| [GMCnet] Ammeter [message #347222] |
Mon, 02 September 2019 14:22  |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
|
Senior Member |
|
|
I’ve been looking to add an ammeter to the house panel.
Most of the meters instructions have the shunt in the negative side of the circuit.
Any reason I could not put it on the positive?
I’m not clear on why they are listing it in the instructions that way.
Thanks.
Dolph Santorine
DE AD0LF
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
Howell EFI/EBL , Reaction Arms, Manny Transmission
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Ammeter [message #347223 is a reply to message #347222] |
Mon, 02 September 2019 14:30  |
Mike Kilroy
Messages: 80
Registered: July 2006
Location: Farmersville, OH (near D...
Karma: 0
|
Member |
|
|
Probablyl safety. If you put it on negative side and a wire shorts to
chassis, no big deal at all; if you put it on the positive side, a
shorted wire can burn down your coach. As for physics, both work the
same exact way.
On 2019-09-02 15:22, Adolph Santorine via Gmclist wrote:
> I've been looking to add an ammeter to the house panel.
>
> Most of the meters instructions have the shunt in the negative side of the circuit.
>
> Any reason I could not put it on the positive?
>
> I'm not clear on why they are listing it in the instructions that way.
>
> Thanks.
>
> Dolph Santorine
>
> DE AD0LF
>
> Wheeling, West Virginia
>
> 1977 ex-Palm Beach TZE167V100820
> Howell EFI/EBL , Reaction Arms, Manny Transmission
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Mike (AC8V) & Vickie Kilroy
'73 Canyon Land 26' sidebath
455/ceramic filled crossovers
|
|
|
|
| Re: [GMCnet] Ammeter [message #347239 is a reply to message #347222] |
Mon, 02 September 2019 17:59 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
|
Senior Member |
|
|
On Sep 2, 2019, at 3:22 PM, Adolph Santorine via Gmclist wrote:
> I’ve been looking to add an ammeter to the house panel. Most of the meters instructions have the shunt in the negative side of the circuit.
Another approach is to avoid the use of a shunt and instead use one of the snap-around hall-effect current transducers that can give you a 0-5V output proportional to current.
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
|
|
|
|
| Re: [GMCnet] Ammeter [message #347270 is a reply to message #347222] |
Tue, 03 September 2019 11:09 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
|
Senior Member |
|
|
I agree with the safety/burn down coach threat, as my 1975 apparently just missed burning to the ground at some point prior to my owning it. Full hot, unfused wire had been run through the firewall to the non-shunt style ammeter below the steering wheel. The evidence I found indicated that something around the gauge shorted, burning the gauge and a few inches along the wire path/plastic dash. It put itself out apparently once it burned what was providing the ground. When I discovered it, early in my coach learning curve, I gingerly went out and disconnected that wire (still intact and full 12 volt to the burned mess). Given that history, I'm going to learn more about the hall effect style mentioned by Jim should I ever decide I need one.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
|
|
|
|
| Re: [GMCnet] Ammeter [message #347293 is a reply to message #347222] |
Tue, 03 September 2019 20:07 |
 |
RF_Burns
Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada
Karma: 3
|
Senior Member |
|
|
The shunt needs to be in the negative line because the electronics measure the voltage drop the shunt with reference to the battery negative. So there will be a wire that picks up battery negative and positive and the voltage drop across the shunt. The voltage at the shunt's "output" will be slightly positive with respect to the battery negative when discharging (it will be opposite when charging).
If you put the shunt in the positive line, then the voltage drop will be referenced to the battery positive terminal. If the shunt is just used to extend the current range of a common series ammeter, it should work fine, proved to keep the ammeter polarity in mine as well.
If the shunt is feeding an electronic ammeter or battery condition monitor, you need to put it where the manufacturer specifies for it to work properly.
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
