undercharged relocated battery w/alternator

[RSB]

but they aren't! Am I reading it wrong?

link to PDF:

http://www.xantrex.com/documents/Accessories/LinkPro-Battery-Monitor/LinkPRO_Installation&QuickStart(975-0429-01-01_rev-C).pdf

Both batteries must be on just one side of the shunt. The same side. Only the leads to both batteries should be on one side of the shunt. In your diagram, you have a battery on each side. No good. The monitor would be inaccurate in the extreme.
All charging sources, all loads must be on the other side of the shunt. Xantrex's directions must say the same thing. Are they written in chinglish?

ok.

Use of a distribution block, or buss bar, or buss stud is recommended. It is to be wired on the load/ charging source side of the shunt.

The shunt must be rated for 500 amps because the starter's amps will run through the shunt. If the starter has is's own ground wire, then that wire alone can goto a negative battery terminal, bypassing the shunt. I've never seen a starter with a separate ground wire. Doesn't mean they do not exist, just that I've never seen one.

 

[wrcsixeight]

I should have mentioned it earlier, but my monitor is designed to only monitor one battery and just the voltage off the other. Perhaps this is why your monitor wiring is a bit different from mine?

This must explain the included xantrex wiring diagram. I cannot/will not argue with the wiring diagram designed by the manufacturer. I also have no experience with national luna's smart solenoids and sense wires.

I am sorry if I confused you with my incorrect assumptions. The xantrex wiring diagram has confused me, as I was unaware of it's intended design, and my own limitations in only understanding my own system, and arrogance in thinking they all had to work the same.

It appears xantrex removed the errors inherent in my system with an unknown portion of the alternator charge going to the engine battery and my monitor thinking amps are flowing from my house batteries while engine starting even If I have them removed from the loop at the time.

Follow xantrex's wiring diagram as close you can. Double check everything you have wired. Sorry for the confusion.

edit: Despite staring at the diagram for 10 minutes, I'm still having a hard time seeing how the shunt is going to read any loads placed on the auxiliary battery. Does the xantrex read how many amps the starter uses? When you plug in the fridge does it read a ~2.7 amp load. Where do the negatives of the accessory devices splice into that diagram?

 

[RSB]

no problem! Like you said, it's about becoming more knowledgeable.

now, back to post #30 & 31. I still need to fix the wiring to the shunt, per Xantrex's instructions.

My alternator's negative runs directly from the alternator to the shunt. My engine ground runs directly from the engine to the shunt. My frame ground runs directly to the alternator, and another wire runs directly to the engine ground from the frame ground.

Would it hurt to use distribution blocks as shown in the sketches?

 

[RSB]

it reads the amps the 'main' batt uses, which in my case, I decided would be my house battery. It only reads the voltage on the 'aux' batt, which I decided would be my starter batt.

edit: Despite staring at the diagram for 10 minutes, I'm still having a hard time seeing how the shunt is going to read any loads placed on the auxiliary battery. Does the xantrex read how many amps the starter uses? When you plug in the fridge does it read a ~2.7 amp load. Where do the negatives of the accessory devices splice into that diagram?

 

[wrcsixeight]

I posted the edit in the wrong post.

I still cannot see how, if wired in the manner of the xantrex wiring diagram, the shunt and monitor can read the status of the auxiliary battery. Isn't that the purpose of a battery monitor?

For current flow to be measured it's got to flow through the shunt. The way I see that diagram is that it will monitor the flow only between the 2 batteries, but not between the batteries and their charging sources and loads.

I don't get it. I don't see the point having it wired as they show. I just don't see how it could measure the remaining capacity of auxiliary battery wired like that. Isn't that the battery you want to monitor?

This is going to bother me, probably keep me up tonight.

 

[RSB]

I don't have a fridge, so I don't know that, but all neg loads connect where circled in red on the diagram:

edit: ...When you plug in the fridge does it read a ~2.7 amp load. Where do the negatives of the accessory devices splice into that diagram?

 

[wrcsixeight]

Okay but if you have anything connected to the (+) on theaux battery as diagramed in that photo, it is not going through the shunt, and is not going to be read by the monitor.

I'm thinking you should move both battery negatives to the same side of the shunt as an experiment. Then it will show the starter's draw, and the full alternators output, albeit to both batteries, but you will not know the percentage going to each.

Are all your auxiliary camping loads (+) all hooked directly to the auxiliary battery(by the diagram). Or are you using the vehicles stock ciggy plugs?

 

[RSB]

but shouldn't it as long as the NEG of the new thing is connected to the NEG on the shunt (system side, the red circled neg shown in the above diagram)?

remember, the monitor is only measuring the voltage of the 'aux' battery in the diagram. It's reading the amps, time remaining, etc. on the 'main' batt in the diagram (which is the batt I want to monitor).

