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Old 07-27-2013, 10:09 PM   #1
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High amp draw from Freedom20 inverter/charger

Checked all my batteries and they seem fine. Charging voltage only seems to get up to 12.9 volts and the inverter is working very hard to try and charge these batteries. The LED panel shows about 70amp draw.

Any ideas what could be taking place?

Thanks in advance,

Hutch
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Old 07-27-2013, 10:16 PM   #2
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It sounds like you have a bad cell in a battery. You say you "checked all my batteries and they seem fine." You may want to check them and KNOW they are fine. I suggest a hydrometer and learn how to use it. At any auto parts store and inexpensive. No one can tell you via a forum if your batteries are good or bad.
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Old 07-27-2013, 10:35 PM   #3
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I did use a load tester but in all honesty , not a great one. Voltage on all batteries are 6.3V under no load. These are Interstate batteries that are 1 year old.

I also think there is a battery problem but just looking for suggestions.


Hutch
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Old 07-28-2013, 12:55 AM   #4
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Measure voltage under load.

Follow me on this one...

Forget that they are batteries and think of them as resistors.

Two six volt batteries each have three identical cells.

First, measure "mid-string" or between the two six volt batteries.

Not under load, place one lead on the connecting wire between them, then place the other wire on an end post, note the voltage, now move that wire to opposite end, should be very close but opposite, one will be six volts, opposite minus six.

Next connect your load to.the 12 volt connection and apply.a load and remeasure, lower voltage but may have one different from the other.

Now measure the cells.

Since all are the same, and we are treating like resistors, all should have same voltage under same load per ohms law.

Place meter probe on end post and other post into only the water in the battery and measure about two volts.

Move probe to next cell, place probe that was on the post in first cell water after checking to be sure no crud on probe.

All need to be close on volts, if one is much different it may be bad, usually one is low and rest are high, or opposite, one high and rest low, this indicates bad cell.

If all are same does not indicate good, just does not indicate bad.

More things can be done, this will get you started
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Old 07-28-2013, 07:02 AM   #5
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Checked all my batteries and they seem fine. Charging voltage only seems to get up to 12.9 volts and the inverter is working very hard to try and charge these batteries. The LED panel shows about 70amp draw.

Any ideas what could be taking place?

Thanks in advance,

Hutch
Your inverter will never charge batteries. An inverter converts 12vdc to 120vac.

You are refering to your converter. The converter and inverter might be housed in the same enclosure but the converter charges the battery and an inverter drains a battery.

You say it is charging at a rate of 70A and the voltage measures 12.9v during this charging rate. In general the converter should provide an output of 13-14v but with the heavy load, 12.9 might be OK. It will still charge.

My question is: What load do you have on the system other than the batteries. Part of the 70A draw could be going to a load other than the batteries. Suggest you turn everything off in the coach and see if that charge rate drops.

Are the batteries getting hot under this scenario?

Are the batteries bubbling a lot?

I don't just mean the hydrogen gas effervesing as the normal electrolysis action takes place. Effervessing hydrogen gas is necessary to remove hydrogen atoms to turn H2O (water) into H2So4 (sulferic acid) The sulfer component is in the batteries already to make the creation of this compound possible.

The charge rate is directly related to the amount of hydrogen gas being emitted. Hydrogen gas is extremely flamable and the droplets of sulfuric acid that come out of the cells also so not only is the gas volitile, the acid is destructive.

Checking your cells with a hydrometer is a good idea but the comment about putting a meter probe into the "water" in the batteries might not be the best thing to do IMHO. If the battery is charged that is "NOT WATER, it is "SULFERIC ACID" to start with, and if a probe accidently shorts two plates together that might complicate things. I would never put a metal object into a charged battery cell.

But if you are measuring 6.3V on each battery, that is 12.6V across both batteries without the charger on, this is normal and if you had a bad cell you would expect to see a lower voltage than 12.6v across both batteries or 6.3 v across each battery.

Bottom line, check load on the 12v ccts, that 70A may not all be going to the batteries.

Be extremely carfull around batteries, especially under high charge or extremly high discharge conditions. Thay can blow up.

Hope my comments help.

Good luck.
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Old 07-28-2013, 04:41 PM   #6
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Thanks for all the help and advice. The Freedom 20 is an inverter/charger , I may have generated some confusion in my original post in regards to the amp output that was being directed towards the batteries but all replies were helpful.

The problem was the 1 year old Interstate batteries (4-6volt batteries). All the batteries are pulling a high amp draw to charge and the voltage will not come up. They sit there at 6.3-6.5 volts and that's the best they will do. The charger amps stay high and the inverter works its butt off to try and charge but they will not come around.

I took a known good 12V battery and connected it and all is well. Charging voltage seems good at 14.5V and the charger goes into a floating cycle which is less than an amp to maintain the known good 12V battery. I did have the batteries connected all winter but had it on for only 2hours per day on a timer so they would not ever overcharge. Not sure if maybe I have done something wrong to bugger up these batteries so quickly. I replaced the batteries out of maintenance and the old batteries were just fine but 7 years old.

