Adding Simarine Pico Monitor

[steilkurve]

Hey all. Planning to add a si marine PICO to be my battery monitor in my 2020 Bambi 22FB. Need some help with the connections. Attached is a photo of the current battery connections under the bed. It's the wiring form Airstream plus the solar added by the dealer. Could be cleaner, I know. On my to do to address. I just want to check that I'm planning to do this right. I will disconnect the negative from the bus on the left coming from the battery and plug it into the PICO shunt. I'll then add another short battery cable between the other connector of the PICO shunt and the bus on the left. I'll then have the voltage sensing wire going from the shunt to the positive bus on the right (and not straight to the battery). Is that correct? Any advice appreciated and thanks in advance for the help!

[steilkurve]

Anyone? Appreciate any input!

[GMFL]

Yes. The shunt will connect to the main Neg lead from the battery that feeds the Neg bus bar and any other DC loads

[Crackerman]

We are looking into adding a complete simarine setup in one of our builds, but it has nothing in common with newer airstream wiring as the trailer is built from the ground up. Sorry.

But in general, the shunt goes in the negative load side from battery, so if there is a negative cable for inverter or another ground attached to the battery, it needs to be relocated to the "load" side of the shunt.

[AKNate]

I’ve looked at the Pico’s online - they look very nice. I’d like to replace my SeaLevel II with one someday. They are supposed to come out with an NMEA 2000 module for them, which would let me easily connect it into my Victron system. Right now I just use a Venus GX and phone to see everything. It’s not ideal, but the Color Control GX was the only other option at the time, and that looked cheap and clunky to me. Victron now has some other options, but they all require too many wires.
I’m not familiar with your trailer model, but on mine the factory wiring splits out at the battery with one line going to the bus bar and one going to the inverter. You want to make sure all loads are going through your shunt. Also, with my Victron shunt, the voltage sense also does temperature sense, so you want it to be attached to the battery. Those are the only things that stood out to me from what you’re proposing, based on no experience with your model trailer or the Pico.
Let us know how it goes. I’d love to see the final install!

[steilkurve]

Originally Posted by AKNate

I’m not familiar with your trailer model, but on mine the factory wiring splits out at the battery with one line going to the bus bar and one going to the inverter. You want to make sure all loads are going through your shunt. Also, with my Victron shunt, the voltage sense also does temperature sense, so you want it to be attached to the battery. Those are the only things that stood out to me from what you’re proposing, based on no experience with your model trailer or the Pico.
Let us know how it goes. I’d love to see the final install!

Thanks!

Will for sure post pictures and how it went.

I don’t have an inverter and so there’s one negative lead that goes to the bus that’s it.

I assume I don’t have to worry about the power jack feeding directly into the batteries and the solar controller stays connected to the bus directly as is?

Pardon my ignorance but you say all loads need to go through the shunt, what do you mean exactly? The shunt will feed the negative bus and all that’s connected to it, no?

[AKNate]

The shunt is used to keep a running total of all the current flow through it, both into and out of the battery, to calculate the charge level of the battery. If your jack is the only thing not going to the bus bar, I’d just extend that wire so it does. Otherwise, every time you use your jack, your state of charge reading will get farther off. Some battery monitors can be set to occasionally reset back to 100% when the full voltage and no current flow is detected for a preset period of time. If you have something like that, maybe you don’t care about the small error the jack will introduce, since it will occasionally be cleared. I’d still just move it since it is a small wire and easy to do.
The solar controller feeding the bus bar is good. You want [Battery]—[Shunt]—[Everything connected]. There should be nothing but a straight wire from the shunt to the battery terminal. You can actually have the shunt on either the positive or negative side and it will work the same, but common practice and the safer way is to use the negative side.

Originally Posted by steilkurve

Pardon my ignorance but you say all loads need to go through the shunt, what do you mean exactly? The shunt will feed the negative bus and all that’s connected to it, no?

