL13]

allen8106 wrote:
Normally the furnace runs off of 12 volts from the battery. It's the converters job to recharge the battery. Likely the converter can't keep up with the 12 volts draw from some reason. Either the converter is defective and isn't charging the battery properly or the battery is defective and isn't accepting the charge.

Actually the furnace will run with no battery at all as long as it is getting "12v" from the converter.

Interesting idea about whether the converter can run the lights (they get brighter when he plugs in shore power), but maybe not enough to run the furnace (or the furnace in addition to the lights) The furnace only draws about two light's worth though.

I am not sure my notion of a 6300 split DC panel where part of the panel isn't working is a valid idea or not.

[allen8106]

Normally the furnace runs off of 12 volts from the battery. It's the converters job to recharge the battery. Likely the converter can't keep up with the 12 volts draw from some reason. Either the converter is defective and isn't charging the battery properly or the battery is defective and isn't accepting the charge.

[westend]

For keyboard diagnostics it helps to list year, make, and model of RV. If asking about 12V issues, state number, age, and types of batteries and the converter model.

The OP needs to establish why his battery isn't charging. My guess is that a disconnect relay or switch is not in the right position or failed. My second guess would be that a circuit breaker or fuse is open between converter and battery. Third, failed converter.

Do you have a meter?

[RJsfishin]

tpnysted wrote:
I have my right plugged into 110. My furnace draws the battery down, motor slows down and won't ignite. All 110 accessories work. Shouldn't the furnace be running on stepped down power from the converter? That's the way I read the operation manual. Any ideas of what is wrong?

Does this sound like the converter is working ??:S

[RJsfishin]

Quote:
You said the lights are brighter when plugged in, so that means your converter is ok,
-----------------------------------------------------
He said the lites dimmed when unplugged. That does mean that the converter does have an output. It does not mean that the converter is ok.

[BFL13]

The converter works the lights but not the furnace or battery charging. The battery with no converter runs the lights and the furnace.

Is this one of those 6300 converters with a split DC fuse panel and a separate charger section?

If so, you can have a stuck relay that gets the battery charger working, while the rest of the things (lights fans) that don't need battery as filter work or as well have only the battery direct side of the panel working with no battery as a filter to run the furnace and other sensitive items (range hood monitor, fridge, WH 12v side.) Or I am all mixed up, not for the first time! 😞

[tenbear]

Another thought, check the converter voltage when the furnace is running. Maybe the furnace is drawing more current than the converter can supply, or there is a faulty connection between the converter and the furnace.

Do your lights dim when connected to the 120v and you start the furnace?

[tenbear]

I agree with BFL13. Your converter is doing its job. Some how the converter voltage is not getting to the battery. It could be a circuit breaker between the converter and the battery, maybe you have a battery disconnect switch that is disconnecting the battery, or maybe just a loose wire between the converter and the battery.

Check the voltage at various points between the converter and the battery to see where the 13+ converter voltage drops to the battery voltage.

[BFL13]

You do not have a bad converter!! Stop right there. Hang onto your wallet 🙂

You said the lights are brighter when plugged in, so that means your converter is ok, but your batteries are not getting any converter "juice" to charge them up, and they are very low so things are getting bad if you are not plugged in and on battery only.

the mystery now is why the battery 11v can reach the lights (fuse panel) but the converter cannot reach the battery to charge it.

the other mystery is why can't the furnace get its "12v" from the converter when you are plugged in, but instead gets its "12v" from the dying battery that is not getting charged.

New one on me--maybe others here can see what it could be.

[RJsfishin]

I didn't see any mention make model of your converter, but whatever you buy, DO NOT BUY A WFCO CONVERTER. I would suggest a Progressive Dynamics PD 9245 w/ the sometimes optional "pendant", which will make it operate as a 3-4 stage converter/charger.

[Old-Biscuit]

Check the converter DC output when connected to shore power/generator
S/B 13.2V DC minimum output. Otherwise replace converter

[tpnysted]

well i've checked all the connections i can find. all tight and clean. when i unplug the 110 the lights dim. i checked batt voltage unplugged from 110, 11.00 volts. measures the same with 110 plugged in. checked battery voltage with generator running, 11.00 volts. started engine and checked voltage at batery, 13.65. only charges from engine alt. lacking any evidence of broken/disconnected wires i think i have a bad converter. i can hear the transformer humming when plugged into 110. any other thoughts before i spend hard earned cash on a new converter? thanks for all your help. tim

[tpnysted]

Wow folks, I thank you for all the info. I will do some checking today. I'll post my findings when I'm done.

[tenbear]

If I had your problem the first thing I would do is check the battery voltage, with the furnace off, first with the 120v unplugged then with the rig plugged in. The voltage should increase with the rig plugged in. Exactly what it should increase to depends on your converter and the battery state of charge.

Lacking a volt meter, have someone plug in the rig while you watch the lights. They should get brighter when plugged in.

The next step depends on the results of this test.