AOlithium 48v and Victron Multiplus II frustration!

[sunshine_eggo]

Yes, you were spot on with the open circuit suggestion! Thank you.

You're welcome, but it's still not clear to me where it is...

I've labelled the whole bus bar in the attached.

Thanks.

The system is 3 phase, so all the leads from the MP's are the same length.

This is not important. Wiring resistance/length is critical for inverters operating in the same phase. When there is only a single inverter for each phase, you can run the shortest wires practical.

Currently, I only have 1 MPPT connected as I don't have all my panels yet.

I have a total of 6 batteries, 3 of them are currently connected. Once everything is settled down and running smoothly, I was planning on adding the other 3.

In the image, I only see two.

Is the 3rd the "spare" you wired to the center power-in?

But you have me worried now @sunshine_eggo! I hope I haven't made a mistake.

It is correct. I just didn't want to make any assumptions.

Are you getting charging to all three batteries?

Now using the new image, and you identify what you did?

 

[ctid]

Yes, charge is getting to all three batteries and all the cells are nicely balanced. The third battery I pulled to put in the middle bus bar as a test, it is back in the series connection now. AOlithium sent me incorrect cables, so I plan to have 2 banks of three batteries in series, and connect these 2 banks in parallel.

To investigate the cause of the initial problem, I took the shunt off and connected the three bus bars together and put the batteries on the third bus bar again. Still not charging, so the shunt was not the cause. Visually, he fuses looked fine, they were not blown. However, when I did a continuity test, both fuses were open circuit.

I pulled them out, and what seems to have happened when I torqued them up, it has twisted them and snapped the fuse. Cheap cr** from Amazon, buy cheap, buy twice. And it wasted a lot of my time and peoples time on here helping me.

The next step on my journey is to configure the system to use selective AC in, batteries first with some solar top up. AC when batteries reach a certain level.

It is very cold and dull in France at the minute, so not much solar production.

 

[sunshine_eggo]

Glad you sorted it.

 

[740GLE]

Yes, charge is getting to all three batteries and all the cells are nicely balanced. The third battery I pulled to put in the middle bus bar as a test, it is back in the series connection now. AOlithium sent me incorrect cables, so I plan to have 2 banks of three batteries in series, and connect these 2 banks in parallel.

Mind explaining this again, I think you’re using the term series and parallel a bit wrong.

If all batteries are native 48v then any battery you are connecting is in parallel. Now you can “cross connect” 3 batteries such that they are daisy chained in parallel, yet only two main leads from the battery to the bus bars.

With 5 batteries it would be difficult to have individual battery leads for each battery.

 

[ctid]

"Mind explaining this again, I think you’re using the term series and parallel a bit wrong."

Most probably!

I ordered 6 batteries from AOlithium, and they sent leads (DC and data) to daisy chain three at a time. So two sets of short leads, one pair of 2 meter leads, for each set of three batteries.

So I have two banks of 3 batteries connected to the bus bar. +ve from the top battery, daisy chained DC to 5 other two, -ve from battery number 3

For the data lead, I have one battery as the host, and have connected this to the cerbo. I have then daisy chained all six battery data leads. I have used the dip switchs to assign their address, from 0 to 5, with the host and 0.

How does this sound? At the moment all are discharging together and they all charged ok overnight. My only concern is everything drifting out of balance.

 

[740GLE]

That’s what I thought, it was just the term series that made me take pause.

Btw I think the issue you had with snapping the mega fuses isn’t that uncommon.

Did you have washer and lock washer on top of the fuse/lug? Victron likes using copper lock washers for some reason.

 

[Detritalgeo]

At the moment all are discharging together and they all charged ok overnight. My only concern is everything drifting out of balance.

If you can hold them at 55.95V to let the passive balancing work away. That way you can get a sense of cell balance per pack and what delta you are working with. The balancing only starts at 3500 mV and is about 70 mA.

 

[Detritalgeo]

Also... you can go past 56V once the delta is pretty low <50 mV.. Until then there is a higher chance that the cell over-volt protection will kick in and stop all charging.

