cancel
Showing results for 
Search instead for 
Did you mean: 

Ok to run shore power without battery?

144Grayling
Explorer II
Explorer II
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?
49 REPLIES 49

144Grayling
Explorer II
Explorer II
Thanks for all the information. The battery is a 12 volt lead acid RV deep cycle battery from Les Schwab. No reason to think it’s not what it says it is. As far as I know the only 12v functions in the trailer are lights, bathroom exhaust fan, radio and propane alarm. All those are fine on what’s coming out of the converter now: 12.9v No slide out, no hitch jack. Checking the panel it also has a few other 12v circuits that we don’t use ( dont need the water pump since we’re hooked up permanently, and the furnace, since we use electric heat instead of propane.) And it says the hood fan is 12v which I didn’t know. So everything we need is working fine off the converter and shore power. I don’t know why the converter was overcharging the battery to the point of boiling, but if it can go without a battery I really don’t need to care about it. I suspect that I killed the battery by leaving it outside uncharged over a couple of winters and that’s my bad. But, again, if I don’t need a battery in the system I’m ok. Still getting mixed opinions on that.

BruceMc
Explorer III
Explorer III
The more experienced amongst us might poo-poo this idea, but for your situation, perhaps a small sealed lead-acid (SLA) battery could act as that buffer.
Small SLAs are used for telecommunication & security equipment, and are readily available at your local stores for around $20-$30.
Search for "12V 7.2AH Sealed Lead Acid (SLA) rechargeable maintenance free battery".
2016 Forest River Sunseeker 2250SLEC Chevrolet 6.0L

JoeH
Explorer III
Explorer III
Why not just get a battery-- you didn't state size-- but something like a Group 24 that will run under $150 and install it. In the event of power outage, you will still have lights and if, by chance, your converter needs a battery, it will be happy too.
Joe
2013 Dutch Star 4338- all electric
Toad is 2015 F-150 with bikes,kayaks and Harley aboard

pbeverly
Explorer III
Explorer III
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.
Ridgeway, SC
2019 26DBH Grey Wolf

valhalla360
Traveler
Traveler
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.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

ScottG
Traveler
Traveler
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
Explorer
Explorer
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.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!

144Grayling
Explorer II
Explorer II
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.

Nv_Guy
Explorer III
Explorer III
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
Traveler
Traveler
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
Explorer II
Explorer II
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.

dougrainer
Traveler
Traveler
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
Explorer II
Explorer II
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?

144Grayling
Explorer II
Explorer II
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.

wa8yxm
Explorer II
Explorer II
I half agree with the person who said something is wrong with the converter.
The reason it's only half is there is a "Suspect #2" (or perhaps #1) and that is the battery.

Either the converter is putting out high voltage (your lights will be super bright and likely not last long story follows) or the battery MIGHT have one or more cells shorted (your volt meter is your friend.. Resting should be 12.6 Put a small load on it (I like automotive test lights.. Look like an ice pick with a bulb in the handle and a wire with clip lead.> Add 25-50 feet of say 18 or 20 ga wire (with a clip on one end and a ring terminal on the other) and you have a very useful tool.... Test fuses swiftly.. Find broken wires (12 volt side of life only) and more very fast and very easy)

If the light goes dim after a few seconds.. Shorted cell (you don't need the extension ground lead for battery testing)

Oh the extension lead.. Like I said put a ring terminal on one end or strip back an inch or two twist loop and solder This is so you can clamp the test lights clip on and a clip on the other.. Then Fold in half and re-roll on the spool it came on (or put one end through the center holes and move it to the middle and re-roll. That way you only need to unroll enough when you need it.

But use a volt meter even if it's a 10 buck horrible frieight special to measure battery and House voltages with the battery disconnected.... Post results.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times