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lndwarrior

Well Known Member
Newly complete with only 2 hours of taxiing on the Hobbs. Lycoming O-235 engine, Brand new B&C 40 amp alternator, VR 166 external voltage regulator, 40 amp ammeter shunt wired to an ammeter gauge on the panel.

My wiring diagram is a almost direct copy of Bob Nichols Z-11 diagram.

Engine starts and runs fine.

Ammeter reads 0 at all times, even with the engine running AND when I pull the Alt. field circuit breaker.

While I put the "copied" wiring diagram together and installed the system - I am really a complete newbie to wiring issues.

I simply don't know where to begin to trouble shoot this problem.

I've done some research online and comments like "test the vr" or "test the alternator" or test the field wire. My problem is I just don't know HOW to do this.

I'm afraid I'll fry something if I test it wrong.

I would really appreciate any help - with very simple explanations of how to trouble shoot this problem.

TIA
Gary
 
First find out if the alternator is doing anything. Put a multimeter (Harbor Freight $3.99 type is fine) across the battery. You should read 12.4vdc or so with the engine off, 14.1vdc or so with the engine on. If this is what you have, then your amp meter is not working or not connected properly. If the battery voltage stays at 12.4vdc or so with the engine running, you have not wired the alternator and/or voltage regular correctly.

Carl
 
Carl Froehlich said:
First find out if the alternator is doing anything. Put a multimeter (Harbor Freight $3.99 type is fine) across the battery. You should read 12.4vdc or so with the engine off, 14.1vdc or so with the engine on. If this is what you have, then your amp meter is not working or not connected properly. If the battery voltage stays at 12.4vdc or so with the engine running, you have not wired the alternator and/or voltage regular correctly.

Carl
Click to expand...

Thanks for the reply.

I'm pretty sure the wiring itself is correct. If so, then i don't have continuity in one of the wires, which I've checked. So that leaves me wondering if the alternator the ammeter or the Voltage regulator is not working. How would I go about getting these?
 
lndwarrior said:
Thanks for the reply.

I'm pretty sure the wiring itself is correct. If so, then i don't have continuity in one of the wires, which I've checked. So that leaves me wondering if the alternator the ammeter or the Voltage regulator is not working. How would I go about getting these?
Click to expand...

There is no helping you until you answer the voltage question. That will tell whether or not the Alt / VR combo is working or not and narrow down the diagnostic steps.
 
lr172 said:
There is no helping you until you answer the voltage question. That will tell whether or not the Alt / VR combo is working or not and narrow down the diagnostic steps.
Click to expand...

" If this is what you have, then your amp meter is not working or not connected properly. If the battery voltage stays at 12.4vdc or so with the engine running, you have not wired the alternator and/or voltage regular correctly."

OK,. But wouldn't the results be the same if the alternator or the Voltage regulator didn't work? ie: no charge indicated at the battery?

Also, you could help me before i did the first test. Without going into an explanation, I can check some things on the plane this week , but I can't start the engine until this weekend. ie; Can't I do some tests on the Voltage regulator or alternator to see if they may be the culprits in the mean time???

Sometimes you have to do what you are able to, whether or not it's in the right order.
 
Carl nailed it, there is no point in troubleshooting until you know what to troubleshoot, i.e., the ammeter or the charging system.
Your stuck until you take that first step.

Tim Andres
 
Looks like this has been an ongoing issue for you. I would say get somebody there to help you! Another set of eyes can be a wonderful thing.
 
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Aha, remember the good old days when you were in training and flying a Cessna 172, climbing out on a hot summer days , taking off and landing never knowing what the cylinder head were ??? And you felt Safe 😬 I'm just Say'n.
 
Step one, put a volt meter on the panel, a small digital one is less than 10.00 then we instantly know the health of our battery before we start, 12.6-12.8 for lead acid and 13.2 for Li ion then when we start, we know the health of our charging system 14.2ish
 
lndwarrior said:
" If this is what you have, then your amp meter is not working or not connected properly. If the battery voltage stays at 12.4vdc or so with the engine running, you have not wired the alternator and/or voltage regular correctly."

OK,. But wouldn't the results be the same if the alternator or the Voltage regulator didn't work? ie: no charge indicated at the battery?

Also, you could help me before i did the first test. Without going into an explanation, I can check some things on the plane this week , but I can't start the engine until this weekend. ie; Can't I do some tests on the Voltage regulator or alternator to see if they may be the culprits in the mean time???

Sometimes you have to do what you are able to, whether or not it's in the right order.
Click to expand...

Your Ammeter could read 0 for many reasons:

1 you wired it wrong
2 you set it up to measure the current in the wrong place
3 ammeter or shunt is bad
4 no charge current
a. because Alt is bad
b. because Alt is wired wrong
c. Voltage regulator is bad
d. Voltage regulator is wired wrong

As you can see, we could write a book on the troubleshooting steps / instructions. If you're looking for interactive assistance, you're going to have to follow some basic troubleshooting steps and here we need to start with a confirmation of the basics and that is to confirm that your alternator is charging the system (voltage tells us that).

If that doesn't work, I suggest you draw a detailed schematic of your wiring and post here for review. We can then help check that your wiring is correct and proper. However, that still won't help with a loose connection, poor crimp, etc.

Larry
 
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lndwarrior said:
OK,. But wouldn't the results be the same if the alternator or the Voltage regulator didn't work? ie: no charge indicated at the battery?

Also, you could help me before i did the first test. Without going into an explanation, I can check some things on the plane this week , but I can't start the engine until this weekend. ie; Can't I do some tests on the Voltage regulator or alternator to see if they may be the culprits in the mean time???

Sometimes you have to do what you are able to, whether or not it's in the right order.
Click to expand...

Let's break it down into some simple steps that you can perform with the engine not running. First, I need to know if you have a volt meter and know how to measure DC volts with it. If so, what is the battery voltage? If not, then we can get even more basic. You won't hurt anything by checking for voltage.

-Marc
Do you have a volt meter?
 
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