Talk me into a Cerbo?

[sailingharry]

Since Victron is mostly power management, figured this is the right forum.


On another thread, Jedi was pushing the value of the Cerbo (well, maybe not "pushing" -- how about "commenting on its value?"). I don't have one, haven't really thought about one. So I went looking, and learned a bit.


Here's my boat:
* Alternators are happily running on Balmar regulators
* No generator
* Four SmartSolar MPPT controllers
* Multiplus
* Watt and Sea
* Victron Pegaus multi-voltage 50A charger -- dumb as they come, but not used much
* Link2000 battery monitor
* Impending DIY LFP bank with "some" BMS (or, if Jedi convinces me, no BMS).
* No onboard always-on WiFi and no desire to have it
* No desire for remote monitoring. I really should walk the 100 feet down the boat a few times a week anyway...LOL
* Existing tank monitoring system that watches 2 fuel, 2 water, and 1 waste tank. Except for the fuel, they all use the external capacitive style monitoring so not compatible with the Cerbo. No desire to replace it.
* Nice digital temperature displays on the fridge/freezer thermostats. Easy to see from most anywhere in the boat.
* All the smarter Victron stuff is linked to my cell when on the boat (bluetooth connections).


So, what does the Cerbo do for me? It seems like a lot of money for something that mostly provides external monitoring. All the sensors it can support are expensive, and replace existing sensors that work fine. Unless you also buy an expensive display, you still need to use your phone. I don't tweak my system much, at least not at present, so the ability to adjust my Bulk/Float/etc on the fly is kind of pointless. I have no dump loads (I guess I could do something fancy with my hot water tank -- but since my inverter is rarely on, that would require turning on the inverter AND enabling the water heater. We tend to motor at least some daily, so water is mostly hot anyway.


So, convince me. Tell me what wonderful Nirvana I'm missing! I know all the cool kids have one.

[rslifkin]

Mine does a few things for me. For reference I'm currently running AGM house batteries.

The DVCC feature on the Cerbo allows the Multiplus and MPPTs to all use the same temperature reading for the batteries. And the MPPTs end absorb based on amps, but they're using the amps actually going into the battery (via the SmartShunt and DVCC) not the amps their putting out, so it's accurate regardless of system load, how many MPPTs, etc.

I have the external display for it, so that shows power status, battery status, etc. I also have always on internet on board, so I do use it for remote monitoring (and it logs data I can look back at later). I don't have my tank monitoring run through the Cerbo (although I may change that in the future), but I have temperature sensors in the cabin and engine room, so it'll send high or low temperature alerts. And the high water alarm in the bilge is hooked up both to an audible alarm and to one of the inputs on the Cerbo, so if I get a high water alarm while away from the boat I'll get an alert to my phone.

In your case it doesn't sound like you have a big need for the Cerbo, but if you ever wanted to start integrating more of your systems and/or have some remote monitoring, then it would be worthwhile.

[fxykty]

Does Jedi recommend no BMS with DIY LFP batteries? I don’t think he does.

Anyway, a Cerbo is a way to control your Multiplus, solar regulators and any other equipment that is compatible with a single command interface from your BM so you don’t have to go to each piece of equipment and update settings there. Doesn’t apply to the Balmar, but your BMS can control their output itself. Same for the Watt & Sea. It if you’re not planning a network either, then probably no need to bother.

[sailingharry]

Originally Posted by fxykty

Does Jedi recommend no BMS with DIY LFP batteries? I don’t think he does.

Yes. https://www.cruisersforum.com/forums...ml#post3937378


He even makes a fairly compelling case. The discussion started with his commenting that the Electrodacus at under $200 was overpriced and unnecessary.


Of course, ABYC isn't relevant for him with a Dutch flag. My insurance (BoatUS) doesn't currently mention LFP in any fashion, but if ever ABYC compliance is even mentioned, a BMS is step one. Since BMS isn't defined, you may well be able to argue that adjustable charge controllers and a BMV/Cerbo is a "Battery Management System."

[barcoMeCasa]

One thought... if your wallet is open anyway... swap the link 2000 for a victron smartshunt, then the smartsolar regulators make decisions based on what is going on in the batteries instead of what is going out of the regulators. Then with LiFePo4 you can stop charging at the top voltage knee at the batteries.

If it's just some sophisticated monitoring you want a raspberry pi 3 will work well running openplotter, it gets victron data over bluetooth so no wiring needed.

Then on any device which can display a web page >

[sailingharry]

I'm pretty impressed with the SmartShunt as a huge cost/benefit item and is super easy to install (no wires to run or displays to mount), and recommend it often. BUT.


The Link 2000 not only provides great info on the main bank (which it will continue to do after LFP), but the same info on my start battery. This is virtually unheard of in modern battery monitors. Push a button, I can see charge amps, volts, Ah, etc. I'm keeping it because of the start battery, and because I can easily see it at the Nav station (the SmartShunt also doesn't easily provide a display).


