If it does, it would most likely be by implementing a separate current limit for AC specifically. But there is one thing you saffers tend to forget (well, I suppose it includes me) because it’s a less common setup: AC-coupled PV. A naive “simple” AC limit would also limit charging from the AC made by a PV-inverter. So already there is a complication that has to be carefully considered…
You see, that is how it goes with every new feature.
YES! I have been listening to you over the years. 
I was more thinking, in my ignorance, that it could have been as easy as a menu item, “Keep Charge with Solar”, that then disables the AC charger for the user.
But that is always too simplistic a view from my side, or it would have been done already.
If I understand @plonkster’s trouble with it, is that people with, for example, a Fronius inverter, might still want to only charge from PV. However, that PV is AC tied, so the Victron’s AC charger would have to be used to store some of that PV in the batteries.
As such, any implementation of such a feature would need to be either carefully documented as “charge batteries only from MPPTs” or they would need to go all fancy in their development to incorporate the AC coupled PV systems out there.
My electricians told me about someone they service, who, with a regular normal house (albeit a very large regular normal house, but no business activity) use on average per hour what I use on a regular day (VRM proved it). I guess there’s some underfloor heating involved or something like that. That person has a sizeable PV array, AC coupled with Fronius and a humongous battery bank behind a few Victrons (if I remember correctly it was a three phase setup, can’t remember which inverters).
Someone with that type of money would be extremely irritated by Victron if they introduce a feature like that without making very sure that it still works with the Fronius setup.
You guys overcomplicate it! 
There is already a PV Inverters section in the settings
All you need is that if a PV Inverter is detected that menu option is disabled.
If not found the option is available, but Off by default.
If some dummy switch it On, they can’t complain that it does not work by default. 
Then again you can already do all this by changing 2 settings instead of a toggle in the GX and the dummies can’t by accident set those. So I can’t see this feature request ever happening.
Very good point …
… that is then sorted, no confusion left.
Right, let me explain where the reuqest stems from, Plonkster knows it is not from yesterday that I’ve been at this. 
Take any day cycle. Morning SOC is say 40%. ESS will get that back to as close to or to 100% SOC during the day, using the stored energy where and as needed, coupled with the sun.
100% with that, no problem.
However, no matter the size of the battery bank or array, one could look at it all and take a different arpproach because
Put differently, spread the battery use over a 24hour period, versus big loads working the batts hard for certain periods of the day.
Now one can say, get more batts, panels, match the 4kw the 5kva can do … but what if the loads are just on average 2.5kw peak times, I just don’t want to use the batts that hard?
Where does one draw the line?
So what I do, as the day progresses, I up the SOC, 40% - 45% - 50% manually so that by 11ish it is about i.e. 84% … cannot go to 85%, that will take Eskom to charge to ±86% SOC, so I Ieave it. That 4% down to 80% can be used by ESS during the peak load periods from 11am-3pm. So batts are not used too hard for extended periods driing the dayly cycle, just i.e. 4% as per the example.
After 3pm I get to back to 100% easily IF I start off with say 80% at 3pm.
From 16h30 I set a Scheduled Charge with SOC of 45% to not use any batts at all until 10pm.
So 95-100% SOC by 10pm is a guarantee, because that is when I want to use the batts again until solar takes over the next day powering the average loads.
The above is especially obvious in Cpt Winters where you want to crawl back up the SOC % for evening use, and not let the system stay at a low SOC for days. Rain and winter combined is a challenge.
If I increase the SOC based on a estimated SOC per hour via a Cronjob, 9/10 times I get it wrong and AC is used to recharge when I have more panels than what the daily loads need, with the right amount of batteries for the loads I have.
So Keep Charge with Solar will do similar, just never use AC, to get back to 100% for evening use.
For me, the goal is simple: Balance the array, the batts nicely over 24 hours.
Peak loads are Eskom peaks - costs cents on the rand and does nto give that good a ROI if any.
24/7/365 loads are 100% solar loads - THAT is where the ROI’s sit.
This is what we in the software development business call “Scope Creep”.
It’s way more complicated than the initial request.
ooo…now you’ve had to open THAT door!
That is what we call in the software development business, listen to the clients, keep track of changing needs, build in optional features because as clients use one’s software creation, THE biggest compliment one can get, is when some of the clients actually suggest good, decent logical improvements on ones already excellent work.
Cutting edge becomes a bleeding edge.
There are two groups:
Developers: Is like toughen up you buttercups! You missed that … Nike! (Just do it)
Clients: I’m watching you … don’t you get silly now, you feel me?
Once the twain have met … awesome results … till the next idea comes along, rinse, repeat.
Ok, in all seriousness, sometimes one gets into a position where no matter how good an idea is, how easily a developer wants to/can do it, it necessitates an entire core re-write, or a large chunk must be redone, and that simply does not make sense most of the time. So there is that too.
Or an idea SOUNDS simple, but in delving deeper into what needs to happen, it turns out to be 100% more complex than what it sounds. And there is that too.
Then again a question my clients used to ask me when I say, I’m watching you! … was:
Who is using the software? The developers who wrote it or the worker bees pounding away at their keyboards every single day?
It is NOT easy!
