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Spark when testing batteries


Gary M
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Got my coach out of shop yesterday. Since it sat there for two weeks I decided to just check volts in house and engine batteries with my VOM. First ground lead then positive and got a spark on both sets. Is the problem my VOM or is it something else? 
Tried testing a truck battery and the VOM did not register. So its now either dead or maybe fuse inside if there is one.

Cheap Cen-Tech VOM by the way but dont want to use my good VOM and screw it up too.

Any help appreciated.

Edited by Gary M
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23 minutes ago, Gary M said:

Got my coach out of shop yesterday. Since it sat there for two weeks I decided to just check volts in house and engine batteries with my VOM. First ground lead then positive and got a spark on both sets. Is the problem my VOM or is it something else? 
Tried testing a truck battery and the VOM did not register. So its now either dead or maybe fuse inside if there is one.

Cheap Cen-Tech VOM by the way but dont want to use my good VOM and screw it up too.

Any help appreciated.

So what is your question???

At a hundred to three hundred dollars a batterie, I wouldn't use anything but a decent meter 

You can make one for a few $$$s with parts from an auto parts store.

Or buy real nice ones for not many $$$s

Call triple A if you don't want to use your meter 

 

 

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Is it a digital meter with a screen for the numbers?   I imagine it is,  anyway the only way the meter should spark is if it's on the wrong setting,  probably set for amps.   If it was, that probably ruined the meter or at least a fuse inside.

Edited by Ray Davis
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22 minutes ago, John Haggard said:

So what is your question???

At a hundred to three hundred dollars a batterie, I wouldn't use anything but a decent meter 

You can make one for a few $$$s with parts from an auto parts store.

Or buy real nice ones for not many $$$s

Call triple A if you don't want to use your meter 

 

 

Sorry my question was in the middle of the post.

Could problem be batteries or VOM which is causing spark. It didn’t spark when I tested truck batts. Why would it only spark on coach batts?

4 minutes ago, Ray Davis said:

Is it a digital meter with a screen for the numbers?   I imagine it is,  anyway the only way the meter should spark is if it's on the wrong setting,  probably set for amps.   If it was, that probably ruined the meter or at least a fuse inside.

It was set on 20 DCV. It sparks on coach batts but not truck batteries.

image.jpg

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Turn your battery switches off.

Turn your inverter off.

 

Remove the ground wire from the batteries. 

Let sit for 30 to 60 minutes without any charge.

 

Then re test and see what happens 

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Well not sure what happened but my good VOM doesn’t have a problem with checking batteries. 12.7 engine, 12.4 house. Fixed my own issue I guess. Human error????

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33 minutes ago, Gary M said:

Well not sure what happened but my good VOM doesn’t have a problem with checking batteries. 12.7 engine, 12.4 house. Fixed my own issue I guess. Human error????

Is that reading during charge 🤔

If so.

It won't tell you the health of the batteries. 

Just the charge they are receiving 

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Gary, the spark indicated that current somehow flowed in your meter test circuit. You probably blew the typical 10 amp fuse in the meter. Easy to replace. The truth about most all handheld digital multimeters is that they all use the same type of transistor which probably cost about a nickel in bulk lots. I once checked a $30.00 Harbor Freight meter against a $5000.00 test bench instrument and found that they agreed to 1 and 2 significant digits ( the resolution limit of the cheap meter) when measuring the 3 basic functions.  An insignificant difference giving what most people use a meter for. What one should look for in an inexpensive meter is one with a button, usually labeled REL, which is used to zero out resistance in the internal circuit and the test leads,  Which in turn compensates for cheap leads, rotary dials, and other assorted things. I've seen $60.00 meters with this function. 

 

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6 hours ago, Gary Cole said:

Gary, the spark indicated that current somehow flowed in your meter test circuit. You probably blew the typical 10 amp fuse in the meter. Easy to replace. The truth about most all handheld digital multimeters is that they all use the same type of transistor which probably cost about a nickel in bulk lots. I once checked a $30.00 Harbor Freight meter against a $5000.00 test bench instrument and found that they agreed to 1 and 2 significant digits ( the resolution limit of the cheap meter) when measuring the 3 basic functions.  An insignificant difference giving what most people use a meter for. What one should look for in an inexpensive meter is one with a button, usually labeled REL, which is used to zero out resistance in the internal circuit and the test leads,  Which in turn compensates for cheap leads, rotary dials, and other assorted things. I've seen $60.00 meters with this function. 

 

Ya know I appreciate all comments but what ever I did all is well including my cheap VOM meter. I checked it with engine running to se out put of alternator. I checked it with gen running  to see charge rate. Checked it with all off. 

4 hours ago, Rikadoo said:

Perhaps, looking at your picture if you had your red lead in the amp hole rather than the voltage hole that could be a issue

I agree but what u see is how it was.

4 hours ago, Rikadoo said:

Perhaps, looking at your picture if you had your red lead in the amp hole rather than the voltage hole that could be a issue

It is in volt hole. Other above is amps.

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11 minutes ago, Gary M said:

Ya know I appreciate all comments but what ever I did all is well including my cheap VOM meter. I checked it with engine running to se out put of alternator. I checked it with gen running  to see charge rate. Checked it with all off. 

I agree but what u see is how it was.

It is in volt hole. Other above is amps.

Right on Gary 

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