Ammeter fitting...help please.

[ROBDEN]

Hi ya,

I've done 'Similar' to what you're suggesting, if you look at the Pic below, Far Left you can see my two Alternator feeds, Shunts, and the Cables going straight to my Amp meters.

https://www.dropbox.com/s/olh6wid80iy14ob/2014-04-30%2016.26.29.jpg?dl=0

This indicates to me while at the helm what's going on with my Alternators at any point whilst underway via a quick glance. (Twin Amp meters at top of switch panel, to right of wheel)

https://www.dropbox.com/s/t0zkoiwapyugrhs/IMAG0222.jpg?dl=0

If a more in-depth knowledge of what state my Batteries are in, or what charge is going where etc then I take a peek at

https://www.dropbox.com/s/kq2g7cllih5t1uo/2014-04-04%2011.52.42-2.jpg?dl=0

Paul thanks for that most informative.

I can see your shunts but I thought I'd read somewhere that it's not a good idea to have them on the pos side or am I wrong (again) about that?

 

Rob....

[Paul's Nulife4-2]

Ime not sure about that, all I can say is it's been ok for me, on my set up for nearly 8 years.

But I would like to know if what you have heard IS the case !.

This is the other end (Amp meter end) you can see the connections of the Cable that leads from the Shunts.

https://www.dropbox.com/s/qtwqz807t3gfdld/IMAG0639.jpg?dl=0

Edited December 21, 2014 by Paul's Nulife4-2

[Theo]

I fitted my ammeter shunt in the alternator output cable. It measures exactly what I need: the alternator current so that I can determine how slowly I can run the engine at any soc. I rarely run it at above tickover for more that 30 mins. I am delighted with it.

 

N

[ROBDEN]

I fitted my ammeter shunt in the alternator output cable. It measures exactly what I need: the alternator current so that I can determine how slowly I can run the engine at any soc. I rarely run it at above tickover for more that 30 mins. I am delighted with it.

 

N

Hello N

 

What size shunt did you use?

I thought it had to go in the -ve side. All I want to do is see what the alternator is putting out.

 

Rob....

[smileypete]

For a lesser budget I'd give these a try. Unlike others on Ebay they have a built in isolator so shouldn't be fussy about supply or where the shunt goes:

 

http://www.ebay.co.uk/itm/DC-200A-Red-LED-4-Digital-Display-Panel-Ammeter-Ampere-Meter-Shunt-AC-DC12V-260V-/231354947935

 

Failing that if it's just for alternator current how about an analogue meter as mentioned, they usually take a 75mV shunt, should cost around £10 all in on Ebay.

 

ETA:

 

I did something like this. Bought an ammeter from ebay, very cheap. just be aware that these cheap ones will not measure the current from the supply source. ie don't try to use the boat's 12 volt to power it, you must run it from a separate 9V battery. I've put in switch to turn it on and off.

The shunt just goes in the line from the alternator to the battery.

Bob

 

If you like you could add a separate isolated converter, could do with a little PCB and some terminal blocks to connect it:

 

http://www.ebay.co.uk/itm/TMV1212S-Isolated-12V-DC-DC-Converter-/291324308742

http://www.ebay.co.uk/itm/Double-Side-Prototype-FR-4-PCB-Stripboard-Universal-Printed-Circuit-Board-8-Size-/370876590149

 

cheers, Pete.

~smpt~

Edited December 21, 2014 by smileypete

[cereal tiller]

For a lesser budget I'd give these a try. Unlike others on Ebay they have a built in isolator so shouldn't be fussy about supply or where the shunt goes:

 

http://www.ebay.co.uk/itm/DC-200A-Red-LED-4-Digital-Display-Panel-Ammeter-Ampere-Meter-Shunt-AC-DC12V-260V-/231354947935

 

Failing that if it's just for alternator current how about an analogue meter as mentioned, they usually take a 75mV shunt, should cost around £10 all in on Ebay.

 

ETA:

 

 

If you like you could add a separate isolated converter, could do with a little PCB and some terminal blocks to connect it:

 

http://www.ebay.co.uk/itm/TMV1212S-Isolated-12V-DC-DC-Converter-/291324308742

http://www.ebay.co.uk/itm/Double-Side-Prototype-FR-4-PCB-Stripboard-Universal-Printed-Circuit-Board-8-Size-/370876590149

 

cheers, Pete.

~smpt~

Fitted one of these without the Power Supply 2 years ago,it works well.

Used a 1 AH 12 volt sealed battery to power it.

Using a single throw double pole toggle switch that enables the meter to display or it's battery to to be topped up by the main 12 volt bank.

CT

[Theo]

Hello N

 

What size shunt did you use?

I thought it had to go in the -ve side. All I want to do is see what the alternator is putting out.

 

Rob....

the shunt was big and chunky but I can't remember its resistance. This depends on the fsd of the display and the max current that you want to pass.

 

I believe that some ammeters do have to go on the -ve side but mine didn't. I bought it at the Crick show years ago and only just got arround to fitting it a couple of months ago.

 

Nick

[ditchcrawler]

If you insist on measuring alternator output ONLY then its 99% sure you will need to put it in the positive lead unless you can guarantee that the negative is 100% isolated.

[smileypete]

Fitted one of these without the Power Supply 2 years ago,it works well.

Used a 1 AH 12 volt sealed battery to power it.

Using a single throw double pole toggle switch that enables the meter to display or it's battery to to be topped up by the main 12 volt bank.

CT

 

The one mentioned has an on board isolated converter (the yellow thing on the right with the little squareish black blob above it) so should be OK without an extra power supply.

 

cheers, Pete.