But who wants it easy!?
Oh yes. So it will always be met with resistance, because the developer does not want to tweak that thing for the next several months… ending up between two different customers both arguing equally convincingly that their use case is more normative… finally in a fit of rage pulling the feature out before the next main release because it is more trouble than it is worth.
Tesla is actually working on a kind of adaptive aka artificially intelligent aka data driven thingamabob where the system will learn your pattern, and together with weather data make things optimal. And guess what, their system also doesn’t exist yet. And this system would need internet access. A substantial number of blue systems don’t have that… 
So it is what it is for the moment.
The problem is not so much that the scope changes. It is that the client still want to pay the same price you quoted for feature A while requesting feature A + 10xB
I’m always flexible if the other guy is also flexible.
Amen to that!!!
That is my job … I do the arguing, negotiations and also take the hits and shots … and getting the funds, with developers guiding me.
When the developers where dealing direct with the customers, that was not fair, not on the develper and not the customer.
Someone must take the lead … and it should not be a developer as they tend to have enough responsibility and work already. Customers need a steel hand covered in velvet, to guide them safely and securely. :vb-drink:
i have a different view on this. Based on the published life expectancy and actual results from the field our lithium batteries will die of old age and not because of cycle count. So i think you will get the best ROI if you cycle them without restrictions. Let the inverter make use of the batteries as much as possible. The only problem with this approach is, that in winter you might have empty batteries when load shedding starts.
Your view is valid and could definitely work.
The way I see it: My batteries exist to make my system viable and provide 2-4 hours of backup power.
I’m not trying to pay them off, they were really a grudge/luxury purchase (AC tied PV would have been better had Eskom not been what it is) so I just want to go as long as I possibly can without having to replace them. In that light I think if I treat them well, i.e. not use them as much as I could, I’ll probably get more time out of them, but not necessarily more power.
Even if I manage to make a whole cycle every day, instead of half a cycle I do now on my 2xUS3000, that is only another 2.5kWh (allowing for DC to AC @ 90% and 80% DoD) for me, compared to the 12kWh I take directly from solar. Therefore, if I get at least 20% more time (12 years instead of 10, for example) from the batteries because I don’t cycle them as hard, I’m better off because my panels are really what is running the ROI for me.
Obviously I’m not guaranteed to get more time because I cycle them less hard and deep, but I think it can’t hurt my chances!
Assuming I am not aware of any planned LS, in winter I cycle them 50%, spring, set at 30-40%, summer 20%. So the batts are cycling, no chance they die of old age.
The problem is midday, to not draw like 1-3kw out of the batts consistently due to weather. That stresses everything. In good weather I don’t need the batteries at all. And that ±4% use for intermittent clouds, fine by me.
As I said before, the 24/7/365 loads are the ones costing us the most, not the MW, kettle.
24/7 loads are what I removed and in that process, I have spare solar, and because I schedule usage, I can heat geyserS, run the dishwasher, even the dryer without batteries, whilst powering the average house load still. I.e. for the last 24 hours the oven has been drying liver for the dogs, all from solar only. Oven at 60deg C.
Stressing any battery bank, increases its temp, decreases its lifespan. Have seen my batt temp sensor touching 58deg when 2kw is drawn midday from the batts for a period of time. All because it is summer now, ambient temp is up. Was never a problem in winter.
It is now 2:40pm. My gird usage, is for kitchen use early evenings, TV’s and computers thereafter. 10pm I take off 600w till the sun takes over.
What a GOOD day … the cost to make more red into blue, orange, is simply not computing ito cost versus ROI. I’m happy as it is … UNLESS Eskom gets worse and so far the new Eskom boss seems to be making big waves, good waves. So use more batts evenings, none in the day, that is a good plan say I.
i agree. In this case i would also limit the discharge current. What battery capacity do you have?
16 x 152ah 1st life cells - so it is about 48v ±7.2kWh bank.
I suspect all of us are getting higher temps … it is a huge issue, no matter lithium or lead acid.
Keep the batts cooler daytime and use them longer at night by upping the SOC slowly during the day … to do that automatically, never using Eskom to recharge daytime, THAT is my challenge.
I would imagine that a battery BMS should already control those things based on temperature readings? (Hopefully)
The problem is that TTT sets the min SOC automatically during the day using his crons. What happens in the blue system is that if your SOC is too far below the new min SOC that was set, then the AC charger will kick in charging the system.
@TheTerribleTriplet have you set your max charge current to 0 on your Multi?
The BMS I have does not have a temp sensor. One I tried, had 4, you put them between the cells.
That high temp measurement I got, came from the Victron temp sensor, installed on the banks negative pole. Only get these higher temps if the ambient temp is also high, and that is inside the house.
Nope … would there be any ripple effects if I make the charge current 0 on the MPII?
I’m quite fortunate that my batteries are in the garage, which is underneath the house and the garage door is facing south. Am quite interested to see how hot it gets in the summer, but typically it stays quite cool. The only problem I see coming up is that there is relatively little air movement in the garage and I introduced a source of heat (the inverter and the batteries) so might start to choke… Will see how it goes. Otherwise I’ll have to open up the door or maybe put a nice big fan on the ceiling above them.
