Xantrex Battery Charger Overheating - Frigoboat Fridge

[Sailormannn]

Originally Posted by btrayfors

Actually, it's very simple:

D U M P T H E X A N T R E X !

You've already spent WAY more than the cost of a new charger just diddling with this thing.

Suggest an Iota.

Bill

Thanks Bill ... I might end up there; but if there's an electrical problem somewhere on the boat that the Xantrex has identified it might not be that simple.

I just checked and tightened the connections at the shorepower inlet where the shorepower comes into the boat (see pic) . I found a couple of the connections looked a bit suspicious. Nothing major but a couple where the insulation had crept into the connection so the connections might not have been making a perfect connection. I adjusted and tightened all the connections there and fired up the charger again. I have it loaded up with all the lights on, refrigerator, my laptop AC power supply and an 110v electrical fan right now. The charger is running at 40% output and the fan seems to be keeping up with the load. The fan came on right away which it hasn't done before. It's been running for 15mins or so now.

I'll have to let it run for a while and see what happens. I hadn't really focused on the AC side since most of the advice I got was on the DC side; have my fingers crossed.

[Kapena]

Here is a simple test for you. Put your multimeter in VAC mode and measure the rms voltage across the terminals at the refrigerator. This will tell you if you have a noise problem or ac voltage on the dc leads. Unlikely, but possible. A battery is a huge capacitor and filters out most noise. If the cable run from the battery to the charger is long then the filtering of the batteries is reduced. Here is the kicker for you. Your model frig is an AC unit with a built in inverter to supply the AC. It is not really a dc unit at all. There maybe a harmonic or switching frequency problem between the frig and the charger circuits. Again, unlikely but possible, easily fixed.

A method is to add a large capacitor directly at the xantrex connection (across the + and -). These are available at Radio Shack, most audio stores. Rating of at least 24v. I would use about .5 farad, no larger. You may have one of these in your car audio system. Another test for this is to move the charger very close (short leads) to the battery. Maybe within a foot or two.

[Kapena]

One more thing for BT. EVERY battery has a limited number of charge and discharge cycles (except no one knows how many vanadium will get). Rechargeable battery - Wikipedia, the free encyclopedia
Look at the chart down the page.
You get far more than this in practical terms as you don't fully discharge your battery each time. Perhaps that is what Richard referred to.

[Sailormannn]

Originally Posted by Sailormannn

Thanks Bill ... I might end up there; but if there's an electrical problem somewhere on the boat that the Xantrex has identified it might not be that simple.

I just checked and tightened the connections at the shorepower inlet where the shorepower comes into the boat (see pic) . I found a couple of the connections looked a bit suspicious. Nothing major but a couple where the insulation had crept into the connection so the connections might not have been making a perfect connection. I adjusted and tightened all the connections there and fired up the charger again. I have it loaded up with all the lights on, refrigerator, my laptop AC power supply and an 110v electrical fan right now. The charger is running at 40% output and the fan seems to be keeping up with the load. The fan came on right away which it hasn't done before. It's been running for 15mins or so now.

I'll have to let it run for a while and see what happens. I hadn't really focused on the AC side since most of the advice I got was on the DC side; have my fingers crossed.

It's been running for more than an hour now and it's working. I've left the refrigerator on and will return in an hour or so and see if it's keeping up. I had some posts earlier that pointed to the AC connections and shore power but most of the feedback was that this was an unlikely cause.

The reason I replaced the charger in the first place was because I was having issues with leaving my refrigerator on and causing my batteries to vent. I've also noticed my anodes have worn more over the past couple of years. I wonder if if any of this could be related to a grounding or connection issue on shore power. I have new batteries in the boat so don't think this is a battery issue.

Any more thoughts would be appreciated especially on the AC connection issue.

[Sailormannn]

No go. Came back to the boat and the charger was flashing charger overheat again. The fan was off of course.

So I'm back to square one.

[Sailormannn]

Originally Posted by Kapena

Here is a simple test for you. Put your multimeter in VAC mode and measure the rms voltage across the terminals at the refrigerator. This will tell you if you have a noise problem or ac voltage on the dc leads. Unlikely, but possible. A battery is a huge capacitor and filters out most noise. If the cable run from the battery to the charger is long then the filtering of the batteries is reduced. Here is the kicker for you. Your model frig is an AC unit with a built in inverter to supply the AC. It is not really a dc unit at all. There maybe a harmonic or switching frequency problem between the frig and the charger circuits. Again, unlikely but possible, easily fixed.

A method is to add a large capacitor directly at the xantrex connection (across the + and -). These are available at Radio Shack, most audio stores. Rating of at least 24v. I would use about .5 farad, no larger. You may have one of these in your car audio system. Another test for this is to move the charger very close (short leads) to the battery. Maybe within a foot or two.

H'mm. Just ran the test for VAC. It showed 28v ACV. And 13.02v DCV if I'm doing this right. Also show 0.6A AC and 3.1A DC. I'm confused. The cable run from the charger to the batteries is maybe 8 feet.

What's this telling me?

[Kapena]

Okay good start. Is shore power plugged in? If so then you have a return or ground missing somewhere in the AC system. If not plugged in then you probably have a frig inverter problem. Measure again but turn the frig off (if possible) (no shore power). Probably means you have a noise problem which is affecting the xantrex unit. Does the charger output go directly to the batteries (good) or to a distribution panel then the batteries (bad)? Can you shorten this run? Can you try the capacitor across the xantrex terminals? Then you won;t need to shorten the cables.