Okay but if you have anything connected to the (+) on theaux battery as diagramed in that photo, it is not going through the shunt, and is not going to be read by the monitor.

ok..

I'm thinking you should move both battery negatives to the same side of the shunt as an experiment. Then it will show the starter's draw, and the full alternators output, albeit to both batteries, but you will not know the percentage going to each.

by Xantrex's diagram? No. The aux batt in the diagram is my starter batt. They're hooked directly to the 'main' batt (by the diagram), the batt I want monitored.

no accessories other than the starter/alternator are connected to the starter batt ('aux' batt by the diagram).

Are all your auxiliary camping loads (+) all hooked directly to the auxiliary battery(by the diagram). Or are you using the vehicles stock ciggy plugs?

 

[wrcsixeight]

I getting even more confused with your switching of the main and aux battery. The main battery is designed to be the engine battery, you have switched this, so you must place the loads and charging sources on the other side of the shunt as well.

The current you want to measure must flow through the shunt. Just keep reminding your self of this.

Any load/ charging source that is placed on the same side of the shunt as the battery, will not be measured in full. It will be pulling only some current across the shunt, not all of it, and less than 50%.

If both batteries are on the same side of the shunt, and all the loads/ charging sources are on the other, then all the current flow will be measured.

The national luna only connects the positives. The batteries will still be isolated with the engine off and batts under 13.2 or whatever the cut off is.

Some experimentation is in order to get the shunt to read what you want it to read.

I've got some errands to run...

 

[RSB]

ya, still trying to figure this one out too. But the Xantrex only measures the amp draw on one battery and that's the 'main' batt. Therefore, I had to be sure this was my house battery.

I getting even more confused with your switching of the main and aux battery. The main battery is designed to be the engine battery, you have switched this, so you must place the loads and charging sources on the other side of the shunt as well.

ok, this makes sense.

The current you want to measure must flow through the shunt. Just keep reminding your self of this.

also makes sense and is what I need to fix first. And Xantrex's diagram appears to be consistent with this.

Any load/ charging source that is placed on the same side of the shunt as the battery, will not be measured in full. It will be pulling only some current across the shunt, not all of it, and less than 50%.

ok, but this isn't what the Xantrex is capable of doing. It measures current flow of only 1 battery, not both. Only reads the voltage on the auxiliary.

If both batteries are on the same side of the shunt, and all the loads/ charging sources are on the other, then all the current flow will be measured.

interesting, wasn't aware NL did it that way.

The national luna only connects the positives. The batteries will still be isolated with the engine off and batts under 13.2 or whatever the cut off is.

indeed. And thank-you again for your added support with this. You've been most helpful! I just hope using the distribution blocks is alright.

Some experimentation is in order to get the shunt to read what you want it to read.

I've got some errands to run...

 

[wrcsixeight]

By the wiring diagram, it does appear as if the xantrex is designed to monitor only one battery, but in a vehicular charging system, both batteries share the same ground. This is where my confusion lies in the diagram, I believe.

When the NL parallels both batteries, both batteries are being charged, whether the shunt sees the full current or not. The NL system needs 2 thin, perhaps only 1 going to ground, sense wires to determine voltage, but it only parallels the positive cables AFAIK.

If it is only seeing 30 amps from the alternator, for 1 64 a/h battery, then that is perfectly acceptable. 6 to 12 amps is going to just run the vehicle, not including lights or blower motor, and a couple more amps are flowing into the engine battery. If the maximum it produces for both batteries were 30 amps then that is not really too bad either, but no way is it reading amps to both batteries if you have it wired according to the diagram.

You need to determine if the loads you place on the battery it is designed to read are showing up. You need to see if loads on the battery it is not designed to monitor are showing up.

Once again, experimentation is in order. I'd still suspect your engine battery, if it is dropping to 12.2, engine running, when the 11.0 volt house battery is paralleled, show the engine battery is weak, despite a resting voltage of 12.6.

DO you know anybody with a clamp on DC Ammeter?

 

[RSB]

ahhh. I see. Perhaps I'll run this by Xantrex today.

By the wiring diagram, it does appear as if the xantrex is designed to monitor only one battery, but in a vehicular charging system, both batteries share the same ground. This is where my confusion lies in the diagram, I believe.

ok.

When the NL parallels both batteries, both batteries are being charged, whether the shunt sees the full current or not. The NL system needs 2 thin, perhaps only 1 going to ground, sense wires to determine voltage, but it only parallels the positive cables AFAIK.

