Installing an Ammeter

[tgalea]

Hi All,

I'm about to install an Ammeter on our boat and need some help with regards to its position in the circuit.

I am unsure if it should first of all be installed in a way that it is live once the batter master switch is on so I can monitor discharge whilst on anchor etc, or if it should only come live when the ignition key is turn out of the OFF position.

Second question is; should the ammeter be installed in a way to read flow of current just in and out of the battery (i.e, prior to any of the buses) or should it be installed to read flow prior to the positive bus ?

Any help would be appreciated ?

Cheers

Tyrone.

 

[halcyon]

Were you put the ammeter depends on what you want to know, i.e. charging current, current being used, net current into service battery. but should allways be after isolater switch.
Also remember starter cureent could be 200-400 amp, if the system is not designed to take it, it will burn out.



Brian

 

[oldsaltoz]

G’day tgalea.
Mine looks like it’s wired as follows. One wire to the starter “SOLENOID”, (not the starter / battery lead) and the other wire to battery. Not the same lead that runs to the starter.
You do not say if you are Positive or negative earth, so you may have to swap the leads if it reads back to front.

Andavgoodweekend Old Salt Oz.

 

[ccscott49]

You can use a "shunt", in the main battery to isolator switch line, this will allow you to use an ammeter to see all current in or out of the battery, You will; need to purchase this shunt specifically for the ammeter you intend to use, try index marine for all this stuff and advice, but theres a rew electrickery wizards on here aswell!

 

[halcyon]

The problem with a shunt in the battery line if it's used for starting is the current, that is it must take 200 to 500 amp depending on engine size.
If it's a service battery there are less probs.
What are you trying to measure ?.



Brian

 

[pvb]

Why do you want an ammeter?

You really need to decide not only which current you're going to measure, but what conclusion you're likely to draw from the reading. In my experience, a plain ammeter is of little use. If you're really interested in what's happening, you need a meter which shows not just the amps, but the amp-hours. Cheapest is the Link 10, about £200 including a shunt. I don't think you'll derive any benefit from a straightforward ammeter.

 

[Budgie]

Re: Why do you want an ammeter?

I agree with the previous post - Link 10 is the way to go. It not only shows current, but more importantly shows ampere hours used and thus how much batttery capacity is left.

It comes complete with a 500 amp shunt, wiring instructions etc. My shunt is directly connected to the negative side of my service batteries, and thus measures all ins and outs from these batteries.

I bought mine from West Marine (USA), but I saw a recent advert from a British supplier in Yachting Monthly.

This website may be of help: http://www.heartinterface.com/LINK10Manual.pdf

 

[VMALLOWS]

Re: Why do you want an ammeter?

These fancy (essentially amp-hour) meters are great, and I would love to have one, but £200 is still quite a lot to spend.........especially since most people planning to install them are probably at the point of buying new batteries as well.

If money is a constraint, I would go for a simple (car shop) ammeter monitoring just the alternator INPUT to the battery(s). It doesn't take much effort to estimate how much you've taken out of the batteries.....more accurately than you'll get from a basic ammeter. You should then be able to form a good opinion as to whether you are putting back enough (time/current) to replenish the battery.
If you're not, we're into manual charge 'regulators', but thats too technical for tonight.