Xantrex Charger and Battery Monitor Not Compatible

[The Mons]

Hello:

Here's the set up, house bank with 4 SCS Trojans, starting bank with 1 Trojan starting battery, Xantrex Truecharge2 - 40 AMP, Xantrex Link 20 battery monitor, 50 amp alternator on single diesel.

The battery switch is a Bluesea off-on-combine that isolates the house and starting circuits. There is no voltage sensing relay, battery isolator, or other like device. The charger has one output to the house bank and one output to the starter battery.

The problem is that the charger shuts off whenever I run the engine. This means that I cannot use the generator underway to charge the batteries the same time I am motoring.

For my limited testing, I suspect that the problem is some sort of incompatibility between the Link 20 and the charger. That is even though the two are isolated from each other, the charger is "seeing" the alternator output and putting the charger output to about zero on both outputs?

Xantrex says each output senses itself. I have tried switching the position of the two outputs in case there is actually only one voltage sensing output. This had no effect. I have even disconnected the starting circuit. This also had no effect.

When I disconnected the Link 20 wire to the starting battery, the problem corrected itself and the house bank began charging. However, now the Link 20 is giving the disconnected battery error as expected.

I did notice while the starting battery circuit was disconnected and the engine was not running that the Link 20 was indicating that the starter battery was getting 0.05 amps.

So this seems to mean that I can't use the battery charger while motoring to charge my house bank. So, I am forced to switch to the combine position in order to charge my house bank while motoring?

Xantrex tech support is clueless.

Maybe someone here should be working for Xantrex instead.

Thanks.

[btrayfors]

Not sure why you want to run the generator to charge batteries while the diesel w/50A alternator is running. Is it that you just want to get a faster charge? Or, maybe, the alternator is connected to the start battery and without a combiner you're getting no charge into the house batteries?

Either way, the correct fix would be to set things up so you don't have to run the generator to charge batteries while the engine is running. Your Xantrex charger is most likely fighting with the alternator output (which likely has a higher voltage, and likely is the reason the Xantrex shuts down or off).

What to do?

Best solution would probably be to rewire all onboard charging sources (generator/battery charger, alternator, solar panels, etc.) to charge the house batteries, and install an EchoCharge or DuoCharge device to maintain the start battery. That way, you'd leave the selector switch on the house batteries and never have to move it, except in an emergency if one or another battery bank dies.

If it turns out that you need more charging when underway, you could upgrade the alternator.

Bill

[Eric M]

Bill is right on - why do you want to run the generator for charging while the engine is on? If you need a faster charge consider a larger alternator. I have nearly the same setup you describe, except my battery switch is 1,2,both,off. 1 is the house, 2 is the reserve, the others obvious. I leave the battery switch on 1, 99% of the time. I'll switch to 2 if the house bank won't start the engine. Once the engine is running, switch back to 1. Battery 2 stays topped off by the charger back at the dock.

[CharlieJ]

I agree with Bill's recommendation however; there is a fundamental flaw present. The Link 20 has no control function over the TrueCharge 2 battery charger. They are two independent pieces of equipment. The response that you got from disconnecting the Link 20 indicates that there is a wiring problem in the Link system including the wiring, the Link or its shunt.

Hope this helps.
Charlie

[gettinthere]

the shunt is a one way device. are you sure it is wired correctly?
don't ask how I know!

[GordMay]

Originally Posted by gettinthere

the shunt is a one way device.

OK - I won’t ask you how you come to believe what you believe; but will ask you what it is that you believe (about shunts).

What do you mean by "one way"?

Current shunts are low resistance, high precision resistors, used to measure AC or DC electrical currents by the voltage drop those currents create across the resistance (I = V ÷ R).
Resistors are not “polarized” devices.

[gettinthere]

My Victron battery monitor would not provide monitoring of amps used. I discovered I needed to reverse the negative leads into and out of the shunt. The flow of current in the negative line has to flow one way through the shunt to work properly. When I reversed the leads on the shunt, the Victron worked properly.

[Mark Zarley]

The Link battery monitor should be monitoring the 4 house batteries, not the single start battery.

[The Mons]

The link monitor monitors the house bank as #1 and the starting battery as #2.

I would like to be able to run the generator because it is necessary to charge my batteries. If I only run the alternator, there is very little true charging capacity left over after the refrigeration and everything else.