I'm going to move this one to a PM for now to keep things organized. Will re-post later for others to see following this thread.

If it is only seeing 30 amps from the alternator, for 1 64 a/h battery, then that is perfectly acceptable. 6 to 12 amps is going to just run the vehicle, not including lights or blower motor, and a couple more amps are flowing into the engine battery. If the maximum it produces for both batteries were 30 amps then that is not really too bad either, but no way is it reading amps to both batteries if you have it wired according to the diagram.

that I believe I have confirmed. When the solenoid is disconnected, I see amp draws under load on the monitored batt (Xantrex's 'main' batt in the diagram). Loads on the other batt do not show amp draw. Just a decrease in the voltage.

You need to determine if the loads you place on the battery it is designed to read are showing up. You need to see if loads on the battery it is not designed to monitor are showing up.

ok.

Once again, experimentation is in order. I'd still suspect your engine battery, if it is dropping to 12.2, engine running, when the 11.0 volt house battery is paralleled, show the engine battery is weak, despite a resting voltage of 12.6.

no, but I will get one.

DO you know anybody with a clamp on DC Ammeter?

 

[RSB]

w/the engine running, I can confirm this test passes. The difference is within 0.5 volts.

alt POS terminal & alt NEG mounting bolt: 14.3 volts
alt POS terminal & house batt NEG: 14.26 volts

While we can rule out your 1 and 0 gauge cabling itself as the cause for voltage drop, we cannot rule out the connectors on those cables.

Next time you have the batteries lower, test the voltage at the alternator terminals. Then test the voltage putting the negative probe on the house battery negative and the positive on the alternator. Even with a depleted house battery this should be within .5 volts of the first reading.

also, the shunt wiring has been fixed and I'm already observing better numbers. For example, instead of the winch drawing only 50 amps under load from the house batt, I'm observing 100+ NOT under load. I'm reading 15.5 amps from my dual 100 watt lights, and anywhere between 20.1-40 amps from my air compressor. These numbers are much higher than they were before and appear to be more consistent w/manufacturer specifications.

with the alt running from a cold start, I read the same amperage going into the batt around 40 amps.

I still need to use a clamp-on ammeter to read the alt directly—and the amperage going to the starter batt to confirm the alt is pushing what it should be.

once I can confirm the alt is working properly, I can finally conduct some rate of charge tests. :sombrero:

 

[RSB]

my apologies for being silent for over a month! Got a bit distracted in preparation for a few trips I've been on...

everything is still looking good, and my numbers appear to be consistent w/what I now understand I should expect to see. The charger brought everything back to normal, and I've since used it a few times. Finally, the monitor is beginning to register 'FULL'! Honestly, I still haven't tested the alt directly—and I haven't tested the amperage going to the starter batt to confirm the alt is pushing what it should be. I need to get that clamp-on ammeter! Then I can conduct some rate of charge tests, as I know I've sad before .

will advise soon. I need to get this done before it starts to get too cold!

also, a few posts back, I moved one of my discussions w/wrcsixeight to a PM in attempt to avoid confusion. Below are some key points from that discussion, for those of you interested...

If it is only seeing 30 amps from the alternator, for 1 64 a/h battery, then that is perfectly acceptable. 6 to 12 amps is going to just run the vehicle, not including lights or blower motor, and a couple more amps are flowing into the engine battery. If the maximum it produces for both batteries were 30 amps then that is not really too bad either, but no way is it reading amps to both batteries if you have it wired according to the diagram.

ok, the +30 amps was what I read on the monitored batt when the solenoid was connected and the alternator was running hot. It was close to 40 cold. So, from the alternator, the reading should be higher, right? 6-12 amps at least to run the truck, + the blower, lights, and other accessories. That would be a rough total of 46-52 amps from the alternator.

however, this is still only 56-65% of the alternators capability of 80 amps, or 66-74% of the 70 amps I thought I should be expecting at higher RPMs from a cold start with a deeply discharged house batt. This is acceptable? Or perhaps I'm not understanding what the 30 amps I'm reading on the monitor really consists of. How would it be different for a higher amp/hr batt vs. my 65?

If you are seeing 30 amps into the 1 battery, anywhere from 2 to 20 amps could be flowing into the engine battery(clamp on DC ammeter), and another 6 to 15 amps could be going just into the vehicles electrics like the computer, fuel pump, Ignition coil, electric fan, and the list goes on.

The alternators rated amperage is rarely ever met, and a useless number to go by.

The maximum I have seen with my "130 amp" alternator is ~107, and it was very short lived.

ahhhh. Now I get it. I didn't account for all those amps recharging the starter batt!