Wiring problem with my Trimetric 2030 battery monitor

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Dooger54

Well-known member
Joined
Apr 4, 2016
Posts
73
Location
Central Illinois
I am trying to run down an issue with my trailer and my Trimetric battery monitor.  For some reason the voltage that my converter is putting out (14.7 in bulk stage) is not showing up on my 2030 monitor.  I can trace the positive lead from the converter up to the frame in front and have verified that 14.7 volts is also reaching there and the battery.  What puzzles me is I can not locate the negative wire coming out of the converter.  Anyone have a clue as to what is standard wiring practice on trailers?  Where does the negative lead from the converter go?  It is not going to the front of the trailer. 
 
The negative from the converter likely connects to the trailer frame.

Did the Trimetric ever work?

The Trimetric has one lead to each side of the shunt (which is in the lead between battery negative and the chassis). And a lead that connects to battery positive. This lead is supposed to be fused. Check the fuse.
 
Heli_av8tor said:
The negative from the converter likely connects to the trailer frame.

Did the Trimetric ever work?

The Trimetric has one lead to each side of the shunt (which is in the lead between battery negative and the chassis). And a lead that connects to battery positive. This lead is supposed to be fused. Check the fuse.
Click to expand...

Yes, the Trimetric is working except for one issue-

It is not getting the current voltage reading when my battery is being charged by shore power.  I have a 3 stage charger/converter and it charges at 14.7v in bulk mode.  When that is happening the monitor reads only about 13.1v.  I have checked the voltage at the positive cable end going to the battery, when it is disconnected, and it reads 14.7 so the power is getting there.  When I check the power on the battery terminal, with the positive now attached to the battery, it reads the 13.1. So the Trimetric is reading that value, not the 14.7. Problem with this is the Trimetric never senses the higher voltage, which does not trigger a ?full charge? reading, and the display always reads - - - when I look at the battery % remaining on the display. 

I am thinking about running a grounding cable from the load side of the shunt to my trailer frame.  That?s why I was trying to figure out how the charger/converter is grounded. I was looking for a negative cable coming from the converter but it sounds like, as you said, the converter is likely grounded to the frame. 

Hope this all makes some sense.
 
Not sure I completely understand but it sort of sounds like the shunt may not be connected correctly.  On the battery side of the shunt, ONLY the cable to the battery negative post should exist.  Every other ground/negative wire must connect to the 'other' side of the shunt (the side opposite the battery).  In other words, ALL negative electrons MUST pass thru the shunt.
 
The converter and/or battery shunt connection to the chassis may be bad.
How long and what gauge wire is the path from the converter to the battery?
You could have that much voltage drop across that path if it?s anything like my factory setup.
 
Heli_av8tor said:
The converter and/or battery shunt connection to the chassis may be bad.

You mean where I attached the shunt to the trailer frame?  Should that be getting a good ground?  I can take if back off and make sure the paint is ground down on the trailer frame. 

How long and what gauge wire is the path from the converter to the battery?

From the converter in back of the trailer to the front is about 25 feet.  Looks to be about 6-8 gauge wire.  I don?t think this is the issue because I tested the voltage on this wire at the front end and it?s about 14.55. So just a little drop from the 14.7 coming out of the converter. 

You could have that much voltage drop across that path if it?s anything like my factory setup.
Click to expand...
 
There is no chassis connection through the mounting bolts of the shunt.
Suggest you study the Trimetric installation drawings to be sure the shunt is wired exactly as shown.
Just because you measure the full converter voltage at the battery with the lead disconnected doesn?t mean ?the voltage is getting there?. You could have a million ohms resistance in the lead and still measure full voltage when there is no current flowing.

I doremember if you said the batteries pass a load test. A shorted cell could cause your symptoms.

Without a connection diagram and leading you through specific troubleshooting steps I probably can?t offer much more. (But will keep trying)
 
Heli_av8tor said:
There is no chassis connection through the mounting bolts of the shunt.
Suggest you study the Trimetric installation drawings to be sure the shunt is wired exactly as shown.
Just because you measure the full converter voltage at the battery with the lead disconnected doesn?t mean ?the voltage is getting there?. You could have a million ohms resistance in the lead and still measure full voltage when there is no current flowing.

I doremember if you said the batteries pass a load test. A shorted cell could cause your symptoms.

Without a connection diagram and leading you through specific troubleshooting steps I probably can?t offer much more. (But will keep trying)
Click to expand...

I?ve studied the diagrams and read the instructions probably 10 times. Of course that doesn?t mean I haven?t done something wrong. The batteries are two brand new Trojan T105?s.

I wii try to get a diagram posted in the next day or so. Maybe this should be moved to the Tech forum.
 
