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Old 08-13-2018, 01:11 PM   #1
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updating my amperage display

On my circuit breaker panel, I have a single 12 volt analog amperage display that goes from 0 to 30 amps. I would like to modify my wiring so I can see my amperage for both the start battery and the house battery. It also seems to me that the amperage should have both a positive and negative scale, depending on whether the battery is getting charged or being drained. My questions are:
  1. Do all 12 volt amperage displays require a shunt? On Amazon.com, some amperage displays definitely include a shunt, and others make no mention of a shunt.
  2. Is an amp-hr display overkill or important information?
  3. What would you recommend for battery #1/#2 amperage readouts?
Thanks.
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Old 08-13-2018, 01:42 PM   #2
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You will need an ammeter with a shunt to read the amount of amps required for the starter. Check out the Victron 700 series.
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Old 08-13-2018, 01:51 PM   #3
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Well, I will try to answer your questions, but then I have a few of my own:

1. No, 30 amps seems to be the crossover point where some require a shunt and some do not. But no shunt means you have to bring all of your dc power up to the meter panel so it can pass through the meter terminals. That might work if you just wanted to read the amperage handled by the panel, but usually there are more loads than that.

2. Amp hours can only be read from an electronic device generally called a battery monitor. They are great if you hang out on the hook and need to know how much DC you are using.

3. Well I have a Blue Seas 30 amp shunt type meter that is installed only on the house bank that works fine.

So my questions:

1. Why would you ever want to read amps drawn by your starting battery. That typically runs 200-400 amps and only occurs for a second or so.

2. What are you really trying to accomplish? They make dual battery monitors which monitor two batteries with one display and two shunts. Xantrex makes one. That might be your best bet, but for the life of me I can't figure out why amps and amp hours is important for a starting battery.

David
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Old 08-13-2018, 01:53 PM   #4
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For the 30 amps you mention no shunt is required, just wire right through your meter like the existing one. Starter/s do not go through meters or shunts.
A shunt can be useful if meters are very remote from battery circuit, very high amperage, or multiple displays (meters) as they cut down the amount of high amp wiring going to and from the meter/s. Picture a large vessel w/ 2 stations: there could be hundreds of feet of wire involved, larger than usual to minimize voltage drop. With a shunt, there could be as many displays as required, as far away as necessary, with very small gauge wire doing the job b/c only milivolts are being sent through the wiring to the meters. As a matter of fact, those meters are really volt meters marked in amps.
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Old 08-13-2018, 02:23 PM   #5
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As already mentioned, you might consider one of these for your house battery bank, as it's so much more than an amp meter.
https://baymarinesupply.com/victron-...y-monitor.html

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Old 08-13-2018, 05:09 PM   #6
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Blue Seas also has a nice looking meter that I've been considering.

https://www.bluesea.com/products/1834/M2_DC_Multimeter

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Old 08-13-2018, 06:41 PM   #7
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I hesitate to mention this, but I will as it illustrates the wide variety of cheap products coming from China. This voltmeter, ammeter, amphour meter is every bit as functional as the Victron, Xantrex, etc battery monitor costing six times as much.

See https://www.amazon.com/DROK-Multimet...attery+monitor

I installed an earlier version on my RV and it works! This one has a neat Hall effect sensor (the same technology in clamp on DC current meters) that you pass the negative lead to your battery through. Then you connect the display to the sensor and a power source and you are in business.

The Victron is definitely nicer and measures up to 500A which might be of academic interest for the OP's starting battery and Xantrex makes a two battery monitor for both the house and starting battery (or more likely two house banks).

And it does more than the $300 Blue Seas meter described in the PP.

David
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Old 08-13-2018, 06:52 PM   #8
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Quote:
Originally Posted by djmarchand View Post
I hesitate to mention this, but I will as it illustrates the wide variety of cheap products coming from China. This voltmeter, ammeter, amphour meter is every bit as functional as the Victron, Xantrex, etc battery monitor costing six times as much.

See https://www.amazon.com/DROK-Multimet...attery+monitor

I installed an earlier version on my RV and it works! This one has a neat Hall effect sensor (the same technology in clamp on DC current meters) that you pass the negative lead to your battery through. Then you connect the display to the sensor and a power source and you are in business.

The Victron is definitely nicer and measures up to 500A which might be of academic interest for the OP's starting battery and Xantrex makes a two battery monitor for both the house and starting battery (or more likely two house banks).

And it does more than the $300 Blue Seas meter described in the PP.

David

Looks very nice. I'll let somebody else see how long a $30 meter will last. I wouldn't be upset about loosing $30 on a piece of Chinese electronics, it's the lost hours spent installing it that would drive me nuts.

Ted
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Old 08-13-2018, 07:54 PM   #9
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Quote:
Originally Posted by djmarchand View Post
I hesitate to mention this, but I will as it illustrates the wide variety of cheap products coming from China. This voltmeter, ammeter, amphour meter is every bit as functional as the Victron, Xantrex, etc battery monitor costing six times as much.

See https://www.amazon.com/DROK-Multimet...attery+monitor

I installed an earlier version on my RV and it works! This one has a neat Hall effect sensor (the same technology in clamp on DC current meters) that you pass the negative lead to your battery through. Then you connect the display to the sensor and a power source and you are in business.

The Victron is definitely nicer and measures up to 500A which might be of academic interest for the OP's starting battery and Xantrex makes a two battery monitor for both the house and starting battery (or more likely two house banks).

And it does more than the $300 Blue Seas meter described in the PP.

David
David,
I bought the very same some times ago (not installed yet) that I am planning to install with my new batteries. Just wanted to give it a try and I like the hall effect sensor that allows installation without cable intrusion like a shunt.
At that price it is like a disposal one, and even if it last 5 years well this would give 30 years of replacement before reaching the price of a BlueSea. I do not expect the same accuracy but at least it should give an idea about charge/discharge state.

If you have any advice for the setup please PM me!!!

L
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Old 08-13-2018, 09:04 PM   #10
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I installed a Trimetric TM-2030 a few years ago based on recommendations and it has been working well TriMetric Model Descriptions - Bogart Engineering.
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Old 08-14-2018, 01:18 PM   #11
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Quote:
Originally Posted by seattleboatguy View Post
On my circuit breaker panel, I have a single 12 volt analog amperage display that goes from 0 to 30 amps. I would like to modify my wiring so I can see my amperage for both the start battery and the house battery. It also seems to me that the amperage should have both a positive and negative scale, depending on whether the battery is getting charged or being drained. My questions are:
  1. Do all 12 volt amperage displays require a shunt? On Amazon.com, some amperage displays definitely include a shunt, and others make no mention of a shunt.
  2. Is an amp-hr display overkill or important information?
  3. What would you recommend for battery #1/#2 amperage readouts?
Thanks.


Iíve installed the Balmar SmartGauge in my last two trawlers. No shunt just run two wires to +/- terminals on your house bank. The gauge will read voltage but also display status -of-charge in percentage. You can select voltage reading for house or start batteries. http://www.balmar.net/products/smart...ttery-monitor/
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