My solar currently gets actual battery volts, not just what it sees, as my Multi has the bluetooth dongle that no only allows bluetooth control of the Multi but gets battery temp and volts (direct, not at the Multi) and shares that data across the entire Victron ecosystem. So all 4 MPPT know the volts right at the battery terminal. When that was set up, I did notice a significant change in solar operation!


The other thing is that in Lead, knowing actual battery current is a critical, but almost always missing, piece of charge data. You fundamentally cannot go to float without knowing what is going into the battery. This is what MaineSail used to call "Premature Floatulation," and virtually all chargers of any type do this and if the MPPT controllers actually use the amps from the SmartShunt to transition to float this would be HUGE. However, this issue completely disappears with LFP, because, as I understand it, you shift from Bulk to Float at a voltage level, and "tail current" is not a factor. Since my MPPT already know the battery terminal voltage (from the dongle), that should already be a non issue. And as an aside, my alternators also know the actual battery volts with the sense lead, so again, no problem.

[barcoMeCasa]

Originally Posted by sailingharry

I'm pretty impressed with the SmartShunt as a huge cost/benefit item and is super easy to install (no wires to run or displays to mount), and recommend it often. BUT.


The Link 2000 not only provides great info on the main bank (which it will continue to do after LFP), but the same info on my start battery. This is virtually unheard of in modern battery monitors. Push a button, I can see charge amps, volts, Ah, etc. I'm keeping it because of the start battery, and because I can easily see it at the Nav station (the SmartShunt also doesn't easily provide a display).


My solar currently gets actual battery volts, not just what it sees, as my Multi has the bluetooth dongle that no only allows bluetooth control of the Multi but gets battery temp and volts (direct, not at the Multi) and shares that data across the entire Victron ecosystem. So all 4 MPPT know the volts right at the battery terminal. When that was set up, I did notice a significant change in solar operation!


The other thing is that in Lead, knowing actual battery current is a critical, but almost always missing, piece of charge data. You fundamentally cannot go to float without knowing what is going into the battery. This is what MaineSail used to call "Premature Floatulation," and virtually all chargers of any type do this and if the MPPT controllers actually use the amps from the SmartShunt to transition to float this would be HUGE. However, this issue completely disappears with LFP, because, as I understand it, you shift from Bulk to Float at a voltage level, and "tail current" is not a factor. Since my MPPT already know the battery terminal voltage (from the dongle), that should already be a non issue. And as an aside, my alternators also know the actual battery volts with the sense lead, so again, no problem.

Ah, one of these? > https://www.victronenergy.com/meters...-battery-sense

Didn't even know it existed

Give a smartsolar the battery voltage & the top knee is so obvious

[pcmm]

Originally Posted by sailingharry

The Link 2000 not only provides great info on the main bank (which it will continue to do after LFP), but the same info on my start battery. This is virtually unheard of in modern battery monitors. Push a button, I can see charge amps, volts, Ah, etc. I'm keeping it because of the start battery, and because I can easily see it at the Nav station (the SmartShunt also doesn't easily provide a display).

I'd argue that the start bank (as its only job should be to start the engine) doesn't have any need for amps and Ah monitoring as nothing should be drawing off that battery anyway. Voltage tells you rough SoC and if its charging. Really that's all that is needed. I'd actually choose a BMV-712 over the smart shunt. You get 2 important features with the 712 that you don't get with the smart shunt. a display (for those times when you just need a quick glance a V) and the ability to trigger a relay if needed. and it still has bluetooth and Ve.direct to connect to the Cerbo with.

I'm just starting to do the same conversion, but I'm using Venus OS, the Raspberry pi based version. to get to the equivalent of a Cerbo-s GX and screen I'm in for $200 instead of $600 which leave me money for the BMV and a Smart MPPT to get my system upgraded from old Linkpro and Tracer equipement.

[rslifkin]

I agree, in a well designed system the start battery shouldn't need much monitoring. I pay no attention to mine for the most part. The 2 start batteries have their own charger, and nothing draws from them when the ignition keys are off. So they're always either sitting there full, being floated by the charger, or charged by the alternators when the engines are running. Basically they're never not full, so the only monitoring is for condition and when it's time to replace them.

[sailingharry]

Originally Posted by barcoMeCasa

Ah, one of these? > https://www.victronenergy.com/meters...-battery-sense

Didn't even know it existed

Give a smartsolar the battery voltage & the top knee is so obvious

I didn't know about that one either! But, no, this is what I have (connects into my MutliPlus to provide bluetooth access, but also provides volts/temp) -- at 3 times the price of the nifty little sensor you found.
https://invertersrus.com/product/ass...smartdongle/td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}

[sailingharry]

Originally Posted by pcmm

I'd argue that the start bank (as its only job should be to start the engine) doesn't have any need for amps and Ah monitoring as nothing should be drawing off that battery anyway. Voltage tells you rough SoC and if its charging. Really that's all that is needed. I'd actually choose a BMV-712 over the smart shunt. You get 2 important features with the 712 that you don't get with the smart shunt. a display (for those times when you just need a quick glance a V) and the ability to trigger a relay if needed. and it still has bluetooth and Ve.direct to connect to the Cerbo with.