 

[ctid]

@740GLE, yes I basically followed the recommendations from a few youtube videos and that was to have a stainless steel washer then the copper lock washer. There is so much mentioned about loose connections, I made sure to get the torque spot on, unknowingly, creating a hard to detect issue.

@Detritalgeo, thank you. I'll watch the cells and keep an eye on the balancing. I've got a VS working nicely controlling the AC in, I'll keep that going and key in your values for the voltage. I think I have them set to switch fro AC to DC when Udc is higher than 51v for 3 minutes.

 

[ctid]

AC kicked in earlier as the batteries reached 20% SoC which was my trigger for AC.

Attached is my current status after a few hours of AC charge.

 

[sunshine_eggo]

Just to make sure I'm caught up...




"Battery Bank 1" set of wires goes to three batteries in parallel.

"Battery Bank 2" set of wires goes to three batteries in parallel.

Or at least they will eventually.

 

[ctid]

Hi @sunshine_eggo - Yes, exactly. Actually everything is connected now, so all 6 batteries in 2 banks of 3.

Just been watching my VS for "dedicated ignore AC input". It seems to have worked fine going into battery mode, then AC mode. Batteries reached 20% SoC and AC kicked in. But, batteries are now 100% this evening, and AC has not switched off. The setting is for AC in to be switched when the batteries are Udc 51v for 3 minutes. It's been above that for a while now and it is still on Grid.

 

[Detritalgeo]

Also, there is monitoring software available to get a better holistic view of the battery cell status. They are generally consistent until nearly full and then you may see the cell min-max delta build up. You will need to find an RS485 to USB adapter.

 

[sunshine_eggo]

Hi @sunshine_eggo - Yes, exactly. Actually everything is connected now, so all 6 batteries in 2 banks of 3.

Just been watching my VS for "dedicated ignore AC input". It seems to have worked fine going into battery mode, then AC mode. Batteries reached 20% SoC and AC kicked in. But, batteries are now 100% this evening, and AC has not switched off. The setting is for AC in to be switched when the batteries are Udc 51v for 3 minutes. It's been above that for a while now and it is still on Grid.

Show me your VS settings.

 

[740GLE]

Hi @sunshine_eggo - Yes, exactly. Actually everything is connected now, so all 6 batteries in 2 banks of 3.

Just been watching my VS for "dedicated ignore AC input". It seems to have worked fine going into battery mode, then AC mode. Batteries reached 20% SoC and AC kicked in. But, batteries are now 100% this evening, and AC has not switched off. The setting is for AC in to be switched when the batteries are Udc 51v for 3 minutes. It's been above that for a while now and it is still on Grid.

That’s still showing 54v on the batteries, that’s isn’t 100% but it’s close.

Can you dive into each battery and determine the highest cell per battery? Hopefully non higher than 3.55v.

 

[sunshine_eggo]

That’s still showing 54v on the batteries, that’s isn’t 100% but it’s close.

Can you dive into each battery and determine the highest cell per battery? Hopefully non higher than 3.55v.

If in float @ 54V after attaining 55.2V+ for a sufficient time, 100% is very likely.

 

[740GLE]

If in float @ 54V after attaining 55.2V+ for a sufficient time, 100% is very likely.

Gotcha, and I see zero current into the battery like it’s locked on AC pass through, not swapping back over to battery.

 

[ctid]

Here are some screen shots from my VS.

But (big but!)

These are the screens I pulled using remote control. These are what I (think) set, last night. It was pulling from the grid even though batteries were 100% this morning when I checked the status. So 100% battery and still pulling from the grid, So instead of uDC, I thought, let's try Absorption as the trigger to go back to batteries, especially as they were sitting there at 100%. So I changed the configuration file to Absorption for 3 minutes, and uploaded the config files, using the remote upload.

Nothing happened after this, no change at all with the status, so I was a bit curious.

(Sorry, this is turning into a complicated drama, But, the only PC in our house that is able to connect to the MK3, is my wife's laptop. And trust me, I've tried every laptop and PC that we own.)

So after I had upload of the Absorption setting and it had no effect, I talked nicely to my wife and connected directly with the MK3 interface. What I found was that the trigger to go to AC had gone back to the default 64v uDC. Is this a bug in the interface?

