Simarine Pico: Good ideas in battery monitoring & more

... written for Panbo by Ben Ellison and posted on Sep 4, 2017

Simarine_Pico+_battery_monitoring_sleep_screen_aPanbo.jpgWhile this boat's main battery bank is at 73% state of charge (SOC) -- a near minimum for some lead acid owners intent on long term battery health -- the lightning icon and blue up-arrow indicate that the charging sources exceed the loads and, in fact, a 100% SOC is expected in 9.5 hours at current rates. The 3.5-inch touchscreen is also displaying time and barometric pressure with trend, and this is just the sleep screen of what seems to be a very modern family of reasonable-cost monitoring products. Say hello to Simarine...

Simarine_Pico_2017_model_line_aPanbo.jpgWhile Simarine only recently showed up on my radar, the company has been developing its Pico monitoring systems in Europe since 2013 and intends to take on the U.S. market next year. But we're living in a time of often easy global connections and commerce, and so it was a sailor who appreciated a Pico while chartering in Slovenia and then purchased a system online when he got home who led to my research. And while it's a bit daring to install a proprietary network of displays and sensors not yet supported locally, I certainly see the attraction.

Consider the value: a Pico Standard Package with a 300 amp digital shunt and lots of additional voltage, tank level and/or temperature sensing costs 399 Euros or about 500 dollars. And every Pico comes with WiFi, a powerful companion app, and a development road map that includes remote monitoring as well as an NMEA 2000 gateway.

Simarine_Pico+_battery_monitoring_load_detail_aPanbo.jpgThe Pico feature that strikes me as truly unusual and useful is the ability to measure individual loads and charging sources, and a good way to see how it works is to install the Pico iOS or Android app and run the demo mode. (And note that the app can also install firmware updates, a terrific modern convenience in my experience.)

While it's helpful to see a boat's major DC current consumers and generators in real time, I think that the holy grail of power management is logging that info for analysis. For instance, after all these years of running refrigeration largely by solar panels and testing many monitoring systems, I still don't know how much juice the reefer used yesterday or how much the panels put back into the battery bank. I have many ways to see the overall voltage state and SOC, but is Gizmo's refrigeration less efficient than it used to be, as I suspect?

Yes, the Stainless Lobster Fridge Optimizer could probably track (and improve) my refrigeration situation, and adding a Victron GX and BlueSolar controller could result in excellent panel and overall SOC monitoring, but Simarine seems embarked on an intriguing from-the-ground-up approach. For example, while it's not yet shown in the Pico app demo or the documentation, I'm told that multiple amp counters are built into the software, and a more comprehensive version, including long term battery voltage statistics, will soon be delivered in one of those easy app firmware updates.

Simarine_Pico_SCQ25T_multi_shunt_plus_aPanbo.jpgAnd what other company offers a shunt that can measure four different currents up to 25 amps, 12 or 24 volts, on either the negative or positive side? This $177 SCQ25T Combo Quadro Digital Shunt also includes four resistance sensing inputs for tank or temperature sensors, three voltage inputs and an alarm contact, and there's a SCQ25 Quadro alternative if you don't want the other sensors or if it makes more install sense to use a separate ST107 module.

Simarine_Pico_sample_wiring_diagram_aPanbo.jpgThis particular wiring diagram (worth clicking bigger) shows how a Combo Quadro might install along with the Pico display and a more conventional SC300 Digital Shunt (or the 500 amp version). Note that the "SiCOM" data network uses telephone style cables and connectors, which are certainly not as robust as the NMEA 2000 equivalent, but they are common on systems like this, and similar Victron and Blue Sky Energy data cables have survived Gizmo abuse fine.

According to the Simarine support FAQ, a bidirectional NMEA 2000 gateway will be available later this year, and that should at least be useful for displaying some of the monitoring values on other displays. Power monitoring does not seem deeply integrated into N2K yet, and most systems are also designed for other markets like recreational vehicles anyway (Maretron excepted and also bigger digital switching systems like CZone's).

