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The flaw with this thinking is that all of this is more complex. My loads (DC/DC and inverter) and chargers each have a simple on/off switch. If the circuit is open the device is off. If it is closed, it is on. None are relying on microprocessors and measurements to decide on/off. I can easily...

My LiFePo4 battery monitor will close a relay to turn on/off the charging. I am wondering if there is a simple MPPT that has no user interface at all. It just needs to keep the voltage of the panels separate from the battery and attempt as high as possible voltage on the battery. I suspect...

I still have not heard anything regarding dumping the cells or measuring cell temps. These are nice to have features. I see no point to switching to a different design and lose that. What performance? You mean the accuracy? You have not made a case that more than 8 bits is useful. I've stated...

Nothing stops you from using 24 BMSs, where each has 13s. To turn off charge/loads, you'd run the control wires through all 24, so that if just one opens the circuit, the thing is shut off. If I did nothing to improve things, you'd have 24 web pages (tabs in your browser) to look at. However...

I cannot delete, so I apologize for the thread clutter. So far as I can tell there is no difference between the Multiplus and Multiplus Compact from a feature or electrical connections standpoint. The two manuals are not identical, but in terms of connections and remote, they seem to be...

I think I agree with this. I was not properly realizing that the transformer can create the other leg of output. I was thinking it had a full transfer switch that would disconnect the output from the transformer and send the input straight out. I think your diagram makes more sense. I will...

Ugh! You two are killing me. I bought the 4kw WZRELB last night. I will find out if I f'd up next week.

No kidding! And I will say there has to be a record for some sort of desire to not comprehend each other. For example, this exchange: Does "eek out more capacity" mean anything different than "maximize capacity available"? Sorry @BiduleOhm, you've been very helpful, but sometimes it seems...

I have 8 of these 280ah cells on order. I am wondering if anyone is going to make, or is interested in, a 3-d printer design to hold these in a pack. I am thinking that it should be possible to design something like the Fortune cell plastic top and bottom that Will was excited about (OK, he's...

I have been attempting to answer @Factory400's question quoted below. Thus the discussion you are commenting on was supposed to be about the choice of using an attiny per cell to measure the voltage, (and temperature of that cell), turn on/off the drain resistor (to do balancing), and...

Thanks for that info, I was pulling my hair out to make sense of this. Is there some victron product that will accept a simple open/close for charge and same for invert and plop those instructions onto the VE.bus? jt

Yea, I saw that too and concluded "thanks for narrowing my choices down, NOT!". But yea, I knew the 4k was less than 3x. Oh, well, we shall see.

This is not correct according to trivial googling. For example "current dramatically changes as irradiance varies, but voltage remains relatively constant" Again, there is no need for the SCC to taper the amps. The Sun does this for free every day. Maybe a more complete description would...

Correct me if I am wrong, but that document shows a projection that, if correct, shows more cycle life. It looks to me like they fitted some curve to the first 750 cycles, then extrapolated that into the future. I'm not saying that prediction is wrong, but I don't see why we would conclude it is...

I don't agree with this. The batteries get damaged as the absolute voltage rises/falls past some threshold. The difference between each cell is rather irrelevant except to balance them which only affects the whole pack capacity. Great, I am all ears. Show me a design that produces better...

This is the situation everyone has learned because all the equipment is descended from lead acid. With lead acid you monitor the pack voltage and you need to run the battery up to 100%, and keep it there as much as possible, which is determined by the voltage. With lithium multi cell packs, it...

I have been collecting data. The controller is capable of delivering data to a server (advbms.com). I am wondering if I should build that out so that one can create their own account on that server and view/control their BMS from afar. I assume someone will want MQTT at some point, and someone...

I too was concerned about making the inverter charger work nicely with the SBMS0. I ended up getting a ZRELB inverter, which has no charge function. Unfortunately it is not a low frequency and will not start my AC. I got a meanwell 27A charger so both inverter and charger can be shut off...

You are correct. I think you are right about the MPPTs. I am looking at DIY MPPTs.

I am able to transmit at 9600baud, which sucks. This is limited by the cheap optoisolator I am using. A digital isolator would be able to transmit much faster. They are aproximately $1each instead of $.1. Each cell needs 1. I figure that at 115k, it can handle 4 strings of 13 cells. So you'd...

There are 2 parts to that UI. One is the hardware, the LCD and the buttons, which needs to be mounted somewhere. The second is everything you mentioned. If he created a headless thing, then he doesn't need to supply an LCD, buttons, and I don't need to mount something in visible/usable area. The...

I third this. Haugen, please do share.

Yea, double check that there is one wire from the battery negative. That wire should go to the shunt. The shunt should have just that same one wire on one side of the shunt. The other side of the shunt can have any number of negatives. That is where you would add any more loads or chargers. Also...

@Cal, over the next few days I will create a proper itemized cost for the 4x cell board. However, I am still hoping to hear other's opinions on what V measurement accuracy is required for this application. I totally get that 12 bits is better than 8, but 16 is better too. Where is the cut off...

Sorry, I just realized how to make the point more succinctly. The Sun does not provide Constant Current charging or Constant Voltage charging on Earth.

Thanks, I am not in any great need for strain relief. I need waterproof. I have 4 of these that have to get inside my RV. I bought https://www.amazon.com/gp/product/B07MDNPMY4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Oh come on. Why do I get this response? I did not say I am uninterested in those concepts, nor did I suggest that. I asked for specifics! I asked how you define performance and robust for this functionality. That's exactly the opposite of uninterested, for goodness sakes. I have reread your...

Have you thought about getting 3 24VDC mini splits?

I am waiting for my batteries from Xuba (shipped by sea day 42), so I have not had a chance to do anything with the SMBS0 yet. I am also going to build a DIY BMS (see ). This will be very cumbersome, but ultimately should arrive at a BMS controlled only via wifi. I will report back when I have...

Again, for what purpose? Balancing is not a self evident goodness. Balancing to less than 10mV is not some sort of self evident truth. Ahhh, finally an acknowledgment that capacity is a reason, and a new reason! Yea! OK, so what degree of balance is needed to ensure equal wear on the cells...