Battery orientation

[mactech]

I just purchased a Vatrer 48v rack mount style battery.

Does it matter how it is oriented?

tia

 

[sunshine_eggo]

Best to ask the manufacturer. Cell orientation can matter, and that depends on the cell manufacturer, so hopefully Vatrer can answer your question.

 

[mactech]

Best to ask the manufacturer. Cell orientation can matter, and that depends on the cell manufacturer, so hopefully Vatrer can answer your question.

that was my first goto

unfortunately they've failed to respond. I will keep it oriented as expected.
This will parallel the other one I have which is their wall mounted with CAN, supposed to talk to my Victron MPII but have yet to get it to function or get support from Vatrer. The battery is great, so I will just operate it open loop.

thanks,

 

[mactech]

I was impressed with the UPS guy walking up the driveway holding it like it weighed nothing.

 

[sunshine_eggo]

that was my first goto

unfortunately they've failed to respond. I will keep it oriented as expected.
This will parallel the other one I have which is their wall mounted with CAN, supposed to talk to my Victron MPII but have yet to get it to function or get support from Vatrer. The battery is great, so I will just operate it open loop.

thanks,

The MPII can't communicate with any BMS. You need a GX device.

Are the batteries the same cell count? You don't want to get caught by 15S vs. 16S

 

[mactech]

The MPII can't communicate with any BMS. You need a GX device.

Are the batteries the same cell count? You don't want to get caught by 15S vs. 16S

That's what I assumed. I will get the GX when I expand but the RPi4 and Venus works well.

The batteries are both the same 16S, that much I was able to get from their online portal chat person. The other question about orientation was supposed to be forward to those in the know.

The chat support indicated it was the same batteries as their wall mounted version. The wall mount model also increased in price by $200 over the rack but those lack any comms.

 

[sunshine_eggo]

That's what I assumed. I will get the GX when I expand but the RPi4 and Venus works well.

Do you have a CAN hat on the RPi4?

If the batteries use the Pylontech protocol, and many do, it should communicate.

The batteries are both the same 16S, that much I was able to get from their online portal chat person. The other question about orientation was supposed to be forward to those in the know.

The chat support indicated it was the same batteries as their wall mounted version. The wall mount model also increased in price by $200 over the rack but those lack any comms.

If the batteries list a nominal voltage, that's a good indicator. 51.2V is 16S and 48V is 15S.

 

[mactech]

Record 1675w output from my 1600w array. 8x200w Bouge RV panels temp is only 68 outside, the coolest it's been since I put the new Victron MPII and SCC 250/100

This makes me wonder about accuracy.

 

[mactech]

Do you have a CAN hat on the RPi4?

If the batteries use the Pylontech protocol, and many do, it should communicate.



If the batteries list a nominal voltage, that's a good indicator. 51.2V is 16S and 48V is 15S.

I am going to move to the Cerbo GX device vs. putting more $ in to the RPi4.

I had the Pi lying around after I upgraded my astrophotography capture software to RPi5.

Both are 51.2 volts

 

[sunshine_eggo]

Record 1675w output from my 1600w array. 8x200w Bouge RV panels temp is only 68 outside, the coolest it's been since I put the new Victron MPII and SCC 250/100

This makes me wonder about accuracy.

View attachment 235502

I've seen as much as 3600W out of my 2970W (I have a 250/100 too) due to cold temps and cloud edging. Cloud edging is a prismatic effect that concentrates solar energy as the sun emerges from behind a cloud. The shaded period also allows the panel to cool which raises the Vmp and power. Ultimately, your panels may be cooler and getting more irradiance than STC conditions, which will yield > STC power.

Given that your peaks are following dips, I would conclude that's what's happening.

I'm the luckiest boy in the world!

"You'll never see max power out of an array." I've said that dozens of times. Sometimes, my pants are on fire! AZ. Panels tilted at 29.5° at Azimuth 165° (peak solar is at about 11:30am). Only ~6 weeks out from the Winter solstice, which is the worst day of the year for solar. Here's what I...

diysolarforum.com

 

[mactech]

I've read about the edging effect and it shows in the graph above.

Never expected to see 100% output and on the prior 24v system with these same panels, it was typically ~1150w. It hit above 1300 watts during the coldest months when it blew out the charge controller. BougeRV replaced the controller, no questions asked.

That's when I decided to go blue.

