Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 23-04-2019, 09:40   #1
Registered User

Join Date: Aug 2011
Location: Everett, Washington
Boat: Yorktown 33
Posts: 18
low voltage reading

My 12 volt voltage meter on the panel is unstable and reads low (9-11 volts). The output of the circuit to my inverter reads 12 volts. Measured with my crude analog volt meter...

I replaced the voltage meter in the panel, but still the same problem.

All systems (pumps, lights, starter motor...) seem to work fine, which wouldn't happen on a 9 volt depleted battery.

Am I leaking voltage? How best to test and isolate?
__________________

joehixon is offline   Reply With Quote
Old 23-04-2019, 10:05   #2
Registered User
 
AndyEss's Avatar

Join Date: Dec 2016
Location: Sea of Cortez/northern Utah/ Wisconsin/ La Paz, BCS
Boat: Hans Christian 38 Mk II
Posts: 381
Images: 1
Re: low voltage reading

Sounds like you have corrosion on some connection. Go through the positive and negative feeds to the voltmeter and clean/replace connections.
You should provide voltages to one decimal place (i.e 12.9 volts).
Buy a DVM, they are pretty inexpensive, the analog voltmeter is pretty useless.
__________________

AndyEss is offline   Reply With Quote
Old 23-04-2019, 11:04   #3
Registered User
 
Spot's Avatar

Join Date: Jan 2019
Location: Minnesota, USA
Boat: 21' trailer sailor & 8' sailing dinghy
Posts: 241
Re: low voltage reading

I always read the battery directly with a portable meter (probe the battery terminals, not the connectors or cables) before I check anything downstream.
After that, you could probe the panel meter on its terminals with the portable meter and see if they see the same voltage. Then go through the connections as Andy described to remedy the loss.
__________________
Big dreams, small boats...
Spot is offline   Reply With Quote
Old 23-04-2019, 13:17   #4
Registered User

Join Date: Apr 2017
Location: Hingham
Boat: Dickerson 37AC
Posts: 454
Re: low voltage reading

Agree with everyone else. I only use Fluke meters but its a buy once cry once purchase. I use them at my company all the time so justified decision.

Ive found a really handy tool to have is a 20' piece of 14AWG wire with crimped on alligator clips. Then i can trace wire leads almost anywhere on the boat. One end of alligator clip goes on one end and the other clips to meter lead. Then i can probe around and get readings. Basically a lead extender. My fluke allows me to zero out the resistance in the 20' wire so i can measure things as if it werent there. Takes up no space and also serves as emergency wire if you need it.

Cheap multimeters never seem to work out for me, that goes for all cheap tools. A boat is the last place i want junk tools that I rely on. Your mileage may vary.
sailah is offline   Reply With Quote
Old 23-04-2019, 15:57   #5
Registered User
 
AndyEss's Avatar

Join Date: Dec 2016
Location: Sea of Cortez/northern Utah/ Wisconsin/ La Paz, BCS
Boat: Hans Christian 38 Mk II
Posts: 381
Images: 1
Re: low voltage reading

Quote:
Originally Posted by sailah View Post
Agree with everyone else. I only use Fluke meters but its a buy once cry once purchase. I use them at my company all the time so justified decision.

Ive found a really handy tool to have is a 20' piece of 14AWG wire with crimped on alligator clips. Then i can trace wire leads almost anywhere on the boat. One end of alligator clip goes on one end and the other clips to meter lead. Then i can probe around and get readings. Basically a lead extender. My fluke allows me to zero out the resistance in the 20' wire so i can measure things as if it werent there. Takes up no space and also serves as emergency wire if you need it.

Cheap multimeters never seem to work out for me, that goes for all cheap tools. A boat is the last place i want junk tools that I rely on. Your mileage may vary.
I like your long lead extender with alligator clips. Most pre-made extension clips are only 2-3 ft long.

I will disagree about using a Fluke or other bench test electronic equipment for 95% of all DIY boat work.

I also used a 4-1/2 digit high end Fluke for my business (I'm now retired) designing and building strain gage instrumentation. A Rolls Royce for business use is often justified.

