Victron Smartshunt Battery Monitor

[cmcardle75]

I'm not really sure that the temp sensor will work that well, at least in my case. It clips to the outside of the battery I believe. But for the purposes of monitoring the battery temp itself, you really want to know about the temp inside it, not just the case, which may fluctuate rapidly.

My battery is under a rear bench seat, in the same space as the Truma (there isn't much alternative to that, other than the opposite bench seat). Idea of it being with the heater is in cooler months, when using the van, the heater will keep the battery toasty so it will be more efficient.

Cooler temps will affect capacity and discharge / charge rates, but also too warm and things will go awry. Sterling's data sheet says max temp is 50 deg C for a cut off (inbuilt BMS) operation temp of -30 to 60 deg C, although the installation sheet says a charging temp range of 0-40 deg and contradicts the operation temp showing discharge as -10 to 55deg C

It depends what you want the temperature for. If the primary purpose is to cut charging below 5C, it just needs to be in the same compartment as the battery. However, if you're using it to squeeze in power at the highest rate without overheating, you need to get closer to the action.

 

[Wissel]

The temp sensor for the SmartShunt goes across the terminals. The one that goes on the outside of the battery (on the casing) is a stand alone part (it's what I have on my starter battery).

I've no idea why, but the discharge temps for LiFePO4 are usually lower than the charge temps. At least mine are.

Like you, my BMS monitors high and low temps. The thing is I prefer no single point of failure where possible, so having a second layer of defence protecting quite a pricey install is a good thing in my mind. Just my opinion though

 

[XxAnthxX]

The temperature sensor for the BMV-702/712 and Smartshunt sits on the same connection as its 12v supply.

Part number ASS000100000 (it’s the piece of wire I didn’t like the price of earlier....)

 

[Wissel]

The temperature sensor for the BMV-702/712 and Smartshunt sits on the same connection as its 12v supply.

View attachment 437077
Part number ASS000100000 (it’s the piece of wire I didn’t like the price of earlier....)

Yep, my mistake just making sure it wasn't this one:

 

[Stacetop]

This is what I am afraid of - and one of the reasons I don't want a smart meter any where near my house

Ha ha don’t worry my addictiveness is settling down! I’ve only checked the app twice today! I’m not using the van though - it’s on the drive and was fully charged by yesterday ha ha

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[autorouter]

The instructions specifically state to connect the starter battery negative to the negative side of the shunt....not a local ground, but maybe it would work? Why not connect to the other side of the shunt, which would be effectively the same as a local ground tho?

The idea of all this is to ensure that the only thing connected to the battery side of the shunt is the battery itself, nothing else. This ensures that all current going into and out of the battery passes through the shunt, and there is no bypass path to introduce inaccuracies

Often the battery negative is connected to the chassis, which acts as a ground. The ground should be connected to the other side of the shunt, not the battery side. The starter battery wiring can be left as it is. There is already a substantial connection between the negatives, often via the chassis or bodywork. There has to be such a connection for the leisure battery to charge from the alternator.

 

[Kannon Fodda]

Well wiring that up was a pain in the wotsit. The Bolts on the smartshunt are 10mm dia. Terminals on the battery were 8mm. Finding the replacement size terminals and worse crimping them without proper tools involved a lot of inappropriate language.

Bluetooth connected fine and seems to link with my solar. Just got to find proper settings for the smartshunt and then learn to ignore it

 

[XxAnthxX]

The Bolts on the smartshunt are 10mm dia.

Mine arrived today.....I’d read that the bolts were M10 so ordered suitable crimped 10mm SC eyes but they don’t arrive till tomorrow

Luckily I have ratchet crimpers and a hydraulic crimping tool

I originally considered drilling the 8mm eyes out to suit.....but it wouldn’t leave much metal on the sides

 

[Ditcha]

You could just use a piece of metal and drill a 10mm and 8mm hole in that's what I did instead of changing the crimps

 

[XxAnthxX]

Kannon Fodda did you create a VE Network on the Smartshunt and add your smartsolar to that network?

