Amp Meter Instaltion

[Biggles]

Hello

 

I want to put an amp meter on my NB, is there any way of doing it so that the main cable doesn't pass through the amp meter. I refer back to the old days where it had to.

 

Basically is there some more modern way of doing it?

[bottle]

Previous topic may help.

 

http://www.canalworld.net/forums/index.php?showtopic=11875

[alan_fincher]

You need a "shunt type" ammeter.

 

A very low resistance, called a "shunt" is introduced into the main cable at the point you wish to measure. As current flows, a small volts drop is caused across this shunt, that voltage rising as current increases. The meter, (designed to be a package with the shunt), now only has to measure that voltage, and no high current passes through it. This means it can be connected by thin cabling, not heavy stuff capable of carrying the current through the shunt, actually being measured.

 

Whatever anyone tells you though, any method of measuring current will produce a very small volts drop in the circuit being monitored.

 

There are loads of references on the forum, search for +shunt +ammeter, for example.

Edited June 18, 2008 by alan_fincher

[NB Phoenix]

Hello

 

I want to put an amp meter on my NB, is there any way of doing it so that the main cable doesn't pass through the amp meter. I refer back to the old days where it had to.

 

Basically is there some more modern way of doing it?

 

Yes but as I clicked reply I noticed both Keith and Alan posting on this thread and the will give a better answer than me.

 

Over to Keith and or Alan

 

EDIT to add Dooh.... Both beat me to it

Edited June 17, 2008 by NB Phoenix

[Roger Gunkel]

Hello

 

I want to put an amp meter on my NB, is there any way of doing it so that the main cable doesn't pass through the amp meter. I refer back to the old days where it had to.

 

Basically is there some more modern way of doing it?

 

Hi,

 

I put a battery condition meter on my boat yesterday, which tells me amps, volts, state and rate of charge/discharge, percentage of battery charge and time remaining to discharge or full charge.

 

Being very nervous of boat electrics and not very knowledgeable, I actually found it straightforward. I took off the negative output cable from the battery and connected it to the 100amp shunt supplied and connected the other side of the shunt to the negative battery post. Then 3 thin wires from the meter were connected to the shunt as per the instructions and 1 thin red from the meter to the positive battery terminal. All other wiring stayed the same and all cabling and instructions came with the unit.

 

The unit is a NASA BM1 cost £89 new, is very easy to read with large LCD and backlight, is about 4in square and even has a protective cover.

 

This morning for the first time ever, I can see exactly what my battery bank is doing and how long it will do it for. I think its brilliant, but I am quite easily pleased.

 

Roger

[Biggles]

Hi,

 

I put a battery condition meter on my boat yesterday, which tells me amps, volts, state and rate of charge/discharge, percentage of battery charge and time remaining to discharge or full charge.

 

Being very nervous of boat electrics and not very knowledgeable, I actually found it straightforward. I took off the negative output cable from the battery and connected it to the 100amp shunt supplied and connected the other side of the shunt to the negative battery post. Then 3 thin wires from the meter were connected to the shunt as per the instructions and 1 thin red from the meter to the positive battery terminal. All other wiring stayed the same and all cabling and instructions came with the unit.

 

The unit is a NASA BM1 cost £89 new, is very easy to read with large LCD and backlight, is about 4in square and even has a protective cover.

 

This morning for the first time ever, I can see exactly what my battery bank is doing and how long it will do it for. I think its brilliant, but I am quite easily pleased.

 

Roger

 

 

Thanks guys, that answers the question.

 

Cheers

[Justme]

Was tempted to get a NASA BM1 till I read the specs that it will only do upto 600amp/h battery banks.

Guess I'll stick to using a volt meter. Cant justify the cost of a smart gauge.

 

Justme

[Maffi]

Whatever anyone tells you though, and method of measuring current will produce a very small volts drop in the circuit being monitored.

 

a few milli-volts

[alan_fincher]

a few milli-volts

Depends on your definition of "a few", I guess.

 

50 mV or even 100 mV doesn't sound to be that uncommontly quoted.

 

Though I'll concede that must be at full current, so at more typical currents the volts drop would indeed be a lot less.

[NB Phoenix]

Was tempted to get a NASA BM1 till I read the specs that it will only do upto 600amp/h battery banks.

Guess I'll stick to using a volt meter. Cant justify the cost of a smart gauge.

 

Justme

 

I have a BM1 and I'm very pleased with it. According to NASA they will monitor a bank up to 999a/h NASA web site but I have also seen other adverts referring to the 600/650 limit?

[John Orentas]

Why not just fit an ammeter and a voltmeter, you will have all the information you need.. There are some very low cost digital units available or you could have a pair of nice attractive analogue ones.

 

http://www.canalworld.net/forums/index.php...=si&img=915

Edited June 18, 2008 by John Orentas

[Justme]

I have a BM1 and I'm very pleased with it. According to NASA they will monitor a bank up to 999a/h NASA web site but I have also seen other adverts referring to the 600/650 limit?

