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Old 01-11-2006, 12:02 AM   #29
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What I am saying is that the effect is much more pronounced at higher current draws.
That follows from the logarithmic nature of the phenomena. Or think resistance losses going up with the square of the current.

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I think you will find the Lifeline AGMs have a similar Peukert coefficient to the Optima AGM, certainly less than 1.2 for flooded cells.
The Optima coefficient is about 1.06 last I checked, while the Lifeline was 1.19. That rather surprised me. What it says is that the Optima amp hour rating for the 20 hour rate should be fairly close to that for its 5 hour rate, especially when compared to Lifelines or wet cell batteries.

But all that isn't really a significant issue when you have batteries run nearly flat and then poorly charged days or weeks later with the typical Univolt.

Best way to test for a defunct battery is to note when the lights start getting dimmer sooner. That is a practical load test.
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Old 01-11-2006, 10:20 AM   #30
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Thanks AZFlycaster

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Originally Posted by azflycaster
Mitch,
Yes, it can happen. Any auto parts store should have a tester that they can hook to your battery and tell you in a few minutes if it is bad. Batteries do not like to be bounced around a lot and sometimes that will make them short out a cell. I have had batteries last for several years and others for a few months. In my autos I average less then 2 years, the Phoenix heat is tough on them.
As always you guys/gals always come through. I'll take in the battery to have it tested.

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Old 01-11-2006, 09:12 PM   #31
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Originally Posted by andoboba
I need to have my '69 Ambassador plugged in full time. Has anyone figured out how to safely charge the battery while leaving the Univolt constantly plugged in?
Well, back to the original question. If you choose not to go with the Intellipower/Charge Wizard, another option would be to use a timer between shore power and your AS. Adapt your 30 amp AS cord to 20 amp (3 prong) and plug in the timer. Mine is set to let current through for one hour a day. I leave the timer and AS cord in the bumper storage and run an extension to power. You'll have to check your battery with a meter for a few days to determine how much daily charge your battery will need.
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Old 01-11-2006, 10:58 PM   #32
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Instead of an adapter and a timer, what about one of these: http://www.batterystuff.com/categori...ttery_chargers
It sounds like you could leave it attached and it would maintain the battery.
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Old 01-12-2006, 10:04 AM   #33
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I can vouch for the 1 amp and 4 amp BatteryMinders. You can keep them attached year round without problems. My 2 Delco Voyager batteries were in excellent condition 4 1/2 years after I bought them when I sold my trailer. When away from home and boondocking, I used a 5 watt PulseTech Solargizer solar panel to keep the juices flowing. That worked fine when being conservative so I decided to add a 30 watt panel and splurged on fan use. Never a problem.
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Old 01-12-2006, 12:39 PM   #34
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Battery/Univolt Question

On this topic...does a functional univolt have the ability to recharge a discharged battery?

My reason for asking is when I checked the Univolt output (without the battery), it read 13.5 without any lights on. However, when I left the 'dead' battery hooked up to the univolt for 12 hours, it wouldn't recharge the battery.

I than attached the battery to a battery charger and it regained a full charge after a full night of charging and I no longer have dim/dead lights.

I looked at the Univolt to see if there is a voltage regulator attached to it, since I'm beginning to wonder why I have the right voltage output, but it won't recharge a discharged battery. Am I missing something?


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Old 01-23-2006, 11:50 PM   #35
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More Battery/Univolt info???

So I've been following this thread all along and am closer to understanding the problem with the Univolt. Now I don't see anymore replies. Is this all there is? I may just decide to replace the univolt, switch to 6volt golf cart batteries like the Trojan T145 model replacing my dying Trojan 12 volt batteries, one of which seems to have been killed by the constant charging of the Univolt (see above). The bad one has been doing the boiling thing (see above) and leaking (see above). I think I need a better charging and converter system. I also have two 75watt solar panels that charge with a charge controller. And I carry a generator (actually two during summer: Honda EU3000 for running the aircon and a recently purchased used EU1000 for light use). We boondock all the time, almost never hooking to a power cord EXCEPT AT HOME. This is where the batteries get left on the Univolt (read: Magnatec) and do the dying routine. We hate the hummmmm so it may be gone by summer.
Enough.
(I just had to add some more words to this thread)
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Old 02-21-2006, 12:38 PM   #36
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Before I read this thread I was sure I knew the univolt answer , now I'm sure I don't . I leave my '76 with original univolt plugged in all the time . First battery lasted 5 years , present battery 2 years old and still good . In the owners manual it says " The charging circut automatically controls the current ,reducing it as the battery increases in charge ". Are some univolts different than others? What is the real story . Thanks

PS I put a small computor fan on it to keep it cool, works great.
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Old 02-21-2006, 02:11 PM   #37
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An older Univolt is a constant voltage current limited power source. If the battery is low, the voltage difference between the univolt and the battery is large and a lot of current will flow to charge the battery. As the battery is charged and its voltage rises, the current to the battery will drop because there is less of a voltage difference pushing it.

If the voltage on the Univolt was set close to 13.2v it probably won't overcharge your batteries but will take a long time to get them fully charged. Many Univolts were set at 13.6v or higher. These charge faster (bigger voltage difference between univolt and battery) but have too high a voltage to float maintain the battery without causing overcharging and electrolyte loss.

New three stage chargers change their voltage output for optimum battery charging current to the battery. That is how they control charging and maintenance charging. The go up to 14.4 volts to charge quickly and then drop to 13.2v for maintenance when the charge is done.
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Old 02-21-2006, 04:49 PM   #38
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Thanks Leipper , the fog is starting to clear
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Old 05-07-2006, 01:44 PM   #39
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Congrat Leipper, You rate a 100 percent in your answers as far as I am concerned.
I am not sure if this was mentioned before but there is a fuse between the Univolt and the battery. If the univolt is reading 13 volts and the battery is not charging make sure that 40 amps fuse is ok before blaming the Univolt. This fuse is located in the Univolt distribution fuse panel.
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Old 05-07-2006, 03:44 PM   #40
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In the instruction sheet that came with my Charge Wizard, they have a charging chart, based on a 55 amp Intellicharger, hooked to a 125 Amp-Hour battery. In the "Boost" mode, (14.4 Volts) it looks like it could take 18 hours to fully charge the battery. In the "Normal" mode (13.6 volts) it looks like about 78 hours. "Storage" mode, (13.2 Volts) about 105 hours! So much for running your generator for "a couple of hours" to recharge your batteries!! So it looks like a plain old dumb Univolt can recharge a dead battery in about 3 days.
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Old 05-26-2006, 10:53 AM   #41
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What about those auto matic peak chargers that sence the battery loosing voltage and apply 2 amp charge to peak it. There charger part is like 3"x3"2" real small one for each battery ? about 50 bucks ...
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Old 05-29-2006, 04:46 PM   #42
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Originally Posted by Mrcrowley
What about those auto matic peak chargers that sence the battery loosing voltage and apply 2 amp charge to peak it. There charger part is like 3"x3"2" real small one for each battery ? about 50 bucks ...
Just realized that wont work sence the univolt powers the twelve volt systems when plugged into a pole ...DOH
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