[senormechanico]

Originally Posted by Sailormannn

H'mm. Just ran the test for VAC. It showed 28v ACV. And 13.02v DCV if I'm doing this right. Also show 0.6A AC and 3.1A DC. I'm confused. The cable run from the charger to the batteries is maybe 8 feet.

What's this telling me?

I'm voting 'squishy battery'.
Sub a preferably new one, or at least a known good one.
I suspect the AC component is fooling the charger.

[Sailormannn]

Originally Posted by Kapena

Okay good start. Is shore power plugged in? If so then you have a return or ground missing somewhere in the AC system. If not plugged in then you probably have a frig inverter problem. Measure again but turn the frig off (if possible) (no shore power). Probably means you have a noise problem which is affecting the xantrex unit. Does the charger output go directly to the batteries (good) or to a distribution panel then the batteries (bad)? Can you shorten this run? Can you try the capacitor across the xantrex terminals? Then you won;t need to shorten the cables.

Ok. Shore power was plugged in and refrigerator on when I took the readings. (I'll have to check with the charger and fridge off tomorrow).

The charger output goes directly to the batteries ... not through a panel. Shortening the run from the charger to the batteries is difficult as there's really nowhere to put the charger closer to the batteries.

The AC runs from the shore power inlet to a breaker located close to the shore power inlet and then into the charger. Assume the return or ground would be missing there somewhere.

On the capacitor, are you saying to put one capacitor (ie. 24v 0.5 farad) across the xantrex DC output + and - terminals for the house bank or one on the engine too. I'ver attached a pic of the unit.

[Captain Bill]

The problem is that Kapena's simple test doesn't give you enough information to tell you where the problem is though it has told you you have a problem. You need an occilliscope to tell you if the problem is on the AC side or feedback from the fridge. The VOM will only tell you you have noise. If it's 50/60 cycle you have a problem in your AC side as he stated. If it's higher frequency it's likely in your fridge controller. You'll probably need to find someone with the right equipment and knowledge to diagnose the problem. My guess would be a AC side problem from a bad ground or AC leaking back through the common ground from something wrong with an AC component. I would think that if the fridge contoller was feeding back that much the fridge would not be cooling. I would repeat the test on battery only with all AC disconnected. I would expect that you will not see the AC component, but that might point you in the right direction.

[Sailormannn]

Originally Posted by Captain Bill

The problem is that Kapena's simple test doesn't give you enough information to tell you where the problem is though it has told you you have a problem. You need an occilliscope to tell you if the problem is on the AC side or feedback from the fridge. The VOM will only tell you you have noise. If it's 50/60 cycle you have a problem in your AC side as he stated. If it's higher frequency it's likely in your fridge controller. You'll probably need to find someone with the right equipment and knowledge to diagnose the problem. My guess would be a AC side problem from a bad ground or AC leaking back through the common ground from something wrong with an AC component. I would think that if the fridge contoller was feeding back that much the fridge would not be cooling. I would repeat the test on battery only with all AC disconnected. I would expect that you will not see the AC component, but that might point you in the right direction.

Good advice Bill. Finding someone with the knowledge and equipment here isn't easy ... even in a big city like Toronto. Hard to imagine its the fridge controller although anything is possible. The fridge manufacturer and Richard Kollman have told me they have never heard of a fridge causing this. That's where this all started and went nowhere. I guess I'll have to check all the AC connections and components and go from there. Not an easy problem for sure.

One question on the capacitor thing. What would it accomplish?

[senormechanico]

A capacitor passes AC but not DC.
In this scenario (across the charger output and the batteries) it would absorb the AC component without affecting the DC.
The beneficial effect would be directly proportional to the frequency.
In other words, bigger capacitance is better.
We don't know if the offending noise (if this is even the cause) is a high frequency or is only that of the square wave chopped compressor waveform.

---/\/\/\/\/___\/\/\/\/\---\/\/\/\___
Best I can do for waveforms on a laptop...

I'd go for a much bigger electrolytic capacitor in parallel with the above.
Something on the order of 10,000 microfarads and observing polarity of same. + to + and - to .

(former electronics tech)

[Caribsailors]

Originally Posted by btrayfors

Actually, it's very simple:

D U M P T H E X A N T R E X !

You've already spent WAY more than the cost of a new charger just diddling with this thing.

Suggest an Iota.

Bill

I had two Truecharge2 go up in smoke and KILL a 300ah AGM battery bank.

I switched to a TrippLite inverter/charger and am totally satisfied.

Cheers

[Sailormannn]

Originally Posted by senormechanico

A capacitor passes AC but not DC.
In this scenario (across the charger output and the batteries) it would absorb the AC component without affecting the DC.
The beneficial effect would be directly proportional to the frequency.
In other words, bigger capacitance is better.
We don't know if the offending noise (if this is even the cause) is a high frequency or is only that of the square wave chopped compressor waveform.

---/\/\/\/\/___\/\/\/\/\---\/\/\/\___
Best I can do for waveforms on a laptop...

I'd go for a much bigger electrolytic capacitor in parallel with the above.
Something on the order of 10,000 microfarads and observing polarity of same. + to + and - to .

(former electronics tech)

I googled around a bit looking for info at Radio Shack, etc on capacitors for this application. Couldn't really find anything. There were a few BIG capacitors for big audio systems but nothing 24v 0.5 farad. Any ideas what and where I would find?

[Sailormannn]

Thinking about this AC issue some more. My boat currently isn't equipped with a ground isolator. I'm wondering if adding this would eliminate the problem with the AC side.