Once again , thanks for the replies.


Hutch
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Old 07-28-2013, 05:08 PM   #7
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Good you found the problem. Wonder what the specific gravity reads on those batteries. I bet they were hot with a consant charge rate of 70A. This would account for the 12.9v output from the converter. But with 4 batteries the current was likely 35A on each pair unless on was bad on one of the pair causing a larger drain for that pair.
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Old 07-28-2013, 05:42 PM   #8
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I do have a hydrometer somewhere but could not find it or I would have taken a reading. Using one is not really much a part of being in the auto industry anymore so it went away a long time ago. When I find it , it will be in the bus for sure.
I tried charging each battery with a 6V charger each one did the same thing. I have never added water to these batteries since new. I would have figured an overcharge to be gassing these batteries badly so I don't think that is the case.


Hutch
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Old 07-28-2013, 06:05 PM   #9
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With never having added water to the batteries I wonder what the electrolyte level is. There must be enough liquid to cover the plates or the batteries will never charge properly.
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Old 07-28-2013, 06:37 PM   #10
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Your inverter will never charge batteries. An inverter converts 12vdc to 120vac.

You are refering to your converter. The converter and inverter might be housed in the same enclosure but the converter charges the battery and an inverter drains a battery.
Libero
A converter will never "charge batteries" either!
(A converter is NOT is NOT a battery charger).

A Freedom 20 "inverter/charger"is actually an "inverter", a "converter" AND a "battery charger".
1.) A 2000 watt "inverter", (which turns 12VC battery power to 120VAC power).
2.) A 12VDC "converter", (which turns 120VAC to 12VDC.
AND
3.) A 3 stage bettery charger, (which charges the batteries, usually/often ONLY the house batteries).

Mel
'96 Sahara w/ a Freedom 20 inverter/charger
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Old 07-28-2013, 07:55 PM   #11
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Libero
A converter will never "charge batteries" either!
(A converter is NOT is NOT a battery charger).

A Freedom 20 "inverter/charger"is actually an "inverter", a "converter" AND a "battery charger".
1.) A 2000 watt "inverter", (which turns 12VC battery power to 120VAC power).
2.) A 12VDC "converter", (which turns 120VAC to 12VDC.
AND
3.) A 3 stage bettery charger, (which charges the batteries, usually/often ONLY the house batteries).

Mel
'96 Sahara w/ a Freedom 20 inverter/charger
I think of converter as a generic term that converts AC to DC voltage. While I do not have the schematic of that particular product, normally the DC voltage from the converter circuit is used to charge the battery and provide power for other DC loads that are connected to the battery circuits, albeit there is additional circuitry to enable charge control, bulk and float conditions etc. I would be surprised if there was additional circuitry that would convert the AC to DC for a seperate "charger" component. If I had a circuit diagram I would be able to determine the function of each component and how it works. Perhaps you could send it to me for analysis.

And the point of this discussion vis-a-vis the OP's question is ???????
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Old 07-28-2013, 11:15 PM   #12
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I think of converter as a generic term that converts AC to DC voltage. While I do not have the schematic of that particular product, normally the DC voltage from the converter circuit is used to charge the battery and provide power for other DC loads that are connected to the battery circuits, albeit there is additional circuitry to enable charge control, bulk and float conditions etc. I would be surprised if there was additional circuitry that would convert the AC to DC for a seperate "charger" component. If I had a circuit diagram I would be able to determine the function of each component and how it works. Perhaps you could send it to me for analysis.

And the point of this discussion vis-a-vis the OP's question is ???????
Libero
And the point of my comment was that although you may "think of converter as a generic term that converts AC to DC voltage", the converter circuitry of the Freedom 20 contains the appropriate circuitry to make it an inverter, a converter AND a 3 stage battery charger.
(the converter and the charger may share circuitry, however the converter does not charge the battery).

As for a wiring diagram, if I wanted one, I would begin my search here: http://www.google.com/url?sa=t&rct=j...49784469,d.aWM
Mel
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Old 07-28-2013, 11:34 PM   #13
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I don't really want a schematic, I offered to do an engineering assessment for your information and I thought by your comments that you must have a schematic and had intimate knowledge of how the unit functioned.

I have done many reverse engineering assessments and system functionality analysis on electronic systems as an active aeronautical engineer for more than 45 years. So if I looked at the schematics I would be able to discern how it worked. I cannot imagine there would be two seperate voltage converters in the unit (But I am not saying it will never happen - but just does not make sense to me.)

I suspect the 12Vdc out of the converter would have additional circuitry to enable the 3 stage charger to work from the one 12V supply.

The matter is closed for me. Thanks for the stimulatiing dialogue.
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