Introduction

This forum has helped me a LOT with information, tips and tricks, and eventually with my decision making process. A massive "thanks" to everybody that contributes (questions and answers!)

So I figured I'd share my experience with the first days with my newly commissioned solar system, in the hopes that it might add a bit to the pool of knowledge, and help some other newbie in the future.

The System

• 3KVA Victron MultiPlus II 48/3000/35-32
• VenusGX running ESS
• 1 x SmartSolar MPPT 150/85
• 990W array (3 x JaSolar 330W Poly)
• 1 x BYD 2.56 Lithium-Ion Batteries
• 1 x Carlo Gavazzi ET112 Energy Meter

Notes

It was officially switched on 17 June 2019.

Based on the sage advice of members on this forum, and my own thinking,the system is as small as I could make it, and still have something usable. 

The plan is to extend, based on gathered data - and of course as finances allow.

The current planned ending spot is:

• total of 9 330W JA panels
• at least one additional BYD 2.56 unit

This was not a DIY job - fiddling near mains with any piece of metal (like a screwdriver) freaks me the HECK out. Also I'm one of those feckless "software types", so there's that 😛

Generally I'm happy with the installer's services, but then again, maybe I just don't know better

We have a 80amp municipal breaker, and new Conlog pre-paid meter, courtesy of Tshwane.

Production, consumption and storage

Short version

• Best (single) day: 5.03kWh produced.  At peak, I have seen 900W from the panels, but generally 750W is what I see as "good" currently.
• We consume about 20kWh per day (looking to bring that down a touch still)
• House "idle" consumption is between 150 to 450 Watts (these are the 24/7 loads)
• We have "spiky" loads that peak anywhere from 1.2kW to 5kW (as measured by the GC energy meter)
• Battery can handle the "idle" consumption for about 6 hours (i.e. between 00:00 and 06:00)
• I'm trying to find a good "staggered" setup of loads during sunlight hours to keep the panels busy during peak sunlight hours - it is a challenge!

Longer version

I'm lazy now - if there are questions, I'll gladly try to provide details

Snags and things

Victron VRM and Venus remote console

Make sure you have access.

Learn it. Love it.

Read the manual before changing things!

Remote Console can be laggy at times. Have patience.

Or build a new interface based on MQTT...

ESS

Initially the installer set the "Limit inverter power" setting to "safe" limit to product the battery. This made sense to me - don't hit the battery with massive spike loads, maximize battery life. Good. Only problem is, as far as ESS is concerned, this "limits DC to AC" conversion. Period. So that includes MPPT supplied DC.  So the nett effect was that MPPT supplied power to loads was also capped. Not so good.

My eventual work-a-round was to drop the "Limit inverter power" setting, and then set up "Charging Schedules".  The main intent of these schedules is to charge from mains (well, AC to be precise), but the nice side effect is that while the schedule is in effect, the battery is NOT discharged. BUT, MPPT power can still flow freely to the batteries, AND flow unthrottled to loads.

Set the "Stop on SOC" value of the schedule to some low value (even below the minimum allowed SOC), and it won't charge from the grid.

The schedules keep the batteries away from loads, until 00:00. Then the house gets fed from battery, until 06:00 - then the schedules kick in again.

You can also set the "Limit charge power" setting to limit AC to DC flow (i.e. how fast you charge from mains). UNLESS you have DVCC turned on...

DVCC

Ok, so initially this was NOT turned on. Based on what I read the last two days, it looked like it sorta probably SHOULD be turned on (with the BYD bats). Asked the installer...he said "yes go ahead turn on".

So I did that - can't really say I see much difference, except that the "Limit charge power" vanished. And I did not notice - so today I charged the battery with mains power to 95%. Oh well - ultimately does not matter I suppose, since it was a "good" direct PV usage day, so PV was not wasted.

So what was added is a "Limit charge current" setting. As far as I understand it, this is a "global" limit on how much amps is allowed to flow to the batteries - but SHOULD not cap the wattage supplied to power loads from MPPT.  I will see tomorrow how that plays out.

Conlog prepaid meter

I was actually pretty worried about this thing tripping when those "accidental" grid feed-ins happened (when big loads turn off).

To prevent this, we had a grid set point of 150W at first.

No trouble presented it self, and eventually dropped that to 70W.

I have now observed short periods of "accidental grid feed-in"  of upwards of 250W (electric stove element that turns on and off during use).

Fingers crossed - nothing tripped or blew up to date.