I changed it back to 51v, and after a quick reboot (and loss of power) it awoke in Inverter mode and all was good on battery.

I really don't understand what the issue is, but my batteries are close to the 20% SoC at the minute and about to go into AC in, I just need to see in AC in them reverts to DC when the batteries are charged and the triggers are activated. This is going to be in the middle of the night for me., so I can update in the morning.

Again, I feel just the slightest incorrect setting can bring the whole house of cards down!

 

[ctid]

I was really surprised to see bulk charging this morning when the batteries were at 100%


I checked each battery bank and they are all 3335mv +/- a few mv.

 

[ctid]

Just to keep everything up to date if anyone if following my journey!

My setting of allowing AC in at Udc 51v for 3 minutes, worked ok but long term I believe it would not be a good balance and could harm the batteries.

Effectively, what was happening is batteries drop to 19% SoC and AC kicks in. Batteries charged until 51v which equates to 22 % SoC in my setup. So my system was hovering around the 19% to 22% SoC constantly. At least solar was being taken in.

As a quick fix, I have extended the Udc 51v trigger for 70 minutes. This is currently the setting so I don't know the final SoC, but I am expecting 50% SoC. I can tweak the timing to get it towards the 80% that I want.

Does this sound sensible?

Two criticisms of Victron, which is of course amazing kit. But why is there no AC OFF based on SoC? Also, why can I not easily prioritise Solar over AC?

I love my setup and it feels really robust and configurable, but it is a touch convoluted.

 

[Adam De Lay]

But why is there no AC OFF based on SoC?

There's a couple different ways you can do this.

Also, why can I not easily prioritise Solar over AC?

Take a look under the Advanced Tab in VE Config. I believe last year they added an option for prioritizing solar. You would want to do some research into the specifics as I haven't used it.

 

[sunshine_eggo]

Two criticisms of Victron, which is of course amazing kit. But why is there no AC OFF based on SoC? Also, why can I not easily prioritise Solar over AC?

You have both options.

I love my setup and it feels really robust and configurable, but it is a touch convoluted.

It is. Victron is very flexible often with multiple methods to accomplish the same thing. This has been based on some preference or a change in approach over time while maintaining support for older methods.

 

[ctid]

Thanks both. Victron is without doubt the ultimate system, but the learning curve is huge! However, I would recommend them without question.

Adam, I read the link for the solar priority and it seems it is designed for boats and RV. The manual advises ESS for houses linked to grid.

I feel ultimately, ESS is the way forward. It is so much more complicated that a Virtual switch though. However, no pain no gain!

Can I ask, How much long term damage would it cause to the batteries, to constantly be cycled to a specific SoC under 100%? I'm about to go on a work assignment for a few months so I need to leave the system for a while.

 

[sunshine_eggo]

Thanks both. Victron is without doubt the ultimate system, but the learning curve is huge! However, I would recommend them without question.

Adam, I read the link for the solar priority and it seems it is designed for boats and RV.

Motivated by boats/RV, but it works for off grid as well. YOU are off-grid with grid backup. NOT grid interactive.

Shitcan ESS.

The manual advises ESS for houses linked to INTERACTING WITH grid.

Fixed.

I feel ultimately, ESS is the way forward.

You are wrong.

It is so much more complicated that a Virtual switch though.

You are right.

However, no pain no gain!

Unnecessary pain when there's an easier path is not sensible.

Can I ask, How much long term damage would it cause to the batteries, to constantly be cycled to a specific SoC under 100%? I'm about to go on a work assignment for a few months so I need to leave the system for a while.

None, but I would target something in the 30-50% SoC range for the 3 month departure. Make sure you have remote access.

 

[ctid]

@sunshine_eggo, you tell it as it is, and I for one appreciate it! Thank you.

So for me, in France electricity us super expensive and unreliable. And I am not interested in sending back to the grid, in fact I am not allowed to.

I want solar energy when it is available to feed my batteries and power my house. This won't cover all my consumption at the moment, so I need grid to chip in when needed.

So do you think I am ok with my current setup using the VS? I am very comfortable with binning the ESS idea!