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Home » Public Forums » GMCnet » [GMCnet] Stock gauges. How to calibrate. As you just don't really know the real temp, or oil pressure numbers.
Re: [GMCnet] Stock gauges. How to calibrate. As you just don't really know the real temp, or oil pressure numbers. [message #329168 is a reply to message #329126] Thu, 15 February 2018 10:00 Go to previous messageGo to next message
Bill Van Vlack is currently offline  Bill Van Vlack   United States
Messages: 419
Registered: September 2015
Location: Guemes Island, Washington
Karma: 14
Senior Member
Johnny Bridges wrote on Wed, 14 February 2018 08:12
Is that 13.9 the float voltage of a charged chassis battery drawing maybe 4 -5 Amps at float, or a battery with a dead cell drawing 40 Amps?

--johnny


I read that as "A voltmeter that reads 13.9 volts does not tell you the condition of the battery, but an ammeter will."


Bill Van Vlack '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.
Re: [GMCnet] Stock gauges. How to calibrate. As you just don't really know the real temp, or oil pressure numbers. [message #329172 is a reply to message #329168] Thu, 15 February 2018 11:14 Go to previous messageGo to next message
k2gkk is currently offline  k2gkk   United States
Messages: 4452
Registered: November 2009
Karma: -8
Senior Member
IMHO, you really need both current AND voltage meters plus knowledge of how to interpret what you see to truly indicate battery condition. AND, there is no such thing as instantaneous results without some serious analysis equipment.


D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com


________________________________
From: Gmclist on behalf of Bill Van Vlack
Sent: Thursday, February 15, 2018 10:00
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Stock gauges. How to calibrate. As you just don't really know the real temp, or oil pressure numbers.

Johnny Bridges wrote on Wed, 14 February 2018 08:12
> Is that 13.9 the float voltage of a charged chassis battery drawing maybe 4 -5 Amps at float, or a battery with a dead cell drawing 40 Amps?
>
> --johnny


I read that as "A voltmeter that reads 13.9 volts does not tell you the condition of the battery, but an ammeter will."
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.

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Re: [GMCnet] Stock gauges. How to calibrate. As you just don't really know the real temp, or oil pressure numbers. [message #329175 is a reply to message #329172] Thu, 15 February 2018 13:33 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
Senior Member
Keith V,
I can tell you at OU, or classes were so into solving math equations, I did
not get the fundamental concepts till I had the wind tunnel lab.
We knew more about a fluid going down a sink.

On Thu, Feb 15, 2018 at 9:14 AM, D C _Mac_ Macdonald
wrote:

> IMHO, you really need both current AND voltage meters plus knowledge of
> how to interpret what you see to truly indicate battery condition. AND,
> there is no such thing as instantaneous results without some serious
> analysis equipment.
>
>
> D C "Mac" Macdonald
> Amateur Radio K2GKK
> Since 30 November '53
> USAF and FAA, Retired
> Member GMCMI & Classics
> Oklahoma City, OK
> "The Money Pit"
> TZE166V101966
> '76 ex-Palm Beach
> k2gkk + hotmail dot com
>
>
> ________________________________
> From: Gmclist on behalf of Bill Van
> Vlack
> Sent: Thursday, February 15, 2018 10:00
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Stock gauges. How to calibrate. As you just don't
> really know the real temp, or oil pressure numbers.
>
> Johnny Bridges wrote on Wed, 14 February 2018 08:12
>> Is that 13.9 the float voltage of a charged chassis battery drawing
> maybe 4 -5 Amps at float, or a battery with a dead cell drawing 40 Amps?
>>
>> --johnny
>
>
> I read that as "A voltmeter that reads 13.9 volts does not tell you the
> condition of the battery, but an ammeter will."
> --
> Bill Van Vlack
> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
> mid November 2015.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>



--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Stock gauges. How to calibrate. As you just don't really know the real temp, or oil pressure numbers. [message #329179 is a reply to message #329071] Thu, 15 February 2018 17:30 Go to previous message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
I am going to jump in here again now that the subject has changed to batteries and the charging there of.....

What I learned most of what I know about batteries, I learned sailing long passages with two men that survived as submariners in the Pacific during WWII. As they survived in a service that had huge losses, one must allow that these men were both knowledgeable and lucky.

They had all the instruments technology could provide. This included bank volt and current meters with 5 significant digit displays. Both conceded that there measurements were indicative, but not very effective for determining actual state of charge (herein referred to as SOC). Batteries are subject to many idiosyncrasies. They were so advanced, that they later in the war, they even had charge current integrators that reported to sum of ampere hours into an out of the Sargo (a BIG flooded cell) batteries. (How's that for a early version of a Trimetric or Victron?)

Both stated at that the only real way to evaluate SOC is by the electrolyte density.

I now have a Trimetric. The SOC it reports is very much in line with the electrolyte density as I measure it with a refractometer. Refractometers are not temperature sensitive. Mine was quite expensive when I purchased it, but there are now CCVs available at reasonable cost if you do not like the idea of a modern current integrator.

Other interesting things:
No two banks will ever be identical.
Even upon departing Electric Boat (in Groton CT where many were built) the engineers would be identifying differences.
Never could any two banks be charged in parallel and be brought to the same SOC. They had to be charged independently.
Discharging in parallel was less problematic, but still, one would go down faster.
Some things never change.

What prompted both of these discussion (that I actually managed to listen to all of - amazing for a lad of my age) was difficulties had with the house bank of three different vessels all in the process of traversing great distances without any support and having to count on the house bank to supply so much essential power. These discussions are why I have rerigged so many vessels with separate house and engine banks. (Kind of like how GMCs were shipped.)

Little aside for amusement. They had an evaporators onboard to distill sea water. Their first job was to make battery quality water. If they had running time left or the unit came out of spec for battery water, then they use that as potable water for the crew. Let's just say it was a tough life. Washing was not a big priority.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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