I pretty much agree 100% with you.


The start battery really doesn't need monitoring. I rarely even look at volts. But the device is there, and can tell me volts, and if I really care I sometimes look at Amps (rarely, but it's nice to see that it's pumping in 1 or 2 amps...). The 712 has an input that CAN be used to monitor a start battery voltage, but not if you use it for mid-point volts, or for battery temp. Pick one of the three! If you use that input for something else, you need a volt meter of some sort for the start battery. But, since I have a fully installed LINK2000, and pulling a different wire from the batteries to the Nav Station would be a major job, it's staying until it dies!


The BMV is much superior to the SmartShunt. However, for retrofit, the SmartShunt is much easier to install. No cable to run, no holes to drill in cabinetry. For me (and most of us here on CF), the added "complexity" of the BMV install is minimal. For those that have weak DIY skills, or pay for work, the SmartShunt is a super simple install. Just one 6" battery cable, and done! And even for me -- my battery bank is buried under the port quarterberth, my Nav Station is midships starboard. Running that cable is not for the faint of heart, and installing the display in the quarterberth removes most of the benefit of the display (but installing it there makes the relay much closer to anything the relay would do).

[Mal Reynolds]

Umm, what problem are you trying to solve? Doesn't sound like you have one.

[barcoMeCasa]

Originally Posted by sailingharry

Running that cable is not for the faint of heart, and installing the display in the quarterberth removes most of the benefit of the display (but installing it there makes the relay much closer to anything the relay would do).

Never really thought about it but the only display I have on the whole boat is depth/log in the cockpit. & VHF if that counts. All the other data (a lot!) is wifi into whatever device is nearby on a webpage, been like that for years now & not a problem 😁

A step too far for many but even then, both would be very useful.

[sailingharry]

Originally Posted by Mal Reynolds

Umm, what problem are you trying to solve? Doesn't sound like you have one.

Exactly. My system, as currently installed and as envisioned with an impending LFP install, seems to provide most of what the Cerbo does. The Cerbo doesn't seem to add any value (that I want -- if you want bilge monitoring, or cabin temp monitoring, or have off-boat access, etc, my system doesn't do that). But since it's the latest and greatest cool thing, and people seem to want it, I am wondering if I'm missing something that I would want. But the general response so far has been "it's great if you want this, and it's great if you are building from scratch, but not so much if you pull out working stuff to put in the same function."


Tearing out my existing tank monitoring system (including the incompatible sensors), buying an always on internet connection, tearing out the existing battery monitor, doubling up on existing fridge temp sensors, adding cabin temp sensors, adding a bilge pump connection, all to get what I already have (except for off-boat monitoring) is a much harder sell than installing it on a bare boat or part of a major refit.

[rslifkin]

Originally Posted by sailingharry

Exactly. My system, as currently installed and as envisioned with an impending LFP install, seems to provide most of what the Cerbo does. The Cerbo doesn't seem to add any value (that I want -- if you want bilge monitoring, or cabin temp monitoring, or have off-boat access, etc, my system doesn't do that). But since it's the latest and greatest cool thing, and people seem to want it, I am wondering if I'm missing something that I would want. But the general response so far has been "it's great if you want this, and it's great if you are building from scratch, but not so much if you pull out working stuff to put in the same function."


Tearing out my existing tank monitoring system (including the incompatible sensors), buying an always on internet connection, tearing out the existing battery monitor, doubling up on existing fridge temp sensors, adding cabin temp sensors, adding a bilge pump connection, all to get what I already have (except for off-boat monitoring) is a much harder sell than installing it on a bare boat or part of a major refit.

Agreed. I put the Cerbo in with the rest of my Victron gear. At the point when I did that, I was adding solar, an inverter, etc. to a boat that never had any of that. The only thing I removed and replaced with the new stuff was a Blue Sea battery monitor and shunt (which I set aside for future use elsewhere as it was working and not all that old). And some of the other functionality (like temperature and bilge monitoring) I've tied in later. Not because I needed it, but because I had an easy opportunity to do it.

The one thing I haven't done but might is replace the existing Blue Sea tank monitoring setup (for fresh water and waste) by moving the sensor connections over to the Cerbo. I haven't confirmed if the Blue Sea ultrasonic sensor in the waste tank will work with the Cerbo, however. I wouldn't mind hooking the fuel level senders up to the Cerbo as well, but I haven't found an easy or cheap solution to do that as they're currently connected only to the gauges at the helm (which are only powered with the engines running, further complicating things and I don't want to lose the dash gauges for fuel).