Conclusion (for now)

• Educate your self, ask questions, verify answers (you now, "trust, but verify" ). Read the manuals!
• You will need to figure out how to stagger your loads during the daylight hours, in order to optimize your production, usage and storage
• Data - you want it. Whatever system (or components) you eventually install - make data capture and analysis a priority! I learned quite a bit from watching the remote console display (and switching things on and off!). Looking at the PV yield and consumption graphs (VRM), is helping me setup up sane "charge schedule" settings. It is also helping me to conclude that "yes, I really actually DO need more panels". I mean, I *knew* that, but know I have STATS to back me up! Data for the win!

Apologies for the lack of photos currently - I'll upload some if anybody asks

 

You did a lot of reading I see. 🙂

 

56 minutes ago, demaniak said:

... eventually dropped that to 70W.

Go lower, see what happens. I have had mine at 10w, then settled on 20w.

See if your meter still does not trip on say 10w / 20w - find the lowest spot. That info will be very valuable.

 

 

O, and do remember the Firmware's:

For most of the connected devices to the VenusGX, via your site on the VRM Portal, go here:

 

Looks so:

 

The VenusGX updates here:

 

And the inverters firmware, need the MK3 cable, from here: https://professional.victronenergy.com/downloads/firmware

Look under: VE.Bus (Multis, Inverters and Quattros)

 

10 hours ago, demaniak said:

Ok, so initially this was NOT turned on. Based on what I read the last two days, it looked like it sorta probably SHOULD be turned on (with the BYD bats). Asked the installer...he said "yes go ahead turn on".

DVCC should be on for BYD batteries. It says so in one of the many many online documentation pages. What it does is it allows the battery to be in charge and to control charge and discharge power. There are some other minor improvements, such as the ability to use surplus PV when the ESS mode is set to keep batteries charged (this does not work without DVCC).

 

10 hours ago, demaniak said:

Conlog prepaid meter

the reverse detection feature can be disabled even on those meters that do support it. I seem to have such a meter in my house. It's a BEC23 and technically has this feature, but it has never tripped... even if I feed back hundreds of watts.

10 hours ago, The Terrible Triplett said:

See if your meter still does not trip on say 10w / 20w - find the lowest spot. That info will be very valuable.

@The Terrible Triplett - I will play around with it August - I have to travel July, would prefer not to leave the family with "untested" config.... I will  NOT hear the end of it.

Firmware versions seems update2date for now, but I will keep on top of it.

 

1 hour ago, plonkster said:

DVCC should be on for BYD batteries. It says so in one of the many many online documentation pages. What it does is it allows the battery to be in charge and to control charge and discharge power. There are some other minor improvements, such as the ability to use surplus PV when the ESS mode is set to keep batteries charged (this does not work without DVCC).

Thanks @plonkster - I saw the "keep batteries charge" bug kept being mentioned, but I never (where I read) with the actual details. Anyway, DVCC is definitely switched on now.

Good to know about your conlog experience - gives me a bit more confidence for when I start dropping the grid set point Aug

As far as I can make out, I got a BEC42 installed.

It's rather annoying that you have to infer/discover these sort of configuration details via experimentation - but I guess for the vast majority of consumers the knowledge would be meaningless, so why bother publishing.

32 minutes ago, demaniak said:

It's rather annoying that you have to infer/discover these sort of configuration details via experimentation

Yes, you can OR you can pay a Victron trained installer to do it all for you. 🙂 

We here opt for self install. So we are going to experience quite a steep learning curve AND our setups do differ subtly on top of that.

Lucky we have the P's here to help, the freedom to change the settings on our installs ourselves.

22 minutes ago, The Terrible Triplett said:

Yes, you can OR you can pay a Victron trained installer to do it all for you.

Just to be clear - I was referring to the Tshwane prepaid meter config!

The rest is fun (well, for me at least), and the info IS there (Victron documentation is pretty damn good in general!)

Edited June 28, 20197 yr by demaniak
Made it clear refering to Victron docs

1 minute ago, demaniak said:

Just to be clear - I was referring to the Tshwane prepaid meter config!

That is a problem yes. Nobody knows if the meter will work or not, not until you try it. Sometimes you are lucky and the feature is disabled. Sometimes you're not. You simply don't know until you try.

25 minutes ago, demaniak said:

Just to be clear - I was referring to the Tshwane prepaid meter config!

And for the foreseeable future, they will keep it "confidential". 

My comment was more aimed at the future readers of this thread, that there is no confusion. 

Alright, here are some nice graphs from the VRM.

If you look carefully, you can actually see where/when I tweaked something

 

 

A few more random thoughts  and comments

Why not Pylontech?

First, cost.

This sounds strange, because Pylontechs are cheaper than BYD, right?

