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Bobert · 09-28-2018, 05:44 AM

Quote:

Originally Posted by wulfraat

This topic comes up so often - I threw together a couple (very basic) diagrams for you. Before & after the viltron shunt install.

disclaimer: These are from memory, but close enough

I am also including a battery disconnect switch diagram. installing a mechanical switch (BlueSea or otherwise) in the battery box will prevent unwanted loads from drawing down your batteries even when they are in the "store" mode. these include propane detector, subwoofer and inverter when in standby mode.

Enjoy.

Thanks for the diagrams. If I wanted to add the Zamp port, which side of the shunt would the negative lead go on?

ROBERT CROSS · 09-28-2018, 06:41 AM

Quote:

Originally Posted by Bobert

Thanks for the diagrams. If I wanted to add the Zamp port, which side of the shunt would the negative lead go on?

Does this help?
You can see the negative goes thru the shunt.

Bob
🇺🇸

uncle_bob · 09-28-2018, 07:47 AM

Quote:

Originally Posted by Bobert

Thanks for the diagrams. If I wanted to add the Zamp port, which side of the shunt would the negative lead go on?

Hi

The negative of *everything* goes to the negative side of the shunt. The only exception to this is the negative of the battery. It goes to the other side of the shunt.

*All* the current from any load or power source needs to go through the shunt. That can only happen if nothing but the shunt connects directly to the negative of the battery.

Crude diagram:

ALL BLACK WIRES ----->. SHUNT - ..... SHUNT + -----> BATTERY NEGATIVE
FROM EVERYWHERE

Bob

ROBERT CROSS · 09-28-2018, 08:05 AM

UB

A question...two batteries in separate compartments, two cables on the +buss and 2 on the -buss.
Am I correct that the shunt can be connected to just one neg cable directly from the battery? 😳

Bob
🇺🇸

rmkrum · 09-28-2018, 10:22 AM

Quote:

Originally Posted by ROBERT CROSS

UB

A question...two batteries in separate compartments, two cables on the +buss and 2 on the -buss.
Am I correct that the shunt can be connected to just one neg cable directly from the battery? ��

Bob
��

It depends. Typically you would want to measure the total current going into or out of the "battery bank". I'm assuming the batteries are tied together on the negative side and the positive side with two cables from the batteries to a negative bussbar and separate positive cables from both batteries to a positive bussbar, and the loads all connect to the positive bussbar.

Therefore, if you want to know the current going to and from from BOTH sets of batteries, connect the two battery negative leads together to the negative battery side of the shunt. All the other return leads, etc from the loads, including any DC chassis ground connection goes to the negative load side of the shunt. The idea is to make sure EVERY electron going in or out of the battery goes through the shunt before it goes anywhere else.

ROBERT CROSS · 09-28-2018, 01:23 PM

Quote:

Originally Posted by rmkrum

It depends. Typically you would want to measure the total current going into or out of the "battery bank". I'm assuming the batteries are tied together on the negative side and the positive side with two cables from the batteries to a negative bussbar and separate positive cables from both batteries to a positive bussbar, and the loads all connect to the positive bussbar.

Therefore, if you want to know the current going to and from from BOTH sets of batteries, connect the two battery negative leads together to the negative battery side of the shunt. All the other return leads, etc from the loads, including any DC chassis ground connection goes to the negative load side of the shunt. The idea is to make sure EVERY electron going in or out of the battery goes through the shunt before it goes anywhere else.

Only three connections on the pos buss... converter and the two battery cables. All 6 on the neg buss are full, some with 2 leads. One 6g wire goes from the pos buss to the use/store then to the 12v fuse panel.

Bob
🇺🇸

uncle_bob · 09-29-2018, 07:28 AM

Quote:

Originally Posted by ROBERT CROSS

UB

A question...two batteries in separate compartments, two cables on the +buss and 2 on the -buss.
Am I correct that the shunt can be connected to just one neg cable directly from the battery? 😳

Bob
🇺🇸

Hi

There is no free lunch in this case. You need to get the negative from both batteries to the top side of the shunt. Everything else goes to the bottom side of the shunt.

I had pretty much the same issue when I put the two lithium's in the battery box and the other two under the sofa. I decided to bring all the "load" wires indoors and put the shunt there. The "negative" wire from the outside batteries had to be added to the setup.

The shunt needs to be indoors / kept dry so even with all the batteries in the battery box, you may well run a negative wire back indoors. Having in with all the other stuff makes the rest of the wiring a bit easier, but that's not the big issue.

Lots of fun !!

Bob

waninae39 · 09-29-2018, 09:37 AM

this is our new monitoring setup after adding the victron controller for the 3000W controller/inverter

**Hans627** · 09-29-2018, 07:12 PM

Quote:

Originally Posted by wulfraat

By the way here’s a picture of the blue sea battery disconnect switch installed in the battery box. You really should consider putting one of these in so you don’t destroy your batteries with a constant draw.

