installing "switchable" ammeter in new solar system?

[centerline]

I have a small analog ammeter like the one shown, that I am going to install in the new solar setup and I would like it to be switchable from incoming (charging) amps, to outgoing (usage) amps..... does anyone have a diagram for hooking it up this way?

I connected one this way several years ago on a powerboat and it worked great, but I cant remember how I did it and im trying to get this done with the least amount of headaches, so a diagram would be nice....

 

[Sumner]

I'd reconsider using that meter. I think it requires all of the amps to run through the meter like what use to come in your car (pre-70's or so). Those caused fires and if they broke then you had no current. Also to look at two sources you would have to not only switch one source through the meter at a time, but also give that source a path around the meter to complete the circuit when reading the other source.

I'd look at an amp meter that uses a shunt like the one we use...

http://www.solarblvd.com/Solar-Mete...mp-Meter,-100A,-12V/24V/48V/product_info.html

... (amps top/volts bottom) or something similar which would be much safer as the shunt is put on the negative side of the circuit by the battery and is really sending a voltage to the meter that then tells us amps.

On our small boats it is easy to read the net amp usage at a moment with a load and a charging source both hooked up. If I want to see what a load draws I switch the solar charge controller off and turn on one or more loads and read what they draw. If I want to read what the panels are putting out then I turn the main load switch off and read what the panels are putting out.

You could get two amp meters with shunts, but our wiring is so simple and after you have checked a few times then you are just looking at system health. I use ours mainly when occassionly charging with the gen-set. It will start off putting in 20+ amps and then over 30 minutes or so get down around 10 amps. Then I'll shut it off and let the solar take over the rest of the charging.

I'll bet that by the time you bought the switches to control that one meter on two different circuits you would have a good start on buying a shunt type and have something easier to read and safer,

Sum

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[onecoolair]

I have a small analog ammeter like the one shown, that I am going to install in the new solar setup and I would like it to be switchable from incoming (charging) amps, to outgoing (usage) amps..... does anyone have a diagram for hooking it up this way?

I connected one this way several years ago on a powerboat and it worked great, but I cant remember how I did it and im trying to get this done with the least amount of headaches, so a diagram would be nice....

My electrical panel uses this type of gauge. Reading not as accurate as my digital ohms meter. Works great other wise. Note small battery selector switch between the voltage gauge and amp gauge to read different battery banks. Has a off position then marked Start/Reserve position, then #1 Bank, Then #2 Bank, Then Generator position. Plus a fifth non marked position. All that is require to sense battery voltages or amps used is a fused wire to battery connection and then wire led to corresponding post on selector then wire from main post of selector switch to in line meter and then meter too ground.

 

[Sumner]

If this...

http://www.bluesea.com/products/8005/DC_Analog_Ammeter_-_0_to_25A_with_Shunt

...is the meter then it is better than the old style meters I was talking about as it does have an internal shunt. Still the wiring to it and from it has to carry the total maximum amperage that would be on that circuit and be sized accordingly as all of the current is going to flow through the meter..

If I was wiring new I'd still go with the meter that has the shunt down on the negative return to the battery or on the negative side of the circuit you are measuring. Then you can mount the meter anywhere you want it with a very small wire to it,

Sum

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[onecoolair]

Very strange,Very strange, Indeed.

Sum.... So based on what you are saying and are presenting here . See the pdf. My set up is wrong. Very strange. But this is the way it was set up and wired from day one 12 years ago. and works fine. When selector is set to house bank that is being used it shows voltage at that battery bank and amp meter showing amp load being drawing. Right down to when the bilge pump kicks on. Even shows when battery charger kicks in and shows voltage being sent to that particular battery. Gives separate reading on each battery weather its being used or not. Just select the battery you want a reading on using the small selector switch. Very strange,Very strange, Indeed.

 

[Sumner]

Sum.... So based on what you are saying and are presenting here . See the pdf. My set up is wrong. Very strange. But this is the way it was set up and wired from day one 12 years ago. and works fine. When selector is set to house bank that is being used it shows voltage at that battery bank and amp meter showing amp load being drawing. Right down to when the bilge pump kicks on. Even shows when battery charger kicks in and shows voltage being sent to that particular battery. Gives separate reading on each battery weather its being used or not. Just select the battery you want a reading on using the small selector switch. Very strange,Very strange, Indeed.

If the amp meter is wired to the common side of the A-B switch and before the loads then it should work the way you are describing. I'll bet that it is wired that way. The voltage could be similar. It gets more complicated if one wants to just read the loads or the charging sources alone which I think Centerline wanted to do.

Most all of the good battery monitors now that show amps/volts don't run the current through them though, but use an external shunt with small wires going to the monitor.

If the meter is going to be near the power switch then it is an option if it needs to be mounted some distance from that area (such as ours) then I wouldn't use one like is shown as you need a large gauge wire to and from it. I wouldn't use one myself regardless of where it was mounted with the alternative available at decent prices, but obviously people do and boat builders have.

Automakers have done away with amp meters and have gone to volt meters instead. They can tell you a lot more about the charging system and battery health than an amp meter and can be mounted anywhere with small wires running to them.

Sum

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[Stu Jackson]

Since ammeters have to be in line with the load, Sum's right that a remote shunt is what you should consider. The loads still have to run through the shunt, of course, but you can switch the meter wiring legs. You'd be better off with a battery monitor.

Here's a discussion of shunts and ammeters

Ammeters & Shunts 101 http://c34.org/bbs/index.php/topic,6032.0.html

 

[walt]

The higher end solar controllers almost always "know" what the current in and out is.

I dont remember what model you have (and probably wouldnt be familiar with it anyhow) but any chance this feature was already built into the MPPT controller you have - and you just need to figure out how to display the numbers?