Cruisers Forum
 


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 28-12-2017, 01:02   #1
Registered User
 
daletournier's Avatar

Join Date: Jan 2012
Location: Australia
Boat: Catalina 470
Posts: 4,578
Shunt wiring

Always something to learn!

My xantrex lite seemed to be inaccurate (Ah) the other morning. I've been meaning to give all the terminals and connections around the battery a good clean for a while . The little screws that attach the the xantrex to the shunt didn't look great. Anyway they snapped off completely upon undoing them.

My understanding is a shunt provides a small resistance to current and the tiny voltage drop is measured and the meter magically determines current in and out?

The option to fix them in the original position is no longer. I put bigger terminals on them and attached them to either end of the shunt where the negative wires attach. Obviously dosent work, meter told me I was pulling 32A,which is about 30A to much!

I'm assuming the distance between the wires on the shunt matters, the meters calibrated to a certain distance between the wires ?? I actually have no idea, anyone know?

Also, I'm purchasing a new battery monitor for my bluesky regs, although it comes with a new shunt it doesn't come with the twisted wire. The wire I'm currently using isn't long enough to reach where I need to put the monitor.

My question, wire is the wire twisted? Can I get any thin wire and twist it up with a drill? Or is there something special about that particular wire?

It's difficult for me to get some stuff in the Seychelles, there's no zip code so online buying systems don't accept any my orders. Defender is great, their customer service via email gets me most things, but not all.

Thanks in advance.
daletournier is offline   Reply With Quote
Old 28-12-2017, 01:29   #2
Moderator and Certifiable Refitter
 
Wotname's Avatar

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,304
Re: Shunt wiring

Quote:
Originally Posted by daletournier View Post
Always something to learn!

My xantrex lite seemed to be inaccurate (Ah) the other morning. I've been meaning to give all the terminals and connections around the battery a good clean for a while . The little screws that attach the the xantrex to the shunt didn't look great. Anyway they snapped off completely upon undoing them.

My understanding is a shunt provides a small resistance to current and the tiny voltage drop is measured and the meter magically determines current in and out?

The option to fix them in the original position is no longer. I put bigger terminals on them and attached them to either end of the shunt where the negative wires attach. Obviously dosent work, meter told me I was pulling 32A,which is about 30A to much!

I'm assuming the distance between the wires on the shunt matters, the meters calibrated to a certain distance between the wires ?? I actually have no idea, anyone know?
It is calibrated to the resistance of the shunt e.g. an 100 Amp shunt might produce a voltage drop of say 50 mV (or perhaps 75 or even 100 mV)
Also, I'm purchasing a new battery monitor for my bluesky regs, although it comes with a new shunt it doesn't come with the twisted wire. The wire I'm currently using isn't long enough to reach where I need to put the monitor.

My question, wire is the wire twisted? Can I get any thin wire and twist it up with a drill? Or is there something special about that particular wire?
Yes
It's difficult for me to get some stuff in the Seychelles, there's no zip code so online buying systems don't accept any my orders. Defender is great, their customer service via email gets me most things, but not all.

Thanks in advance.
Sorry don't have time right now to write more: others will chime in and expand the information.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 28-12-2017, 01:51   #3
Registered User

Join Date: Jul 2005
Location: Bellingham
Boat: Outbound 44
Posts: 9,319
Re: Shunt wiring

If the meter is reading significantly more amps than it should, that means it is seeing a larger voltage drop across the sense wires. This can be caused by poor connections at either end.
__________________
Paul
Paul L is offline   Reply With Quote
Old 28-12-2017, 02:05   #4
Registered User
 
daletournier's Avatar

Join Date: Jan 2012
Location: Australia
Boat: Catalina 470
Posts: 4,578
Re: Shunt wiring

Quote:
Originally Posted by Paul L View Post
If the meter is reading significantly more amps than it should, that means it is seeing a larger voltage drop across the sense wires. This can be caused by poor connections at either end.
Hi Paul, I've put the connectors on top of the negative cables, was just thinking this would be extra resistance. I'll put them at the bottom this afternoon and see if there's a difference. It's a temporary thing until new monitor turns up, if I can get around the zip code thing.
daletournier is offline   Reply With Quote
Old 28-12-2017, 02:25   #5
Registered User

Join Date: Jul 2005
Location: Bellingham
Boat: Outbound 44
Posts: 9,319
Re: Shunt wiring

Quote:
Originally Posted by daletournier View Post
Hi Paul, I've put the connectors on top of the negative cables, was just thinking this would be extra resistance. I'll put them at the bottom this afternoon and see if there's a difference. It's a temporary thing until new monitor turns up, if I can get around the zip code thing.
Make sure the crimps are good and clean the studs and connector.
__________________
Paul
Paul L is offline   Reply With Quote
Old 28-12-2017, 02:47   #6
Registered User
 
CatNewBee's Avatar

Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 3,755
Images: 3
Re: Shunt wiring

Quote:
Originally Posted by Paul L View Post
Make sure the crimps are good and clean the studs and connector.
I do not know what type of shunt you have, but I assume the resistor wire in the shunt has a bad connection to the terminals, so internal resistance is higher and therefore the voltage drop is higher too. If you cannot fix it by cleaning and fastening of the terminals you probably will need to replace the shunt.
CatNewBee is offline   Reply With Quote
Old 28-12-2017, 02:48   #7
Registered User
 
daletournier's Avatar

Join Date: Jan 2012
Location: Australia
Boat: Catalina 470
Posts: 4,578
Re: Shunt wiring