Correct. I just mean the only current path to the battery negative terminal should be through the shunt. No electricity gets into or out of the battery without going through it. It sounds like you have that, minus the jack.

[steilkurve]

Originally Posted by AKNate

The shunt is used to keep a running total of all the current flow through it, both into and out of the battery, to calculate the charge level of the battery. If your jack is the only thing not going to the bus bar, I’d just extend that wire so it does. Otherwise, every time you use your jack, your state of charge reading will get farther off. Some battery monitors can be set to occasionally reset back to 100% when the full voltage and no current flow is detected for a preset period of time. If you have something like that, maybe you don’t care about the small error the jack will introduce, since it will occasionally be cleared. I’d still just move it since it is a small wire and easy to do.
The solar controller feeding the bus bar is good. You want [Battery]—[Shunt]—[Everything connected]. There should be nothing but a straight wire from the shunt to the battery terminal. You can actually have the shunt on either the positive or negative side and it will work the same, but common practice and the safer way is to use the negative side.


Correct. I just mean the only current path to the battery negative terminal should be through the shunt. No electricity gets into or out of the battery without going through it. It sounds like you have that, minus the jack.

Got it. Thanks. I’ll see if I’m able to fish the jack cable insiste. Cables from the tongue are nicely sealed. Not sure I want to mess with that. Trailer is pretty new still.

At any rate, will report back with the job done. Thanks again for the help.

[rmkrum]

You don’t need to fish the Jack positive side wire into the trailer. It’s on the positive side of the battery already.

All you need to do is make sure the jack is grounded only to the A-frame. The load side of the shunt is tied to the frame ground at the DC negative bussbar.

The only wire on the negative terminal of the battery should be the one going to the battery side of the shunt.

[steilkurve]

Originally Posted by rmkrum

You don’t need to fish the Jack positive side wire into the trailer. It’s on the positive side of the battery already.

All you need to do is make sure the jack is grounded only to the A-frame. The load side of the shunt is tied to the frame ground at the DC negative bussbar.

The only wire on the negative terminal of the battery should be the one going to the battery side of the shunt.

Ok. Thanks. Since I have all you knowledgeable folks' attention, I'll push my luck and add a few more questions:

1) The Pico monitor itself needs power and is attached to a splitter, as they call it, that receives comms from the shunt and has 18-gauge wires for power. I'll connect those to the battery directly as I want it on all the time. Now, isn't 18-gauge wimpy? I get it's LED and all but seems under wired!

2) The AS battery cables are 6 AWG. The small piece I've bought to connect the shunt to the bus is 4 AWG. Thought I'd go better to avoid loss, if that's even a thing. Will that be a problem?

3) What's the black box above the bus in my photo above.

Thanks again all!

NP

[AKNate]

1) 18 gauge is more than enough for powering the Pico. From their website it looks like it draws 90 mA at max illumination, which is just over a Watt. You can easily power over 100 W at 12 V with an 18 awg.
2) No problem upsizing to 4 awg. Are you crimping lugs on?
3) No idea what that box is. My model trailer doesn’t have it. If you email Airstream, they’ll send you the electrical drawings for your trailer, which will show that and they’re good to have anyway. I’m sure someone on here will also be familiar with that box and can tell you.

[steilkurve]

Originally Posted by AKNate

1) 18 gauge is more than enough for powering the Pico. From their website it looks like it draws 90 mA at max illumination, which is just over a Watt. You can easily power over 100 W at 12 V with an 18 awg.
2) No problem upsizing to 4 awg. Are you crimping lugs on?
3) No idea what that box is. My model trailer doesn’t have it. If you email Airstream, they’ll send you the electrical drawings for your trailer, which will show that and they’re good to have anyway. I’m sure someone on here will also be familiar with that box and can tell you.

Thanks! Appreciate it. And yes, I’ll be crimping a lug on the existing 6 AWG cable from the battery as it doesn’t have one given the bus AS uses. The 4 AWG I’ve ordered online has lugs on already. I’ll just remove the lug and strip the end that goes into the bus.

