Victron SmartShunt & battery cutoff switch installation

Marceline

While waiting for CA campgrounds to open I'm trying to complete my latest (and hopefully last) electrical project.
I have a 2013 clamshell that did not have a battery cutoff switch. So I'm adding a cutoff switch and the Victron SmartShunt at the same time. 
I bought an oversize battery box which will hold both my battery and the shunt, with a barrier between them. This eliminates the need for a separate watertight box for the shunt. I plan to mount the switch on top of the battery box. I've come up with a way to get a cable around the box so I can lock it all up.

The SmartShunt goes on the negative line per Victron instructions. My question: do I put the cutoff switch on the positive line or on the negative line? If on the negative line, do I put it 1) between the SmartShunt and the battery or 2) between the junction box and the SmartShunt?  My inclination is to install the cutoff between the SmartShunt and the battery so there is absolutely no drain on the battery (even the SmartShunt) while the trailer is in storage (no power).

Discuss.

CrabTab

Cut off switch goes on the hot (positive) side. Otherwise the electrical current could flow if there was an alternative ground for any reason. 

This will eliminate parasitic drain or shock if you were to contact a wire.

ScottG

At the risk of rekindling an old argument, positive side.

Electrically it doesn't matter if everything else is installed and functioning properly. However, as CrabTab indicated, that is not always a given. It's also what the instructions that come with those cut-offs tell you to do--probably for a reason.  ;-)

Note that when removing or installing a battery, the negative connection should be the first off and last on. There are good arguments for that, too, but they are different from those that apply to cut-off switches.

Sharon_is_SAM

@Marceline, I can understand why you want to avoid battery drain, but I wonder if every time that you turn off the battery and monitor, will you need to “reset” the monitor when you turn it back on?  Will it simply resume the settings?  Having asked that, the amount of battery drain is so small, it may not be worth it.  We picked up our TaB after 6.5 months in storage and the AGM battery was still at 100%.  Crazy!

Denny16

According to Victron, the Shunt is connected directly to the battery, it’s current drain in standby is very minimal, and will not normally effect a correctly charged battery.

Cheers

Cbusguy

There is a box in setup under battery tab that says reset stats to 100 percent after reset.....I turned this off and my stats hold when I turn the dc power off

Marceline

Denny16 said:

According to Victron, the Shunt is connected directly to the battery, it’s current drain in standby is very minimal, and will not normally effect a correctly charged battery.

Cheers

I'm concerned about how it would affect the battery over the longer term. I haven't been able to use my trailer since February. I store my trailer about an hour away from where I live. I need a solution that completely shuts off any drain on the battery when I park the trailer.

pthomas745

The spec sheet for the Smart Shunt says it uses "less than 1 milliamp."  One thousand milliamps equals one amp.  Every thousand hours (check my math!) it would use 1 amp hour.  So, one amp every 41 days.

https://www.victronenergy.com/upload/documents/Datasheet-SmartShunt-EN-.pdf

Marceline

pthomas745 said:

The spec sheet for the Smart Shunt says it uses "less than 1 milliamp."  One thousand milliamps equals one amp.  Every thousand hours (check my math!) it would use 1 amp hour.  So, one amp every 41 days.

https://www.victronenergy.com/upload/documents/Datasheet-SmartShunt-EN-.pdf

Right. So if I have to leave the trailer unused for 3-4 months, when I pick up the trailer the battery will be down ~3-4ah or about 4% of the battery capacity. I would much prefer that didn't happen. It seems to me that the entire point of having a cutoff switch is to prevent that.

CrabTab

@Marceline why don't you route the positive from the shunt to the same lug on the switch that would send power to the rest of the trailer? The switch would then control the positive to the trailer and the shunt...

Marceline

CrabTab said:

@Marceline why don't you route the positive from the shunt to the same lug on the switch that would send power to the rest of the trailer? The switch would then control the positive to the trailer and the shunt...

Now that's an interesting idea. Thanks!

Denny16

But hen you need to rest your Smart Shunt setup for the battery.  Also, a RV battery in storage without any load will loose the same amount of charge just sitting, which is why you should recharge a battery every six months while it is in “storage/not connected mode.  The shunt drain is so small, I would not worry about it.  

cheers

jkjenn

FYI, I recently heard that the Smart Shunts are out of stock and US dealers are looking at a 3-4 month lead time, right now, due to Covid.