This is true, BUT, for the Victron inverter, I would need to start with 2 2.4 Pylons (see https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom )

BUT, with BYD - I can start with a single module (see https://www.victronenergy.com/live/battery_compatibility:byd_b-box ).

This means the upfront cost for going BYD is actually lower than for the cheaper Pylons. Go figure.

Next,  according to this ITP Renewables testing lab, BYD has (had?) a slight advantage over the Pylons in a few areas. It really is not that much of a difference, but it was enough to put me over the edge.

I have attached their 2018 report for your viewing pleasure.

Changes in house hold behavior

Fancy way to say we are trying to make sure we run the dishwasher and washing machine during daylight hours.

Oh, and we also dug out these fancy Hot Water Batteries (I understand some people refer to them as "thermos flasks"). Before  boiling the kettle, check if there is hot enough water stored. If you do boil the kettle, dump whatever is left into the flask. Magic.

Pool pump timer and Geyserwise control is a given.

 

Battery-Testing-Report-September-2018.pdf

First I've heard of BYD. I'm on the verge of buying my battery and had pretty much decided on 1 Pylontech US2000 - now  I read this. I also have the Multiplus II. If you really need 2 for things to work correctly then I may also be better off with the BYD if I want to start with a small bank?

 

Well, all I can do is tell you about my experience/reasoning, @deapsquatter

Let me try to summarize:

1. I based on my decision on the info I already pointed to above - so you can draw your own conclusions from all of that
2. Maybe the guru's here could elaborate on how "hard" a requirement the 2 Pylons are. I mean, the docs does state you want 2, but maybe there are some "iffs and butts" involved?
3. This is really just my own thinking at this time... your mileage may vary, use with caution! I'm currently coming to the conclusion that with my current battery size, I might be better of switching to "keep batteries charged", until I put up more panels. Maybe - still thinking it over. Essentially, if you just want to primarily be able to ride out load-shedding (which was/is a priority for me), then a smaller bank still makes sense - you just want 2.5 hours , twice a day, and be able to recharge in between.  But to get optimal use out of ESS, I figure you kinda want to harvest and use PV during the day, store excess, and then use that excess during the evening. So in total produce 90%+ of your actual usage in a 24hour period. A "small" bank limits this ability. So - depends on your specific needs.
4. Another thing to take into consideration possibly: your initial cost might be lower for the BYD (assuming the Pylon x2 requirement holds true), but after that, you can add a single US2000, at a lower cost than a single BYD module.
5. Prices fluctuate - keep that in mind. Also, both batteries  need specific cabling, cabinets, fuses etc. Should be fraction of the cost of the actual battery, but still, something to keep an eye on
6. The BYD must be connected on CANbus (afaik).  If you then also want to use a MPPT with a Venus device, it apparently must be a Venus GX, not the Color Control. It is explained in the Victron-BYD docs linked above. If you are DIY'ing it, I would suggest you study both those links for the finer installation points! And chat with the smart people here.

It's really early days for me, but so far I'm happy with the BYD.

BYD is huge in the Chinese EV market btw. Reputation seems solid as far as I could make out.

But Pylon reputation is also apparently excellent - I do'nt think you will really go wrong with either (ignoring budget considerations!).

29 minutes ago, demaniak said:

... twice a day, ...

Assuming day means when the sun shines and not 24 hour day?
During the sunshine day the panels are the power source, not the batteries. Factor that in.

 

31 minutes ago, demaniak said:

... how "hard" a requirement the 2 Pylons are.

Remember, Victron is based in Europe, not SA, so SOME of the suggestions need to be read with that in mind. We have longer hours and more reliable sunshine than they do over a one year period.

Now, not disagreeing with this nice comparison you made and the case made for BYD, my 2 cents to add to the thinking:
1) get one bank, see the data, see the system working, make those lifestyle changes, see summer and winter operations and THEN decided you are satisfied or you need another bank. It is not like lead acid, you are free to add as you wish over time.
2) my second cent. Remember, bigger bank = bigger array to carry the daytime load AND the daily recharge.
3) one freebie ... grid tied is where the savings are. I am told that Pylons are cheaper per kw/h that Eskom, assuming I presume you bought them cash and that they do last as long as advertised. The jury is still out on the cycles claimed, time will prove that, or not.
4) ok, due to popular demand, one more freebie ... "Matching the load to the batts and not the batts to the load" is cheaper - you can always add another bank later with lithiums.

And one on the house: It is a good idea, with solar systems, that you sit on your hands after having hidden the plastic.
Walk the talk in your own shoes ... then, after careful deliberation, only then decide the next step or IF there is a next step.

