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diy solar

Sunny Island SI-6048 BMS communication

Trukinbear said:
Shunt connected along with Whizbang Jr, Classics networked together 'follow me' and and no longer connected to SI - they are behaving flawlessly I might add.

VRLA 200Ah 51v nominal
54.5v boost, full and absorb, 53.5v equalization

Unfortunately the SI won't let me pull the battery below what it thinks is 20%, and triggers an SOC calibration reset.

Currently the BMS says 100%SOC, along with the Classics... But SI says 49.5% SOC @ 58.7% SOC error.
As it operates now, after the sun goes down the SI shuts off in Battery Protection Mode when the batteries are still above 75%SOC. I can't make it through the night without SI starting the recalibrate over again. :-(

Id run the generator but the BMS shuts off current when it's done, so no more charge current running through the shunt.

Is there a way to trick the shunt?
Click to expand...
Thats a tough one. No grid connected?
 
Trukinbear said:
The Midnight Solar 500A/50Mv that the Whizbang Jr is also attached to - calibrated and commissioned by SI
Click to expand...

OK, so Whizbang Jr is connected to shunt sense, sends digital data to Classic, and SI is also conected to shunt sense.

But which side of shunt is Classic (and other) SCC power cable connected to?
When you first connected shunt to SI, Classic was on the wrong side for the case of digital communications Classic <--> SI, and it resulted in wrong battery charging. You moved the Classic to opposite side of shunt. Is it still there now? If communications are no longer working, I think Classic needs to move back to where it was before (SI side of shunt, not battery side?) Any other SCC or DC coupled charger too. Shunt has to measure all DC coupled charging that isn't otherwise communicated to SI.
 
Hedges said:
OK, so Whizbang Jr is connected to shunt sense, sends digital data to Classic, and SI is also conected to shunt sense.

But which side of shunt is Classic (and other) SCC power cable connected to?
When you first connected shunt to SI, Classic was on the wrong side for the case of digital communications Classic <--> SI, and it resulted in wrong battery charging. You moved the Classic to opposite side of shunt. Is it still there now? If communications are no longer working, I think Classic needs to move back to where it was before (SI side of shunt, not battery side?) Any other SCC or DC coupled charger too. Shunt has to measure all DC coupled charging that isn't otherwise communicated to SI.
Click to expand...
Everything is connected to the SI side of the shunt - I don't even see a way to be connected otherwise. The SI's read of the shunt is spot on with the WBjr. The in and out and movement of the SOC indicated match, except they didn't both start at the same number if I ad 50%, they match.
 
When I was playing around with new battery setups every time I went through the setup on the SI with VRLA it started the battery SOC at 45% (why that and not 35% ?) regardless of the battery voltage, it did come in line until after a heavy charging session when once the SI saw the voltage and peak reset to 100%.

Have a look at the parameter 222.13 BatChrgVtgMan and see what it is set to.
 
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kommando said:
When I was playing around with new battery setups every time I went through the setup on the SI with VRLA it started the battery SOC at 45% (why that and not 35% ?) regardless of the battery voltage, it did come in line until after a heavy charging session when once the SI saw the voltage and peak reset to 100%.

Have a look at the parameter 222.13 BatChrgVtgMan and see what it is set to.
Click to expand...
Well, 222.13 isn't in my manual, but it is in my SI as ChrgVtgLim... What is this?
It isn't in the menu, but comes up on direct entry - can't change with installation password. 2.62v WAY TOO HIGH for my BMS. How do I adjust?
 
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As of this morning, the operating range of my SI is 22%-49% last night. Showing 38% now at 100% SOC
 
Okay, I've tried every combination of settings that I can try to get it to recognize my BMS and it still just says external lithium ion BMS time out so I've reverted it's not so it to vrla (again,) and we show 45% indicated at 100% SOC. By the time the rest of my batteries get here, I'll have a lot more invested in them than the inverter. Anybody having an idea of an inverter that might work with these with aolithium batteries?
 
Well a JK BMS of the same type I have would work, you have to check if it will work as a replacement BMS in your battery, a lot cheaper than a new inverter or new battery.

Also if your SI has an external shunt it's settings and calibration are blanked every time you tell the SI a new battery is attached, so you need to re-enter the shunt settings and recalibrate.
 
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kommando said:
Well a JK BMS of the same type I have would work, you have to check if it will work as a replacement BMS in your battery, a lot cheaper than a new inverter or no ew battery.
Click to expand...
I dunno - I've got $7200 + tax in Aolithium batteries inbound, and bought my SI6048 (and a spare) for less than $1500 during the DC solar sales... I'll have 600ah when they're all here
 
Awe crud, I hate recalibrating the shunt
 

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Oh, well I thought I had it going, but the SOC on the SI set to 0% and the batteries were totally charged so only a slight trickle went through the shunt I never could get enough SOC showing for it to even pull a load and not just shut off. So now I'm back to my original vrla settings
 
(Krazy off the wall idea #43)
What if I reverse the polarity of the sense leads from the shunt so the SI sees discharge as charge - let the batteries discharge until the numbers intersect... But it'll still show 50% SOC error, so that might not last long, but at least they could (maybe) start in agreement, and after I reverse the leads back the batteries will be somewhat discharged and the SI can measure some actual charge current.

Bad idea? 🤞🙂
 
Trukinbear said:
(Krazy off the wall idea #43)
What if I reverse the polarity of the sense leads from the shunt so the SI sees discharge as charge - let the batteries discharge until the numbers intersect... But it'll still show 50% SOC error, so that might not last long, but at least they could (maybe) start in agreement, and after I reverse the leads back the batteries will be somewhat discharged and the SI can measure some actual charge current.

Bad idea? 🤞🙂
Click to expand...
Hmm that is definitely a wild idea. But might just work 😎
 
Anybody have experience with Midnite's MN5048DIY series inverters, and LiFePo4? Everything else except my inverter is Midnite Solar. Since it looks like it would replace my SI6048, AND both of my Classic 250's I would probably have money left over if I sold them, and bought the MN5048DIY.

Neither SMA, nor Aolithium has anything I'd call technical support, but Midnite even answers the phone
 
Trukinbear said:
Anybody have experience with Midnite's MN5048DIY series inverters, and LiFePo4? Everything else except my inverter is Midnite Solar. Since it looks like it would replace my SI6048, AND both of my Classic 250's I would probably have money left over if I sold them, and bought the MN5048DIY.
Click to expand...

I should hope there would be change left over.

It isn't in the same class at all.
Have any motors you need to start?
If I was you I'd want to figure out how to make the Sunny Island work.

I'd be quite happy to pick up 1x SI 6048US and 2x Classic 250 for the price of a DIY.

Cheap, but low or no stock.


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MidNite Solar MN5048DIY MPPT Inverter/Charger 120VAC 48VDC

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The DIY line was just a relabel.
Midnight's "The One", 10kW AIO, may be more capable.
But if you want an Art Deco replacement for German Engineering, Rosie is the one to consider.

 
The SMA works with canbus set to pylontech, deye or goodwe protocol's based on my working setup, it's your battery that is not meeting these protocol requirements. So any solution must not expect to use canbus from the battery unless you have confirmation from another owner that it works with that combination.
 
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