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Erratic voltage readings on EMON II

PostPosted: Mon Jul 23, 2012 1:29 pm
by SheltieJim
When I purchased my sailboat, it had an EMON II installed (H1 variant), as well as a Next Step regulator. A couple of years ago, the Next Step regulator went bad, so I replaced it with an SAR v3.

A couple of months ago, the EMON II started reporting erratic, and often wildly incorrect, voltages on the second battery bank (which is my starting bank). For example, I have connected a multimeter directly to the second battery bank (two T145 6 volt batteries in series) and observed the multimeter indicating (e.g.) 12.6 volts while the EMON II indicates anywhere between 3.5 volts and 12.6 volts. I've got my EMON II set up so that it cycles through 5 or 6 different measurements at intervals of 2 seconds each. The "bank 2 voltage" changes radically each time through the cycle. I've not been able to notice any pattern in what voltages are displayed.

I've carefully checked all cables and connections that connect between the second battery bank, the EMON II, etc. I found no evidence of loose connections nor of corroded cables.

Can you suggest what I should example, inspect, measure, test, etc. to track down the cause of these erratic readings?

Re: Erratic voltage readings on EMON II

PostPosted: Mon Jul 23, 2012 1:31 pm
by SheltieJim
"what I should EXAMINE" (not "example").

Re: Erratic voltage readings on EMON II

PostPosted: Mon Jul 23, 2012 2:06 pm
by Coulomb
Clean the in-line fuse and fuse holder from the starter battery to the monitor.

Re: Erratic voltage readings on EMON II

PostPosted: Sun Jul 29, 2012 12:43 pm
by SheltieJim
I'll be on my boat later this week and will do this right away. If that does the job, then I'll confirm it here with my thanks. If not, I'll ask for additional ideas. Thanks!

Coulomb wrote:Clean the in-line fuse and fuse holder from the starter battery to the monitor.