will the Univolt converter work with no batteries?

[Bill M.]

Both batteries seem to have died dead. I am storing the trailer from Jan to April and not taking a trip before that. If I just remove both batteries and tape up the leads can I still use 12 volt things when plugged in?
Thanks.

[TG Twinkie]

Yes, you can use the converter without batteries. The multi stage converters are more suited for this application than the old Univolt. In most cases the multi stage converters limit the output voltage to about 14.5 volts. The Univolt can go as high as 17 volts, which could be detrimental to light bulbs an such.

[Zeppelinium]

not only will the voltage most likely be high, but it will be "noisy," eg, not well regulated (if it ever was) and will have a lot of 60 cycle noise in the voltage.

If you're still using an original Univolt, my recommendation is to put replacing it very high on your list, even higher than new axles. These old converters tended to boil batteries dry, so you have to check your batteries often (like quarterly or more) for water level. The new converters are so good I've found that I only need to check once a year, plus their DC output is much better regulated and filtered.

Zep

[dirtturner]

Could you tell me what year the newer univolt units were installed in the AS. We have a 87 excella an are leaving the batteries in and pluged in for the winter, are there some things we should be doing.
Thanks Russ

[nm1oqrz]

Hi Dirtturner. I don't know when AS upgraded the converters but my 88 Excella has the older univolt. My manual states that the univolt should not be operated without a battery installed. Not that it would damage the univold but the higher voltage outputted by the univolt used without a battery could damage other thinge like radios and pc bds in the furnace, refer or water heater. The battery is what helps keep the voltage somewhat regulated.
Of course if these things are not in operation, or disconnected then its a mute point.
Regards nm1oqrz

Originally Posted by dirtturner

Could you tell me what year the newer univolt units were installed in the AS. We have a 87 excella an are leaving the batteries in and pluged in for the winter, are there some things we should be doing.
Thanks Russ

[osoblanco]

I have 69 sovereign univolt system .last 15 yrs used different converter with no battery, suddenly i have no power to converter which works, but rest of trailer has 110 volts working. Does this have a separate breaker other than the one controlling rest of trailer?

[dbj216]

The converter is powered by 115vAC from shore power through the main breaker box. The converter is on one of the 3 or so 115v circuits. You may have one of the breakers tripped. Maybe you can verify there is 115vAC power to the converter.

The converter may have it's own fuse protecting it on power coming in, or power going out. Check your owners manual and see.

David

[Bill M.]

Could have a switch that turns the power to the converter off.

[A W Warn]

I have used the the old single stage converters without batteries, but my owners manual says do not.

As late as the 1990s and early 2000s trailers originally had single stage converters (only one voltage output). The label on those old Magnetek converters said 13.6v output. Though, I have measured them as high as 13.9v and low as 13.3v. I replace mine with multi stage converters when they began to malfunction. (fan ran constantly and output voltage began to vary)

[uncle_bob]

Hi

Even the old Univolts were two stage converters. Trying to work out what was what based on years isn't a perfect solution. They did as they do today. Different stuff went into different trailers.

A better way to approach this is "how old is to old?". Any converter than has been in use for more than 15 years has lived a long and useful life. You have gotten your money out of it. Even if it's technically a 5 stage converter, things have changed firmware wise. You have likely replaced batteries three times already. They have cost you *way* more than a new converter. Upgrade the converter and get another year out of each of the next three batteries.....

Bob

[TG Twinkie]

With a modern 3-4 stage converter. You don't need battery(s).

[A W Warn]

Originally Posted by uncle_bob

Even the old Univolts were two stage converters. <<snip>>

On and Off?

[osoblanco]

Originally Posted by dbj216

The converter is powered by 115vAC from shore power through the main breaker box. The converter is on one of the 3 or so 115v circuits. You may have one of the breakers tripped. Maybe you can verify there is 115vAC power to the converter.

The converter may have it's own fuse protecting it on power coming in, or power going out. Check your owners manual and see.

David

replaced converter puts out 18 volts. can only find one 110v breaker which keeps everything on except to converter. cant find any other breaker or fuse in manual. any suggestions where to look?

[uncle_bob]

Originally Posted by A W Warn

On and Off?

Hi

Off and smoking badly

A two stage charger runs in a current limited mode up to the point that it levels out at some voltage. That's pretty much what all chargers do. A three stage cuts back to a float voltage. A four stage adds a boost occasionally to equalize things.

Bob

[68 Overlander]

Hi Bill,
I don't recommend it. Older converters were not regulated and those high voltage spikes will damage lights, DC control boards etc. All modern switching converters have internal filtering and don't need the battery or a battery emulator to filter or stabilize the voltage.