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[Kannon Fodda]

Mine arrived today.....I’d read that the bolts were M10 so ordered suitable crimped 10mm SC eyes but they don’t arrive till tomorrow

Luckily I have ratchet crimpers and a hydraulic crimping tool

I originally considered drilling the 8mm eyes out to suit.....but it wouldn’t leave much metal on the sides

Crimping tool would have been good but as a one off too expensive for that wire thickness. Ended up with a junior vice to squash it. Sort of worked but I’m sure the automotive bods would shudder.

Did try and drill out but the ends started to twist as metal became too thin.

 

[Kannon Fodda]

Kannon Fodda did you create a VE Network on the Smartshunt and add your smartsolar to that network?

Yes, but not really sure what benefit it has.

 

[Googlebot]

Crimping tool would have been good but as a one off too expensive for that wire thickness. Ended up with a junior vice to squash it. Sort of worked but I’m sure the automotive bods would shudder.

Did try and drill out but the ends started to twist as metal became too thin.

I drilled mine to 10mm.

To crimp I used a cold chisel and a big hammer.....

Sorry to all electricians out there.

 

[68c]

Crimping tool would have been good but as a one off too expensive for that wire thickness. Ended up with a junior vice to squash it. Sort of worked but I’m sure the automotive bods would shudder.

Did try and drill out but the ends started to twist as metal became too thin.

If you have to drill thin metal again suggest clamping it between two pieces of wood then drilling through. You may need to pre drill the wood so you can align the hole.

 

[XxAnthxX]

Yes, but not really sure what benefit it has.

Ah....that’s what I was going to ask

I noticed in the instructions it said create the network on the Smartshunt first and then add the smartsolar.....but was curious as to why.

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[eddie]

Style over substance. Victron are massively into the marine market, where the electrical installations are far more complex and data sharing and multiplexing is required.

I also love boats and have tended to swap backwards and forwards between little boats and bigger boats.

Our last ‘bigger’ (To us) was a 44’ Trawler yacht, it could be helmed from three different places on the boat, and it had massively more complicated electrical requirements, than my 29’ camper van

A bank of two large batteries for each of the two engines, totally independent of each other, likewise, a completely independent battery for the generator. Four large auxiliary batteries (leisure) and a separate pair of batteries as back up for the bow thruster.

All had to be independent, against the risk of failure.

All had to charge when on shorepower or running the genset, and all had to charge when running the engines, or running either engine, and the data (what was going on) was available anywhere

A lot of the installation of Victron and Mastervolt equipment we see in overkill, and only installed in our opinion as a result of upselling, }This one’s more expensive Sir, so must be better!}

 

[Kannon Fodda]

Ha ha don’t worry my addictiveness is settling down! I’ve only checked the app twice today! I’m not using the van though - it’s on the drive and was fully charged by yesterday ha ha

Hmm apparently I chewed through 30Ah of my 120Ah last night. And I thought I was holding back with one measly light and tv for a few hours. No wonder the original 75Ah lead acid didn’t cut it. Negligible solar today so by tomorrow especially if I fire up the laptop for a couple of hours work off a small inverter that Lithium is going to have worked hard.

 

[eddie]

The information is addictive but invaluable

 

[Wissel]

Yes, but not really sure what benefit it has.

With the additional temp sensor and the VE.Network connected, the MPPT can be set to stop charging if the battery temp is too low. This is the advantage I wanted.

Charge currents should also be more accurate, but doubt this would make much difference in a motorhome (just my opinion).

 

[Lenny HB]

Crimping tool would have been good but as a one off too expensive for that wire thickness. Ended up with a junior vice to squash it. Sort of worked but I’m sure the automotive bods would shudder.

Did try and drill out but the ends started to twist as metal became too thin.

I drilled mine to 10mm.

To crimp I used a cold chisel and a big hammer.....

Sorry to all electricians out there.

Tight wads hydraulic crimping tool is only £25

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[Kannon Fodda]

Th

Tight wads hydraulic crimping tool is only £25

thats more than the cost of the cable and terminals

 

[engelside]

I installed the smart shunt at the weekend and have been monitoring what is going on with battery over the last couple of days or so.

