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iand avatar image
iand asked

Solar and wind priority

According to the documentation, the way the new solar/wind priority feature works doesn't make sense for boats/RVs which are plugged in for long periods... :-(

It works fine for the first week so that all the solar energy can be used to charge the batteries, but after that it reverts to 100% SoC just like a system without it enabled -- which means that if the solar generates more energy than is consumed it has nowhere to go, and shore power is used instead.

What would make far more sense is to have a setup like generator autostart/stop where you can set SoC for the shoreline to start and stop charging (e.g. 30%/70%), to guarantee that the batteries never go flat but there's always space for solar to be used for charging.

If desired there could be a regular "charge to 100% SoC" burst (e.g. every week or month) for users who are concerned about equalisation.

This should all be trivial to do, and would make the option much more usable.

solar
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6 Answers
cardy01 avatar image
cardy01 answered ·

You can do what you describe using the Ignore AC virtual switch .... works nicely

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iand avatar image iand commented ·
Doesn't that mean the shoreline is never used? What's needed is either separate limits for "shoreline autostart" so that it kicks in before the generator would, or to have the generator autostart limits apply to shoreline when plugged in. I can't see any way to do this...


(without running Node Red which is not an option if I want support from the boatbuilder)


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cardy01 avatar image cardy01 iand commented ·

You can set various limits to use Shore Power based on battery voltage or SOC .... so no it doesn't always ignore AC In ....

https://www.victronenergy.com/live/ve.bus:solar-and-wind-priority

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iand avatar image iand cardy01 commented ·

Except that after 7 days it goes back to 100% SoC... :-(


Looks like Ignore AC is what I actually want... :-)

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Philipp Trenz avatar image Philipp Trenz ♦ iand commented ·

@IanD See this blog post on how to configure it: https://panbo.com/maximizing-solar-production-with-victron-gx/

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cardy01 avatar image cardy01 iand commented ·
Yes I know ... it's why I stopped using it ... in the link I posted AC ignore is discussed as the option when you want AC loads supported by the battery.


In my case the shore power tops up the battery about every 3-4 days as there isn't so much solar at the mo .....

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iand avatar image iand cardy01 commented ·

That's exactly what I need -- this is what my system is doing right now, almost all the loads are DC. Quattro is set to inverter-only to disconnect shoreline, I have to manually switch over th charger every few days.vrm-snapshot.png

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oyfant avatar image oyfant iand commented ·
Same problem...
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iand avatar image
iand answered ·

So if Victron already had a solution which worked and did the job, why introduce a new one which doesn't?

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cardy01 avatar image cardy01 commented ·
I guess it was targeted at people with low AC loads and big(ger) DC loads
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iand avatar image iand cardy01 commented ·
Which is exactly what I've got when the boat is moored, see snapshot above...
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cardy01 avatar image cardy01 iand commented ·
What can I say? My AC fridge pulls about 55W for about 5 mins every 2 hours. My DC loads are small (alarm, trickle charge start battery etc) when moored and unattended.


AC Ignore works fine for me, I just leave it on .... has been running about a month now and has halved my AC consumption from shore. In the summer solar will cover all my unattended consumption.

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iand avatar image iand cardy01 commented ·

But do your batteries ever get charged to 100% SoC, even for short periods?


My (series hybrid) boat draws something over 100W typical when moored, most of this is the zero-load power of the Quattro (specced at 60W but I suspect it's a bit higher), the rest is a few watts each consumed by everything else like the router, Cerbo, Touch50, MPPT controllers, various Orion DC-DC converters, lighting controllers -- all of which connect to the 48V battery bank. Solar is currently providing about a third of this power, it would provide all of it for about 7 months in summer.


I need to keep AC running on board because things like the water pump and heating (needed for frost protection) use it, so I can't turn the Quattro off -- anyway if you do this remotely, you can't turn it back on...


And I'm not happy about the batteries sitting there for months never being taken up to 100% SoC because this is needed to run any cell balancing and also reset the SoC counter.


The new solar priority mode would be perfect if only the time between charging to 100% from shoreline was programmable together with the interval, and if it didn't go into this mode after 7 days and stay there... :-(


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cardy01 avatar image cardy01 iand commented ·

"But do your batteries ever get charged to 100% SoC, even for short periods?"

Yes - around every 3-4 days in the late summer, currently around every 2 days.

Have you tried AC Ignore?

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iand avatar image iand cardy01 commented ·

The problem is now in winter when there isn't enough solar so SoC drops gradually every day -- from my understanding of solar priority it will then turn shoreline charging on (e.g. at 50% SoC), and charge up to the specified upper threshold (e.g. 80% SoC).


Then it will turn off and this will repeat, which is fine. However after 7 days not ever reaching 100% SoC it will come out of sustain mode, charge up to 100% SoC, and stay there.


Which means little or no solar power is accepted any more. Which means solar priority only works for the first week after the boat is plugged in in the autumn.


AC ignore will just do the first part (cycling up and down between the the two thresholds) but will never get to 100% SoC -- and it's difficult to override this manually because it can't be done from the control panel.


