Steve, I followed the link to the Ebay auction in your post above, and was scratching my head as to why you were opting for the nickel plated steel bars??? And then I read further down where you realized the error.There will be no hammering of copper pipe, worst case I'll keep the heavy aluminium IF I can't get good 110 copper bar stock from the local metal shop.
Unfortunately I cannot make my app available as it contains proprietary Samlex Modbus protocol stack info in it which I have access to, due to having signed NDA's with Samlex which prevents disclosure. My first "touch it P.O.C." project was just getting to talk to my Midnite Classic Controller and pulling it's Modbus registers. It has no Samlex info in it, so you can look at that but WARNING... It is a "touch it" app meaning very rough, just get it going and see if it works test, It's semi documented and laid out here, may be worth a look if your interested."The Current RS232 <-> PC protocol info for the programmers out there. (I'm adding this into my Node-Red Solar Control project)"
Hi Steve,
I read that you use the BMS 8T and that your adding the PC protocol to your Node-Red-Solar Control project.
I'm very interested in how I can read the data of the RS 232. Can you give me a link where I can find this project?
Thanks
Thanks steve, just as i thought, but great to have confirmationYou can use any size of shunt you want as long as it does now exceed 75mv. I personally use the Deltec 500A/50mv ones. The Amperage on the shunt is for the maximum load it can handle and does not affect the accuracy. The Relays on the other hand are also important as they have to handle the max load you can put through them. Again, it's one of those things that you should use care with... It is better to get ones that handle bigger loads and have a margin rather than to try and squeeze a few cents and nd up short & frying a relay.
I just do not like the type of shunt they provide, it has no backing or mounting / affixing method and they are not pure brass. I'm sure they work within spec but it is a personal "picky" thing. I did suggest to Chargery that they should offer a better quality shunt but I don't think they will.
You can use any size of shunt you want as long as it does now exceed 75mv. I personally use the Deltec 500A/50mv ones. The Amperage on the shunt is for the maximum load it can handle and does not affect the accuracy. The Relays on the other hand are also important as they have to handle the max load you can put through them. Again, it's one of those things that you should use care with... It is better to get ones that handle bigger loads and have a margin rather than to try and squeeze a few cents and nd up short & frying a relay.
I just do not like the type of shunt they provide, it has no backing or mounting / affixing method and they are not pure brass. I'm sure they work within spec but it is a personal "picky" thing. I did suggest to Chargery that they should offer a better quality shunt but I don't think they will.
@astronomAre you sure that the caliber of the shunt does not impact the precision of its current mesurement? It's my understanding that a "x A / y mV" shunt is basically a very low resistor that will provoke a "y" mV voltage drop when "x" amps go through it. As the relationship between current and voltage drop is linear, it is then this voltage drop that is measured by the Chargery BMS to infer the current. So if the electronics that is dedicated to the shunt can measure the voltage with an accuracy of +/-1 mV for instance (I don't know what the real value is for the Chargery), this means that a shunt rated at 100A/75mV will allow to measure the current with an accuracy of (100A/75mV)*(+/-1mV) = +/-1.33A. If instead you use a 500A/50mV shunt, you will get an accuracy of (500A/50mV)*(+/-1mV) = +/-10A. So I believe that accuracy decreases quite substantially with the rating of the shunt.
Also I'm not convinced that it would be bad to occasionally have currents going through the shunt that are higher than its rating. The shunt itself should handle it quite easily even though it might then dissipate more energy than a higher-rated shunt would have (remember it's just a very low resistor, and higher-rated shunts have lower resistance). It's more on the electronics side that I would be concerned, but I doubt that the measurement circuit of the BMS would not handle a ponctual overvoltage, especially since we're talking about millivolts here... Maybe it won't measure it correctly but if it's just transitory current peaks at the start of some loads for instance I don't think it matters. However I cannot back this up with experimental results, I actually don't see how I could produce a current higher than 100A yet ^^
So personally I went with the 100A shunt with the Chargery, to try to have the most accurate measurement, plus I don't expect to often cross 100A as it will ben installed on a 48V battery pack.
RE: the Balance 1.2A Chargery BMS16T 2S - 16S LiPo lifepo4 LTO Li-ion Battery BMS Smart and theI recently purchased a ShunBin 24/400AH LFP ( <- the thread) pack, upon investigation, I determined that the BMS is too dubious "for my liking" and with no temp monitoring, no info and no way to know what it is doing, not interested. I also wanted to have a Battery Monitor to be able to see the state of affairs within the pack. Will has a video with a Bluetooth equipped 8-16S Smart BMS which is particularly interesting and at a good price point. OK, I'm feeling pinched with the pack purchase. But I would prefer PC / RaspberryPi access to the monitor/bms and there are a few out there. Of course there is TinyBMS and I also found this one which is quite a complete "Kit" and also at a reasonable price.
Balance 1 2A Chargery BMS16T 2S 16S LiPo lifepo4 LTO Li ion Battery BMS Smart for sale | eBay
Find great deals on eBay for Balance 1 2A Chargery BMS16T 2S 16S LiPo lifepo4 LTO Li ion Battery BMS Smart. Shop with confidence.www.ebay.ca
There is also the version from Will's Video for 24V up to 300A, including LCD display, Bluetooth and the harnesses etc.
8S 10S 24S Lifepo4 li ion Lipo LTO Battery Protection Board Bluetooth Smart BMS for sale | eBay
Find great deals on eBay for 8S 10S 24S Lifepo4 li ion Lipo LTO Battery Protection Board Bluetooth Smart BMS. Shop with confidence.www.ebay.ca
I was looking at Daly BMS but they do not seem to have a 24V 100A / 150A smart BMS that can also talk PC, that I could find.
If anyone has suggestions for known good Smart BMS that would do the job, much appreciated. One which won't break a stressed budget,
The Pack is 16 LFP Cells setup as 8s - showing it's provided BMS.