One charger not working

[jelmore]

It appears one charger isn't charging. Our Liberty has two 2500 watt Freedom inverter/chargers. I don't know how they share the charging loads. We've been dry camping a lot lately and I noticed charger #1 would indicate an overheat, would reset, and then start charging again. Charger #2 doesn't seem to be doing anything. The dc amp load on charger #1 would be up at 130 and #2 would be at 0-10 amps.

3 or 4 months ago I changed the dip switch settings to the Liberty default which is all off. That setting disables "power sharing" and, I guess, lets the charger charge at full rate. The chargers are rated at 130 amps. To solve this until it gets fixed, I changed the power sharing setting to 20 amps on charger #1 and it is working, I guess, ok and is charging the batteries without overheating, though slowly. The dc load on #1 is around 70 amps and the batteries are slowly increasing voltage over many hours, something like 11 volts to 14 volts in 6 hours. Doesn't sound quite right to me. The charger breaker on #2 isn't tripped.

We're close to Liberty in Chicago and I am thinking they might be best to figure this out.

Or, would this maybe just for sure be a bad charging board? Maybe it needs further diagnosis?

Perhaps a call to Gusdorf might be in order before visiting Liberty?

What do you think? I know some here have repaired their inverters or had similar situations.

Does any of this sound familiar?

A basic question: how do the two chargers share the charging load? Do they talk to each other? If they are set to allow full current through, 130 amps, does each only deliver 65 amps? Surely they wouldn't deliver 130 amps each! I've never seen it so I don't think that happens.

Need some more school.

[truk4u]

Jim,

You have a lot going on, but check the internal inverter fan(s) and make sure they're running on the one that overheated.

[garyde]

Hi Jim. I would call Troy at Liberty. My understanding is limited, but I was told the inverters were working together, one being a back up to the other. When mine charge they charge at about the same load rate which indicates to me both are running & sharing the output charge. If you turn one off the other one will pick up the charging load. The 4 batteries I have are in parralell / Series so they are all connected to both Invertor/chargers.

[jelmore]

Gary, we're in Chicago so I'll check with Tony or Bill up here. Good to know yours charge at the same rate. Tom, the fans seem to be working. When I said 130 amps, that was total. Other dc loads were probably 30, so the charger was actually putting out maybe 100 amps. The second charger is for sure not charging.

[Joe Cannarozzi]

Jim when I needed repair Mr. Gusdorf diagnosed the problem on the phone.

He then inquired if I were capable and inclined to remove the "board" to reduce shipping and then proceeded to tell me every screw it the exact correct order of removal.

It was not hard. If I were inclined to have someone do that for me I would expect, maybe, take 2 hr out 2 in.

It will be interesting to see if you find another source for your part and repair after a conversation with the boys in N. Chicago in the morn. Take pictures.

[Jon Wehrenberg]

One thing everyone should know about our inverters is when charging either by being connected to shore power or receiving power from the generator they both have the ability to supply charging current to the batteries at the same time. They may charge equally as Gary has indicated, or one may handle the load. If there is ever any question about whether both are working because one always seems to carry the charging load, turn it off and see if the other one starts to pick up the charging load. You should be able to see on the remote panel when the inverters are charging, but if you want to verify it, hook your voltmeter to the house batteries and check the voltage with one or the other turned off. As long as the batteries are receiving a charge the voltage will be well in excess of 13 volts and possibly as high as 14.3 volts depending on where the inverter(s) are in the charging cycle.

A set of batteries not being charged will fall back to 12.7 volts or lower depending on their state of charge.

There is also a misconception that if a bus has two inverters the available power for 120V AC electric devices is their combined wattage and that they supply 120 V AC power together like they do on the 12 or 24 V DC output. Not true. Well, almost not true.

The inverter output when functioning as chargers can be combined and is combined.

The AC (alternating current) output on the 120V side is not combined. Each inverter either passes through shore or generator power to the circuits it is dedicated to power, or in the absence of generator or shore power converts battery power to supply 120 V AC power to the dedicated circuits and those circuits are isolated from one another. You cannot combine the outputs of two inverters to create one single circuit. The must always remain isolated. If your coach is set up with 2500 watt inverters for example, and one inverter has outlets, a refrigerator and an air conditioner on its circuits, the combined amperage or wattage for all circuits supplied by the inverter must not exceed the inverter rating. A 2500 watt inverter therefore can only supply 2500 watts of output power, or a little more than 20 amps total. Since a typical air conditioner will draw 13 amps when running there is not much additional capacity, and a refrigerator, or the TV's may exceed the output if added.

[jelmore]

Good description, Jon.

