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Topic: VMSpc Battery Voltage Indication (Read 474 times) previous topic - next topic

VMSpc Battery Voltage Indication

Is the battery voltage displayed on the VMSpc indicating the alternator output? or just the battery voltage? It is showing 12.6 (with engine running) volts which I think is too low for either.
OH

Re: VMSpc Battery Voltage Indication

Reply #1 –
My DC voltage read low also, so I hooked my DVM directly to the engine battery set and adjusted to 13.8 volts while on fast idle.  Now the VMSpc also reads the same.

Re: VMSpc Battery Voltage Indication

Reply #2 –
Dave, I believe that 13.8 volts with alternator charging is too low.

I set mine to 14.3 volts and find that my DVM (inexpensive) does not provide a reliable reading. I use a large face analog meter with a needle and notice that it fluctuates about 0.15 volts constantly.

My Reece Neville alternator has the three step regulator, which I set to 14.2v (mid), then added a resistor to the sense wire to obtain 14.3v.

The AGM battery manufacturer recommends 14.4 or higher but I also have a Gel battery. I tried 14.1v but found the batteries were undercharged after driving with the fridge powered by the inverter. 

I have never read the VMSpc voltage but am curious how it compares to the analog meter.



 

Re: VMSpc Battery Voltage Indication

Reply #3 –
Quote from: Old Hippie –
Is the battery voltage displayed on the VMSpc indicating the alternator output? or just the battery voltage? It is showing 12.6 (with engine running) volts which I think is too low for either.
OH
My VMSpc got down to that mid 12 voltage...and that was my first clue that my alternator needed rebuilding.  I had them set the regulator to 14.0 and have been happy sine.  My VMSpc usually varies from 13.8-14.0 while driving.

Re: VMSpc Battery Voltage Indication

Reply #4 –
My normal saying is "Do what makes you happy".  Along that line, I use a Fluke 87, (Have four of then)  I trust them over 99.9999% of the analog sweep needle meters including my Triplett and Simpson 260.
Could have said that the charge was set to 13.784, I said 13.8. Will try to be more precise.
I read the Battery, not the alternator output .
Yes, I am happy ;D

Re: VMSpc Battery Voltage Indication

Reply #5 –
12.9 VMSpc
13.45 Link2000

13.2 MidNite Controller

best, paul