I was suggesting inexpensive DVMs (not cheap) as these are more than adequate for wiring work. I also recommended that the DVM (and all other tools) be 100% dedicated to the boat, and not travel back and forth to home, to work, or for other projects like working on cars.

There's another thread active today about forgetting things at home, in your car, on the dock. The stories included wives and friends being left behind.

There's nothing worse on a boat in having an emergency and finding out you left your traveling toolbox at home.

I also sail saltwater. Corrosion is always an issue. I have no qualms about running out and buying a $25-55 DVM if my one has died. I can say that even my $25 DVMs have lasted for decades, with little degradation in quality.
As for zeroing, most $25 DVMs have this, and all $55 DVMs have this, plus clamp on ammeters, etc.

Because of my business, I did have to equip 5 different mobile pieces of equipment with full sets of tools. The brute strength 1/2 inch socket sets were always the best. Other tools were appropriate for field checks and minor repairs. Most heavy duty high end equipment stayed in the shop. The mandatory rule was that each piece of equipment had its own, dedicated set of tools and nothing was moved back and forth. IMO, my boat needs its own set of tools.

Every solution doesn't have to be a Rolls Royce. Especially when the OP was talking about replacing bell wire and mis-wiring a ciggie socket, and using a incandescent bulb as his wiring check. You wouldn't buy a carbon frame bike to teach someone to ride a bicycle, would you? A Corvette for a new driver?

I do stay away from total carp though - and over the yeas have learned to recognize carppy tools and such.
AndyEss is offline   Reply With Quote
Old 23-04-2019, 17:14   #6
Registered User

Join Date: Apr 2017
Location: Hingham
Boat: Dickerson 37AC
Posts: 454
Re: low voltage reading

I use a Fluke 79 dedicated to the boat. Bought used on ebay for $50. I trust it and thats something i can't say for any Chinese DMMs.

Sometimes i use one of my Fluke 179 because it has peak capture and backlight which comes in super handy.

Yes overkill for most but ive been burned by cheap tools so now i only use what i trust.

Speaking of overkill, i used my $20k Keysight N6705 to power my Balmar regulator today because it was on my desk lol. But it was cool to see the power draw...

Ive bought enough cheap DMMs that i have tossed to buy a nice new Fluke. And all my flukes work and stay in calibration.
sailah is offline   Reply With Quote
Old 23-04-2019, 17:37   #7
Registered User
 
AndyEss's Avatar

Join Date: Dec 2016
Location: Sea of Cortez/northern Utah/ Wisconsin/ La Paz, BCS
Boat: Hans Christian 38 Mk II
Posts: 381
Images: 1
Re: low voltage reading

Well, if you got it on Ebay (and it worked) for $50 - it's exactly in the price range of the inexpensive DVMs I was suggesting.
I had two Radio Shack DVMs I bought in the late 80s for about $30 each. One still works and they were a part of my maintenance tool kits. By today's standards they were crappy, but they took a lickin and kept on tickin (old Timex watch commercial jingle).
The Fluke (which is in my shop 1500 miles away so I can't see the model #) was $800 new. I bought it at a bricks and mortar auction in 1989 for the price of a metal lab bench I wanted. The DVM was in a drawer. Most of the other bidders were into the machine shop tooling that was being auctioned off, and could care less about DVMs. I got the lab bench and the very, very nice 4-1/2 digit DVM for $75 from memory.
As long as you have budget and experience with what you are buying, more power to you. Beginners need to start slow, and gain experience.
Good to hear you know what you are about.
__________________

AndyEss is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Low voltage vs higer voltage solar Singleprop Electrical: Batteries, Generators & Solar 11 06-07-2015 19:35
Low voltage reading on turned off circuit. RDW Electrical: Batteries, Generators & Solar 27 15-11-2014 17:12
Floating Ground on Aluminum Boat: Voltage Reading? msponer Electrical: Batteries, Generators & Solar 15 31-08-2013 05:44
Link 10 showing 0.05V on a voltage reading. phorvati Electrical: Batteries, Generators & Solar 7 25-06-2012 06:45
Voltage reading battery/fuse board seafox Electrical: Batteries, Generators & Solar 14 28-07-2007 17:52



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:15.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.