MarkAl

Having just installed the Smartshunt in my new 320S AND found that the metal bucket holding the batteries severely limits the already marginal BT range, I need to move it inside the trailer.  Looking through this thread and the hand drawn diagram referenced, my question is it still as simple as it shows? That one of the white wires comes from the WFCO under the driver bench seat and the other to the trailer's hitch connection? If so the only significant hassle is extending the hitch ground into the trailer (for TV charge monitoring) and repurposing the existing WFCO Neg wire as the Battery Neg and under the bench connect the WFCO in the load side of the shunt with the trailer current monitor.  Also have to pull the battery temperature line from the battery Pos into the same bench area. Easy Peasy - One Battery Pos and the hitch negative wires (following the existing white wire), I was worried about ripping a lot of covers apart and drilling holes. My bench now has the Hughes Power Monitor, the Solar Controller and now the Smartshunt with Bluetooth and soon another controller for the portable array, actually I may just physically network the Victron products, less RF confusion ... Comments?

(diagram on https://tabforum.nucamprv.com/#/discussion/comment/53031)

Oh yeah, I tried releasing the probe wires on the Smartshunt - I failed, short of calling Victron, anybody done it? I tried pushing a paper clip into the little holes under the probe inserts.

DesertDweller

@MarkAl. Did you eventually move the SmartShunt to the inside of the driver side bench? I just bought a SS, but if the Boondock metal tongue box hinders its BT capacity, I may just return it if installing it near the WFCO is more complicated than my limited skills allow for. If you did move it, can you post some images of the connections?

Marceline

DesertDweller said:

@MarkAl. Did you eventually move the SmartShunt to the inside of the driver side bench? I just bought a SS, but if the Boondock metal tongue box hinders its BT capacity, I may just return it if installing it near the WFCO is more complicated than my limited skills allow for. If you did move it, can you post some images of the connections?

I think that you should go ahead and try it out in the tub before you give up on it. I have mine inside a Boondock tub at the front of the trailer and the BT range is sufficient for me to read the SmartShunt inside my car and inside my trailer. I installed my Smartshunt inside an oversize plastic battery box that I divided so that the battery is on one side and the smarthsunt on the other.

DesertDweller

Thanks @Marceline.  I can just wire it up in a non-permanent way and check the BT range.  I have been reading about the SmartS on the Victron Energy community forums and it seems that limited BT range is a common complaint about the SmartS.  I assumed it was universal.  Glad to hear that your unit has an effective range.  I will give it a try before my return window closes.  

BTW what AWG gauge of wire did you use to connect the -battery terminal to the corresponding terminal on the SmartS?  I noticed @MarkAl used a 6AWG battery cable, but I was wondering if something less beefy would be as safe.  

VictoriaP

Marceline said:

DesertDweller said:

@MarkAl. Did you eventually move the SmartShunt to the inside of the driver side bench? I just bought a SS, but if the Boondock metal tongue box hinders its BT capacity, I may just return it if installing it near the WFCO is more complicated than my limited skills allow for. If you did move it, can you post some images of the connections?

I think that you should go ahead and try it out in the tub before you give up on it. I have mine inside a Boondock tub at the front of the trailer and the BT range is sufficient for me to read the SmartShunt inside my car and inside my trailer. I installed my Smartshunt inside an oversize plastic battery box that I divided so that the battery is on one side and the smarthsunt on the other.

@DesertDweller I agree with @Marceline trying it first makes the most sense. Is it possible that MarkAl had trouble due to having the new 2021 tub? Doesn’t that have a mostly solid metal back panel with just some vents? I suspect that might interfere more with BT strength than our older BD tubs with no back panel, but I don’t know enough to say for certain. 

Will be watching as I plan this upgrade myself next year.

DesertDweller

I will post my results after I wire it up.  Yes, I do have the older tub w/o the solid backing (although I did add a "chicken wire" back just so stuff (tarps, etc.), do not fall out).  

MarkAl

I've left my shunt in the bin as I didn't want to cut wires under the bench without a good chance it would work. I know I can get most of the loads under the bench but I'm unsure about the TV charging current. In the bin I know I get everything. I am mystified why others with the metal bin works well. If the 2021's have more metal that could be it. I'm considering other options but at this time I go outside morning /evening and check battery status. Knowing the current used for different devices in the trailer because I have the shunt is a huge help. Then experience and solar situations during the day is enough for planning. I do not stress anymore on possibly ruining the battery, it's easy to plan.

Watching the shunt I've found a better understanding of how the refrigerator uses the battery power and is key. With my two 6Vs I have plenty of energy for it IF I have a few hours of access to sun. We've needed to turn it off after 3 days if we haven't had sun. In the winter the sun is so low it's very difficult to get solar in a campground for any length of time. Battery energy state (not just the voltage reading) is key then.

