Volt ammeter issue

[lrrowe]

I was correct I drew a new simple diagram, hope it helps.

rps20151105_201238.jpg

Thanks again. And ypur sketch is different then the photo. Glad I waited. You were sure up late last night based on the time stamp.

Now for another confusion moment. I want to meausre the total load from the batteries to all loads, not just one load. Imwill play with examples to see what I come up with.

[Breytie]

I see one possible reason for the error-like display. In the initial diagram the power supply is shown completely separate from the main battery and load - ie completely floating. In your diagram the load battery is also the power supply. Try to use a separate battery to power the module and see what happens.

Good luck
Andre

[lrrowe]

Breytie,

The error message was from a different volt/ammeter then these last two photos/sketches. For this newer gauge, I am not sure how to wire it regardless if I use the system battery or separate battery. My confusion comes in the definition of the "load" that Graniterich shows in his sketch. Even though the meter is supposed to have a built in shunt, I do not see how to wire it without one.

[Breytie]

Breytie,

The error message was from a different volt/ammeter then these last two photos/sketches. For this newer gauge, I am not sure how to wire it regardless if I use the system battery or separate battery. My confusion comes in the definition of the "load" that Graniterich shows in his sketch. Even though the meter is supposed to have a built in shunt, I do not see how to wire it without one.

From what I can see in the sketch, the internal shunt is located between LOAD- and BATT-.
LOAD will normally be the total 12V DC system powered from the battery. The LOAD+ connection would normally go to the +12V bus bar and hence to the fuses/breakers while the -LOAD connection would go to the -12V bus bar and hence to the loads. That means the meter module must be rated for the full expected system load current (plus a bit extra for safety).
Connecting the supply and BATT connection together may short out internal voltage references and other circuits causing weird readouts.

Hope that helps

Andre

[lrrowe]

Please excuse my lack of knowledge in this area. But if you are saying that I wire this meter in series between the battery and PD4045, for all the loads added up, I cannot believe this meter and small wires are adequate for up to, say 20 amps, or so.

Therefore I know I am misunderstanding something here.

It might be clearer if I can get Graniterich to take a photo of his actual installation if possible.

CORRECTION.
I just looked at the meter and see that it has no leads coming out of it, just terminal screws. So one could add large gaige wire. It looks like you could use maybe 10 gauge with it. But my battery wires are 4 gauge and I do not want to downsize them just for an amp meter.

BTW, the reason I ask Graniterich to post a photo of his install is because I believe I ordered the same meter as he has.

[Graniterich]

Mine is not visible without disassembly. You are correct that I used ten gauge wire, right after my main battery disconnect. Ten gauge handles fifty plus amps, I rarely exceed five amps. I do understand your concern about putting in line with four gauge

[lrrowe]

Mine is not visible without disassembly. You are correct that I used ten gauge wire, right after my main battery disconnect. Ten gauge handles fifty plus amps, I rarely exceed five amps. I do understand your concern about putting in line with four gauge

Thanks...and this makes me feel better as it shows I understood a little more then I was thinking I knew. I may have to go back to the shunt style meters and just add this one I am using for another project that may come up.

[Graniterich]

What is your max load? Do you have a refrigerator or inverter running off 12 volts?

[lrrowe]

I did have a refrigerator, 120v, but it died before I finished the wiring. I am now planning on getting a Truckfridge 12v unit early next year. And I will have an inverter should we want to run a microwave when camping with my wife while off the grid (maybe we will, maybe we will,not...time will tell). I want to keep the largest battery to PD4045 unit as I can, more for efficiency then capacity. Solar will come next spring. I think the cost for another meter with a shunt is not that big of a cost deal.

[Dale M.]

A little late with explanation but....

image.JPG (44.14 KiB) Viewed 3295 times

Dale

[lrrowe]

Thanks Dale,
No input is too late. Your sketch is what I am going to go with, but I need to get a new meter without a built in Shunt (at least I do not think I can use the one with a built in Shunt if it says it has one built in).

[Dale M.]

Whether the shunt is built in or external, concept is all the same.... For amperage reading to be correct the shunt has to match meter specification (for shunt)... For shunt, its important the load does not exceed "meter" specification (total amperage) so you don't "smoke" shunt and meter ...

Dale

[Graniterich]

Problem I had was low current Accuracy on the cheap 100 amp external shunts, off by a factor of two below five amps.

[lrrowe]

That is not good.

But I think I need to stay with the external shunt style because of the wire size I use (4 ga).
I am willing to spend more to get accuracy. What about the analog dial single purpose style (Volt and Amps separate)?
Maybe others might submit their experiences also.

[H.A.]

.&.