Topics

Wiring question, about 24 volt and "bridges"


Electri-Cal
 

Probably Myles Tweete has this, but others may wonder about this.  I just got in a new round gauge for Surprise. A dual amp and volt type, that should show all I need in a small package.  The info shows it will handle decent numbers of current, and also shows on several web sites where it is hooked up.  I'm not fond of running the full 24 volts through the wires, even though the draw is miniscule.  There has got to be more to thisthan i'm seeing ??

All my other gauges hook through the twin bus bars, with drop screws on each end so full power drops 24 volt to 12 volt.  I have fused blocks for these 12 v, accessories, lights, radio etc.  This new guage does not show that bus bar anyplace in the on line circuit, several I liiked at do not show any bus bar>>.  How does that work??  Do I just run light instrument wires at full power??  Is there another voltage drop bar, that  is assumed to be there??  Do I just connect to the pack 24 v. and it is handled inside the guage??  Hook to the regular 12v. take off, and the variable senses what is required??  maybe my confusion is because I haven't  done a mini//multi guage like this I recall.    Or last, just touch the terminals and hope the guage hangs together.

My normal inclination is to just visually double tha amp draw, but it was suggested I need to have the right numbers on the guage.   I figured colored tape at correct cruise speeds was good enough, but I bought tha guage since it is a lighted colored digital one.

Anybody with the right info on this ??  Thanks,  Cal



   


Jove Lachman-Curl
 

Hey Cal,
Can you see us images and a website where we can look up the Guage in question other wise this is really hard to give input on.
I can say that current is usually measured via voltage drop across a calibrated low resistance resistor (typically called a shunt). That might be integral to your unit, and if so there would be fairly large terminals on your Guage to match the current.
You will not have much success running full amps through thin instrument wires but im sure you know that.

On Sun, Aug 30, 2020, 8:39 AM Electri-Cal <calboats@...> wrote:
Probably Myles Tweete has this, but others may wonder about this.  I just got in a new round gauge for Surprise. A dual amp and volt type, that should show all I need in a small package.  The info shows it will handle decent numbers of current, and also shows on several web sites where it is hooked up.  I'm not fond of running the full 24 volts through the wires, even though the draw is miniscule.  There has got to be more to thisthan i'm seeing ??

All my other gauges hook through the twin bus bars, with drop screws on each end so full power drops 24 volt to 12 volt.  I have fused blocks for these 12 v, accessories, lights, radio etc.  This new guage does not show that bus bar anyplace in the on line circuit, several I liiked at do not show any bus bar>>.  How does that work??  Do I just run light instrument wires at full power??  Is there another voltage drop bar, that  is assumed to be there??  Do I just connect to the pack 24 v. and it is handled inside the guage??  Hook to the regular 12v. take off, and the variable senses what is required??  maybe my confusion is because I haven't  done a mini//multi guage like this I recall.    Or last, just touch the terminals and hope the guage hangs together.

My normal inclination is to just visually double tha amp draw, but it was suggested I need to have the right numbers on the guage.   I figured colored tape at correct cruise speeds was good enough, but I bought tha guage since it is a lighted colored digital one.

Anybody with the right info on this ??  Thanks,  Cal



   


Myles Twete
 

Ditto.

If this round gauge is a descendant of the Link-10, which was a descendant of the E-Meter (designed/built in Arlington, Wa.), there’s definitely a need for an external shunt.  Worse, to the extent that these new round multi-function gauges (Amps/Volts/Amp-Hours, etc.) are knock-offs without a redesign, beware that both the E-Meter and Link-10 meters have a design flaw whereby the current monitoring (and A-H) features die a quick death if power is not applied in the right sequence to the inputs.  I didn’t want to risk it, so I did what others did and mounted a connector at the back end so that all the connections could be connected simultaneously, which works.  Still, I ultimately bricked at least one of these…

So hopefully these new Amphour gauges out there have been made more robust.