Solar falls into two categories:
1) the main goal is saving.
2) it is a hobby.
Hobbies don't have no price tag. 🙂 

 

Thanks for both responses. I want to buy one battery and then play/experiment. If the result of those experiments means I need a second then so be it. The Victron docs suggests 2 Pylontechs for the Multiplus II. But it does come across as more of suggestion than a hard rule? Try one and if it doesn't work get a second. Or get a BYD or even a Solar MD...

Good info, thanks for sharing. 

Just one question, are you running the ESS assistand. Is that the "standard" to use in SA? I'm still learning all about assistants. 

Also did you install a ziehl relay to prevent backfeed?

Hi @MrVolt.

Yes, running the ESS assistant. 

I don't know about "standard", but it has many advantages. 

To the best of my knowledge, the MultiPlus 2 does not require the separate Ziehl device for anit-islanding. it has certified built in protection mechanisms. 

But @plonkster or @The Terrible Triplett could probably elaborate with more technicalities than I. 

57 minutes ago, MrVolt said:

Also did you install a ziehl relay to prevent backfeed?

4 minutes ago, demaniak said:

MultiPlus 2 does not require the separate Ziehl device for anit-islanding. it has certified built in protection mechanisms. 

Spot on!

57 minutes ago, MrVolt said:

ESS assistand. Is that the "standard" to use in SA?

Yes, it is the new standard all over the world to use ESS if you are grid tied and use Victron equipment that works with it.

Edited July 1, 20197 yr by Guest

5 minutes ago, The Terrible Triplett said:

Spot on!

Yes, it is the new standard all over the world to use ESS if you are grid tied and use Victron equipment that works with it.

Good to know, thanks. It would make commissioning much easier i would imagine?

As far as I know the quattros do require the ziehl relay? 

10 minutes ago, MrVolt said:

As far as I know the quattros do require the ziehl relay? 

Yes BUT check with your local regulations. I CoCT there are some heated debates with the officials ongoing for them to allow it, which they currently do not.

Yes, ESS makes it so muhc simpler.

3 minutes ago, The Terrible Triplett said:

Yes BUT check with your local regulations. I CoCT there are some heated debates with the officials ongoing for them to allow it, which they currently do not.

Yes, ESS makes it so muhc simpler.

Thanks will do, Its a rural installation, directly connected to Eskom. (3 phase, turning meters)

On the ESS documentation it mentions phase compensation where the inverter balances the phases to use minimum grid power. I assume this cannot be done in SA, as i understand it feeds back power on one phase to compensate for the other? 

 

 

2 minutes ago, MrVolt said:

... , directly connected to Eskom

From what I see, Eskom does not yet allow that, so being rural, go with you gut feel! 🙂 

2 minutes ago, MrVolt said:

On the ESS documentation it mentions phase compensation where the inverter balances the phases to use minimum grid power. I assume this cannot be done in SA, as i understand it feeds back power on one phase to compensate for the other? 

That must be answered by someone else.

On 2019/07/01 at 11:35 AM, The Terrible Triplett said:

That must be answered by someone else.

Depends on your supplier. Cape Town typically gives you one meter that does all the phases, and you are billed for the total over all three. So phase compensation would then be turned on (this is really a horrible name, and there is a long outstanding issue for coming up with something better). But sometimes -- I am told this happens with Eskom a lot -- you might have three individual single phase meters, and you are billed individually. So then you'd have to turn it off.

 

An additional important question is whether doing this will trip your meter!

Is the logic used to detect reverse power-flow (i.e. a tamper event) calculated on the overall 3-phase power flow or on a per-phase power flow? 

1 hour ago, NigelL said:

An additional important question is whether doing this will trip your meter!

Is the logic used to detect reverse power-flow (i.e. a tamper event) calculated on the overall 3-phase power flow or on a per-phase power flow? 

Not sure, but i have seen a three phase conlog meter operate without any issues with two of its phases connected to grid-tie inverters, grid limiting is activated so it does not push back, but it does not trip either.

Just an update regarding the Conlog prepaid meter Tshwane installed for me. 

So to date, the thing has not actually tripped, per-se. 

I initially had the grid-set point at 70w.

All was well. 

It was then lowered to 10w.

What I then observed was momentary "dips" on the mains input. I could not immediately make the connection, since my earthleakage was also tripping. This has been resolved (new E/L installed). 

After the E/L issue was resolved, we still saw the momentary dips on mains. 

Yesterday, I moved  the grid set-point to 50w.

So far, so good. 

Below I attach some graphs screenshots that show the dips I am talking about. 

It looks like the magic number is 3A feed-in for something like 30min. Your milage will probably vary.