VictoriaP

@MarkAl The older Boondock bin had no back at all, so yes, your bin has significantly more metal surrounding the shunt. Guess we need to hear from a few more 2021 owners to see if that’s the issue, but I bet it is.

Glad to hear you find it useful in spite of having to go outside. I never wanted the monitor display, so I’m glad Victron came out with this model.

kbdigitiqe

2021 320s BD and my shunt is in the bin, perfect BT reception in both the trailer and tow vehicle

Denny16

@kbdigitiqe Is your Smart Shunt located close to one of the large holes in the back,of the 2021 Bin?  If som this would improve BT reception in the trailer.  

Mark, where in the front bin is your shunt located?  Can you move it close to one of the rear cutout next to the LPG regulator?  The smaller driver’s side cutout is near the battery switch and is where the battery wires are rounded through.  Try to get your Shut mounted close to this area, to increase BY reception.
cheers

MarkAl

I'd like to get a pic from @kbdigitiqe to compare! I was worried how much water would get into the bin so I stuck the shunt in a plastic conduit box - a bit bulky but I'm comfortable it won't get water onto the circuit board. The box limits where I can put it considering I've also got two 6V batteries in there. I've had it in a couple locations but always approximately above the batteries. I considered moving it closer to the holes but I didn't think it would help much. I still need access to the Propane and Bat. Switch so I can't put it very close. Looking at this again I could fairly easily move it under the Propane regulator. At least it's closer to a hole... Since it's pouring rain currently I'll wait to try it.

kbdigitiqe

sorry to clarify, I’m using the shunt plus monitor and it’s the monitor that has BT. This setup fit quite well too - the shunt is in the water proof box from Amazon tucked in behind the battery and I just double stick taped the monitor to the lid of the battery cover

kbdigitiqe

I wouldn’t be surprised either if the monitor had a more powerful BT antenna than the shunt 

kbdigitiqe

aaand if anyone is curious I’m using the 170ah Renogy Li battery and we run everything for 4+ days now with no sun and pretty much infinite with a little solar here and there to top us back up 

Marceline

MarkAl said:

I'd like to get a pic from @kbdigitiqe to compare! I was worried how much water would get into the bin so I stuck the shunt in a plastic conduit box - a bit bulky but I'm comfortable it won't get water onto the circuit board. The box limits where I can put it considering I've also got two 6V batteries in there. I've had it in a couple locations but always approximately above the batteries. I considered moving it closer to the holes but I didn't think it would help much. I still need access to the Propane and Bat. Switch so I can't put it very close. Looking at this again I could fairly easily move it under the Propane regulator. At least it's closer to a hole... Since it's pouring rain currently I'll wait to try it.

Is there any chance that mounting the shunt to the metal wall of the tub is interfering with the BT? 

MarkAl

I agree the different monitor may be better, the solar controllers under the bench are no problem picking up when in the vicinity of the trailers, only the shunt is an issue. I've found that the controllers can pick up the shunt's temp and data presence it's just my phone can't in the trailer.  I've thought being connected through the same power return may enhance the BT signal.

Also interesting on the 170 AH Li battery for 4 days what is your remaining capacity at 4+ days? I think about switching but we plan on winter camping and I wanted to get some experience in real (cold) conditions before committing to Li. I should mention the 2 1/2 days gets me to about 78-80% based on my 215 AH Lead Acid. After that we've either driven home or the next site or sun came out. I'm still learning to trust the %, I seem to see the voltage only when the refrigerator is running and start getting worried on the 3rd day. I've never seen remaining capacity under 70%  which is much better to monitor than the voltage! 

VictoriaP

MarkAl said:

Also interesting on the 170 AH Li battery for 4 days what is your remaining capacity at 4+ days? I think about switching but we plan on winter camping and I wanted to get some experience in real (cold) conditions before committing to Li. 

@MarkAl Lithiums work in the cold, they just can’t charge in below freezing temps. If you’re winter camping and considering lithium, you might look into some of the low temp LiFePo batteries out there now. They’re basically wrapped in a heater. The charge when you first plug in powers the heater to warm the battery, then feeds power to the internal charger once the battery temp is above 32°F. 

LifeBlue has a low temp option, but there are others out there too.

I believe the shunt with monitor having a stronger BT signal has been mentioned around here previously. A little frustrating, since the whole point of the SmartShunt is BT!

MarkAl

@VictoriaP These Lead acid batteries are my training wheels as this is our first trailer. I expect when these are retired we'll go to Li and by then the price may be more affordable. Though I didn't appreciate the weight penalty when going to two 6V. Mainly I wasn't knowledgeable enough on pitfalls of mixing both TV Lead and Li trailer systems with the different charging systems. I'm okay now but not then.