Shunt usage for two displays

[legacyturbo]

Dont know if its the right place for this post but maybe someonne knows if its possible to use one amp shunt for two different displays. (i have an victron bmv and an chargery bms, wonder if i can use one shunt for both)

Thanks for your help.

 

[GVSolar]

Great question... would love to see the answer as I have a couple of different meters but I'd prefer to use one beefy shunt.

 

[Craig]

yes it will work without issue

 

[markb]

I would think so. It’s just like using two multimeters simultaneously to measure the voltage drop across the shunt.

 

[GVSolar]

As an aside, is a 75mv shunt interchangeable with a 50mv shunt, and if so, how does it affect the readings?

 

[jasonhc73]

Yes, it will work.

Why do you want to know the amperage twice?

 

[GVSolar]

Basic math. ?Three story house... two legs.

 

[legacyturbo]

Yes, it will work.

Why do you want to know the amperage twice?

Because the original chargery shunt is very inaccurate

 

[SCClockDr]

As an aside, is a 75mv shunt interchangeable with a 50mv shunt, and if so, how does it affect the readings?

NO & YES
If depends on the equipment reading the shunt's output. Most displays are limited to either a specific current/mv rating or a few specific current ranges all. @ the same mv rating.
If the display is programmable (Arduino, Pi, etc) or has a shunt profile setting matrix, then yes.
A 75nv 100 amp shunt develops a 75mv voltage drop @ 100 amps current flow. 75/100=750uv per amp.
A 50nv 100 amp shunt develops a 50mv voltage drop @ 100 amps current flow. 50/100=500uv per amp.
Without adjustment the meter will read 40% low with the 50mv shunt.
Deltec markets hi quality stunts in several amp to mv ratios. I prefer them for my DIY Arduino protects. More $$$ though.

 

[Steve_S]

I use the Deltec 500A/50mv shunt with the Chargery which of course required it to be recalibrated for it. I have been using Deltec's for years (It's what Midnite Solar uses) and never had issue with accuracy. I never used the shunts sent by Chargery. You can run two gauges / monitors off one shunt but you do have to be careful when connecting them up, this isn't a problem. I'm paying $30 CAD for each 500A/50mv Deltec (from the bulk box, not separately packed ones) from my local solar supplier. Shop them around a bit BUT note there are many models to pay attention, some have provision to add a Negative Bus Block on the side as well, which is handy for tapping into for some devices.

MKB & MKC series is what your interested in.

DC AMMETER SHUNTS | Deltec Shunts, LLC

 

[Solarfun4jim]

NO & YES
If depends on the equipment reading the shunt's output. Most displays are limited to either a specific current/mv rating or a few specific current ranges all. @ the same mv rating.
If the display is programmable (Arduino, Pi, etc) or has a shunt profile setting matrix, then yes.
A 75nv 100 amp shunt develops a 75mv voltage drop @ 100 amps current flow. 75/100=750uv per amp.
A 50nv 100 amp shunt develops a 50mv voltage drop @ 100 amps current flow. 50/100=500uv per amp.
Without adjustment the meter will read 40% low with the 50mv shunt.
Deltec markets hi quality stunts in several amp to mv ratios. I prefer them for my DIY Arduino protects. More $$$ though.

@SCClockDr
So does that imply that a 100mv100A shunt will be twice as accurate as a 50mv100A shunt(i dont know why i seem to have a mental block on this...lol)

 

[BiduleOhm]

All other things being equal, yes.

 

[SCClockDr]

@SCClockDr
So does that imply that a 100mv100A shunt will be twice as accurate as a 50mv100A shunt(i dont know why i seem to have a mental block on this...lol)

I would say a finer resolution ie. more mv deviation per amp. A 100mv 100 amp shunt is 1:1, a 50mv 100 amp shunt is 0.5:1.
The resistive material the shunt uses is more related to its accuracy than its mv rating.

 

[Solarfun4jim]

I would say a finer resolution ie. more mv deviation per amp. A 100mv 100 amp shunt is 1:1, a 50mv 100 amp shunt is 0.5:1.
The resistive material the shunt uses is more related to its accuracy than its mv rating.

Thanks SCClockDr, so how can you tell from the specsheets, which is going to be the most accurate at measuring...or is this solely down to practical experience/recommendations/heresay reviews etc?

 

[SCClockDr]

Thanks SCClockDr, so how can you tell from the specsheets, which is going to be the most accurate at measuring...or is this solely down to practical experience/recommendations/heresay reviews etc?

A quote from their site. "The resistance blades are made from manganin shunt metal for its low temperature co-efficient, long-term stability and strength."

 

[Solarfun4jim]

A quote from their site. "The resistance blades are made from manganin shunt metal for its low temperature co-efficient, long-term stability and strength."

Thanks SCClockDr.
However, if comparing several different manufacturers, all using the same materials, is there any way of going by the figures in the datasheets to determine which is likely to give the highest accuracy?
I was thinking along the lines of a 100mv100A shunt being more accurate than a 50mv600A shunt(both being made of the same materials) in a setup where normal loads are 30-40A with occasional 100A loading..... or do these figures simply not affect the accuracy to any noticable extent?

 

[BiduleOhm]

However, if comparing several different manufacturers, all using the same materials, is there any way of going by the figures in the datasheets to determine which is likely to give the highest accuracy?

Look for the tolerance or class figure. Most good ones are 0.5 % accurate.

I was thinking along the lines of a 100mv100A shunt being more accurate than a 50mv600A shunt(both being made of the same materials) in a setup where normal loads are 30-40A with occasional 100A loading..... or do these figures simply not affect the accuracy to any noticable extent?

It will, but I'd recommend to not use a shunt to full rated current, only around 50 % max. In your case a 200 A shunt would be better.

 

[Solarfun4jim]

Look for the tolerance or class figure. Most good ones are 0.5 % accurate.



It will, but I'd recommend to not use a shunt to full rated current, only around 50 % max. In your case a 200 A shunt would be better.

Much appreciate your input.

 

[SCClockDr]

What @BiduleOhm said ^^^^!