Simarine Pico - modern touchscreen battery monitor & tank level display

jmaikamon

New member
Rob, I meant to ask you before. For the black tank do you have any issues with paper or "anything else" hanging on to the float whereby making it sink or hang up giving false readings?
 

robzr

Member
Rob, I meant to ask you before. For the black tank do you have any issues with paper or "anything else" hanging on to the float whereby making it sink or hang up giving false readings?
I don't have a black water tank (just a cartridge toilet), so I have no idea from personal experience, but an ultrasonic sensor might be smart for that one. Also, KUS makes the SHS series for this purpose, that has the float inside a protected tube. Zero experience with it myself, but one of those two options would be what I'd look at. Let us know how the sensor installation goes!

Rob
 

jmaikamon

New member
Rob, I ordered the sensor for the blackwater and gray water tanks today. Even though they are different manufactures I think they should work. Will let you know how the installation goes. Thanks again.
 

Wyuna

Member
Wow thats a great looking system, although i like the panel board with the switches and the matching light switches more.

I hate having different looking switches and panels, i must have OCD.

I ended up with Votronic system, as everything from there panels and switches tie together.

if i build again, i'm going to have to look at this Simarine gear.
 

jmaikamon

New member
Rob, I got the sensors today and I couldn't wait to get it done. After a few hundred "@#$#^$%* *&s" and "#wx5trrk6gis" I finally got her done. The SHS sensor on the black tank worked like a charm. I filled it and watch the Pico as it went up and emptied it. The KUS sensor is giving me an issue. I filled the tank about half (i think) but it said 100%. The instructions for the sensor said "electrical" so I changed it to the voltage side of my ST107 and changed the settings on the Pico. Still not right and it got dark I figured I'll hit it again tomorrow. I wanted to ask you which side did you use voltage or ohms. Also what did you use as your calibration points 240-33? Thanks.
 

robzr

Member
Rob, I got the sensors today and I couldn't wait to get it done. After a few hundred "@#$#^$%* *&s" and "#wx5trrk6gis" I finally got her done. The SHS sensor on the black tank worked like a charm. I filled it and watch the Pico as it went up and emptied it. The KUS sensor is giving me an issue. I filled the tank about half (i think) but it said 100%. The instructions for the sensor said "electrical" so I changed it to the voltage side of my ST107 and changed the settings on the Pico. Still not right and it got dark I figured I'll hit it again tomorrow. I wanted to ask you which side did you use voltage or ohms. Also what did you use as your calibration points 240-33? Thanks.
Glad to hear the install went smooth. It definitely needs to be on the resistance side. I'd recommend calibrating it when it's actually full and actually empty. I think mine is around 37 ohms full and 235 ohms empty (from memory). Make sure you aren't flip-flopping empty and full! Also, the interface was a little wonky when trying to set the calibration points, it took a few tries.

If you'er still having trouble, post the actual resistance (ohm) measurements when empty and full and we can hopefully figure out what's happenin'.

Rob
 

jmaikamon

New member
Glad to hear the install went smooth. It definitely needs to be on the resistance side. I'd recommend calibrating it when it's actually full and actually empty. I think mine is around 37 ohms full and 235 ohms empty (from memory). Make sure you aren't flip-flopping empty and full! Also, the interface was a little wonky when trying to set the calibration points, it took a few tries.

If you'er still having trouble, post the actual resistance (ohm) measurements when empty and full and we can hopefully figure out what's happenin'.

Rob
Rob, I installed the sensors and they are working great. Thanks for the advice.
Now I'm working a different issue. I'm using a 260AH lithium battery but I can't find the C20/C10/C5 numbers the system requires. When I'm programing the system I get a whole range of % remaining and time remaining. I talked to the battery MFR (Greenlife) and they gave me one number, 1C. The rep said that is the only C rating for their batteries. Now I'm stumped.
 

john61ct

New member
Run load tests yourself.

Need that done regularly as SoH declines over time anyway for accuracy.