Some observations: when the charger is on, ac input to the circuits powered by that inverter seems to be passed through to those circuits. When the charger is off, the inverter seems to power those loads. On my charger #2 that does not seem to be charging, when I turn off the charger, the ac load displayed on my control panel drops approximately .3 amps. Turn the charger on and the ac load goes up the same amount when the ac input kicks in. Interestingly, there is enough of a delay (measured in milliseconds probably) in the switch from ac power to inverter power that sensitive items, like a powered usb hub or hard drive, will disconnect from the computer. Nothing else seems to notice, like a refrigerator or a lamp on an outlet.

The remote panel seems to be doing a fairly accurate job of measuring ac and dc loads, so if charger #2 doesn't show any charging load similar to charger #1, then I would assume that it isn't charging. I can't readily get to my house batteries so I can't verify that.

[Jon Wehrenberg]

As soon as an inverter that is supplying 120V AC power receives 120 V AC power the transfer is as fast as it takes a relay or some similar electric device to switch. You are right in saying it might be milliseconds.

There is a delay in charging however. I can't measure it, but when I turn the charging inverter off, the one that has been sitting idle picks up the charging responsibility, but there is a delay of a second or three.

If I am correct we also have delays in our transfer switch so as we go from power source to power source, or even device to device there are gaps.

You do not need to get at your batteries. Go to the electric bay and hook your voltmeter to one of the buss bars and a ground to measure battery voltage. Better yet, look at the house voltmeter on the dash.

[jelmore]

The dash house voltmeter matches, approximately, the display at the control panel for inverter/charger #1. Right now for example, both read 13v and a dc load of about 70 amps (+70 on the dash voltmeter). All of that dc load is coming out of charger #1 and #2 is idle.

Another observation:

Yesterday, I tried turning off charger #1, and charger #2 did nothing. Left it that way all day. And this is curious. The generator was in autostart mode and running. When the batteries got down to 11v, the generator stopped. I was able to restart it after turning off autostart. Glad I was there to see it happen. After turning on charger #1, and the generator again in autostart mode, the batteries got to 14v after about 6 hours of 20amp charging and the generator stopped. Someone asked if the generator stopped after the batteries are charged and I guess this confirms that.

[Joe Cannarozzi]

Jim I just got off the phone with Mr. G he said to shut the good inverter down, give a hard rap with your knuckles on the front of the faulty inverter in the upper right hand corner and see if the charger starts.

He has seen many loose connections to the internal switch that would cause this and that is where it is.

He also said yours are still not obsolete parts are still available for them out there and many repair shops are in the habit of just replacing the board to the tune of 600 bucks and they are repairable for much less.

[jelmore]

How about my rubber mallet! I've used that piece of stuff only once. It's time to make it useful. Thanks. Great info.

[Joe Cannarozzi]

Jim here is his #505-983-4095 goood luck

[jelmore]

Nope. Thought I heard a click, but that didn't do it. Might take it all off line and disassemble it to see, but fiddling around with those kind of things makes me nervous.

[jelmore]

Joe, like I've told you, you da' man. When I tried that the first time, I didn't turn off charger #1. Tried again, following instructions this time, and dang, that did it! Both chargers are working dandy, for now. I will break it down and tighten things up, maybe this evening when it's cooler.

[jelmore]

I just talked to Dave Gusdorf and what great help! He explained about the connector from the main board to the ac board. It's in the front, upper left hand corner. The connector, 10 pins or 14 pins, could be tin or gold contacts depending on the age of the inverter. That's my recollection of his explanation, it's close. The authorized way of making a repair is to clean the contacts with something like d-oxit and it is not considered user-serviceable. I'll probably try it.

I have three disconnects switches in that electrical bay, 12v house, inverter #1 and inverter #2. I'm pretty sure that those will disconnect all power to the inverters. Jon -- do you know for sure? I've done that before to replace an inverter fan with no issues, but Dave said I may have been lucky.

[Jon Wehrenberg]

Jim,

I am not familiar with the 12V set up. When I installed the by-passes on my inverters I turned off my inverters, then my inverter 120V switches which are labeled battery charger one and two, then turned off all four house battery shut off switches, then I unplugged the bus from the shore power.

To be certain the power was off I used my voltmeter to check for power at the battery cables and at the 120 Volt power in and out from the inverters.

Call me chicken.

[jelmore]

I'll follow you on that chicken part.

[Joe Cannarozzi]

How cool is that:cool::)

[jack14r]

Jim,I am almost certain that Liberty charges in the auto start mode by time(6 hours) and not by voltage,they assume that if the generator runs for 6 hours the batteries are fully charged.

[jelmore]

Jack, now that's interesting. Good to know. I haven't done the math, but if the chargers are set to deliver only 5 amps, which these can be set at, I wouldn't think a battery bank at 11v would get fully charged. But then again, the Liberty default setting on these chargers is to let them charge a full rate until the charger circuit determines that the batteries are fully charged, which would be well under 6 hours.