~smpt~

[rogeriko]

Me I like all those needles that bounce around much prettier.. Get yourself a few of these connect them everywhere. Only 8 pounds including shipping from Shanghai.

 

 

[ROBDEN]

For a lesser budget I'd give these a try. Unlike others on Ebay they have a built in isolator so shouldn't be fussy about supply or where the shunt goes:

 

http://www.ebay.co.uk/itm/DC-200A-Red-LED-4-Digital-Display-Panel-Ammeter-Ampere-Meter-Shunt-AC-DC12V-260V-/231354947935

 

Failing that if it's just for alternator current how about an analogue meter as mentioned, they usually take a 75mV shunt, should cost around £10 all in on Ebay.

 

ETA:

 

 

If you like you could add a separate isolated converter, could do with a little PCB and some terminal blocks to connect it:

 

http://www.ebay.co.uk/itm/TMV1212S-Isolated-12V-DC-DC-Converter-/291324308742

http://www.ebay.co.uk/itm/Double-Side-Prototype-FR-4-PCB-Stripboard-Universal-Printed-Circuit-Board-8-Size-/370876590149

 

cheers, Pete.

~smpt~

 

Thanks for that Pete.

I think I'll try one of them.

 

As I only want it while the engine is running will it be ok to pick up the live from the ignition side?

Last question. Will it be ok to put the shunt in the main battery negative lead even though it goes to the starter as well?

 

Rob....

[by'eck]

If you want to go monitor mad with the Sterling Power Management panel..................

 

[RLWP]

'Basic twin alternator wiring'!

 

Richard

[by'eck]

'Basic twin alternator wiring'!

 

Richard

Well when you consider some of the suggestions for such on previous threads it probably is

[RLWP]

From memory the wiring for a single alternator is: wire from alternator to starter motor, wire from starter motor to battery via isolator, wire to warning light on panel and then to ignition switch

 

Richard

[smileypete]

As I only want it while the engine is running will it be ok to pick up the live from the ignition side?

Last question. Will it be ok to put the shunt in the main battery negative lead even though it goes to the starter as well?

 

1. Don't see why not.

2. How about putting the shunt in the domestic batt bank negative.

 

Problem with putting it in the engine block return is that it will take the starter current too, which it may not like.

 

With the meter, bear in mind the blue terminal block is for power and the little white plug/socket for the shunt.

 

cheers, Pete.

~smpt~

Edited December 22, 2014 by smileypete

[cereal tiller]

 

1. Don't see why not.

2. How about putting the shunt in the domestic batt bank negative.

 

Problem with putting it in the engine block return is that it will take the starter current too, which it may not like.

 

cheers, Pete.

~smpt~

The 200 amp Shunt i mentioned earlier has coped with Starter demands on several hundred occasions.

Some times the meter digital display will wobble but it is all working nicely

E.T.A. the Shunt is in the Master negative cable to the battery bank

CT

Edited December 22, 2014 by cereal tiller

[smileypete]

Thanks, that's good to know.

 

cheers, Pete.

~smpt~

Edited December 22, 2014 by smileypete

[Bod]

http://www.autoelectricalpartsuk.co.uk/products/Workshop_And_Test_Equipment/Handheld_Meters,_Testers_and_Sundries/Durite_Induction_Ammeter_75-0-75___053475.html

 

I suppose one of these would be too simple?

 

Bod

[ROBDEN]

http://www.autoelectricalpartsuk.co.uk/products/Workshop_And_Test_Equipment/Handheld_Meters,_Testers_and_Sundries/Durite_Induction_Ammeter_75-0-75___053475.html

 

I suppose one of these would be too simple?

 

Bod

Thanks Bod but it's too hard to read when steering the boat.

 

Rob....

 

The 200 amp Shunt i mentioned earlier has coped with Starter demands on several hundred occasions.

Some times the meter digital display will wobble but it is all working nicely

E.T.A. the Shunt is in the Master negative cable to the battery bank

CT

 

Thanks CT. That's what I'll do.

 

Rob....

 

 

1. Don't see why not.

2. How about putting the shunt in the domestic batt bank negative.

 

Problem with putting it in the engine block return is that it will take the starter current too, which it may not like.

 

With the meter, bear in mind the blue terminal block is for power and the little white plug/socket for the shunt.

 

cheers, Pete.

~smpt~

 

Thanks again Pete.

 

I've ordered one and will fit it after Christmas.

 

Have a good one Rob....

[Detling]

I would not recommend having the starter current through the shunt, but if you do you need at least a 200 amp shunt and preferably a 500 amp shunt as starter motors an a stiff/almost seized cold engine will take well over 200 amps, how long before something gives. The meter with the overvoltage from the shunt or the shunt resistance melting.

[nicknorman]

If the -ve lead to the engine comes off the starter battery (or can be moved to it) then put the shunt between the starter negative and the domestic negative, then it will only detect current in and out of the domestics.

[RLWP]

But not the current going into the starter battery though

 

Richard

[rogeriko]

If you want to detect charging current ONLY then the shunt should ALWAYS be put in the positive lead coming from the alternators. Anywhere else and you will be detecting other currents. The shunt is kind of like a fuse it will get slightly warm at full power rating, If you put it in the negative lead and there is an overcurrent event anywhere on the boat the shunt will overheat and could set fire to something.

 

I am an off grid solar installer I am used to working with large batteries and large inverters and large currents.

 

Pictures of my work https://www.flickr.com/search/?q=mykonos+solar+wind

Edited December 24, 2014 by rogeriko

[by'eck]

If the -ve lead to the engine comes off the starter battery (or can be moved to it) then put the shunt between the starter negative and the domestic negative, then it will only detect current in and out of the domestics.

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