With LFP should be needed less frequently, start off manually.
 

robzr

Member
Rob, I installed the sensors and they are working great. Thanks for the advice.
Now I'm working a different issue. I'm using a 260AH lithium battery but I can't find the C20/C10/C5 numbers the system requires. When I'm programing the system I get a whole range of % remaining and time remaining. I talked to the battery MFR (Greenlife) and they gave me one number, 1C. The rep said that is the only C rating for their batteries. Now I'm stumped.
That's funny. So for SLAs like AGMs, the faster you draw current (higher amp discharge rates), the battery becomes less efficient. So typically the number you see advertised for an AGM is the C20, which is the capacity if the battery were drawn down from 100% to 0% in 20 hours. But if you draw it down faster, like over 10, 5 or 1 hours, the capacity decreases due to increasing inefficiency. My Fullriver 115 Ah AGMs have a C20 of 115 Ah, C10 of 104 Ah and a C5 of 91 Ah - so it's a pretty significant decline as discharge current goes up. The Pico (and every SoC monitor) has to compensate for how fast the discharge happens at different times (not just how much discharge total) to properly estimate remaining capacity. This effect is formalized as Peukert's law, if you google it you can see an actual calculation that may be the basis for the algorithm that SoC monitors use internally.

Lithiums based batteries do not suffer from a dramatic Peukert effect like AGMs do, this is one of their big advantages in some applications. So the mfg is basically saying, just use C1 for everything. Like John said if you REALLY wanted accuracy you could try load testing and measure for yourself, but personally that wouldn't be high on my priority list of things to do, unless you noticed in actual use that the SoC monitor was giving you questionable readings. I have never done that, it sounds like a fair bit of work to do it right, one of those things I'll do when I have excess free time :)

Rob
 

Midwestdrifter

Engineer In Residence
Capacity reduction with regards to AH at high discharge rates for lithium is pretty minor. I would just use the same value for all entries and then see how accurate it is. You can make adjustments based on your observations.

Lithium batteries will deliver fewer kilowatt hours at higher discharge rates. Although this effect is substantially lower than lead acid.
 

jmaikamon

New member
Rob, you are RIGHT, I'll add that to a list of things that I would do if I was really bored. Load testing would be long and arduous. Since I have that one 260AH battery instead of multiple batteries I am pretty trusting of its performance. I think something that would be worth my time more is to get more information on the whole of my energy performance. I want the PICO to tell me how many Volts/amp my panels are producing, how many Volts/amps my charge controller is putting in my battery, how many Volts/amps is my inverter/charger putting in my battery.
For now I'm gonna work on monitoring my consumers on the PICO. I know I can't do 110V consumers and my 12V only power lights, fans, actuators, and pumps so I'll monitor those. I have a question for the way you wired your SCQ25. In the manual it shows the the consumer going to the "out" side of the SCQ25 and the "in" goes to/from the battery.Is that right? It seems backwards to me.
 

robzr

Member
In the manual it shows the the consumer going to the "out" side of the SCQ25 and the "in" goes to/from the battery.Is that right? It seems backwards to me.
You can do it either way, in the setup on the Pico you reverse it (in software settings)... I wired the shunts both ways, depending on which had cleaner/shorter wiring.
 

mjuevos

Member
rob is this kus sensor ok to be in drinking water reserves? im considering going your pico route.
thanks for the knowledge :)

While installing the Pico I redid some cabling; bought some bulk welding cable and a hydraulic crimper. Wired up 2 AWG to the inverter, 4 AWG to the rear and front sub panels and 6 AWG from the MPPT controller. The 4x 25 amp shunts on the SCQ25T module are nice, they can go up to 35A for 1 minute or 50A for 5 seconds, and can be run in parallel to double the rating if needed. In hindsight I wish I had paid a little extra for a ST107 and a SCQ25 to separate the quad shunt shunt module from the tank and temp module, as it was a pain to fit everything in such a small spot while I spent hours wedged under the bed in an awkward position, but I'm happy with how it came out.

Wired up the 0-90 ohm Rochester TS011 that's on the frame mount manchester 7 gallon LPG tank, and it was super simple to program, and works like a charm.

The KUS USA SSS 240-33 ohm level sensor was also a quick install onto the 16 gallon freshwater tank, just had to run to the hardware store for some nice self tapping screws, no silicone needed, and programming it into the Pico required just two calibration points (enter the level and corresponding ohms, it calculates the curve).

Attaching some pics, I'll try to get some better pics, the iPhone doesn't do so hot in low light.

