Thoughts on installing Victron SmartShunt battery monitor

[GraniteStaters]

I purchased a Victron SmartShunt battery monitor because I believe it will provide my wife and I with better information about our 4 AGM batteries.  When I reviewed some of the recent posts about the install of Victron monitors, I see what appears to be best practice is to install it right after the negative battery terminal and before the inverter, solar controller, and main ground.  I was thinking of installing in the basement next to the inverter on the street side adjacent to the pantry.  What would I miss being able to monitor doing it the easy way, solar statistics?  Also, I know that I should use AWG 4/0 cable with THHN/THWN covered copper stranded wire with copper lugs, but as I read the spec, a smaller diameter wire can meet the spec if it has sufficient number of strands.  Does anyone know a reason why we should install battery AWG 4/0 wire for this application.  As I always, I appreciate the perspective of the more experienced owners in this forum.  I will heed your advice.

I will eventually post pictures of the install once the final design and install is completed.

David

[Overland]

I think if you have the 2000w inverter then you can go smaller.  There were some comments on this a little while ago but I can’t find the thread.  I think maybe it was about John Davies’ install.

I’m not sure what you mean about solar statistics.  The victron monitor is just a more accurate and more intuitive way of checking your charge, as opposed to going by the voltage level. 

[mossemi]

According to the Victron installation instructions, the battery negative wire goes directly to the shunt and it is the only wire connected to the negative side of the battery and the battery side of the shunt.  
What size wire you place between the battery and the inverter is determined by the voltage loss per foot of the connecting wire.  Since Xantrex specs a 0 gauge wire 6 feet or less, the stock 4/0 wire is overkill.  So you can connect the stock negative wire to the battery side of the shunt and connect the other side of the shunt to the inverter with 0 gauge wire and meet Xantrex specs.

It wouldn’t make any sense to reduce the size of the stock 4/0 unless you were really bored or wanted to reduce weight.

And you might want to reach out to AndrewK via PM.  He has helped multiple OTTO's with their BMS installs.

Mossey

 

 

 

[John E Davies]

I installed my shunt directly across the “gap” from the inverter, and used a short length of 4/0 cable..... I just cut the big negative cable going to the battery by that amount and crimped and soldered two new terminals. The cut-off scrap became a short jumper cable. I could have a used smaller size but this worked fine. The big cables Oliver uses are way, way overkill. I would have chosen 2/0 if I had bothered to go buy a new piece.

4/0 terminals are harder to find locally, more expensive and harder to crimp and solder. I don’t see anything positive about using such massive wire in this particular situation. 2/0 welding cable and fittings are universal.

John Davies

Spokane WA

Edited July 17, 2020 by John E Davies

[GraniteStaters]

Thanks, everyone.  I am going to do the I Install the shunt right before the inverter using a 4/0 gauge copper wire with soldered copper lugs fastening it to a piece of PVC that I will epoxy to the fiber glass between the inverter and the outlet there.   I will take pictures to add to the thread.  
 

I neglected to say that I did crimp the lugs too.  

Edited July 18, 2020 by GraniteStaters
Omission

[mossemi]

It is my opinion that you should not use soldered terminals.  A soldered terminal is subject to vibration and it is hard to apply that much heat to that large cable and terminal.  Just crimp them if you do it yourself.  And let me say that it is hard to crimp in the lower hull if that is what you were thinking unless you have a hydraulic crimper.  I would suggest checking the lug hole diameter on the existing terminal and make sure it is the right diameter for the shunt because I do not remember what size is needed.  Do not use a 3/8" terminal on a 5/16" bolt.  And a local battery shop can make up a short custom cable for the shunt to inverter connection.

I was lucky in that I had to remove my negative cable completely because of a broken cable gland, so all of my cable work took place at the bench.  But that means I was also unlucky having to remove that cable because it is a pain.

Mossey

[Overland]

I agree on the crimps. Some people do both, crimp but leave some exposed copper and solder that. Supposedly the solder seeps into the crimped area for a better bond. That may be the case for bad crimps, but I found with a hydraulic crimper that the crimp is so tight that the copper strands are practically fused together, so I think soldering would just be a placebo.  A hydraulic crimper is a worthwhile investment. 

Edited July 18, 2020 by Overland

[ScubaRx]

I bought a 16 ton hydraulic crimper off eBay for under $50.  I have used it for everything from crimping 4/0 cable to fixing my glasses. Yep, glasses. You can easily make your own dies for it and crimp (or crush) just about anything.

[John E Davies]

10 hours ago, ScubaRx said:

I bought a 16 ton hydraulic crimper off eBay for under $50.  I have used it for everything from crimping 4/0 cable to fixing my glasses. Yep, glasses. You can easily make your own dies for it and crimp (or crush) just about anything.

Do you think this is a smart buy? I am always a little leery of really cheap tools, can this be serviced it it should leak? (Orings, replace or bleed fluid). It says it is "greatly ideal for high-altitude working tasks. Made of superior carbon steel material as well as delicate workmanship". 

I am not quite sure how to interpret that.... Thanks for your comments. Maybe you could start a thread on this?

John Davies

Spokane WA

Edited July 19, 2020 by John E Davies

[BackofBeyond]

I once only purchased high quality (high dollar) tools and such, but honestly, the last several air tools, testing equipment and elec  tools, and such - that were almost give away cheap from the "freight" place have performed so well I cannot complain if they fall apart the next time I use them.  However, if I was full time needing the same equipment - perhaps not.

$50 for a working hyd crimper - If I could get a good number of crimps out of it - great. I have used one of the "hammer" crimpers - and I was happy with the results - for the job at the time.

RB

[Overland]

That looks like the same crimper I have. I got mine on amazon for ~$50. I’ve definitely gotten my money’s worth out of it and it hasn’t shown any sign of wear.  It had some reviews saying it broke easily but then what amazon product doesn’t. Overall the reviews were good. The only thing I don’t like about it is that you need three hands sometimes to use it. I wish it had a little stand that would make it stable on the ground so that you can easily hold the cable with one hand and operate the crimper with the other. 

Edited July 19, 2020 by Overland