Found something by mistake today as I was mapping my shunt wiring.  When I disconnect the negative wire on the shunt that comes from the battery, the voltage goes up to 14.8, where it should be when the charger/converter is running in bulk mode.  Obviously the AC power is connected and running the charger.  And yes, this is the only wire on that side of the shunt, per Trimetric instructions.
 
Dooger54 said:
Found something by mistake today as I was mapping my shunt wiring.  When I disconnect the negative wire on the shunt that comes from the battery, the voltage goes up to 14.8, where it should be when the charger/converter is running in bulk mode.  Obviously the AC power is connected and running the charger.  And yes, this is the only wire on that side of the shunt, per Trimetric instructions.
Click to expand...
Dooger54 said:
Yes, the Trimetric is working except for one issue-

It is not getting the current voltage reading when my battery is being charged by shore power.  I have a 3 stage charger/converter and it charges at 14.7v in bulk mode.  When that is happening the monitor reads only about 13.1v.  I have checked the voltage at the positive cable end going to the battery, when it is disconnected, and it reads 14.7 so the power is getting there.  When I check the power on the battery terminal, with the positive now attached to the battery, it reads the 13.1. So the Trimetric is reading that value, not the 14.7. Problem with this is the Trimetric never senses the higher voltage, which does not trigger a ?full charge? reading, and the display always reads - - - when I look at the battery % remaining on the display. 

I am thinking about running a grounding cable from the load side of the shunt to my trailer frame.  That?s why I was trying to figure out how the charger/converter is grounded. I was looking for a negative cable coming from the converter but it sounds like, as you said, the converter is likely grounded to the frame. 

Hope this all makes some sense.
Click to expand...

I believe your shunt and and Trimetric are installed correctly. 

As I understand your readings, they are:
--  14.7V at the converter (which is 25' from the batteries, and the negative return to the converter is the frame ground)
--  You are only seeing 13.1V at the battery terminal with everything connected, and 14.7V when at the shunt when the cable from the shunt to the battery is disconnected.

What is the amps reading on the Trimetric when everything is connected and you are on shore power and the Trimetric is showing the 13.1V reading?

You are seeing the voltage loss through a combination of too small a positive cable from the converter to the battery combined with the fact that using the chassis frame as a negative return path is a poor conductor (compared to copper wire) and adds a lot of resistance to the round trip current path.  So yes, what you are seeing is a 1.6V loss in voltage in that 50' round trip wiring. 

Your converter is trying to charge what is probably a much larger battery pack than what you originally had in the trailer, so the converter is trying to put out a lot more current than it used to.

You may need to relocate the converter to within 2-3 feet of the batteries, or run a pair of copper heavier copper wires from the converter to the batteries. 
 
AStravelers said:
I believe your shunt and and Trimetric are installed correctly. 

As I understand your readings, they are:
--  14.7V at the converter (which is 25' from the batteries, and the negative return to the converter is the frame ground)
--  You are only seeing 13.1V at the battery terminal with everything connected, and 14.7V when at the shunt when the cable from the shunt to the battery is disconnected.

What is the amps reading on the Trimetric when everything is connected and you are on shore power and the Trimetric is showing the 13.1V reading?

You are seeing the voltage loss through a combination of too small a positive cable from the converter to the battery combined with the fact that using the chassis frame as a negative return path is a poor conductor (compared to copper wire) and adds a lot of resistance to the round trip current path.  So yes, what you are seeing is a 1.6V loss in voltage in that 50' round trip wiring. 

Your converter is trying to charge what is probably a much larger battery pack than what you originally had in the trailer, so the converter is trying to put out a lot more current than it used to.

You may need to relocate the converter to within 2-3 feet of the batteries, or run a pair of copper heavier copper wires from the converter to the batteries.
Click to expand...

I don?t recall the AMPS reading when hooked up to shore power.  I think it varied depending on the mode my 3 stage charger was in and the state of charge of my batteries.  As they ?filled up? the AMPS go down, as they should.  But when running on battery power and I apply a load the AMPS reading goes negative as it should depending on the load.

So today I tried something else - I hooked up my original 12v batteries as was connected before I bought the new 6v Trojans.  The voltage now is correct when charging: 14.7.  I don?t think it is voltage loss because the wrong 13.1v reading only happens with my 6v batteries connected.  I have also checked the voltage of the wire coming from the converter at the front of the trailer(looks like about 6 gauge) and it shows 14.55, so a little drop in the 25 feet run, but not much. 
 
It sounds like your new batteries have more capacity than the ones they replace, so they act as more of a current sink until they're fully charged.  They're absorbing any voltage above 13.1 volts.

Your charger may be putting out 14.7 volts, but there is wiring loss between the charger and the battery when the battery is pulling charging current.  You saw this to a limited extent with your old batteries, it's more pronounced with the higher capacity of your new ones.  Thus the 13.1 volts at the battery terminals, which agrees with the TriMetric reading.