Simarine_Pico_app_settings_collage_cPanbo.jpgSo if you choose a monitoring system like Pico, you are committing to a proprietary network of sensors and displays, but, then again, the developers can work fast with total control. And the results seen in the Pico app impress. For instance, the collage above shows what seemed like excellent sensor management, naming, and alarming, and while I've yet to put my fingers on an actual Pico display, I'll bet that using the app is preferable for setup work no matter how able the little touchscreen is.

The WiFi connection that enables the app (and easy firmware updates) is also a possible path to remote Pico monitoring, either directly via marina WiFi or through a boat router that might have a high power WiFi, cellular, or satellite connections. Pico router support is in the works and so is "a 3G/4G module that will be able to monitor as well as manage PICO products..." communicating "...two-way with a cloud platform so all data will be accessible at all times and the power usage will be very low." Modern!

Simarine_Pico+_tanks_n_barometer_aPanbo.jpgThe Pico manuals are a little vague about possibly important nuances like tank calibration, but I liked the implication that you can make an adjustment whenever you know a tank level with certainty. I also liked the barograph display and how I could specify the units and time period I like best.

Simarine_Nereide_power_panel_aPanbo.jpgSimarine has also developed the Nereide Smart Power Panel, though so far it's only mentioned on their Facebook page. Obviously, the Pico monitoring integrates well, and apparently the "Safety of Analog, Comfort of Digital" feature means that there are manual switches on the back of the panel in case something like lightning takes out the digital ones.

While there's already a Nereid app on iTunes, it doesn't yet demonstrate the panel setup and features like Scene Settings. The rich possibilities seem obvious, however, as does the combination of remote monitoring with remote control. Plus the Elan GT5 performance cruiser will be at several European and U.S. boat shows where the curious might poke around their standard Nereid and Pico installs. Hello Simarine!

Simarine_Nereide_power_panel demo app_aPanbo.jpg


Like many Battery monitors, this one left out the battery temperture sensor. If your monitor doesn't know the tempeture of the battery, its only taking a guess at when its fully charged. A fully charged battery at 10C wont be fully charge at the same set voltage as a battery at 30C. 10C battery at 100% SOC will be sitting at a much higher resting voltage, and counting amp flow alone doesn't catch a system leak or bad cell. This is why the Trimetric and Victron and Maretron are the only recommened monitors from the professionals.

Posted by: Walter at September 4, 2017 9:48 PM | Reply

Thanks, Walter, but you missed the fact that the big Pico shunts "precisely monitor battery voltage on 12V and 24V systems, battery temperature and continuous currents" at 300 or 500 amps.

Posted by: Ben in reply to Walter at September 4, 2017 10:37 PM | Reply

I see now in the manual that its included on the large shunts. But I still stand by if its not included in all packages it reflects poor corporate governance.

Posted by: Anonymous in reply to Ben at September 5, 2017 12:18 AM | Reply

Dear Walter, a battery temperature sensor is always included in the package with all of our 300A and 500A shunts. I am sorry, we need to make this information more clear on our website. The quadro shunts SCQ25 and SCQ25T are not intended to monitor battery banks, but instead the current draw/generation of the light consumers (eg fridge) or generators (eg solar). That is why the temperature sensor is not included with the SCQ25 and SCQ25T, because monitoring tempearature of the consumers/generators would not have any effect . We are new on the market and we highly respect our competition you mentioned. And I am certain we will join the list of recommended solution for professionals after our system will be put to use. Kind regards, Jaro from SIMARINE

Posted by: Jaro - SIMARINE at September 5, 2017 7:17 AM | Reply

That clears things up greatly, Thank you for the quick correction. And a big thank you for actually monitoring Battery banks correctly. I did notice the puplished manuels appear to be missing sections, so hopefully the manuel will catch up soon. The rest of the product really intrigued me and now knowing battery temperture is included, I will diffenetly take a look when this because available in Canada. Thank you again Jaro

Posted by: Walter in reply to Jaro - SIMARINE at September 5, 2017 10:06 AM | Reply

Interesting. Much to like here for the price. Also, I like how the date/time/baro pressure is included. It gives more justification / function to taking up real estate in the cabin somewhere.

4 shunts? Once I become curious about one device's power needs, then I become curious about more than 4. Can there be multiple shunts?

In regards to tank monitoring, how to deal with irregular tank shapes? Are there compatible sensors for measuring tank level by fluid pressure at the bottom of the tank? Would that work with bladder style water tanks?

