Advanced monitoring of onboard electronics (Victron) using Raspberry Pi

[IanD]

1 hour ago, nicknorman said:

One member has the predecessor of the Wakespeed alternator controller, before it got expensive! Now it is $500 which is a bit pricy. My home made equivalent cost about £50, plus a lot of time of course. One problem is that such things are not plug-in accessories, they require “surgery” on the alternator to make the right connections.

I said it was good, not cheap ? [but $500 is cheap if it doubles the life of a $5000 battery bank]

 

Home-made is obviously much cheaper if your time is free and you have the knowledge to do it without killing alternator or batteries, which excludes many people...

 

On a new engine Beta Marine can supply alternators ready-configured for an external regulator, otherwise as you say some hacking is needed.

Edited October 9, 2020 by IanD

[Tony Brooks]

1 hour ago, IanD said:

I said it was good, not cheap ? [but $500 is cheap if it doubles the life of a $5000 battery bank]

 

Home-made is obviously much cheaper if your time is free and you have the knowledge to do it without killing alternator or batteries, which excludes many people...

 

On a new engine Beta Marine can supply alternators ready-configured for an external regulator, otherwise as you say some hacking is needed.

Are you sure about that. I don't know but suspect they just fit a fly-lead to the relevant rotor feed/earth and if so that will not allow any external controller to drop the voltage below the standard regulated voltage.

[IanD]

48 minutes ago, Tony Brooks said:

Are you sure about that. I don't know but suspect they just fit a fly-lead to the relevant rotor feed/earth and if so that will not allow any external controller to drop the voltage below the standard regulated voltage.

Yes I'm sure, they told me they fit a brush-box in place of the internal regulator, this brings both ends of the field winding out (two wires) to connect to an external regulator -- but you then have to use one configured correctly, without it (or if you screw it up) you'll destroy the alternator and/or batteries.

Edited October 9, 2020 by IanD

[nicknorman]

1 hour ago, IanD said:

Yes I'm sure, they told me they fit a brush-box in place of the internal regulator, this brings both ends of the field winding out (two wires) to connect to an external regulator -- but you then have to use one configured correctly, without it (or if you screw it up) you'll destroy the alternator and/or batteries.

All I had to do with mine (Iskra 175A) was to get a cheapo brush box/regulator module off eBay (around £15 IIRC), remove old one (3 screws, having taken the plastic back off the alternator). Snipped wires from brushes to regulator on eBay unit, connected one brush to case and the other taken out as a wire to the regulator. So not really major surgery - no surgery to actual alternator, just the brush/regulator module, but probably something a non-engineer might be reluctant to do to their shiny new alternator. The up side is that if my regulator dies, it will only take 15 mins or so to revert to the old regulator/brush box. But then at £50 or so for parts, I can obviously afford to carry a spare smart regulator.

[IanD]

3 hours ago, nicknorman said:

All I had to do with mine (Iskra 175A) was to get a cheapo brush box/regulator module off eBay (around £15 IIRC), remove old one (3 screws, having taken the plastic back off the alternator). Snipped wires from brushes to regulator on eBay unit, connected one brush to case and the other taken out as a wire to the regulator. So not really major surgery - no surgery to actual alternator, just the brush/regulator module, but probably something a non-engineer might be reluctant to do to their shiny new alternator. The up side is that if my regulator dies, it will only take 15 mins or so to revert to the old regulator/brush box. But then at £50 or so for parts, I can obviously afford to carry a spare smart regulator.

That's probably exactly what Beta do ?

[MoominPapa]

21 hours ago, Tony Brooks said:

As three members here have demonstrated is that you do not need expensive control systems on LIs, just an understanding of of the requirements and ensuring these are met in an economical way.

As one of the three members in question, I have to partially disagree. The control system I use doesn't rely on the user understanding the requirements of the batteries at all, and will do the necessary balancing and protection without any user intervention. It provides an accurate SoC indication, and the only knowledge needed to "use" it successfully is that average use is about 30% per day, and you for sure won't run out of juice if you keep the SoC above 10%. An advanced user might understand that leaving the batteries unused at 100% SoC is undesirable, and be able to operate the single control on the system to limit charging before leaving the boat, but that's not really necessary.  

 

I's say that for the vast majority of boaters, a control system that does that hard work is vastly preferable (and likely to be succesfull) to staring at ammeters and voltmeters and sucking teeth. One huge advantage if Li chemistry is that a control system can stop the user from doing stuff to break the battery. A huge disadvantage of Pb chemistry is that no control system can stop the user from doing stuff which results in a terminally sulphated battery.

 

MP.

 

[Dr Bob]

1 hour ago, MoominPapa said:

One huge advantage if Li chemistry is that a control system can stop the user from doing stuff to break the battery. A huge disadvantage of Pb chemistry is that no control system can stop the user from doing stuff which results in a terminally sulphated battery.

Fully agree.

It is not difficult to come up with a control system with off the shelf stuff for Li if you dont want to develop one yourself.

[Dr Bob]

On 08/10/2020 at 15:24, cairanvanrooyen said:

I thought i would share this - i have used code from https://github.com/diebietse/invertergui to log data from my Victron Multiplus (and USB interface) and create some really nice interactive graphs. I will extend this to include other bits as i grow the platform - temperatures, solar etc. I am also in the process of ordering a nice display to install on the boat to display the data in real time.

 

This seems to loads better than the £500 odd colour controller from Victron and have the ability to add other bits to.

 

Essentially the interface looks like the attached image and is accessible from any webpage.

 

As Nick says above to the OP, ignore the ludites!

 

Interesting post but is this the best use of the Pi? I too have a Pi connected to my system but it is connected to the 2* BMV battery monitors so it is measuring the 12V system rather than the 240V system. Connecting to the multiplus just helps you with shore power stuff or 240V use when the inverter is active. As Tony says, it is no use for monitoring the state of the battery. If however you connect up to the BMV, then your Pi is then measuring and storing V, A, Ahrs in/out which is far more useful information as that is what is actually happening at battery level. You can review the data at your lesiure (and when in the pub) so can see rested voltage vs Ahrs out during the night when you get up the following morning. You still cant believe the SoC data from the BMV but the voltage and Ahrs out help estimate your SoC.

 

Below is a typical graphical output of what is stored on the Victron portal. This was a graph I annotated to send to our boat builder to show we had been given  a set of knackered batteries (but cant remember the details). For me it is far better to record the data from the BMV rather than the multiplus. Either way, the connecting cables were more expensive than the Rasp Pi - total cost around £60 rather than the £300 for the venus GX solution from Victron.