Rob
 

robzr

Member
rob is this kus sensor ok to be in drinking water reserves? im considering going your pico route.
thanks for the knowledge :)
I'm learning as I go! The KUS is stainless and rated for drinking water... we've been using it and we're still reasonably healthy and definitely alive :) It is a Chinese company, so a bit of a trust-me situation, if you were really concerned about that you probably can't go wrong with an ultrasonic sensor instead, but that probably bordering on paranoia. I personally wouldn't use the no-name asian imported senders in my drinking water, but they are probably identical to the KUS ones. So far the KUS has been working great!
 

robzr

Member
I replaced the Morningstar ProStar MPPT with a Kisae DMT-1250, swapped out our 2x Group 31 115h AGM bank for a single Renogy 170 Ah LiFePo4, and replaced our starter & aux lead acid's with new Napa/Deka 9AGM49 AGMs. All our old batteries were aging, the SLAs were on their last legs and the main bank AGMs were definitely showing diminished capacity. Haven't had it out on a trip yet, but everything seems to be working as hoped after a week or two of testing.

The DMT-1250 is set for a 35a charge rate which matches the recommendations on the LiFePo4, and should keep the alternator draw closer to the 40a mfg recommendation. I'm hoping to baby this setup and get a long, reliable life out of it. The Renogy LiFePO4 is pretty new to the market, so it's a bit of a gamble, but we were unwilling to go with a single 100 Ah LiFePO4 and dual 100's were out of the budget. Time will tell if this was a smart choice.

The Renogy battery is likely a relabeled Chinese OEM battery as available on Alibaba for $950 shipped. The cell construction (3.4 Ah IFR26650 4S53P, weight, size, appearance and BMS parameters are all identical. However, the Renogy is $1349 shipped from Amazon and comes with a prorated 5 year warranty, while the Chinese one has no warranty, probably takes ages to ship and if it arrives damaged, good luck. It's a bit early to say much about it, the physical build quality seems fine, it's half the weight and roughly the same size as one of the Group 31 AGMs (fits in the same battery box). It takes a charge and seems to hold it, other than that it's too early to say much else about it.

The DMT-1250 I'm pleased with. The interface is very simple, has a basic LCD UI. I won't buy the remote when it is available, I don't see it being very useful once setup, as I'm running the output into two of the 25a Pico shunts, so I can see the current output which is all I really need. It is nicely configurable, so I'm running the Renogy recommended 35a current/14.4v bulk and 13.5v float with a conservative 7 amp termination current. The CH2 (alternator input) is connected to my aux battery, so that can act as a buffer. So far, when charging at 35a, with a fully charged aux battery, it continues charging ~10-30 minutes after ignition is terminated, which is great (until the AGM drops to 12.0v). I figure when the LiFePO4 is fully charged, I can go quite a bit longer than that in float and power supply mode, which allows the Aux to effectively be the first tier in discharge before isolating to the LiFePO4. With a low discharge rate, this might allow us to use somewhere up to ~50% of the AGM capacity before it cuts off, which is just about perfect.

I'm planning on wiring up a Blue Sea 2146 SPDT with a small relay for full control (always-disconnect, auto, always-connect) to allow for combining the starter and aux AGMs with the engine off, which would let us tap into ~50% capacity of both starter and aux, which would cut the discharge current to half and let us more effectively tap into the AGMs. Can't think of a downside...:thinking:

Rob
 

Midwestdrifter

Engineer In Residence
The DIY route is a bit involved. The prismatic cells do offer better charge/discharge rates, but I wouldn't say they are necessarily more robust, especially over 100AH per cell. The smaller cylindrical ones are pretty resistant to vibration and impact damage. However in the 12V nominal application you end of with lots of parallel strings, which can cause its own issues.
 

john61ct

New member
Starting to wonder if I shouldn't have gone the route of a DIY pack based on something like 4x of the CALB 200Ah LiFePO4 cells with a simple 200a BMS or so, for more capacity, better rates, more durable cells for less money. :thinking:
Yes, known-good quality cells are only assured from the top makers **and** a trusted supply channel.

Otherwise a roll of the dice.

And the internal BMS without comms to outside controls can be very limited.

But I am skeptical of BMSs too, would want to see the spec sheets and user docs on that ECPC unit.
 

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