What model disconnect switch did you use?

Thanks!

ROBERT CROSS · 09-29-2018, 07:24 PM

Quote:

Originally Posted by uncle_bob

Hi

There is no free lunch in this case. You need to get the negative from both batteries to the top side of the shunt. Everything else goes to the bottom side of the shunt.

I had pretty much the same issue when I put the two lithium's in the battery box and the other two under the sofa. I decided to bring all the "load" wires indoors and put the shunt there. The "negative" wire from the outside batteries had to be added to the setup.

The shunt needs to be indoors / kept dry so even with all the batteries in the battery box, you may well run a negative wire back indoors. Having in with all the other stuff makes the rest of the wiring a bit easier, but that's not the big issue.

Lots of fun !!

Bob

Well another 2' needed...👌🏽🤓

Bob
🇺🇸

uncle_bob · 09-29-2018, 07:27 PM

Quote:

Originally Posted by ROBERT CROSS

Well another 2' needed...👌🏽🤓

Bob
🇺🇸

Hi

You don't want to know just how many shipments of wire (and lugs and ...) came in from Amazon while I was re-wiring the trailer .....

Bob

ROBERT CROSS · 09-29-2018, 07:34 PM

Quote:

Originally Posted by uncle_bob

Hi

You don't want to know just how many shipments of wire (and lugs and ...) came in from Amazon while I was re-wiring the trailer .....

Bob

Tell me about it...Amazon missed todays delivery, new crimper set and Zamp solar harness. 👎

Hans...I went simple.

Bob
🇺🇸

uncle_bob · 09-30-2018, 07:22 AM

Quote:

Originally Posted by ROBERT CROSS

Tell me about it...Amazon missed todays delivery, new crimper set and Zamp solar harness. 👎

Hans...I went simple.

Bob
🇺🇸

Hi

They did that to me a couple of times while I was rewiring. We had a deadline and everything ran right up to it. There still are one or two other chores that need to be done as a result.

I also have this giant pile of wire and lugs if anybody else wants to stop by and wire their trailer ....

Bob

jftompkins · 10-01-2018, 08:38 AM

Maybe a dumb question - to simplify 712 shunt install: Have two Lifeline GPL-4CT 6V in series. If the battery box is sealed with a weatherproof gasket could the shunt be installed simply between the two batteries in series to measure current...as what goes through the batts must go out to cover all flow of charge in/out?

ROBERT CROSS · 10-01-2018, 09:18 AM

If this style Bbox... I don't see how it will be sealed 100%. We have the 'box' on the Classic, (but no batts in it), and I had to drill drainage in the bottom even after putting a gasket on the lid.

...I believe the shunt will live better inside. Maybe you could encapsulate it. Even in a bag condensation may be an issue.

Bob
🇺🇸

kb7our · 10-01-2018, 09:19 AM

I think this represents what you are asking about the shunt between the 2 batteries which is what I did:

jftompkins · 10-01-2018, 11:30 AM

Quote:

Originally Posted by ROBERT CROSS

If this style Bbox... I don't see how it will be sealed 100%. We have the 'box' on the Classic, (but no batts in it), and I had to drill drainage in the bottom even after putting a gasket on the lid.

...I believe the shunt will live better inside. Maybe you could encapsulate it. Even in a bag condensation may be an issue.

Bob

[emoji631]

Thanks....will probably go with conventional wisdom from this forum....thinking now “outside the box”.

jftompkins · 10-01-2018, 11:36 AM

Quote:

Originally Posted by kb7our

I think this represents what you are asking about the shunt between the 2 batteries which is what I did:

Yes....thanks for sharing another way to do it.

uncle_bob · 10-02-2018, 09:24 AM

Hi

The gotcha with the shunt isn't the shunt it's self, but the circuit board attached to the shunt. It's very much an un-protected item and not designed for outdoor use. Having spent my life designing that sort of stuff, it takes a lot to protect a board like that from the elements. Mounting it in some sort of box helps, but is far from perfect.

Of course, they aren't all that expensive. If it fails, just buy another 712 and replace it....

Bob

gator.bigfoot · 10-02-2018, 09:42 AM

Quote:

Originally Posted by jftompkins

Maybe a dumb question - to simplify 712 shunt install: Have two Lifeline GPL-4CT 6V in series. If the battery box is sealed with a weatherproof gasket could the shunt be installed simply between the two batteries in series to measure current...as what goes through the batts must go out to cover all flow of charge in/out?

The batteries need to "breathe" if they are not lithium, which the Lifelines are not. Therefore do not put the batteries in a sealed box. That hydrogen gas has to go somewhere.