Fridge not working from battery

[Craig V]

It seems our fridge is not running from the battery option. It doesn’t get cold at all.
When I select run from battery, the battery indicator goes good to low immediately. If I have the roof vent fan on, I hear it slow down when I select run from battery . So something from fridge is drawing current. I also connected battery to charger but same results. With fridge off, charger output 4A to charge battery.
Fridge seems to work fine running from 120V and propane.

So I think battery is shot or something is wrong with fridge.
Battery water level was OK. Battery came with TM so I’m not sure of its history prior to us (bought TM in November).

Thoughts?

[gonzo628]

Originally Posted by Craig V

It seems our fridge is not running from the battery option. It doesn’t get cold at all.
When I select run from battery, the battery indicator goes good to low immediately. If I have the roof vent fan on, I hear it slow down when I select run from battery . So something from fridge is drawing current. I also connected battery to charger but same results. With fridge off, charger output 4A to charge battery.
Fridge seems to work fine running from 120V and propane.

So I think battery is shot or something is wrong with fridge.
Battery water level was OK. Battery came with TM so I’m not sure of its history prior to us (bought TM in November).

Thoughts?

Are you still connected to shore power whilst running the fridge on battery (ie just testing it)? I ask because I thought the fridge was a pretty signficant drain on the battery.. I know you said you see some kind of current draw, so perhaps that answers the fuse question, but "have you checked the fuse"? Also, have you brought the fridge down to temp via another source (A/C... Propane) and seen if the battery can "maintain" that temp? Have you read the battery voltage with a multimeter?

...Just some thoughts.

[Craig V]

When connected to shore power, it runs fine. Haven’t checked the voltage or fuses. If fuse was blown though, I wouldn’t expect the current draw to occur.
Haven’t tried to maintain temp from battery after it’s already cold.

We tried to start running it while traveling from battery but was not cold at all after about 2-3 hours. Fridge fan may have been off during travel.

Not sure it ever worked from 12V since we got it (last year).

[Craig V]

Was not connected to shore power when testing running from battery.

[Bill]

Craig V -

On DC (battery), the refrigerator uses 10-12 amps of current. If your charger will supply only 4 amps, then the refrig will attempt to pull the remainder from the battery. If the battery is discharged or bad, it is not able to supply 6-8 amps, so the refrig does not work.

When you connect shore power, the TM's built-in charger (sometimes called a converter) is able to supply the missing current, so the refrig works.

There are two bottom line lessons here.

1. The refrig cannot operate solely on battery for more than a very short time, even if the battery is good and starts out fully charged. Most TM batteries have a capacity of about 70 amp-hours when new, and it can be discharged about halfway before it starts to incur damage. So if the usable capacity is 35 amp-hours, and you pull 12 amps from it, you will get about 3 hours of operation before the battery is discharged.

2. If you are driving down the road with the refrig set to battery, your tow vehicle is supposed to be recharging the TM battery as you drive. In reality, the tow vehicle can't/won't supply more than about 4 amps, so again, the refrig pulls the remaining 6-8 amps from the TM battery. And again, the TM battery gets discharged, and you will arrive at the destination with the TM battery near dead. In practical terms, this means you can't run the TM refrig on battery as you travel. You can run it on propane, which works but is discouraged for safety reasons (think about an open propane line in an accident). Or you can simply turn the refrig off, and it will function like a simple styrofoam cooler. It actually is a pretty good cooler - we routinely travel for 8 hours, and find it is still cool when we arrive.

FYI, our member Padgett has built himself a system with very large batteries, and the numbers above do not directly apply to him. However, his mod involves considerable expense. Another one of our members (rickst29) has overcome the tow-vehicle-can't-charge problem, again with a fairly elaborate fix. It involves changing the tow vehicle's 12-volt charging line to 24 volts, so it can push more charge current down the line. You can look up posts from either for more detail.

Bill

[inghamm]

You can test the fridge on DC by plugging into shore power and leaving the fridge on DC. Just keep in mind that it works poorly at best. It may take longer than 2-3 hours to get cool. We always followed the standard advice. Pack it and turn it on AC the day before, turn the fan on and switch to DC just before you close it down. Then the DC just lets it coast so to speak. It HAS to have the fan on to work at all when closed.

