diy solar

diy solar

~100kwh for 24/7 off grid home

I've made a breakthrough in my attempts to directly communicate with the Daly SmartBMS (16s/150a) over it's UART port.

Posted elsewhere on this forum, I've seen some partial documentation for the protocol, but it didn't really make sense until I was able to see it in action. What I did, was wire the 0/RX1 pin of my Teensy 3.2 to the BMS end of the factory supplied USB cable, and made a tiny program to eavesdrop on the communication between the Daly BMS PC software and the BMS and log it out to the console.

Actually seeing what was going back and forth made the documentation make sense. I'm also able to observe the software as it does more than just read from the BMS, so it shouldn't be too hard to decipher the various commands that write settings too. The Teensy has a builtin CAN transceiver... so reformulating this data and making inverter-compatible messages is a not too distant possibility.

I'm 99% sure that this is the same protocol that's being used over Bluetooth, and a complete understanding should make it possible to build a new, better app.

Fun, fun fun!
 
that’s awesome!! glad you got the teensy talking with the daly BMS. fun!!

please feel free to share data samples or whatever, i’m currently learning about CAN and i2c and uart for energy storage inter-device communication

so cool that the teensy has a CAN transceiver built in

am evaluating this as CAN interface for a project, thought to share just in case it’s helpful

chose it for isolation features of the chipset
 
Was the cost the utility company wanted to bring service ever mentioned in this thread?
 
that’s awesome!! glad you got the teensy talking with the daly BMS. fun!!
Well, so far it's just eavesdropping, but the talking will probably get going tonight. :)

Please feel free to share data samples or whatever, i’m currently learning about CAN and i2c and uart for energy storage inter-device communication
Will do. I expect I'll put up a GitHub project later this week, after I knock the kinks out.

so cool that the teensy has a CAN transceiver built in
Most of it... I think you still need an interface chip to finish up the job, but it's just a couple of wires.
 
Was the cost the utility company wanted to bring service ever mentioned in this thread?
They estimated somewhere in the $30-40k range. We have a really long driveway, and would need transformers and poles and we'd have to draw up a utility easement, etc. etc. etc.

All in, with inverters and all the fixin's, I should come in at well under $20k. The panels will be more, but will still leave us well under their estimate.
 
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Moving right along, today on box #5. Picked up the enclosure for box #6, and placed it on the trailer. I'm going to fit-out the insulation and the framing for #6 after lunch.

The Anderson SB175 is going to fit perfectly, allowing a flush mount. I need to work up a metal bracket for it and 3D print a faceplate. It'll look hot when it's done. For now, I'll just use the rubber cover that came with the box and leave the connector loose.

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All in, with inverters and all the fixin's, I should come in at well under $20k. The panels will be more, but will still leave us well under their estimate.
That is just capital cost. Then there is the operating cost. My back of the envelope estimate is about $0.5 -0.10 per kWhr for my system. That number can vary depending on the life expectancy of inverters, panels and batteries.
 
That is just capital cost. Then there is the operating cost. My back of the envelope estimate is about $0.5 -0.10 per kWhr for my system. That number can vary depending on the life expectancy of inverters, panels and batteries.

And don’t forget the operating costs of the utility company

Higher and virtually guaranteed to increase.

Much less giving up an easement to your property. Avoiding that alone is worth the cost IMHO.
 
Higher and virtually guaranteed to increase.
Absolutely guaranteed to increase. I'm in California and my highest rate is $0.51 per kWhr. I don't have a choice about having a connection but I do have a choice about when I buy power and how much I buy. Other than a monthly fixed charge, I have eliminated other utility costs.
 
That is just capital cost. Then there is the operating cost. My back of the envelope estimate is about $0.5 -0.10 per kWhr for my system. That number can vary depending on the life expectancy of inverters, panels and batteries.
...those poles and transformers all come with the promise of a monthly bill, too, and no guarantee against power cuts in the winter (it happens here alot.) Using the grid, on this particular property makes very little sense when batteries and solar are becoming so cheap. Whatever it shakes out to, it'll be less than the grid hookup by a country mile.
 
I've made a breakthrough in my attempts to directly communicate with the Daly SmartBMS (16s/150a) over it's UART port.
Have you seen this Daly bms interface layer on Github?
This guy did already find out things about the Daly UART interface. Could be of some help?!

 
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I'd run across that the other day, and it's all very hard-coded -- not a knock against it, as most embedded things tend to need to be, but not as flexible or easy to follow as I'd like. I'll cook something up and put it up for it's share of abuse. ;)
 
Is this system going in an out building (shed) that's temp controlled?
No. It'll live in the great outdoors, on a concrete pad. The boxes have 2" of insulation, a radiant barrier and will be fitted with some heating elements between the packs before winter.
 
They estimated somewhere in the $30-40k range. We have a really long driveway, and would need transformers and poles and we'd have to draw up a utility easement, etc. etc. etc.

All in, with inverters and all the fixin's, I should come in at well under $20k. The panels will be more, but will still leave us well under their estimate.
You can bury the entire line with transformer at the end, how long of a driveway are we talking?
 
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