Repair the old UNIVOLT.

[Wolf]

For those that are bound and bent to get a new 12 volt system, I would be interested in the old UNIVOLT for parts.

I have recently had to repair my own univolt.When I enquired about having it fixed, the overwhelming suggestion was to replace it ( I found that this was suggested because no one knew how to fix them.)

Well, from fixing my own I now know how to fix them. They really are quite an interesting piece of engineering. Simple but effective.

Wolf

[Craig]

I may be willing to part with my old univolt. I've been thinking of listing it on ebay. For all I know, it may work fine. I was having other electrical issues and decided to replace it a while back.

[markus]

so many threads on this subject, so I just picked this one.
I just replaced the capacitors on my Univolt 5.
Instead of using the the 660 volt caps[original equipment] I opted instead for the 440v caps.The reason you may ask?
Price and availability.
The 440 caps @ $5 a piece are a common stock item.
And match the excisting mounting brackets.
After bench testing/installation the charging output was just under 13v. agreed, not your 13.8 or 14 but in the ball park.

[markus]

To add to the above and also the confusion, I also installed a on/off switch for ..well obvious reasons

mark

[Chas]

Originally posted by markus
To add to the above and also the confusion, I also installed a on/off switch for ..well obvious reasons

mark

Whatever for?,

Old "mister buzzy" still keeping you up at night?

Just chuck it and get yourself an IntelliPower.

Chas

[markus]

That is a good point! And really there is no comparison between the Inverters of now w/ the old univolts of yesteryear!
If I was fulltymin or relied heavyly on "it", then there would be no question.
But for week end trips and the occastional week or two vacation,the old univolt works really well w/ newlly installed smart switch.
Also, I like to keep "her" hooked up to shore power all winter, have a little heater inside.
"AS" she is a work in progress. No need for worry about frying batteries.

mark

[Tinsel Loaf]

That's a large voltage change for the univolt caps. will be interesting how long the unit lasts. Keep us posted.

[87MH]

To switch the univolt on and off......

For anyone with an "Instant Water Heater" equipped with a switch in the sink area , and having the univolt installed within the kitchen cabinetry, both of the appliances (water heater and univolt) are plug in - not hard wired.

Just unplug the water heater, plug the univolt into the switched wall receptical, and you can have a good nights sleep. More importantly, the shore power can stay plugged in without any fear of boiling the batteries.

You just have to be a bit more aware of the "power management" side of the 110 system. On the 345, this takes the univolt from the rear GFI protected circuit to the front/galley non-GFI circuit.

[wb13798]

i burned up enough battery's to pay for my intella power . the charge wizard is a great piece of electronics. set it to maint mode and forget it. batteries will not boil. and don't buzz at night. i wouldnt pitch my univolt unless it was bad.

[overlander63]

Originally posted by markus
so many threads on this subject, so I just picked this one.
I just replaced the capacitors on my Univolt 5.
Instead of using the the 660 volt caps[original equipment] I opted instead for the 440v caps.The reason you may ask?
Price and availability.
The 440 caps @ $5 a piece are a common stock item.
And match the excisting mounting brackets.
After bench testing/installation the charging output was just under 13v. agreed, not your 13.8 or 14 but in the ball park.

A fully charged 12 volt battery should have around 12.75 volts. If your new configuration Univolt puts out that it should be good, and cause less gassing of the batteries, and, of course, less tendency to boil then dry. I would also like to know how long it lasts, enquiring minds want to know!
Terry

[markus]

The results of my bench test were not promising!
Thinking that 12.92v might be to low of a charging value
I called upon our resident expert on electricity, he pointed out the reliability of my test meter[s] and the fact that the voltage is not that much off,I just went for it![thank-you JohnHD] .
Also to prvent the "frying" of the battery I added the on/off switch.
Will keep all informed of performance/life.

~mark~

[john hd]

hey mark

have you installed it and tested it under load yet. kinda curious about the result...

if you don't have it installed yet, perhaps another bench test you could try is to wire up a couple of 12 volt lamps in parallel and recheck your voltage.

as we discussed, many voltmeters are off, some way off! at the power company our voltmeters are checked against a "certified" supply. some are off by 4 volts! and they are not the $9.99 models from harbor frieght either!

since the univolt is a ferro resonant charger, i would not be suprized to see a higher voltage on it with load.

the real test will be when you reinstall it.

go for it!

john

[Navigator]

One thing that I found out the hard way is that if the polarity to your univolt is reversed, bad things happen, and it is a bear to figure out!
Dick

[TomW]

Several of the posts above mentioned the voltmeter may be out of calibration. Although it would be nice to check your meter against a known 12.0000 VDC source, an inexpensive alternative is an ordinary, carbon-zinc battery (NOT alkaline).

A fresh carbon-zinc battery puts out almost exactly 1.5 VDC.

[overlander63]

Originally posted by Navigator
One thing that I found out the hard way is that if the polarity to your univolt is reversed, bad things happen, and it is a bear to figure out!
Dick

At the very least, your battery will discharge VERY quickly, and recharge opposite polarity, with a resulting loss of amp capacity and amp/hour rating, not to mention strange things happening like your water pump running backwards. And these are the least bad things. If this happens, hook up a non-polarity specific load to the battery, like a light or two, and completely discharge the battery again, and use a slow charge to charge the battery back up with the correct polarity.
Terry

[markus]

installation test #1

Installed battery this morning, and made sure every thing in the trailer was turned off.
Flipped on my newly installed "smart" switch and the enclosed pic tells the reults.Now its a bitt higher charging output than my "on the work bench" test and thats just ok w/me.

[markus]

installation test #2

Here is the results of test #2. With just the over head [oven]
fan running and the over the kitchen sink ligh switched on!
John hd, you say there should be an increase in voltage?
Should I worry bout a small decrease?
Ideas? suggestions? congradulations?

~mark~

[john hd]

markus

looks like congrats are in order!

assuming your battery is charging, the voltage should continue to drop a bit.

the increase in voltage i was referring to was the open lead voltage vs. the voltage with the battery connected.

looks like it is working.

hit your "smart switch" with the lights in the trailer turned on, do they get brighter when you energize the univolt?

john

[markus]

We'll call that test #3

Yes indeedy, the lights get brighter all right!

Thanks John, and every one else,all those two cents add up!

Good learning experience!


thanks all

~mark~

[overlander63]

As a quick rule of thumb, when amps are high, as in a low battery being charged, volts are low, when the volts get up there, the battery is charged.
Terry