On Sunday I went in the van on drive and switched all electrical appliances on i.e. all the lights and the gas heating on full to cause the fan to run on full.

Some general observations!

I am assuming that all the shunt is doing is measuring the current flowing through the battery (load or charge) and the voltage across the terminals. The power figure is calculated from these - hence it fluctuating over the hour or so that everything was running. What is confusing is why over that period the current draw went from 6.22A to 8.1A? (some of that might be down to falling Solar input)

The current actual state of my battery is unknown as I had an issue with it a few weeks ago while in Scotland that has led me to believe it is not in a great state of health. See thread at Strange Battery problem

At the point I shut everything down on Sunday the app was showing 91% and 12.35V (under load) and 12.73V (no load). I went out later that evening and it was 91%/12.8V. The next morning 91%/12.79V (really overcast so no Solar input). By the end of yesterday (after sunset) the figures were 91%/12.88V. There had been a little bit of sun but mostly overcast all day so it had not really picked up much from panel.

This morning was bright and sunny and by 9:13 the solar input was 0.34A and the battery state was 91%/13.09V.

At 10:30 the battery was at 100% - 13.24V/0.65A.

This didn't make a lot of sense so I checked the connect manual and it states that

In case of a 12V battery, the SmartShunt will reset the battery’s state of charge to 100% when all these
parameters have been met:
• The voltage exceeds 13.2V,
• the charge current is less than 4.0% of the total battery capacity (e.g. 8A for a 200Ah battery) and,
• 3 minutes have passed while both the voltage and current conditions are met.

So this explains why the app thinks it is back at 100% - which it can't be can it having used about 8Ah on Sunday. There is no way it has put that much back in this morning via the panel.

It is possible to configure the app to change these parameters so I will have a think about what is appropriate. Alternatively I could just use the manual synchronise.

Can someone also explain how the voltage increases once the load is removed? i.e. just before switching everything off the Voltage was indicating 12.35V and after 12.73V.

 

[DBK]

I installed the smart shunt at the weekend and have been monitoring what is going on with battery over the last couple of days or so.

On Sunday I went in the van on drive and switched all electrical appliances on i.e. all the lights and the gas heating on full to cause the fan to run on full.

Some general observations!

I am assuming that all the shunt is doing is measuring the current flowing through the battery (load or charge) and the voltage across the terminals. The power figure is calculated from these - hence it fluctuating over the hour or so that everything was running. What is confusing is why over that period the current draw went from 6.22A to 8.1A? (some of that might be down to falling Solar input)

The current actual state of my battery is unknown as I had an issue with it a few weeks ago while in Scotland that has led me to believe it is not in a great state of health. See thread at Strange Battery problem

At the point I shut everything down on Sunday the app was showing 91% and 12.35V (under load) and 12.73V (no load). I went out later that evening and it was 91%/12.8V. The next morning 91%/12.79V (really overcast so no Solar input). By the end of yesterday (after sunset) the figures were 91%/12.88V. There had been a little bit of sun but mostly overcast all day so it had not really picked up much from panel.

This morning was bright and sunny and by 9:13 the solar input was 0.34A and the battery state was 91%/13.09V.

At 10:30 the battery was at 100% - 13.24V/0.65A.

This didn't make a lot of sense so I checked the connect manual and it states that

In case of a 12V battery, the SmartShunt will reset the battery’s state of charge to 100% when all these
parameters have been met:
• The voltage exceeds 13.2V,
• the charge current is less than 4.0% of the total battery capacity (e.g. 8A for a 200Ah battery) and,
• 3 minutes have passed while both the voltage and current conditions are met.

So this explains why the app thinks it is back at 100% - which it can't be can it having used about 8Ah on Sunday. There is no way it has put that much back in this morning via the panel.

It is possible to configure the app to change these parameters so I will have a think about what is appropriate. Alternatively I could just use the manual synchronise.

Can someone also explain how the voltage increases once the load is removed? i.e. just before switching everything off the Voltage was indicating 12.35V and after 12.73V.

I don't see anything odd in anything you've described.

These shunts and power monitors only give an estimate of remaining capacity which is why it has its own internal rules which reset the capacity to 100%. If it didn't over time if it was only counting amps in and out it would drift too far away from the actual state of charge.