 

Still not enough as my bank is 1550amp/h at the 5c rate. Also need a bigger shunt as the inverter "could" drain 200amps.

 

 

Justme

[Collectors]

Still not enough as my bank is 1550amp/h at the 5c rate. Also need a bigger shunt as the inverter "could" drain 200amps.

 

 

Justme

 

 

I might be wrong? But could you use a coil instead of a shunt. I know the ones on this site sell at about £20.00, but are in the US & dont have an EU outlet. But one of the members might know where to get one.????

 

Only an idea.

 

Chris.

[Roger Gunkel]

Why not just fit an ammeter and a voltmeter, you will have all the information you need.. There are some very low cost digital units available or you could have a pair of nice attractive analogue ones.

 

http://www.canalworld.net/forums/index.php...=si&img=915

 

I thought about an ameter and voltmeter, but my NASA BM1 gives me both, in one neat little backlit LCD readout. It also gives me approximate estimates of remaining charge, time to discharge/charge etc. which saves me working out my own estimates. It was very simple to connect and I like the manual parameter setting so I can adjust to suit my batteries.

 

One man's attractive analogue meters is also another man's old fashioned clunky dials!

 

Roger

[Ex- Member]

This thread has just come in handy.

 

I just had 2 x 12 to 20 volt digital display meters and a matching amp meter & 200amp shunt arrive from China £23.00 through e-bay all in delivered.

 

The idea of 2 12v displays was so I could have one in the saloon to keep an eye on the volts level without traipsing up to the engine room. I know there will be a voltage drop in the saloon, but when I know what it is compared to the engine room reading it won't matter I'll just need to bear it in mind.

 

The amp meter will just be for assessing the 12 volt side of things, not directly on the feed to the inverter. I'm hoping this will give me a good idea of how my alternators are charging, and play around with engine running speed to make sure i'm getting the best out of the Alt's I can. I'm not sure where's the bast place to fit the shunt though, I would assume between the battery bank and 12 volt panel. But what side of the isolater switch?

 

Is there any wiring diagrams around for fitting these?

[Greybeard]

All credit for this goes to Stuart who posted this originally but it may be what you're looking for.

 

http://www.canalworld.net/forums/lofiversi...php?t13364.html

[Ex- Member]

All credit for this goes to Stuart who posted this originally but it may be what you're looking for.

 

http://www.canalworld.net/forums/lofiversi...php?t13364.html

 

 

Brilliant, that's the one, i have seen it before, but couldn't remember if it was on here, clearly so though, just what i need cheers

[Greybeard]

Brilliant, that's the one, i have seen it before, but couldn't remember if it was on here, clearly so though, just what i need cheers

 

 

I've got this saved on my favourites - it's so much easier to use than the original.

 

http://www.ledgardbridge-boatcompany.com/C...arch/index.html

 

nb

 

I'm not employed by, related to, paid by or sleeping with any member of the company that produced this search..........

 

Good products are just hard to find!!!!!!!!!!!!!!!!!!

[wonderdust]

To the MODS, is there a reason that this type of info cannot be put in a sticky , maybe called Projects?

 

 

 

All credit for this goes to Stuart who posted this originally but it may be what you're looking for.

 

http://www.canalworld.net/forums/lofiversi...php?t13364.html

[magnetman]

Whatever anyone tells you though, any method of measuring current will produce a very small volts drop in the circuit being monitored.

 

what about a clamp-meter?

[Ex- Member]

To the MODS, is there a reason that this type of info cannot be put in a sticky , maybe called Projects?

 

Good idea on many car forums there's a How to Do threads where members do a certain jobs, just as Stuart has done and it's there for reference.

 

Cheers Greybeard this printed off brilliantly with all photo's

 

http://www.ledgardbridge-boatcompany.com/C...arch/index.html

[John Orentas]

Another photo of a typical shunt installation, when buying an ammeter instrument digital or analogue make sure it is of the center reading reading type, it will show positive or negative flow.

 

http://www.canalworld.net/forums/index.php...si&img=1734

 

The sense conductors are the black sheathed twin cable, they carry only a tiny current at typ. 50mV

 

The units above the shunt are two doubled up relays for the 'split charge' facility.

[Ex- Member]

Another photo of a typical shunt installation, when buying an ammeter instrument digital or analogue make sure it is of the center reading reading type, it will show positive or negative flow.

 

http://www.canalworld.net/forums/index.php...si&img=1734

 

The sense conductors are the black sheathed twin cable, they carry only a tiny current at typ. 50mV

 

The units above the shunt are two doubled up relays for the 'split charge' facility.

 

I'll check that out.

 

Some very neat and tidy electrical installation there John, looks good

[Ex- Member]

Just a quick thank you to Stuart, I used his, Guide: Installing An Ammeter & Shunt. Like most these things you realise how simple the job is once you,ve done it The guide was great though cheers

 

Not fitted the ammeter yet, I'm sorting a nice panel for the 2 volt displays and ammeter display, should be all done next weekend, so I'll post some photo's then.