That being said, normal for us was arriving with a very low battery. We did it that way for a couple of years. I discovered the UHaul add-on 7 way Bargman we had installed on our TV did not include any charging wire. We tow with a Hybrid that doesn't have an alternator, so remedying that was going to be more complicated than usual. An easier fix was installing Solar panels and switching to a compressor fridge that is way more efficient on battery. We can go days (maybe forever) running the fridge on just solar power recharging our batteries.

[ThePair]

Originally Posted by Craig V

When connected to shore power, it runs fine. Haven’t checked the voltage or fuses. If fuse was blown though, I wouldn’t expect the current draw to occur.
Haven’t tried to maintain temp from battery after it’s already cold.

We tried to start running it while traveling from battery but was not cold at all after about 2-3 hours. Fridge fan may have been off during travel.

Not sure it ever worked from 12V since we got it (last year).

The fridge will need more than 2-3 hours to get cool, even on AC, so that's not the best test of function. However, if you stick your hand carefully in the back and feel heat from the heater, then you know it's working -- just slowly! It's that, or finding the proper wires and testing for the voltage. But the ultimate test is if the heater gets hot on DC, then the DC system is "operational". To make sure the rest of the fridge is working is as simple as: does it get cold eventually on AC? If yes, then the whole system works, since the DC and AC use the same heater sleeve and same cooling system. If the heater doesn't get hot at all, then you'll need to troubleshoot.

As others have said -- use AC to get the fridge cool while at home, and DC is more of a "nice to have on the road" mode than anything else--at least for those of us without monster solar set ups.

[rickst29]

Originally Posted by ThePair

The fridge will need more than 2-3 hours to get cool, even on AC, so that's not the best test of function. However, if you stick your hand carefully in the back and feel heat from the heater, then you know it's working -- just slowly! It's that, or finding the proper wires and testing for the voltage. But the ultimate test is if the heater gets hot on DC, then the DC system is "operational". To make sure the rest of the fridge is working is as simple as: does it get cold eventually on AC? If yes, then the whole system works, since the DC and AC use the same heater sleeve and same cooling system. If the heater doesn't get hot at all, then you'll need to troubleshoot..

Here's a hint: If the DC "heater" doesn't create heat while receiving 12V, but the 120VAC "heater" works - with shells up - then you've got only one possibility: the DC heater coil is blown.

But, when people test "AC Operation", they've always got the shells up. When people use 12VDC on the road, the shells are down - and air flow through the floor-mounted fan becomes critical. This creates two more possibilities for cooling failure, even when the DC heater coil is 100% functional: #1, you forgot to turn on the fan (the upper vents don't help very much, when covered by the front shell sidewalls.). #2, your fan is turned on, but it's trying to pull hot air through a collapsed tube. (Fix the tube).

For everything else, I could write a really long post - but I don't need to do that, because we've got the factory service manual online. It covers everything, except for the TM "shells down" venting arrangement. Use it!

THE Norcold Service Manual: http://www.trailmanorowners.com/foru...7&d=1268332435

A friendly and "more chatty" interpretation, created as an "article" by an online magazine: http://www.trailmanorowners.com/foru...ad.php?t=17615

[Bailey'sMom]

Originally Posted by ThePair

.

As others have said -- use AC to get the fridge cool while at home, and DC is more of a "nice to have on the road" mode than anything else--at least for those of us without monster solar set ups.
__________________

I agree use shore power to cool down.

Question..... have fridge set on AC to cool down. if you close camper down the night before, and turn on the fan, can you leave it set on AC and have fridge plugged in all night running off shore power and then simply disconnect it when ready hit the road?

That way it won’t run on battery while traveling yet will maintain its cool during the trip. Then when reach your destination you switch from AC to propane and your batteries have a full charge still.

[Craig V]

So I recall I forgot to turn the fan on when running from battery while towing. Perhaps it’s as simple as that (why it wasn’t getting cool from battery while towing).
I don’t need to have the main TM power switch on the right side of fridge on when running from battery (while closed), right?

Our TM is stored about 40 minutes away so normally we just hook up and go. Would have to make a special trip the night before to cool down fridge from AC shore power. Was mainly looking to have a cool fridge by the time we get to where we’re going. But we bring our food in an ice chest anyway so not that big of a deal.

Battery under load was 11.88V.