Quote:
Originally Posted by Paul L View Post
Make sure the crimps are good and clean the studs and connector.
Will do. It sounds crazy but there's some simple stuff I just haven't got around to yet. Purchased the boat 12mths ago, quick refit, made sure I was happy she was safe and then took off across the Indian ocean, I've been cruising full time since, approximately 7500nm. I'm now on the boat alone for two mths and plan to do all the little jobs that I haven't got around to, not going to move,looking forward to it.
daletournier is offline   Reply With Quote
Old 28-12-2017, 05:28   #8
Registered User
 
daletournier's Avatar

Join Date: Jan 2012
Location: Australia
Boat: Catalina 470
Posts: 4,578
Re: Shunt wiring

Thanks guys, sorted. Simple clean up of terminals Duh!
daletournier is offline   Reply With Quote
Old 28-12-2017, 05:47   #9
Zil
Registered User

Join Date: Mar 2013
Location: South Jersey
Posts: 361
Re: Shunt wiring

My Victron does not have twisted wire for the shunt to meter.
Zil is offline   Reply With Quote
Old 28-12-2017, 06:56   #10
Registered User
 
Hartleyg's Avatar

Join Date: Mar 2014
Location: Atlantic Ocean
Boat: Tayana 48DS 48'
Posts: 326
Images: 8
Re: twisted Shunt wiring

The reason the wire is twisted is to provide resistance to interference from radio transmissions - primarily HF (SSB). If you don't have an SSB or you don't see the current meter go wild when you transmit, don't worry about it

Hartley
S/V Atsa
Hartleyg is offline   Reply With Quote
Old 28-12-2017, 07:37   #11
Registered User
 
daletournier's Avatar

Join Date: Jan 2012
Location: Australia
Boat: Catalina 470
Posts: 4,578
Re: Shunt wiring

Ive also seen them insulated like coaxial cable, silver foil insulation.
daletournier is offline   Reply With Quote
Old 28-12-2017, 07:56   #12
Registered User
 
CatNewBee's Avatar

Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 3,755
Images: 3
Re: Shunt wiring

CAT5e cable is shielded twisted pair cable (4 pairs), also telephony cable is TP.
CatNewBee is offline   Reply With Quote
Old 28-12-2017, 10:34   #13
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
Shunt wiring

Quote:
Originally Posted by daletournier View Post
Hi Paul, I've put the connectors on top of the negative cables, was just thinking this would be extra resistance. I'll put them at the bottom this afternoon and see if there's a difference. It's a temporary thing until new monitor turns up, if I can get around the zip code thing.


This will not work. There are 4 connections to a shunt. 2 are high current connections. 2 are just for measuring the voltage which is related to current. The big connections can never give the right voltage and the current measured will always be wrong and and it will vary too much with temperature.

Either fix the small broken connections or get a new shunt.
transmitterdan is offline   Reply With Quote
Old 28-12-2017, 10:46   #14
Senior Cruiser
 
BlackHeron's Avatar

Join Date: Jan 2016
Boat: Bathtub
Posts: 889
Images: 19
Re: Shunt wiring

Like others have said, the wire doesn't need to be twisted unless you are picking up interference from a SSB or other device on the boat that is creating radio interference. You can reuse the old twisted wire and just extend it a few inches or feet if it isn't long enough to reach the new shunt using untwisted wire and it shouldn't make much of a difference over that short untwisted distance.

You can also twist wire with a battery drill if you want to as well to create a twisted duplex (or triplex, whatever.) The rate of twist in the wires is calculated not to be "in tune" with the frequencies they are trying to suppress. If you count the number of twists over given number of inches or cm, you can replicate the twist fairly closely if your wire will hold the twist after it is wrapped. Some wire tends to spring back some, some springs back a lot and won't hold a twist. It depends on how many and how fine the strands are inside. Be aware that if you make your own twisted wire it will 'shrink' when it is twisted and not reach as far since it is now taking a spiral path instead of a straight line from point A to point B. The amount of shrinkage can be significant so be sure to buy extra wire if you make your own twisted cable runs.
BlackHeron is offline   Reply With Quote
Old 28-12-2017, 12:22   #15
Registered User

Join Date: Oct 2016
Location: Southeast Alaska
Boat: Allweather 26
Posts: 85
Re: Shunt wiring

I have a little bit unrelated question. Is a shunt generic other than amp rating? Can a various amp meters be connected to a shunt? Only one connected at a time of course.
fritzdfk is offline   Reply With Quote
Reply

Tags
wiring

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
Want To Buy: Link 2000 with Shunt - 84-2000-06 yacht_planb Classifieds Archive 2 21-02-2010 12:44
Location of Shunt bobelon Electrical: Batteries, Generators & Solar 9 27-03-2009 12:11
Battery Shunt ? ? ? S/V Mother Ocean Electrical: Batteries, Generators & Solar 5 22-10-2008 09:32
Battery Shunt ? ? ? S/V Mother Ocean Multihull Sailboats 3 21-10-2008 18:22
link 10 shunt on +? Ryan Electrical: Batteries, Generators & Solar 6 27-09-2005 14:17

Advertise Here


All times are GMT -7. The time now is 16:24.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.