Ok to run shore power without battery?

[144Grayling]

I have a 2007 Komfort trailer with a WFCO ultra distribution panel model WF8955an with a 3 stage converter. Lately the fan in the panel has started running for hours at a time. I checked the battery and it is boiling HOT. We don’t travel, the trailer is plugged into shore power 100% of the time. Is there any problem with removing the battery and just having the 12v lights and bath fan run off the converter?

[pbeverly]

With my TT if I do not have a good battery while hooked up to shore power 12v things are not 100%. Last week went on trip, night before we left my slide-out came in no problem. Camper stayed plugged in overnight before trip. Got to a destination and hitchjack had trouble getting hitch off of truck, but it managed. Went to put slide-out out. Moved maybe two inches. Plugged into shore, still nothing. Went to Walmart, sadly, and got a new battery. Slide-out worked fine now that a new battery was in place.

[valhalla360]

144Grayling wrote:
Also the NAPA guy said that a deep cycle RV battery is not really appropriate for my set up (basically kept at full charge by the smart converter) since it never discharges. Opinions on that?

Lead acid batteries are happiest at 100% charge. All types of lead acid. But if the charger keeps charging after full, it will boil off the water causing damage.

Lithium are not happy staying for long periods at 100%. Better for storage at 20 to 80%.

Unless you are running 6v batteries, 99% chance the internals of your battery are a starting battery just with a different label slapped on.

[ScottG]

Nv Guy wrote:
My guess is your battery is internally shorted. I would put a new battery in the coach. The battery acts as a "shock absorber" for the converter, stabilizing the output & giving the converter a stable voltage reference.

They haven't been built like that since the old Magtek 63XX days, prior to somewhere around 2000. Anything (even a WFCO) will have no problem making clean DC without a battery.

[ktmrfs]

144Grayling wrote:
The 12.9 was with the battery disconnected. (In fact the battery was at the NAPA shop miles away??) Looks like one vote for “it’s ok to run without a battery” and one vote for “you should put in a battery” Anyone else wanna break the tie?
And if I really do need a battery to protect the system should it be a deep cycle RV battery or a plain old car battery, knowing it will never be without shore power.

high quality working converter likely no problem running w/o battery.

low quality converter or not regulating voltage no battery likely issue. The battery acts like a 12V load and filter.

my opinion, just install a 12 marine or car battery since you run with shore power.

will give protection for other more valuable stuff in the trailer, fridge, wh, furnace, lights etc.

[144Grayling]

The 12.9 was with the battery disconnected. (In fact the battery was at the NAPA shop miles away??) Looks like one vote for “it’s ok to run without a battery” and one vote for “you should put in a battery” Anyone else wanna break the tie?
And if I really do need a battery to protect the system should it be a deep cycle RV battery or a plain old car battery, knowing it will never be without shore power.

[YC_1]

Why would you need a battery to protect the system?

Batteries boiling is a sign of a bad battery, over voltage charging, and in some cases the overvoltage is caused by a bad battery temperature sensor. Yours does not have a temp sensor. But your voltage is not too high. In fact, it is low. However, not knowing the "quality" of the DC charging voltage, your meter may read it low until a battery is present. Some chargers put out a great deal of trash that gets filtered by the battery. This trash generally is not severe enough to cause any damage without a battery in place. To give yourself peace of mind, use some battery from anything that is a 12 volt type for a temporary test. But I would not worry about running the converter without a battery with the voltage you show. 

[Nv_Guy]

My guess is your battery is internally shorted. I would put a new battery in the coach. The battery acts as a "shock absorber" for the converter, stabilizing the output & giving the converter a stable voltage reference.

[ScottG]

Disconnect the battery and see if it's still 12.9. I'm thinking possibly your battery is shorted internally and without it, your voltage will rise to normal levels.
I too, suggest you don't get your advice from a NAPA counter guy and yes, it's fine to run your particular rig on shore power without a battery.

[144Grayling]

Ok. I just checked the voltage coming off the converter, no battery in place. It is 12.9, which is a bit low, but enough to run the lights. Haven’t heard back from NAPA on the condition of the battery. Unfortunately I left the battery outside not on a charger over a couple of winters, which I figure killed. A stupid expensive mistake. But if I don’t need a battery as long as I’m plugged in, I’d rather not spend a couple hundred bucks. So back to my original question: can I just run on shore power with no battery? Will this harm the converter? Thanks for the help.

[YC_1]

Checking the specs for the converter shows it has approx 55 amps available. This is usually divided between battery charging and housekeeping. Since you don't want a battery, the 55 amps is available for your operation without one. No, it does not look like the manual requires a battery in place. Some chargers require a battery voltage to be present before they will start putting out voltage but not the one you have. 

[dougrainer]

144Grayling wrote:
Also the NAPA guy said that a deep cycle RV battery is not really appropriate for my set up (basically kept at full charge by the smart converter) since it never discharges. Opinions on that?

Auto Parts guys are total experts on RV charging systems. NOT! Doug

[144Grayling]

Also the NAPA guy said that a deep cycle RV battery is not really appropriate for my set up (basically kept at full charge by the smart converter) since it never discharges. Opinions on that?

[YC_1]

Baloney. Deep cycle is what you want for an rv house battery. 

[MNtundraRet]

I am happy to see you finally found your old RV.Net posts. 

Welcome back! 

[144Grayling]

Thanks for the input. The battery is at the NAPA shop being tested. I’ll check the converter output when I get to the trailer. Lights aren’t extra bright.