[steilkurve]

Hey all. Kinda stuck with my install as fishing the power wires from the monitor straight to the battery is proving to be more of a challenge than I thought. Afraid to disconnect or damage something else as I go through the congested passage I’ve found. I also need a comms cable between those two points but luckily, it seems Airstream was kind enough to put a spare compatible RJ cable between the bus at the front where my Pico shunt will be and where the SeeLevel is at the back And where my Pico monitor will be. My question: Can I tap into the gas detector power cables which are easily accessible from where I’ll mount the monitor? These are powered straight from the battery, right? Thanks again.

[AKNate]

Originally Posted by steilkurve

Can I tap into the gas detector power cables which are easily accessible from where I’ll mount the monitor? These are powered straight from the battery, right? Thanks again.

On mine the LP detector is powered straight from the battery on a wire with a 1 A fuse. This wire is not downstream of the battery disconnect Use/Store relay, so it is always powered. That’s something to keep in mind if you decide to go that route - your Pico will always be powered.

[steilkurve]

Originally Posted by AKNate

On mine the LP detector is powered straight from the battery on a wire with a 1 A fuse. This wire is not downstream of the battery disconnect Use/Store relay, so it is always powered. That’s something to keep in mind if you decide to go that route - your Pico will always be powered.

That would actually be a good thing and why I was asking. The Pico always needs to be powered to properly calculate battery SOC. Only question is whether or not it would blow the fuse to have both the Pico and the LP detector connected through the same fuse?

[AKNate]

The Pico is only 90 mA and the propane detector is also very low draw. It should say on the back of it what the draw is, but I don’t think you’d be anywhere close to blowing the 1 A fuse. I would put a separate in-line fuse rated less than 1 A on the wire you run to the Pico so if the Pico faults it will blow that fuse and not the 1 A, which would also take out your propane detector.

[steilkurve]

Finally! Install completed. Pico is now functional in my Bambi 22FB! I was able to fish the comms and power wires from the bathroom in the back where I located the Pico to the bus/battery wires are at the front under the bed, where I installed the Pico shunt and made the battery connections. I didn’t have to tap into power wires along the way. Haven’t tried it on the road but early verdict: very good! I’m impressed by it. Useful additional information and unheard of UI for an RV product. I now have an estimate of time left until the batteries are depleted or charged. Thanks all who helped me prepare for this small project.

[steilkurve]

Originally Posted by steilkurve

Finally! Install completed. Pico is now functional in my Bambi 22FB! I was able to fish the comms and power wires from the bathroom in the back where I located the Pico to the bus/battery wires are at the front under the bed, where I installed the Pico shunt and made the battery connections. I didn’t have to tap into power wires along the way. Haven’t tried it on the road but early verdict: very good! I’m impressed by it. Useful additional information and unheard of UI for an RV product. I now have an estimate of time left until the batteries are depleted or charged. Thanks all who helped me prepare for this small project.

And here's a quick video of how I installed it:

https://youtu.be/fq7WdJ3DnBk

[AKNate]

Very cool. I can’t wait for them to release their NMEA 2000 module. It was supposed to be available Q3 of last year. They haven’t updated their FAQs to say when it is expected now.

[steilkurve]

Updating this thread with more current information about this installation.

I initially couldn't find the C ratings of my 2 Intersate SRM-24s required by Simarine for accurate calculation of the SOC. Interstate's email support didn't know and referred me to dealers. Didn't even tried that as I had no hope they would know. I guesstimated initially.

Had some time this week so called their live support who didn't know either but was very friendly and transferred me to one of their engineers' voice mail. Left a message and to my surprise, he called me back rapidly. He was super helpful and gave me the ratings as well as sent me the tech sheet. I thought I'd share with everyone in case anyone needs it. Below are the C ratings and attached is the full spec sheet from Interstate.

SRM-24

C20 = 81
C10 = 75
C5 = 66