 

-MT

 

From: oregoncoots@groups.io [mailto:oregoncoots@groups.io] On Behalf Of Jove Lachman-Curl
Sent: Sunday, August 30, 2020 9:47 AM
To: oregoncoots@groups.io
Subject: Re: [oregoncoots] Wiring question, about 24 volt and "bridges"

 

Hey Cal,

Can you see us images and a website where we can look up the Guage in question other wise this is really hard to give input on.

I can say that current is usually measured via voltage drop across a calibrated low resistance resistor (typically called a shunt). That might be integral to your unit, and if so there would be fairly large terminals on your Guage to match the current.

You will not have much success running full amps through thin instrument wires but im sure you know that.

 

On Sun, Aug 30, 2020, 8:39 AM Electri-Cal <calboats@...> wrote:

Probably Myles Tweete has this, but others may wonder about this.  I just got in a new round gauge for Surprise. A dual amp and volt type, that should show all I need in a small package.  The info shows it will handle decent numbers of current, and also shows on several web sites where it is hooked up.  I'm not fond of running the full 24 volts through the wires, even though the draw is miniscule.  There has got to be more to thisthan i'm seeing ??

All my other gauges hook through the twin bus bars, with drop screws on each end so full power drops 24 volt to 12 volt.  I have fused blocks for these 12 v, accessories, lights, radio etc.  This new guage does not show that bus bar anyplace in the on line circuit, several I liiked at do not show any bus bar>>.  How does that work??  Do I just run light instrument wires at full power??  Is there another voltage drop bar, that  is assumed to be there??  Do I just connect to the pack 24 v. and it is handled inside the guage??  Hook to the regular 12v. take off, and the variable senses what is required??  maybe my confusion is because I haven't  done a mini//multi guage like this I recall.    Or last, just touch the terminals and hope the guage hangs together.

My normal inclination is to just visually double tha amp draw, but it was suggested I need to have the right numbers on the guage.   I figured colored tape at correct cruise speeds was good enough, but I bought tha guage since it is a lighted colored digital one.

Anybody with the right info on this ??  Thanks,  Cal



   


johnacord
 

Good comments Myles.  I have read many comments about the problems with Link and other similar.

I have used the Victron BMV-702 for 5 years or so without any problems, good readings and accuracy.  The power connection is on the shunt and connected directly to the battery through a fuse.  So power up is simultaneous with battery connection.  Installation sheet attached showing the arrangement graphically.

I did modify the arrangement in my installation so that the power to the BMV readout from the battery was after the main battery switch.  The BMV does draw a little current so doing this reduces a small battery drain when the boat is parked.

John A


Electri-Cal
 

I just spent today mainly staring at wiring I did maybe 4 years ago.  Not much fun, but I did get some stuff redone, other stuff is maybe for later.  The results matter, but all works better if not perfect, but works.   

The first voltage gauge was partially shot, as it s led numbers showed low voltage and about  half a lighted green, yellow red outer statuss ring about  half working also.  I changed for the new similar gauge, voila -- there was the same voltage as my meter said.  Then I plugged in a voltahe lighted meter into my ciggie lighter, the voltage was within .01 of  the other meter, so thats a help.  Then after fooling around I found a different unused plug, which had 24 volts, so I could use that as the amps plug, big maybe !!   I can now read the pack voltage two ways, and when it drops to where to depth finder dies, switch packs, reading that voltage figure as safe.   

Shunts I got !!  Each set of cables connect to shunts, with recommended fuses for power maximums, trickle chge., 12v. accessories consoles, and etc.  Up to the  point where I have no more bolt space for new connections.  any more adding stuff and it would take custom fuse, acc. link holders.  Don't think I'd like to go there.   I don't think it will be fun to add another plug  system for the third pack.  Almost easier to think I can plug in the genset to the standard charge plug, and less weight too, yeah some noise !!  Think i'll call local Honda shop for the slightly odd size fuses required, shorter  length.