I guess I have never had the autostart on while the generator is on for that long. I've run the generator longer, but I guess without the autostart on.

Liberty is pretty smart on all of this. Well thought out. Almost everything I've found is operator error (or misunderstanding).

[Jon Wehrenberg]

Jim,I am almost certain that Liberty charges in the auto start mode by time(6 hours) and not by voltage,they assume that if the generator runs for 6 hours the batteries are fully charged.


Jack, if that can be verified then the starting voltage can easily be modified with a resistor in the sense circuit. (Our guy Peter V can probably figure out the value of the resistor if we stop picking on Marathons).

The only problem then is the question about the six hour run time. It won't hurt anything except burn more fuel than required.

[jack14r]

You are right Jon,on my last trip I noticed that the generator auto start did not activate until the voltage was below 22 volts,this is by all gel battery manufacturers far below their 50% discharge point.I was told by the owner of watchdog Russ Churchill that Liberty did their charging by time.Jon,what do you think would be the time to charge 6-8D AGM batteries if the auto start were activated at 24.2 volts and my chargers are set up for 18 and 10 amps of incoming AC,I can change the outbacks to charge the AGM batteries to 100%.I can change the voltage and time for bulk as well as float.Bill at Liberty said that he would help me change the watchdog program but he has not gotten back with me yet.The newest watchdog has web pages in it that can be modified by the user with a computer but it will not plug into the older watchdog.Bill is trying to get it to plug and play with the old system.

[truk4u]

Jack,

I just finished some inverter updates and new AGM's and here's a couple numbers for you relating to Lifeline:

Charge - 100%
Bulk/Absorbtion - 14.3
Float - 13.2

On my CC and Marathon with large battery banks, 3+ hours was about the normal charging time to get to float. My Liberty gets there in about 2 hours with 125 amps DC charging that steps down as batteries charge. My start point is 12.2.

Keep us posted on the Watch Dog settings, mine is probably too old to easily change the start voltage.

[jack14r]

truk,I will try to call Bill tomorrow and see if he has made any progress yet.

[jack14r]

I called Bill at Liberty and he said he was still working on getting electronic applications(watchdog) to agree to modify the older style unit.I also asked if there was any way the newer unit would plug and play in place of the old unit,he said he did not think so and that the new unit had not been very reliable.At the end of the conversation we talked about charge times that I want and he said that he would call watchdog again and call me back.

[Jon Wehrenberg]

Jack,

We would have to do the math on time based on how the inverters are set up and this may vary per individual.

I have my inverters set up for the lowest charge rate. We rarely dry camp, or if we do I leave my generator running. No sense dragging it around with me If I will not use it. Others only want to run the generator when the batteries need charging. So rather than me changing my dip switches to a different charge rate i prefer to leave them and then I know I can plug in at a campground, run a bunch of electric stuff on my 120 V AC circuits and not trip the 50 amp breaker.

You may want to modify the time, and set the rate of charge to the preferred 18 and 10 amps. I think the timing is going to be based on when the autostart kicks in, and what other 24 V loads you are using.

If autostart kicks in when you are using your tivoli lights and you have other inside house lights lit the batteries have a fairly good sized load. But if autostart kicks in when the coach is dark you have very little load on the batteries. I almost think this is something that can be tested. Run the batteries down to your target voltage, kick on the generator and see how long it takes to fully charge them, both with the lights on and without.

I think Truk has the right start voltage. (double it for yours)

[jack14r]

Jon,I have done some calculations and without any loads I think that 3 hours is enough but the safe bet would be 4 hours.Bill confirmed today that the watchdog uses time as the charging parameter.

[GDeen]

The Trace system on my Marathon shows a time set by the user for bulk charging. It is currently set at 3 hrs. The Marathon owners manual however says it charges on bulk until the batteries reach a threshold voltage.:confused:

Also noticed that after a power problem at Kerrville caused us to draw the batteries down, inverter #2 was in bulk charge mode longer than #1 which would seem to indicate it is not a set time.

Any comments from the Trace / Marathon guys on this?? Need to carve out a couple of days to read the Trace manuals and figure it out.

[Jon Wehrenberg]

Gordon,

This site is a wealth of information and if you follow the information here your batteries will last a long time.

The chargers should get out of bulk charge as soon as a voltage threshold is reached. It is important to charge to the correct voltage, but it is also correct to step down as soon as that is reached.

http://www.windsun.com/Batteries/Battery_FAQ.htm#Using%20a%20deep%20cycle%20battery %20as%20a%20starting%20battery

[GDeen]

Thanks Jon.