So right now it seems that neither AC ignore or solar priority does what I want the boat to do in winter.


Is this all correct, or am I misunderstanding something?

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cardy01 avatar image cardy01 iand commented ·
You can configure AC Ignore to switch on at a given threshold - In my case AC Load is less than 99W for 3 minutes. There is then a threshold for not ignoring AC - in my case 1000W for 2 secs (to deal with fridge compressor in-rush current or boiling the kettle).


The battery conditions can be voltage based or SOC based - mine is set to 12.45v 60 sec or 80% currently.

Ignore AC is switched back on when either a voltage is reached or bulk is finished or absorption is finished for a time period.

I currently use absorption finished for 5 mins.

It works seamlessly and automatically ....

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iand avatar image iand cardy01 commented ·
I'm now confused -- if you set an upper AC Ignore threshold (e.g. 80% SoC) to allow headroom for subsequent solar charging, how do you ever get into the absorption/balancing state unless there's enough solar to get there? (which there isn't in winter)
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cardy01 avatar image cardy01 iand commented ·
The AC ignore thresholds are in AC Watts ..... the "resume charging" threshold is DC V or SOC based.



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iand avatar image iand cardy01 commented ·
I still don't get it -- my understanding is that if you don't want the AC shoreline to work all the time, with AC Ignore you set a lower threshold (so shore charging kicks in when SoC drops to this) and an upper threshold (so it stops again when SoC reaches this). How does the battery ever get to 100% SoC?


Or am I misunderstanding what the thresholds do?


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cardy01 avatar image cardy01 iand commented ·

Yes you are :-)

Thinking about AC only for a moment

AC Ignore switches on when the AC load is below a threshold in Watts and back off if the load is above a 2nd threshold (can be different values or the same)

Then in the DC side based on battery SOC the AC Ignore switches off until the battery is charged to a defined level

See below:

1699276325354.png

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1699276325354.png (21.6 KiB)
iand avatar image iand cardy01 commented ·

In my case almost all the load is DC, as the snapshot I posted showed.


If I understand it correctly, with your settings AC (shoreline only, or shoreline and generator -- is Ignore AC set individually, or does it only apply to shhreline?) will be ignored until SoC drops to 80%, then it will start to charge from shoreline.


What sets when it stops -- just having reached 100% SoC and absorption mode finished 5 minutes ago? (though what this means for LFP isn't clear...)


The other big problem is that once "ignore AC" is set there's no way to turn it off from the Touch50 or VRM, which means you can't then use the shoreline to charge the batteries up when you want to if you're in the "ignore" region -- for example before leaving the marina (to reduce generator use).


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iand avatar image
iand answered ·

Need to wait for option to enabled by boatbuilder, but plan would be to have something like the following (35kWh LFP battery bank, 7kW charging from generator, 3.7kW charging from shoreline):

Generator autostart 50% SoC

Generator autostop 60% SoC

Shoreline AC start 70% SoC

Shoreline AC stop 80% SoC

This allows 20% SoC headroom for the solar once shoreline has stopped -- this is about 7kWh, which is expected solar yield for a day in summer (2kW of panels).

Any comments/problems?

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cardy01 avatar image cardy01 commented ·
Looks sensible to me ......
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iand avatar image
iand answered ·

I talked to my boatbuilder about this, he says AC ignore is what they used to use but the problem is that there's then no easy way of turning it off from the Touch 50 or VRM, you need to use VEConfigure (or Node Red, which is not supported).


This then means the batteries never get to 100% SoC since the AC ignore works for both generator and shoreline, so they never get top-balanced and the SoC calibration can gradually drift away from the correct value... :-(


So I'll try out the solar/wind priority and see how it goes. Once it's gone from sustain to 100% SoC (float) mode after 7 days, can it be pushed back into sustain mode by switching to inverter-only mode and then back to sustain -- does this reset the 7-day timer?

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cardy01 avatar image
cardy01 answered ·

VE Configure works remotely via VRM ... takes maybe 2 mins to change if you keep an "on" config file and an "off" one ...

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iand avatar image iand commented ·

Thanks, I know that's possible but it's a bit inconvenient, especially if the boat is being used by family not me, I don't want them messing around with VE Configure.


I don't understand why Victron can't fix the solar/wind option to get round this and allow the user to choose the length and intervals between charging to 100% SoC (e.g. for 1 day every 14 days), it really would be trivial to do...

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cardy01 avatar image
cardy01 answered ·

You don't need to be physically on the boat .... you can monitor SOC remotely and change settings via VRM (ussuming you have a GX device) .... mine is an hour away and I can do it from my desk.

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iand avatar image iand commented ·
I know, that's what I do right now to switch between inverter-only (to let SoC drop and make use of all the solar) and charger-only (to get SoC back up when it drops too far) -- my boat is more than 3 hours away... ;-)


It would be far better if this was dealt with automatically -- with a properly functional solar/wind priority mode -- than having to remember to manually switch modes, and certainly better than having to use VE Configure which is dangerously powerful for non-expert users...


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