The voltage rises immediately when the load is removed because under load there is a voltage drop due to the internal resistance of the battery. Subsequently, it will usually rise further due to chemical changes within the battery.

 

[Deneb]

I believe I originally got this from Victron, but I no longer have the link:

Victron Energy Battery Monitor – BMV 600-602

Recommended settings for Solar Systems to avoid inaccurate State of Charge readings.

Example System:

500A/H Battery Bank @ 12V
150/70 Blue Solar MPPT Charger
2000W Solar Array
BMV-600 Battery Monitor

Normal settings in set up menu of Battery Monitor

• CB – Battery Capacity
• DF – Discharge Floor

The rest of the default settings are usually correct for most applications where Battery Chargers are used to charge a battery bank with a Bulk-absorption-float charge characteristic. When the battery has absorbed the charge current the charge voltage drops to float charge and charge current slowly drops to almost nothing.

In Solar Application where charging is done via a Solar Charge Controller it is important to adjust the following settings. With Solar Charging the charge current varies all the time which affect the battery voltage also, the BMV monitors the Charge current and battery voltage as indicators of the state of the battery.

In the Set up menu the following setting must be looked at, here is the description of each.

Vc: Charged voltage. The battery voltage must be above this voltage level to consider the battery as fully charged. Make sure the voltage-charged-parameter is always slightly below the voltage at which the charger finishes charging the battery (usually 0.1 V or 0.2 V below the ‘float’ stage voltage of the charger).

It: Tail current. When the charge current value is below this percentage of the battery capacity (Cb), the battery can be considered as fully charged. Make sure this is always greater than the minimum current at which the charger maintains the battery, or stops charging.

Tcd: Charged detection time. This is the time the charged parameters (It and Vc) must be met, in order for the battery to be considered fully charged.

To summarize these settings, the BMV looks at both the VC and It settings and when these conditions are met for the time set in Tcd the BMV will assume the SOC is 100%.

The default settings for each are as follows:

Name Range Default Unit
Vc 0-90 13.2 V
It 0.5 – 10 4 %
Tcd 1-50 3 Min.

Taking our example system above we can see the following issues that can arise when the default settings have not been changed.

If after a night time cycle the battery SOC is 65% and the next morning the sun comes up and starts to charge the battery bank, we are assuming there is no other discharge taking place for the first 2 hours.

The charge current will not go to maximum because of sunlight and in turn the battery voltage will not rise to absorption level very quickly.

The situation now occurs that the battery voltage and charge current can settle within the default settings of the above settings for SOC synchronization to 100%!

How do we prevent this from happening, usually the Vc settings must be adapted to the battery bank voltage whether 12/24/48V, keeping it just below float level is advised. The It level is most often changed, here the level can be lowered to a 1 or 2%, this depends on the battery capacity and the possible (installed solar charger size) charging that can take place.

The Tcd is also increased to a longer time interval.

It is important to remember when during the charging process the battery monitor reads a negative current or discharge the whole process is reset.

When these settings are made, careful attention must be paid to how power is used on the site, if there is a constant discharge then the battery voltage will increase very slowly as the sun rises. If the main power usage is at night then more charging will take place into the battery and the voltage will react differently.

It is not always the case that the first settings made work perfectly.
---------------------------------------------------------------------------------------------------------------------

I find the following work well for me:

Charged voltage 14.4v (my solar regulator puts out 14.5v during absorption stage)
Tail current 2.00% (regulator drops below this threshold when switching to float charge)
Charged detection time 3m
CEF 95%
Time-to-go averaging period 12m (prevents large swings in monitor readings caused by intermittent high loads such as compressor fridge)

But I try not to rely on automatic synchronisation too much, and always do a manual synch reset when I know the batteries are 100% charged as determined by the battery full indicator on my Votronic solar regulator, that I have found to be a reliable indication.

To answer your final question, when a battery is under load the voltage will drop as it is "working". When the load is removed (switched off or disconnected) the battery rests, and its voltage will slowly recover to its natural resting voltage according to its current SOC.