I thinks me need a Daromer!!

chuckp

chuckp

Member
Joined
Jul 29, 2018
Messages
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Here's my problem (Sorry if this has been discussed before) coms ain't my thing.

Sofar solar Mass Energy ME3000SP AC Coupled charger inverter has an RS485 coms port that takes an RJ45 lead out to the BMS.


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I have at the moment a cheap 14S 100A Chinese BMS
https://www.aliexpress.com/item/32828948173.html?spm=a2g0s.9042311.0.0.8de94c4dDWRTkM that has a RS232 coms for a three wire Bluetooth or a four wire PC module.


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Question is how do I connect the two together and get them talking nicely to each other.
Would an RS232 to RS485 converter like this work?
https://www.amazon.co.uk/gp/product/B01LVVI1XI/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1


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Obviously I'll need to get a DB9 male to RJ45 and a DB9 female header if this would work. Or if not has anyone found a work around that will, maybe using a Raspberry Pi or similar?

The Chinese BMS is only until funds permit a Batrium, but that said it may well be a year or more before that's going to be possible.

Thanks

So I was wondering what was inside the pc module and decided to open it up and have a look.

This is what I found inside.


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It has the RS485 connections on the board next to the RS232, so I'm wondering if this could in some way be utilised?
 
You need a device in between that talk both devices language and can forward messaged. Like a Raspberry and some software.

Just connecting Them wont work
 
Just connecting them won't work at all - you need to write the glue logic in whichever language you decide to use on the hardware you use to glue them together.

Also, 90% of that PCB in your bottom picture is unpopulated...
 
Thanks guys.

I thought that would be the case as nothing is ever that simple.

Now the problem I have is I know absolutely nothing about coms, data or programming. Wouldnt really have a clue where to start either.

Has anyone else in here done the same thing or something similar? Ive seen some great things done with RasPi and it looks amazing displaying all the info etc. But could that also be used to control the inverter?

At the moment my inverter is basically a glorified data logger. Displays what Im importing/exporting to and from the grid, what Im producing from the panels and my consumption. Nothing on the battery as without the BMS data it just sits in fault mode. I can see the battery voltage but thats about all.

Please excuse my ignorance with this subject. So dont the RS232 to RS485 converter thingies convert the signals?

HughF said:
Also, 90% of that PCB in your bottom picture is unpopulated...
Click to expand...

Yes I see what you mean. Sorry I know sod all about pcb electronics. All I ever do is replace whole boards wouldnt have a clue about most of it at component level.
 
A 232 to 485 converter does the physical conversion... That doesn't help the fact that the BMS is talking in one language and the inverter is talking in another language.

Unless these two languages are documented (a list of commands that the inverter will expect and values it will output, the same for the BMS) then you are basically shit out of luck getting this to work.
 
HughF said:
A 232 to 485 converter does the physical conversion... That doesn't help the fact that the BMS is talking in one language and the inverter is talking in another language.

Unless these two languages are documented (a list of commands that the inverter will expect and values it will output, the same for the BMS) then you are basically shit out of luck getting this to work.
Click to expand...

I see get it now.
 
Its possible to do it but you know your thing around how to "glue" them together. Imagine having a Greek and an Chinese to talk to each other :D You need a translator in between hehe
 
Ok guys this is probably the most stupid question ever asked but here goes.

The ME3000SP can be set to different battery types and the charge/discharge parameters can be customised.

How feasible would it be to set battery type to lead acid and adjust the charge/discharge parameters?

If I can set it to lead acid it won't be looking for a BMS to be connected, the Chinese BMS will still monitor the packs and shut off in the event of any problem with the packs.

What's your thoughts on this as a solution until such time that i can stretch to a Batrium.

Side note I still like what's being done with the Raspberry Pi's and would also like to do somethin. Maybe also use it to switch a Shunt Trip on the battery breaker if there was an issue with the battery.
 
Thats how most of us do it today with batrium
We run la charging algoritm and the bms do the protection
 
Yep, a normal bulk/absorption/float LA algorithm when suitably set for the lithium voltage requirements will work just fine.

It needs a little tweaking of the absorption timer and setpoint, and you can run a risk of overcooking your balancing/bypassing resistors, but it does work.
 
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