When you disconnect the wire from the battery, the current flowing through the wire disappears.  Voltage loss along a wire is proportional to the current flowing through it, so when the current goes to zero so does the voltage drop and you read the charger's full 14.7 volts at the far end of the wire.
 
Dooger54 said:
I don?t recall the AMPS reading when hooked up to shore power.  I think it varied depending on the mode my 3 stage charger was in and the state of charge of my batteries.  As they ?filled up? the AMPS go down, as they should.  But when running on battery power and I apply a load the AMPS reading goes negative as it should depending on the load.

So today I tried something else - I hooked up my original 12v batteries as was connected before I bought the new 6v Trojans.  The voltage now is correct when charging: 14.7.  I don?t think it is voltage loss because the wrong 13.1v reading only happens with my 6v batteries connected.  I have also checked the voltage of the wire coming from the converter at the front of the trailer(looks like about 6 gauge) and it shows 14.55, so a little drop in the 25 feet run, but not much.
Click to expand...
As long as your original batteries are fairly well charged the converter will not try to pump a lot of amps down the wire (and back through the frame ground return).  When you put your new batteries in and the converter sees they need a large amount of amps to charge you will see the voltage loss. 
 
Using this wire size calculator:  http://nooutage.com/vdrop.htm  A 25' run of #8 wire carrying 40 amps at 14V will have a 11% voltage drop.  So just to start with that shows almost a 1.6V drop.  Then you add in what the perhaps a larger resistance of using the frame for the return path, it is very easy to come up with the 1.6V voltage drop your figures show.

Even if you have #6 wire or only 20 amps going to the batteries, I would still look at the frame return path as part of the problem.
 
Here is a copy of information I sent to Bogart when they asked torun some tests-

Yesterday I had discharged the batteries by about 30% and then charged the batteries. I then unhooked the AC power last night. So The next morning I tested the batteries and Trimetric before I connected power.

12.75 on multimeter
12.8 on Trimetric

I then hooked up to power as you instructed-

14.15 multimeter
14.1. Trimetric

So those reading look good I assume.

Amps on Trimetric- when I first checked the Amps on the Trimetric they measured 6.8 but as I watched they went down and after about a minute or two they dropped to 4.9. When I checked the Mv reading across the Kelvin screws it was .4. 

I then went back to the Trimetric after about 15 minutes and the voltage was down to 13.3 and Amps down to 2.2.
 
Lou Schneider said:
It sounds like your new batteries have more capacity than the ones they replace, so they act as more of a current sink until they're fully charged. 
Click to expand...

Yes, the new Trojans have a combined capacity of 225 ah.  The 12v battery I hooked up for my test only had about 75ah. 
 
Dooger54 said:
Here is a copy of information I sent to Bogart when they asked torun some tests-

Yesterday I had discharged the batteries by about 30% and then charged the batteries. I then unhooked the AC power last night. So The next morning I tested the batteries and Trimetric before I connected power.

12.75 on multimeter
12.8 on Trimetric

I then hooked up to power as you instructed-

14.15 multimeter
14.1. Trimetric

So those reading look good I assume.

Amps on Trimetric- when I first checked the Amps on the Trimetric they measured 6.8 but as I watched they went down and after about a minute or two they dropped to 4.9. When I checked the Mv reading across the Kelvin screws it was .4. 

I then went back to the Trimetric after about 15 minutes and the voltage was down to 13.3 and Amps down to 2.2.
Click to expand...
Was the 13.3 volts measured at the converter and the battery?  If the 13.3V was at the converter, then the converter detected the batteries are full and went to "float" mode.
 
AStravelers said:
Was the 13.3 volts measured at the converter and the battery?  If the 13.3V was at the converter, then the converter detected the batteries are full and went to "float" mode.
Click to expand...

No, just the battery.  According to the Boondocker converter specs, the voltages are 14.7 in bulk mode, 13.6 absorbtion, and 13.2 float.  After two days of charging the voltage is now steady at 13.1v.
 
Dooger54 said:
No, just the battery.  According to the Boondocker converter specs, the voltages are 14.7 in bulk mode, 13.6 absorbtion, and 13.2 float.  After two days of charging the voltage is now steady at 13.1v.
Click to expand...
At this point is seems like we don't know if you are going to have a large voltage loss from your converter to your batteries when the batteries need a high charge rate and the converter puts out 20-40 amps of 12V (nominal voltage).  The actual amps from the converter will depend on how far down the batteries have been discharged and what is the max number of amps the converter will produce.

One of the issues which came up in this topic is that the converter was putting out 14.7V but you were only measuring 13.1V at the batteries.
 
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