Posted by: Dan Corcoran (b393capt) at September 5, 2017 12:42 PM | Reply

Very interesting, Ben (and Jaro)! I've been living with a pair of Link 10s for a looong time - something smarter would be nice :)
Examining the catalog of products saved me making some poor assumptions - for example, the 25 amp limit on the smaller shunts can be doubled to 50 amps by combining two channels. Since I have a 50 amp AC charger, this was a relief!
I agree that an N2K interface would be even better - especially if useful values could be displayed on my i70s (probably not, at least at present)
- And I love the mounting - one non-critical 13mm hole! Raymarine, take note...

Posted by: Hartley at September 5, 2017 12:44 PM | Reply

This seems great, but as the user of 2 fantastic systems monitors, 1 whole boat with remote access and 1 dedicated 4-bank power monitor, both no longer in production nor supported by their vendors (both of whom are still in business)... the obvious question is which system AND vendor does a boat owner back with their $ today in the hopes that either will be around tomorrow?

Let me add that on the subject of power monitoring, I'd like to see a return to current loops instead of shunts for measuring amperage. My old power monitor uses them, making installation trivial... just disconnect the power lead, slip on the loop, reconnect the lead, and wire in the sensor. These loops are pretty common parts. By comparison shunt installation is far riskier and more of a PITA.

Regarding that big Q, Practical Sailor endorsed at least 1 of those products (perhaps both), and both were built by veteran firms, not startups. 1 of those products was created ~20y ago. The lessons these guys learned, as well as their commercial scar tissue remains invaluable. Perhaps their products were way ahead of their time, but neither is re-entering the marketplace today. So for both today's new vendors and their prospective boat owner customers, both should invest/spend their $ in the recreational marine market carefully and with eyes wide open.

(And yes, if I had the chance to revisit my $ spend on these 2 systems 15y ago, I would still spend it today... it drives me nuts that neither is still available.)

Posted by: Liberty NY at September 5, 2017 1:26 PM | Reply


RE: Temperature monitoring.

As someone who has designed battery monitors with and without temperature sensors, I have a slightly different view on the matter.
The battery temperature affects the total capacity of the battery. All that is really needed is to indicate the lowest expected battery temperature and that will reduce the effective capacity of the battery. For those monitors that don't have the internal calculation you can manually reduce the capacity of the battery when entering it into the configuration parameters.
As for full charge determination, almost every SOC meter (Balmar being the notable exception) looks for the charging current to tail off as the charger goes from bulk charging to float. In this case it is important for the charger to have a temperature monitor so that the battery is properly charged to 100%.

Best Regards,

Andy Brown
Blue Sea Systems

Posted by: Andy Brown in reply to Walter at September 5, 2017 2:23 PM | Reply

When critical systems rely on a properly performing indication of SOC, a guesstimate is a fatal flaw. I could not reless Helicopters, or trust a remote renewable charge refueling station in the high arctic in my day job, based on a system that don't understand the true SOC of the batteies. Nor would I trust a battery bank in an offshore vessel with people onboard based on a guess of SOC. A battery monitor that doesn't take into account Battery tempeture can't tell the difference between a solar panel or wind turbine output droping off instead of the batteries reaching bulk charge, counting Ah's is only half the story because you can current leakage after the shunt, weather its internal of the battery or not. Batteries preform on chemical reaction, and every chemical reaction is 100% dependant on temperature. If I was to sail a boat north from the Baja to the Alaskan coast with a battery monitor not sensing battery tempeture. It would show fully recovered battieries at the end of the day when the solar panels stoped producing high amperage loads but the batteries are sitting at 14.4 volts. But the batteries really need to be sitting at a voltage closer to 15 volts when sitting at lower temptures. And to suggest the a consumer could make some calculated adjustment to make up for the lack of Temperature sensing is the problem I was pointing out above. 0.4-0.6 Volts difference is Substainial capacity when the difference betweeen full and damaged is only 3 volts. Its part of my professional career in releasing Aircraft to remote isolated destinations from -40°C to +40°C too understand that Temperature monitoring is absolutely critical. If your swapping batteries out every 3 years, often either your charger or your monitor is to blame.