Now I'll reread all your good  previous notes, and see what to change or think about next, ---  a bit  hot to do much more right now,  Thanks coots, ---  Cal

 


 

It sounds like you just got the gauge itself. Cal. You need a properly rated shunt to hook it up. The gauge needs a particular mV rating, and needs to be rated well above the amperage you expect to draw. The instructions for the gauge should say something like, "use with a 50 mV shunt", or whatever. Unfortunately, the mV rating doesn't seem to be standardized... You mentioned that you've got a bunch of shunts lying around; if you're lucky maybe you've got one to match the gauge. Use one shunt per ammeter. Don't just hook the digital gauge to the shunt you use with your dial gauge, even if it's the proper mV rating.

Hook the shunt up into the common ground going into your battery bank(s) so the gauge reads all the current going out, or in, to the batteries. It should be easy enough to hook you temporary backup pack through the common ground.

If that gauge is indeed a Link 10 knockoff, it'll run on 24 volts with no problem.

On 8/30/2020 8:39 AM, Electri-Cal wrote:
Probably Myles Tweete has this, but others may wonder about this.  I just got in a new round gauge for Surprise. A dual amp and volt type, that should show all I need in a small package.  The info shows it will handle decent numbers of current, and also shows on several web sites where it is hooked up.  I'm not fond of running the full 24 volts through the wires, even though the draw is miniscule.  There has got to be more to thisthan i'm seeing ??
...
--
John <@Jkohnen>
In this world of sin and sorrow there is always something to be thankful for; as for me, I rejoice that I am not a Republican. (H. L. Mencken)
--
This email has been checked for viruses by AVG.
https://www.avg.com


 

I've got a Link 10 in Tuffy. I wish I'd done more research before I bought it. <sigh> It's designed for an installation where it's permanently (or nearly) hooked up to the batteries, and the batteries are charged in situ. I first hooked up the gauge on the downstream side of the battery switch, but when the switch was turned on the power introduction to the gauge was too "ragged" (Link 10's term) and more often than not the gauge display would freeze up. Now I've got the Link 10 hooked up directly to the battery bank, and the gauge only occasionally freezes up when it awakes. I pull the fuses to the gauge when I take the batteries out to charge them, and carefully reinsert them in the right order after the batteries are reinstalled. Sometimes it even works right on the first try! <g>

Maybe someday Tuffy will get a Victron BMV-702 as a present. <g>

https://www.victronenergy.com/battery-monitors/bmv-702

On 8/30/2020 11:22 AM, John A wrote:
Good comments Myles.  I have read many comments about the problems with Link and other similar.
I have used the Victron BMV-702 for 5 years or so without any problems, good readings and accuracy.  The power connection is on the shunt and connected directly to the battery through a fuse.  So power up is simultaneous with battery connection.  Installation sheet attached showing the arrangement graphically.
I did modify the arrangement in my installation so that the power to the BMV readout from the battery was after the main battery switch.  The BMV does draw a little current so doing this reduces a small battery drain when the boat is parked.
--
John <@Jkohnen>
I have always a sacred veneration for any one I observe to be a little out of repair in his person, as supposing him either a poet or a philosopher; because the richest minerals are ever found under the most ragged and withered surface of the earth. (Jonathan Swift)
--
This email has been checked for viruses by AVG.
https://www.avg.com


 

John A informed me that the BMV-700 is a bit cheaper, but will do all most of us need:

https://www.victronenergy.com/battery-monitors/bmv-700

https://www.victronenergy.com/upload/documents/Datasheet-BMV-700-series-EN.pdf

Thanks, John!

On 8/30/2020 8:38 PM, I wrote:
...
Maybe someday Tuffy will get a Victron BMV-702 as a present. <g>
https://www.victronenergy.com/battery-monitors/bmv-702
--
John <@Jkohnen>
I am patient with stupidity but not with those who are proud of it. (Edith Sitwell)
--
This email has been checked for viruses by AVG.
https://www.avg.com