I cannot use a larger alternator due to the size of the engine, the potential bearing issues with my model engine, etc.

[goboatingnow]

from your description, there must be faulty wiring, either the link 20 ( its definitely a link 20 not a link 2000 right), is wired wrong, for example both shunts should be in the respective negatives wires to the battery and the sense wire is on the side of the shunt not connected to the battery. Removing this wire if correctly wired would not affect the domestic circuit. somethings wrong.

[Stillraining]

Im still real green with sparky stuff...but my understanding is there is no +- to a shunt untill hooked up...and then one side becomes the positive and the other negitive.

This desigination remains the same regarless of which end of the shunt is flip floped.

So pulling sencing wires off the shunt before current flowes through it is the positive and after curent flows through it is the negitive.

[GordMay]

Originally Posted by Stillraining

Im still real green with sparky stuff...but my understanding is there is no +- to a shunt untill hooked up...and then one side becomes the positive and the other negitive.
This desigination remains the same regarless of which end of the shunt is flip floped.
So pulling sencing wires off the shunt before current flowes through it is the positive and after curent flows through it is the negitive.

Not a very elegant technical description; but near enough ACCURATE.

[gettinthere]

Is this plus/minus issue aimed at my statements? Not sure.

But I damn well know this was applicable to my Victron battery monitor.
It's in the directions,
it was described to me by Victron tech support,
it was pointed out to me by an ABYC certified electrician
and the shunt has a "battery" label affixed to one side of the shunt.

Oh, BTW, the monitor did not work properly until I reversed the polarity of the negative lead to the shunt. The negative lead has to go to the "battery" side of the shunt from the battery and then from the other side of the shunt to the rest of the negative side of the house system. Anyone that disagrees with this is plain flat wrong, period.

So the Victron battery monitor shunt is definitely a one way device with regards to the house system negative lead.

Whether this applies to the OP's original issue I can't tell.

[Maine Sail]

Originally Posted by gettinthere

Is this plus/minus issue aimed at my statements? Not sure.

But I damn well know this was applicable to my Victron battery monitor.
It's in the directions,
it was described to me by Victron tech support,
it was pointed out to me by an ABYC certified electrician
and the shunt has a "battery" label affixed to one side of the shunt.

The only reason the Victron shunt is directional is because it has a pre-wired Cat 5 type connector already mounted to it which is wired in a fashion that forces you to use it in the correct flow direction. If you removed that Cat 5 connector and used that shunt on another brand of battery monitor, which uses stranded wire for connections instead of the pre-terminated cable that Victron does, it could be wired either way. Technically the shunt itself is not directional but the way it is wired from the Victron factory requires you to only use it in one direction.

The Link monitors, which were made by Cruising Equipment for Xantrex, use shunts that can be wired either way.

[hellosailor]

Mons, unless I missed something you have not fully described the way your equipment is set up. You leave us to infer the "charger" is not an AC powered shore charger--the conventional meaning of charger--and that perhaps it is powered by 120VAC produced by your genset instead?

I can think of a very good reason that a genset-powered charger would shut down when you run the engine. Many gensets are rigged so that they automatically turn on under load and turn off when there is no load. You don't say. And many chargers will cut out and shut down when they detect full battery voltage, i.e. 13.8 volts. We don't know.

So form the bits and pieces, it is possible that when you start your engine, your alternator puts out a proper 14.4 volts, which the "charger" then properly interprets as menaing "the batteries are fully charged, I should shut down now" and voila, you can't use them both at once.

There are many ways to design and integrate the pieces of a system and many ways to get the integration wrong when every piece isn't fully documented. I'd suggest checking the manuals and intended design setup of each piece of your equipment, before concluding that it is not behaving exactly as it was designed--or set up--to do.

Integrating multiple charging sources, when each source needs to be separately regulated, can be problematic. Typically you need to find one regulator that can integrate your sources (not easy, not always possible at all) or shoot craps with using unregulated sources and manually supervising them, or not use multiple sources at the same time. Or, use them but expect at least one to be almost totally wasted unless the batteries are really really hungry.


And FWIW, current shunts are not directional. A shunt is basically a precisely trimmed bar of metal. It has no "front" or "back" and can be reversed with absolutely no change in how it works. The current meter that is hooked up to it, will very likely need to be connected with the right polarity--one way only--but that's the meter/computer/gizmo, not the shunt, that has a polarity "problem".