 

[mactech]

That was an easy install, albeit a heavy one.

Charging it up now as it came delivered at 53% SOC. The individual cell voltages all look great and are displayed on the front display.

My old 24v system came in handy as the AC grid supply to the Multiplus II. Lots of conversion loss but it comes with a 7.5kw battery giving me a total of 20kw. Originally I was going to sell it but it works well with an LV2424 and 1200w solar.

To get started, I am going to run with just the new battery and see how it performs, give it a couple weeks of cycling before paralleling it with the other battery. It's easy to isolate each one with the enclosed switch on each battery pack. If one gets super low I can turn switch to the other one easily. We will see how they play together, same brand, voltage and cells. I think the BMS is different, haven't verified any of that with the company.

 

[sunshine_eggo]

That was an easy install, albeit a heavy one.

Charging it up now as it came delivered at 53% SOC. The individual cell voltages all look great and are displayed on the front display.

Don't get your hopes up. Voltage doesn't correlate to balance until they're all above 3.40, i.e., even imbalanced cells will show identical voltages until the first cells approaches full. I'd aim for 55.2V (3.45V/cell) and see how it goes.

My old 24v system came in handy as the AC grid supply to the Multiplus II. Lots of conversion loss but it comes with a 7.5kw battery giving me a total of 20kw. Originally I was going to sell it but it works well with an LV2424 and 1200w solar.

Yeah, I kept my "learner" system as a backup... 'cause I'm a hoarder.

To get started, I am going to run with just the new battery and see how it performs, give it a couple weeks of cycling before paralleling it with the other battery. It's easy to isolate each one with the enclosed switch on each battery pack. If one gets super low I can turn switch to the other one easily. We will see how they play together, same brand, voltage and cells. I think the BMS is different, haven't verified any of that with the company.

Sounds like a plan.

 

[mactech]

Don't get your hopes up.

Hey, where is all the sunshine? At least they all work but I understand what you're saying.

 

[sunshine_eggo]

Hey, where is all the sunshine? At least they all work but I understand what you're saying.

Sometimes I'm like the black sun of Giedi Prime.

 

[mactech]

I'd aim for 55.2V (3.45V/cell) and see how it goes.

Here is a typical day for battery voltage 56.75 volts appears to be maximum.

 

[sunshine_eggo]

Is that below your MPPT absorption?

 

[mactech]

Is that below your MPPT absorption?

Yes, absorption is 57 and float is 56

 

[sunshine_eggo]

What are you MPPT states for the same timeframe?

 

[mactech]

What are you MPPT states for the same timeframe?

 

[sunshine_eggo]

It looks like you have a voltage measurement error. What is your MPPT battery voltage at this time?

 

[mactech]

It looks like you have a voltage measurement error. What is your MPPT battery voltage at this time?

56.75 volts

The Vatrer battery and SCC both show the same voltage.

 

[sunshine_eggo]

Unless the battery is in control of the system or has an internal convert that can spoof a voltage, it can't override the MPPT. You're set to 57V, but you get to 56.75 with the MPPT showing absorption, BUT it's also at 0A. This does not indicate there's a battery maximum of 56.75. It indicates the MPPT can't maintain a perfect voltage (it's not flat) at zero or near zero current.

Recommend you set absorption to 57.6, fixed 30 minutes, float to 54.4V. Observe if the behavior changes.

 

[mactech]

Unless the battery is in control of the system or has an internal convert that can spoof a voltage, it can't override the MPPT. You're set to 57V, but you get to 56.75 with the MPPT showing absorption, BUT it's also at 0A. This does not indicate there's a battery maximum of 56.75. It indicates the MPPT can't maintain a perfect voltage (it's not flat) at zero or near zero current.

Recommend you set absorption to 57.6, fixed 30 minutes, float to 54.4V. Observe if the behavior changes.

Looking at the graph from the last 30 days, it never approaches that voltage. I suspect it is from the longer length battery cables I have.

I did not shorten them as I have not determined its final position in the solar shed.

The brand new battery is running exactly 57v the last two days which has 18" long vs. 6 foot.

I will implement your recommendations and see where we are.

 

[mactech]

Yesterday with new battery, shorter cables because it's all I have compared to the very long ones on the other battery, hanging on the wall.

It's right at 57v and relatively flat with steady load.

Edit : my bad, this below is Solar Charger Voltage and Current vs. System Battery

see what old age can do...