Posted by: Walter in reply to Andy Brown at September 5, 2017 4:52 PM | Reply

Ben - The Pico system is impressive, especially the beautifully designed displays - kind of the polar opposite of the 1950's -style Smartgauge appearance.
But where did your comment about "73% state of charge (SOC) -- a near minimum for the long term health of many battery types -" come from?
To the best of my knowledge, 50% depth of discharge was the rule of thumb, even for traditional flooded lead acid deep cycle batteries - and the focus in newer technologies, like your own carbon Firefly's, is to drive that to 70 or even 80% discharged without impacting the long term health. Were you perhaps confusing the 73% SOC (charged) display with 73% DIS-charged?

Posted by: Grant at September 5, 2017 8:19 PM | Reply

Hi Grant. I could have phrased it better and just tried, but I was thinking of some lead acid comments put up on Panbo when I first thought about replacing Gizmo's house bank, like:

"The key to longevity is minimizing recharge cycles; try not to discharge more than 25% and never more than 50%."

It's the phenomenon RC Collins calls "Dead Lead"

Posted by: Ben in reply to Grant at September 6, 2017 7:52 AM | Reply

Hi Ben,
I see that comment now, from Don Parker in 2016.
I'm not sure what Mr. Parkers qualifications or experience are, or why he feels a 75% SOC threshold is a desirable target.
I am familiar with the term "dead lead", which quite aptly refers to the unusable portion of a batteries capacity as it affects long term battery life. I've also read Calder's work extensively, and to a lesser degree RC Collins, and I don't recall any cautions on discharging down to the 50% threshold.
Frankly, if the house battery can't provide AT LEAST that much useable capacity, it's hardy worth considering, given todays improving deep-discharge technologies. Accurate battery monitoring, which the Pico system seems to offer, is certainly important in leveraging that advantage. Sorry if this is heading off-topic, but I couldn't let that opening statement go completely unchallenged!

Posted by: Grant in reply to Ben at September 6, 2017 10:35 AM | Reply

I have a few question about the Pico in relation to SOC determination.

#1 How does the Pico deal with PSOC cycling as related to charge efficiency calculations and keeping SOC accurate during PSOC use?

#2 Is the Pico smart enough to know the difference between bulk and absorption as related to the highly variable charging efficiencies during each stage? In other words is the charge efficiency a single factor such as minus 10% or minus 15% on the re-count or is it smart enough to track varying charge efficiencies during re-charging.

#3 Can the Pico self-calibrate for charge efficiency on a full recharge?

#4 How does the Pico deal with the Peukert effect on both the high amperage side (loads above the 20 hour rate) and low amperage side (loads below the 20 hour rate)? A battery bank discharged at a fraction of the 20 hour rating, as most house banks are, on average, will have more usable Ah capacity than one that is discharged at the 20 hour rate or one that is discharged in excess of the 20 hour rate.

#5 Can the Pico track battery aging and declining Ah capacity?

#6 Does the Pico use learning software or data tables to compare with expected behavior?

#7 Does the Pico use any sort of SOC self calibration/correction such as comparing OCV to assumed SOC during periods of zero current flow?

#8 Is this an entirely new Ah counting software developed by your company, or an adaptation of the existing Ah counters already out there only in a nicer GUI?

Thanks in advance.

Posted by: Compass Marine at September 8, 2017 12:01 PM | Reply

I am so sorry if you are having trouble leaving a comment! Panbo security settings were recently changed and regular site visitors must clear their browser cache of site data in order to make registered or even anonymous comments. The command "Control-Shift-R" should do the trick on a Windows PC and I'm collecting info on how to clear other caches here:

Posted by: Ben at September 9, 2017 9:17 AM | Reply

Thanks, RC; I'm hoping your questions will spark more discussion with Simarine and others here. I'm also happy to see your work on your new website, particularly this very relevant entry:

Posted by: Ben in reply to Compass Marine at September 9, 2017 11:09 AM | Reply

Hi all: I am so sorry if you are having trouble leaving a comment! Panbo security settings were recently changed and regular site visitors must clear their browser cache of site data in order to make registered or even anonymous comments. The command "Control-Shift-R" should do the trick on a Windows PC and I'm collecting info on how to clear other caches here:

Posted by: Ben at September 9, 2017 11:09 AM | Reply


I think you are misunderstanding my point.
First, we aren't talking about monitoring helicopter batteries in the Arctic, we are typically in a more controlled environment where the battery temperatures are moderated by the water.
Second, all battery monitors drift overtime and can only be synchronized by approximating the capacity based on the Open Circuit Voltage or re-syncing once we have 100% state of charge. As best that I can tell, all marine based battery monitors determine state of charge once a particular voltage and current threshold is obtained or if an open-circuit voltage can be calculated. Solar power often fools these monitors into thinking the battery is 100% charged thus triggering a synchronization event. It is a tricky problem that I'm not sure anyone has found an optimum solution.
In any case we know that the apparent capacity of the battery decreases as the temperature drops, thus you can plan for a worst case temperature scenario by under stating your capacity. (You are going to want to plan for that anyways).
If you dig through the math you will find this is exactly what is happening internally in the SOC monitors.

The whole thing is further complicated in that the capacity of batteries vary widely from the published data (usually less).
As an added bonus, shunts are typically 1% and the meters are also roughly 1%, they also ask you to enter Peukert’s exponent and how accurate is that number?

BTW, as far as temperature monitoring, I am only talking about capacity monitoring. Your charger should always monitor temperature.

Hope this clears up some of the misunderstanding about how SOC is calculated.

If anyone has any questions, catch me at METs or contact me at Blue Sea Systems.

Posted by: Andy Brown in reply to Andy Brown at September 12, 2017 7:21 PM | Reply

Dear all,

here are the answers to some of the above questions.

#1, #2, #3, #6: Pico's algorithm is not a simple Ah counter. It is constantly monitoring battery current and voltage and temperature.
These data are compared to the internal battery model and its parameters are constantly being adjusted so that the model fits to the actual data.
The algorithm needs some time to adjust the parameters (learning phase) and it will improve accuracy during the first few cycles.

#4: You can can input battery capacities C/20, C/10 and/or C/5 in battery settings.
From these data, Pico can calculate Peukert.

#5: The screen for monitoring battery health (declining capacity) is not yet available in current firmware.
But Pico is capable of detecting these changes, and the screen will be available in one of the firmware updates in the near future.

#7, #8: Yes, since Pico is constantly measuring voltage and current (not only during periods of zero current flow).
So it is not only a simple Ah counter with a nice GUI, its algorithms are much more complex. It also shows you SOC for the battery without the shunt, but of course this value is not as accurate.
And last but not least, it is also a tank monitor and a barograph.

Kind regards,
Jernej - Simarine

Posted by: Jernej - Simarine at September 13, 2017 7:29 PM | Reply


I´m a follower of your web from Europe, really cool site, I just want to share my experience with PICO, just purchased PICO battery monitor Active shunt S300 and SC07. I really like the touch screen and its resolution really cool, also for the same amount of money you have some extra features like tank,temperatures,baro meter... monitoring. I really happy with this device and I can´t wait to get the future NMEA2000 bidirectinal hands on. I think it's worth every cent, and I want to pay for it.

I got in touch with Simarine due to a software bug and post sales support was flawless.


Posted by: Javier at September 16, 2017 7:31 AM | Reply

"While it's helpful to see a boat's major DC current consumers and generators in real time, I think that the holy grail of power management is logging that info for analysis."
Victron has been doing this for a long long time with their FREE VRM portal.
I can see daily and monthly usage for ac/ dc / solar, plus I get warnings if any of the alarm settings are met
Many of these devices reviewed by you also want a monthly fee, and Victron with their VRM has been providing the fore free

Posted by: serenity at September 16, 2017 9:05 AM | Reply

Thanks, Serenity; I agree that the VRM portal looks great, but that's why I linked to this Victron entry in the Pico discussion above:

Also note that none of these services is truly free if they only work with particular hardware, Victron does not provide the communications link between boat and cloud like many monitoring systems with subscriptions do, and I don't think that Victron has a multi-shunt like Simarine's.

Posted by: Ben in reply to serenity at September 17, 2017 4:51 AM | Reply

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